Full download test bank at ebook textbookfull.

com

Disruptive Technology Enhanced

Learning: The Use and Misuse of
Digital Technologies in Higher
Education 1st Edition Michael
CLICK LINK TO DOWLOAD

https://textbookfull.com/product/disruptive-
technology-enhanced-learning-the-use-and-
misuse-of-digital-technologies-in-higher-
education-1st-edition-michael-flavin-auth/

textbookfull
More products digital (pdf, epub, mobi) instant
download maybe you interests ...

Re-imagining Technology Enhanced Learning: Critical

Perspectives on Disruptive Innovation Michael Flavin

https://textbookfull.com/product/re-imagining-technology-
enhanced-learning-critical-perspectives-on-disruptive-innovation-
michael-flavin/

Universities, Disruptive Technologies, and Continuity

in Higher Education: The Impact of Information
Revolutions 1st Edition Gavin Moodie (Auth.)

https://textbookfull.com/product/universities-disruptive-
technologies-and-continuity-in-higher-education-the-impact-of-
information-revolutions-1st-edition-gavin-moodie-auth/

Teaching Learning and New Technologies in Higher

Education N. V. Varghese

https://textbookfull.com/product/teaching-learning-and-new-
technologies-in-higher-education-n-v-varghese/

Education, Narrative Technologies and Digital Learning

Tony Hall

https://textbookfull.com/product/education-narrative-
technologies-and-digital-learning-tony-hall/
Digital Technology as Affordance and Barrier in Higher
Education 1st Edition Maura A. Smale

https://textbookfull.com/product/digital-technology-as-
affordance-and-barrier-in-higher-education-1st-edition-maura-a-
smale/

Assessing the Role of Mobile Technologies and Distance

Learning in Higher Education 1st Edition Patricia
Ordóñez De Pablos

https://textbookfull.com/product/assessing-the-role-of-mobile-
technologies-and-distance-learning-in-higher-education-1st-
edition-patricia-ordonez-de-pablos/

Higher Education 4.0: The Digital Transformation of

Classroom Lectures to Blended Learning 1st Edition
Kevin Anthony Jones

https://textbookfull.com/product/higher-education-4-0-the-
digital-transformation-of-classroom-lectures-to-blended-
learning-1st-edition-kevin-anthony-jones/

Technology Enhanced Learning: Research Themes 1st

Edition Erik Duval

https://textbookfull.com/product/technology-enhanced-learning-
research-themes-1st-edition-erik-duval/

Handbook of Research on Digital Content, Mobile

Learning, and Technology Integration Models in Teacher
Education (Advances in Educational Technologies and
Instructional Design (AETID)) 1st Edition Jared Keengwe
https://textbookfull.com/product/handbook-of-research-on-digital-
content-mobile-learning-and-technology-integration-models-in-
teacher-education-advances-in-educational-technologies-and-
DIGITAL
EDUCATION
AND LEARNING

DISRUPTIVE TECHNOLOGY
ENHANCED LEARNING
THE USE AND MISUSE OF DIGITAL
TECHNOLOGIES IN HIGHER EDUCATION

MICHAEL FLAVIN
Digital Education and Learning

Series Editors
Michael Thomas
University of Central Lancashire
Preston, United Kingdom

John Palfrey
Phillips Academy
Andover, Massachusetts, USA

Mark Warschauer
University of California
Irvine, California, USA
Much has been written during the first decade of the new millennium about
the potential of digital technologies to produce a transformation of education.
Digital technologies are portrayed as tools that will enhance learner collabora-
tion and motivation and develop new multimodal literacy skills. Accompanying
this has been the move from understanding literacy on the cognitive level to an
appreciation of the sociocultural forces shaping learner development.
Responding to these claims, the Digital Education and Learning Series explores
the pedagogical potential and realities of digital technologies in a wide range of
disciplinary contexts across the educational spectrum both in and outside of
class. Focusing on local and global perspectives, the series responds to the
shifting landscape of education, the way digital technologies are being used in
different educational and cultural contexts, and examines the differences that lie
behind the generalizations of the digital age. Incorporating cutting edge
volumes with theoretical perspectives and case studies (single authored and
edited collections), the series provides an accessible and valuable resource for
academic researchers, teacher trainers, administrators and students interested in
interdisciplinary studies of education and new and emerging technologies.

More information about this series at

http://www.springer.com/series/14952
 Michael Flavin

Disruptive Technology
Enhanced Learning
The Use and Misuse of Digital Technologies
in Higher Education
Michael Flavin
King’s College London
London, United Kingdom

Digital Education and Learning

ISBN 978-1-137-57283-7 ISBN 978-1-137-57284-4 (eBook)
DOI 10.1057/978-1-137-57284-4

Library of Congress Control Number: 2017930493

© The Editor(s) (if applicable) and The Author(s) 2017

The author(s) has/have asserted their right(s) to be identified as the author(s) of this work in
accordance with the Copyright, Designs and Patents Act 1988.
This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher,
whether the whole or part of the material is concerned, specifically the rights of translation,
reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any
other physical way, and transmission or information storage and retrieval, electronic adaptation,
computer software, or by similar or dissimilar methodology now known or hereafter developed.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this
publication does not imply, even in the absence of a specific statement, that such names are
exempt from the relevant protective laws and regulations and therefore free for general use.
The publisher, the authors and the editors are safe to assume that the advice and information in
this book are believed to be true and accurate at the date of publication. Neither the publisher
nor the authors or the editors give a warranty, express or implied, with respect to the material
contained herein or for any errors or omissions that may have been made. The publisher
remains neutral with regard to jurisdictional claims in published maps and institutional
affiliations.

Printed on acid-free paper

This Palgrave Macmillan imprint is published by Springer Nature

The registered company is Macmillan Publishers Ltd.
The registered company address is: The Campus, 4 Crinan Street, London, N1 9XW, United Kingdom
To Geraldine, Liam and Rosie
 SERIES PREFACE

Much has been written during the start of this millennium about the
potential of digital technologies to radically transform education and learn-
ing. Typically, such calls for change spring from the argument that tradi-
tional education no longer engages learners or teaches them the skills
required for the twenty-first century. Digital technologies are often
described as tools that will enhance collaboration and motivate learners to
re-engage with education and enable them to develop the new multimodal
literacy skills required for today’s knowledge economy. Using digital tech-
nologies is a creative experience in which learners actively engage with
solving problems in authentic environments that underline their productive
skills rather than merely passively consuming knowledge. Accompanying
this argument has been the move from understanding literacy on the
cognitive level to an appreciation of the sociocultural forces shaping learner
development and the role communities play in supporting the acquisition of
knowledge.
Emerging from this context the Digital Education and Learning series
was founded to explore the pedagogical potential and realities of digital
technologies in a wide range of disciplinary contexts across the educational
spectrum around the world. Focusing on local and global perspectives, this
series responds to the shifting demands and expectations of educational
stakeholders, explores the ways new technologies are actually being used in
different educational and cultural contexts, and examines the opportunities

vii
viii SERIES PREFACE

and challenges that lie behind the myths and rhetoric of digital age educa-
tion. This series encourages the development of evidence-based research
that is rooted in an understanding of the history of technology, as well as
open to the potential for new innovation, and adopts critical perspectives on
technological determinism as well as techno-scepticism.
While the potential for changing the way we learn in the digital age is
significant, and new sources of information and forms of interaction have
developed, many educational institutions and learning environments have
changed little from those that existed over one hundred years ago. Whether
in the form of smartphones, laptops or tablets, digital technologies may be
increasingly ubiquitous in a person’s social life but marginal in their daily
educational experience once they enter a classroom. Although many people
increasingly invest more and more time on their favourite social media site,
integrating these technologies into curricula or formal learning environ-
ments remains a significant challenge, if indeed it is a worthwhile aim in the
first place. History tells us that change in educational contexts, if it happens
at all in ways that were intended, is typically more incremental’ and rarely
‘revolutionary’. Understanding the development of learning technologies
in the context of a historically informed approach therefore is one of the
core aspects of this series, as is the need to understand the increasing
internationalisation of education and the way learning technologies are
culturally mediated. While the digital world appears to be increasingly
‘flat’, significant challenges continue to exist, and this series will
problematize terms that have sought to erase cultural, pedagogical and
theoretical differences rather than to understand them. ‘Digital natives’,
‘digital literacy’, ‘digital divide’, ‘digital media’—these and such mantras as
‘twenty-first century learning’—are phrases that are being used in ways that
require further clarification and critical engagement rather than unquestion-
ing and uncritical acceptance.
This series aims to examine the complex discourse of digital technologies
and to understand the implications for teaching, learning and professional
development. By mixing volumes with theoretical perspectives with case
studies detailing actual teaching approaches, whether on or off campus, in
face-to-face, fully online or blended learning contexts, the series will exam-
ine the emergence of digital technologies from a range of new international
and interdisciplinary perspectives. Incorporating original and innovative
volumes with theoretical perspectives and case studies (single authored
 SERIES PREFACE ix

and edited collections), the series aims to provide an accessible and valuable
resource for academic researchers, teacher trainers, administrators,
policymakers and learners interested in cutting-edge research on new and
emerging technologies in education.
Michael Thomas
John Palfrey
Mark Warschauer
 ACKNOWLEDGEMENTS

I am grateful to Dr Stylianos Hatzipanagos for his feedback on an earlier

draft of Chap. 2 and to my research assistant, Valentina Quintero-
Rodriguez.

xi
 CONTENTS

1 Introduction 1

2 Free, Simple and Easy to Use: Disruptive Technologies,

Disruptive Innovation and Technology Enhanced Learning 19

3 ‘Why Can’t I Just Google It?’ What Disruptive Innovation

Means for Higher Education 53

4 Whatever Happened to the Digital Natives? Disruptive

Innovation in the Higher Education Community of Practice 87

5 Bidding the Waves Go Back: Engaging with Disruptive

Innovation 111

Index 145

xiii
 LIST OF FIGURES

Fig. 3.1 First-generation activity system (After Vygotsky 1978, p. 40) 55

Fig. 3.2 The second generation activity system
(After Engestr€om 1987, 2015, p. 63) 63
Fig. 3.3 Revised second generation activity system
(After Engestr€om 1993, 2015, p. 63) 64
Fig. 3.4 Wikipedia as a disruptive technology 77
Fig. 3.5 Disruptive technologies in the university activity system 80
Fig. 5.1 Disruptive technology enhanced learning as a second generation
activity system 127
Fig. 5.2 The balance between practice and technologies in strategy
documents, in relation to technology enhanced learning 131

xv
 CHAPTER 1

Introduction

This introductory chapter sets out the theoretical frameworks used in the
book, provides a chapter by chapter summary and introduces the book’s
core arguments.
Technology has promised a lot to education. The telephone, film and
radio were all going to revolutionize the classroom. Television promised to
be similarly transformational, as did the internet (Bok 2003; Flavin 2016;
Horrigan 2016). Yet, and despite generations of technological onslaught,
education systems have not changed fundamentally, and the university as an
institution appears remarkably resilient; Gordon (2014) in a Higher Edu-
cation Academy (HEA) report in the UK states university education ‘is
likely to remain the gold standard for some time’ (p. 21). Technologies
come and go but the university remains, in a recognizable and largely
unchanged form.
Why has the internet not truly revolutionized learning and teaching in
universities? To those who argue that it has, it can be pointed out that the
lecture is still the dominant pedagogical tool, and the essay and the exam
remain the dominant assessment instruments. This book therefore attempts
to address the issue of technology use and misuse in higher education by
identifying and analysing disruptive technologies, their impact and univer-
sities’ responses.
The aim of this book is to understand how universities can engage con-
structively with disruptive technologies for learning and teaching (when this
book uses the word ‘technologies’ it is referring to digital technologies). It is
not the purpose of this book to predict what technologies will be adopted in

© The Author(s) 2017 1

M. Flavin, Disruptive Technology Enhanced Learning,
DOI 10.1057/978-1-137-57284-4_1
2 M. FLAVIN

the future to support learning and teaching in higher education, though the
book does identify criteria and practices that are relevant in this respect.
The book pursues its aim by examining how technologies are used in
practice to support learning and teaching in higher education. In addition,
the book examines the implications of disruptive technology usage. Uni-
versities can engage constructively with disruptive technologies by recog-
nizing the ways students and lecturers use technologies to support their
learning and teaching. The book further argues that universities need to
understand why disruptive technologies are being used in order to inform
their strategies around technology enhanced learning.
The book identifies misalignments between the technologies supplied by
universities, often at considerable expense, and the disruptive technologies
used in practice by students and lecturers. Moreover, the use of disruptive
technologies has implications for the division of labour in higher education,
for assessment and for the higher education community as a whole. In
addition, the use of disruptive technologies challenges the role of the
university as gatekeeper to knowledge and signifies the possibility of a
more open borders approach.
Specific disruptive technologies considered in this book include the
internet search engine Google and the online encyclopaedia Wikipedia.
Both are now established. Head and Eisenberg’s (2010) research showed
82% of their undergraduate respondents used Wikipedia to support aca-
demic work, though an even greater number used Google. Colon-Aguirre
and Fleming-May (2012) interviewed –21 undergraduate students, all of
whom used Wikipedia for their research, commonly being directed to
Wikipedia following an initial search on Google; one of their interviewees
stated, ‘I feel like it’s hard to get a lot of information out of a book unless
you want to read the entire book’ (p. 395). Colon-Aguirre and Fleming-
May (2012) also state that the majority of their respondents acknowledged
that library resources were superior to those found via online search engines,
which poses the question, why do users prefer to go online? The answer, this
book argues, relates to the simplicity, ease of use and convenience of
Google, Wikipedia and similar technologies. By looking at how and why
Google and Wikipedia have become established in higher education, we get
a sense of disruptive technologies, their appeal and their impact.
The book challenges the argument that a wide range of technologies is
used to support learning and teaching and argues instead that students and
lecturers use a small range of technologies to accomplish a wide range of
tasks. Google is used as a hub technology from which a range of resources is
 INTRODUCTION 3

accessed; Hillis et al. (2013) argue, ‘the internet and Google and the
#hashtag now constitute their [undergraduate students’] primary access to
information’ (p. 6). Students and lecturers are efficient technology users
and are interested in getting jobs done, simply and conveniently.
The term technology enhanced learning, which has become a standard
phrase in higher education, is used, as stated by Kirkwood and Price (2014),
‘to describe the application of information and communication technolo-
gies to teaching and learning’ (p. 6); Gordon (2014) defines technology
enhanced learning as, ‘the use of Information Communication and
Technology. . . in its widest sense to support and improve the learning
experience’ (p. 4), and the Joint Information Systems Committee (JISC
2009) states that the term emphasizes ‘how technology adds value to
learning’ (p. 8). That said, the term is not universal and has been criticised
(Bayne 2015). Furthermore, a Higher Education Funding Council for
England (HEFCE) report (2009) resisted a definition of technology
enhanced learning, ‘it is important not to create fixed definitions,’ while
recognizing, ‘innovative developments in technology will only be relevant if
the enhancement of learning and teaching is the core purpose’ (p. 8). This
book, however, takes the view that technology enhanced learning says
enough about learning and teaching with technologies to be useful; the
Universities and Colleges Information Systems Association (UCISA 2016)
definition, ‘Any online facility or system that directly supports learning and
teaching. This may include a formal VLE, e-assessment or e-portfolio
software, or lecture capture system, mobile app or collaborative tool that
supports student learning. This includes any system that has been developed
in-house, as well as commercial or open source tools,’ (p. 1) is used as a
working definition for this book, notwithstanding that it prioritizes institu-
tional over disruptive technologies. This book avoids the Web 2.0 label for
technologies (O’Reilly 2005), partly in order not to bombard the reader
with too many terms, and partly because there is a risk of the term Web 2.0
lapsing into cliché.
This book responds to a need to better understand how technologies are
used in practice in order to practise technology enhanced learning more
effectively. Given the ubiquity of technology usage in higher education,
there is a need to understand more fully the technology practices of students
and lecturers, with a view to rethinking approaches to technology enhanced
learning. Kirkwood and Price (2014) summarize articles on technology
enhanced learning from 2005 to 2010 and conclude, ‘many interventions
were technology-led’ (p. 25) and ‘there seemed to be many cases of
4 M. FLAVIN

deterministic expectations that introducing technology would, by itself,

bring about changes in teaching/learning practices’ (p. 26). For this
book, practice is primary. An approach to technology enhanced learning
based on practice, rather than on the intrinsic qualities of technologies,
enables and encourages engagement with disruptive technologies to sup-
port learning and teaching.
A hierarchy of theoretical frameworks is used in the book. Disruptive
Innovation is used to identify relevant technologies. Having used Disruptive
Innovation to identify disruptive technologies (in Christensen’s sense, see
below), Disruptive Technology Enhanced Learning analyses the impact of
Disruptive Innovation on higher education, using Activity Theory
(Vygotsky 1930; Leontiev 1978, 1981) to explore how Disruptive Innova-
tion reconfigures learning, teaching and assessment and, more widely, social
relations in higher education. Moreover, the book uses second generation
Activity Theory (Engestr€om 1987 (rev edn 2015)) as a lens through which
to consider the impact of disruptive technologies on higher education.
Recent work is used to analyse current applications of Activity Theory and
their relevance to technology enhanced learning.
Finally, the Community of Practice theory (Lave and Wenger 1991;
Wenger 1998) is used to complement the main frameworks, to identify
and illuminate the community under examination, to outline how technol-
ogy usage can enable progress within a community and to consider how
higher education communities can respond to Disruptive Innovation. The
Community of Practice theory enables analysis of how Disruptive Innova-
tion impacts on higher education communities as a whole (identifying the
community as the locus of innovation), as well as analysing the structural
composition of academic communities and the opportunities and threats
posed to universities by Disruptive Technology Enhanced Learning. In
essence, Disruptive Innovation identifies technologies, Activity Theory ana-
lyses and the Community of Practice theory contextualizes.
These three theories are used in the book to help understand how
universities can engage constructively with disruptive technologies for learn-
ing and teaching. Universities are in a position to devise strategies for
technology enhanced learning based on actual practices with technologies,
rather than have strategies determined by technology.
This book therefore views learning and teaching as social practices.
Consequently, psychological theories of technology adoption are not appli-
cable because this book sees identity as determined historically and socially.
A designed intervention in relation to technology enhanced learning can be
 INTRODUCTION 5

conducive to change and may catalyse change, but it does not make change
happen in a mono-causal sense; when technological change happens within
a higher education community of practice, this book argues that it is caused
primarily by social factors identified in the second generation activity system
such as changes in rules (for example, assessment methods) or the division
of labour.
As this introductory statement has presented a number of specific terms
and ideas, these are defined synoptically below. Fuller exploration of each of
these terms will be provided in Chaps. 2, 3, and 4.

DISRUPTIVE TECHNOLOGIES AND DISRUPTIVE INNOVATION

The term ‘disruptive technology’ derives from Clayton Christensen’s (1997)
book, The Innovator’s Dilemma. The term is used in this book to signify
technologies that are not designed to support learning and teaching but are
used by students and lecturers, having found a market and a use value. More
precisely, disruptive technologies conform to four key criteria identified by
Christensen (1997); they are cheaper, simpler, smaller and more convenient
than the rival, incumbent technologies they frequently displace as market
leaders (p. xv).
The work of Christensen (Kim B. Clark Professor of Business Adminis-
tration at the Harvard Business School) has been highly influential in
business studies; he argues that well-established, well-run businesses can
get unseated by technically inferior rivals, by virtue of the latter’s afford-
ability, ease of use and convenience. He defines this process as Disruptive
Innovation, which enables innovative goods and services to gain footholds
in markets, from which they develop technically and eventually become
market leaders. Christensen identifies specific disruptive technologies which
prompt new forms of practice, adopting a case study approach (including
the disk drive industry and Honda motorcycles in the USA) and basing
Disruptive Innovation on the core criteria for disruptive technologies.
Christensen (1997) also constructs a dualism between sustaining tech-
nologies and disruptive technologies. The former allow us to do something
we had already been doing a little bit better than before (for example, a
slightly more fuel-efficient car), whereas the latter prompt new forms of
practice (for example, the invention of the car itself).
Disruptive Innovation has critics; Christensen’s case study approach is prob-
lematic because it allows him to retrospectively cherry pick examples that
validate the theory, as argued by Lepore (2014) and Danneels (2004, 2006).
6 M. FLAVIN

Moreover, Christensen’s own venture into predicting Disruptive Innovation,

the Disruptive Growth Fund, was singularly unsuccessful, though Christensen
has downplayed his role in the Fund (see Chap. 2 and the conclusion).
However, from the perspective of this book, Christensen’s theory comprises
an interesting and revealing lens for exploring both the intrinsic qualities of
technologies and their use in practice. Christensen et al. (2011) argue, ‘What
the theory of disruptive innovation suggests is that the business model of many
traditional colleges and universities is broken’ (p. 10); it is part of this book’s
purpose to assess that claim.

ACTIVITY THEORY AND EXPANSIVE LEARNING

This book uses Activity Theory and expansive learning as a lens through
which to analyse the impact of disruptive technologies on higher education
learning and teaching. The former term, Activity Theory, a framework for
analysing purposeful human activity, was conceptualized by Leontiev
(1978, 1981) following initial work by Vygotsky (1927, 1930). Expansive
learning was devised by Engestr€om (1987, 2001), whose work was
informed significantly by Activity Theory which provided the original,
triadic representation (see Chap. 3), which Engestr€om developed by adding
additional social elements to the original formulation. Furthermore, while
Vygotsky’s work had focused on the development of children and their
acquisition of language, Engestr€om focused on adult learning. References
to Activity Theory in this book allude to the original theoretical works on
human activity and consciousness with particular reference to the argument
that subjectivity is historically and socially determined. References to second
generation activity theory refer to Engestr€om’s specific framework for
understanding purposeful human conduct and its attendant social relations.
Engestr€ om argues that the contradictions within an activity system can
result in expansive learning, leading to the creation of a new activity system
(Engestr€ om 1987, 2001).
Engestr€ om (in common with Activity Theory) uses the term ‘subject’ to
denote a human participant or participants and uses the term ‘tool’ to refer to
real or symbolic artefacts. Consequently, in this book, ‘tool’ refers to tech-
nology, in the sense of an artefact used to accomplish a purpose. Within an
activity system, the term ‘object’ is used to denote purpose. Consequently, in
this book, subjects refer to participants, tools refer to technologies accessed
via the internet, and object signifies purpose.
 INTRODUCTION 7

COMMUNITY OF PRACTICE
The Community of Practice theory (Lave and Wenger 1991; Wenger 1998)
contextualizes the use of disruptive technologies. For example, individuals
on the periphery of a community of practice, such as new entrant students,
can have a significant impact by introducing a new technology to their peer
or study group. The periphery of a learning community can be a prime site
for Disruptive Innovation. The Community of Practice theory therefore
enables an understanding of how disruptive technologies can impact on
higher education communities, moving from the micro level of the individ-
ual learning and teaching situation from an Activity Theory perspective to
the macro level of the institution and the higher education sector, through
the Community of Practice lens.
This book refers to learning and teaching to describe a pedagogical
totality. The book does not distinguish between learning and teaching
and examine each separately, because, and in order to reinforce the Com-
munity of Practice perspective, a range of roles is seen to be contributing to
collective, institutional aims.
The hierarchy of the theoretical frameworks for the book is reflected in
the book’s chronology. Therefore, most attention is given to the work of
Christensen and others around Disruptive Innovation, and secondary atten-
tion is given to Activity Theory and expansive learning, a perspective which
is used to analyse the impact of the technologies identified as a result of the
Disruptive Innovation approach. Finally, the Community of Practice theory
is used to contextualize the impact of Disruptive Technology Enhanced
Learning in higher education.

TECHNOLOGY USE IN HIGHER EDUCATION

It is a truism to state that technologies support learning and teaching in
higher education. At the most mundane level, text messages can be used to
alert students about room or lecture time changes. However, the use of
institutional technologies such as academic journal aggregators (proprietary
databases such as Academic Search Complete) is less widespread, and the
use of virtual learning environments (VLEs) is often limited relative to
VLEs’ design features and potential; Gordon (2014) defines the VLE as
‘little other than a flexible and accessible library’ (p. 10). VLEs have the
potential to transform learning and teaching as they can enable any time
anywhere peer collaboration through their discussion facilities. However,
8 M. FLAVIN

discussion facilities on VLEs are often underused (Hemmi et al. 2009). Far
from changing pedagogical practices, VLEs have reaffirmed traditional,
transmissive modes of teaching.
Disruptive Innovation suggests VLEs are sustaining technologies, offer-
ing improvements in terms of access (a VLE allows students to access
content at any time, not just in a timetabled slot) but not changing the
relationships operating in learning and teaching. That said, if VLEs work
well as content repositories, there is an argument for using VLEs in precisely
this way. In line with Disruptive Innovation, practice creates purpose, and
VLEs are often used, in practice, simply to store and access content.
Students may be making limited use of VLEs, but they are enthusiastic
users of technology more widely in their lives; Madge et al. (2009) claim
over 95% of UK students regularly use social networking sites. However,
out of the 213 students sampled in their research on the use of the social
networking site Facebook, less than 10% were in favour of Facebook being
used as a teaching tool. Similarly, Jones et al. (2010) found that, while over
70% of their sample of students drawn from four universities had a social
networking account, they rarely used social media for educational purposes.
These results differ from those presented by Selwyn and Gorard (2016) in
an Australian context. Their results indicate Facebook is used by students to
support their learning but, in general, students seemingly prefer to demar-
cate their technology usage, an argument also made by Timmis (2012) and
reinforced in this book.
VLEs are used widely but their full range of learning and teaching
potential is seldom realized. VLEs are ubiquitous, and students and lec-
turers use the internet extensively to undertake research (Littlejohn et al.
2012; Henderson et al. 2015b). The use of plagiarism detection software
and online submission tools is similarly widespread (UCISA 2014, 2016),
highlighting the across-the-board institutional adoption of technologies in
higher education. Moreover, students are often energetic users of social
networking technologies, but do not in general want to use these technol-
ogies to support learning and teaching. Design may enable technologies to
perform a range of functions but (and as this book argues) practice deter-
mines purpose. Technologies are used widely in higher education to sup-
port learning and teaching, but not all individual technologies are used
widely, and usage of individual technologies is determined by users who,
in turn, determine specific and distinctive purposes for specific technologies.
Assumptions can easily be made about students as users of technologies.
Prensky (2001) constructed the dualism of digital natives and digital
 INTRODUCTION 9

immigrants to define the space between a generation of students who had

grown up with digital technologies and prior generations of teachers to
whom the technologies were unfamiliar. However, subsequent research has
painted a different picture. Jones and Healing (2010), for example,
interviewed first-year undergraduate students in England and found that
over a third of the interviewees were not confident about using VLEs
(p. 349). Other researches have also shown students to be largely passive
users of technologies (for example, Margaryan et al. 2011), while Jelfs and
Richardson (2013) found no evidence to support the digital natives hypoth-
esis in a survey of more than 4000 distance learners in higher education.
Furthermore, in research involving 1658 undergraduates in Australia,
Henderson et al. (2015a) found that students’ use of technologies was
logistical (catching-up on lecture content, for example) rather than participa-
tory (see also, Flavin 2016). Jones (2012) summarizes the research on digital
natives and finds that there is no such thing as a generational cohort (p. 30).
One aspect of technology enhanced learning highlighted by Johnson
et al. (2016) in the USA is learning analytics, defined by Siemens and
Gasevic (2012) as, ‘the collection of data and analytics in order to under-
stand and inform teaching and learning’ (p. 1). Learning analytics gathers
details of students’ actions in online environments. Its aims can include the
identification of at-risk students and the gathering of data to effect real-time
or just-in-time improvements in learning and teaching.
The use of analytics has commercial implications, analysing data in order to
target specific markets through advertising campaigns (Burd et al. 2015).
There are, however, limits to the value of data drawn from students’ interac-
tions with online resources, because, for example, it records visits undertaken
to a VLE but not the quality of learning undertaken on the VLE, a problem
recognized by Gasevic et al. (2015) and Rienties et al. (2016).
Learning analytics poses further problems relating to privacy and the
safety of student data (Johnson et al. 2016, p. 39). Furthermore, and as
identified by Ferguson et al. (2014), learning analytics needs the engage-
ment of learners and teachers, and of support staff and administrators. That
said, the reformulation of technology enhanced learning, from providing
resources or interaction to providing analysis to determine future delivery, is
a radical one with implications for programme content and student support.
Baer and Campbell (2012) see analytics as both a sustaining and disruptive
innovation; a sustaining innovation in the sense that predictive analytics can
identify at-risk students, but a disruptive innovation because analytics could
be used ‘to power adaptive systems that adapt to the learner’s needs based
10 M. FLAVIN

on behaviours of the individual as well as of past students’ patterns’ (p. 62),

thus creating more personalized forms of learning. Sharples et al. (2015)
build on learning analytics to identify ‘adaptive teaching’ (p. 5), whereby
data about a learner’s online practice can be used to personalize learning,
and ‘stealth assessment’ (p. 5), whereby data on learners’ usage of online
environments enable ongoing monitoring of their progress. However,
Sharples et al. (2015) also note: ‘Concerns have been raised about collec-
tion of vast amounts of data and the ethics of using computers to monitor a
person’s every action’ (p. 5). Setting ethics to one side, there remains a core
issue of using learning analytics effectively, but a significant incentive to
personalize learning, an outcome with the potential to enhance learning,
teaching, assessment, retention and student satisfaction (Flavin 2016).
Bring Your Own Device (BYOD), the use of mobile devices owned by
the user to support learning and teaching (a related term to mobile learning,
or m-learning), is increasingly commonplace. Smartphones have become
progressively more multifunctional to the point at which they can supersede
established technologies. UCISA (2014) identified ‘notable progress
towards the optimisation of services for mobile devices’ (p. 10) and the
UCISA survey of 2016 shows 60% of Higher Education institutions
optimising services for mobile devices, and with an increase in optimising
library services; universities are amending their practices to accommodate
BYOD. The growth of smartphones and similar technologies is such that,
‘the question is no longer whether to allow them in the classroom, but how
to most effectively integrate and support them’ (Johnson et al. 2016, p. 36).
Johnson et al. (2016) also note the spread of BYOD at universities and
argue, ‘BYOD policies have been shown to reduce overall technology
spending’ (p. 36), as the cost of the hardware is shifted from the institution
to the individual, a process exemplifying the increasing privatization of
higher education. In this sense, BYOD is symptomatic of wider trends, as
Lawton et al. (2013) note: ‘there is, however, a movement away from
public funding towards privately supported higher education. Although
this shift now coincides with an economic downturn in large parts of the
developed world, it predated it and will not be reversed in the likely event of
an economic recovery before 2020. The gradual withdrawal of the state
from HE funding in developed countries is set to stay’ (p. 43). As individ-
ually owned technologies supersede institutional technologies, the role of
the institution is reconfigured to the point at which students arguably
purchase a brand endorsement but supply the apparatus of learning and
teaching themselves. This argument overlooks the expertise of the academic
 INTRODUCTION 11

community but highlights how technology use is interwoven with, and

influenced by, economic and social factors.
There are disadvantages to BYOD, including the cost, which can exclude
users from less privileged backgrounds, and the market for mobile devices, in
which obsolescence is a frequent occurrence, given the speed with which
technologies advance (Yeap et al. 2016). Gikas and Grant (2013) study the
use of mobile devices in higher education and demonstrate how ease of use and
convenience are central to their adoption (pp. 21–22), thus implying the value
of Disruptive Innovation as a means of better understanding BYOD in higher
education. Moreover, if the disruptive technology is affordable, the student is
not obviously disadvantaged; a JISC report (2011) claimed, ‘The low cost of
ownership means that some students can afford newer-specification devices
than colleges and universities can supply’ (p. 7). As costs fall, so does digital
exclusion.
On an institutional level, technology enhanced learning is expensive; a
HEFCE report of 2011, Collaborate to Compete, noted, ‘Quality online
learning is not a cheap option’ (p. 5). Technology enhanced learning
represents a significant investment of time and money on the part of
universities, but specific questions of cost remain unclear: ‘Costing studies
for new technologies have given little help to innovators and managers
because they have tried to give a definitive and generalised answer to the
question of whether they are cost effective. . . it is not feasible to determine a
definitive answer’ (Laurillard 2007, p. 38). Smith et al. (2013) further note
the problem of costs being expressed quantitatively while benefits are
recorded qualitatively, a problem noted previously by Cohen and Nachmias
(2006). Cohen and Nachmias (2006) also argue that the highest cost is
faculty time, unless technology enhanced learning is made less interactive
(p. 85), but this leads to a transmissive curriculum which does little to foster
understanding. Technology enhanced learning is costly but actual costs in
relation to benefits are hard to pin down. Moreover, the effects of technol-
ogy enhanced learning are hard to identify and quantify (Flavin 2016).
Having outlined the core ideas in this book and having contextualized
the issues through a brief survey of technology use in higher education, a
summary of the following chapters is now presented.
12 M. FLAVIN

CHAPTER SUMMARIES
Chapter 2: ‘Free, Simple and Easy to Use: Disruptive Technologies, Dis-
ruptive Innovation and Technology Enhanced Learning.’ This chapter lays
out the core theoretical framework for the book. It summarizes the work of
Christensen (1997), which first identified the criteria for disruptive tech-
nologies, and Christensen and Raynor (2003), which further developed the
theory of Disruptive Innovation.
The chapter also summarizes and analyses more recent work by Christensen,
together with subsequent critique of Disruptive Innovation, including sources
that argue against the validity of Christensen’s approach. The chapter demon-
strates how the Disruptive Innovation lens can be applied to technology
enhanced learning in higher education, as the theory foregrounds practice
over the intrinsic qualities of technologies. Moreover, Christensen’s approach
is useful for identifying specific disruptive technologies.
The chapter uses case studies from Christensen’s work and data from
more recent research on Disruptive Innovation. The chapter analyses the
challenges posed to technology enhanced learning by Disruptive Innova-
tion, which argues implicitly that technology enhanced learning in higher
education has been misdirected to date because it has focused more on
technologies than on practice with technologies. The chapter as a whole
provides a grounding in Disruptive Innovation and identifies specific dis-
ruptive technologies in higher education.
Chapter 3: ‘Why Can’t I Just Google It? What Disruptive Innovation
Means for Higher Education.’ Having analysed Disruptive Innovation to
understand the use of digital technologies to support learning and teaching
in higher education and to identify specific disruptive technologies, this
chapter analyses the impact of Disruptive Innovation on higher education.
Activity Theory is used as the framework for this chapter, enabling explo-
ration of how students and lecturers interact with technologies. The original
research on Activity Theory is surveyed (Vygotsky 1930; Leontiev 1978,
1981), which argues that purposeful human activity is mediated by tools
(either material or abstract) in an interactive process. Second generation
Activity Theory (Engestr€om 1987) is also analysed and is especially useful
because of its inclusion of social as well as material factors in purposeful
human activity. More recent Activity Theory studies are used to analyse
contemporary usage of technology tools to achieve specific goals.
The chapter argues that Disruptive Innovation, viewed through an
Activity Theory lens, impacts most significantly on social relations in higher
 INTRODUCTION 13

education, as the widespread use of disruptive technologies challenges the

gatekeeper role of the university, with students and lecturers frequently
preferring disruptive sources. The chapter also argues that Disruptive Inno-
vation affects learning, teaching, assessment and the division of labour in
higher education because students may by-pass module reading lists and
technologies made available by their universities and, instead, select
resources of their own choosing, a process facilitated through disruptive
technologies and exemplifying Disruptive Innovation.
Chapter 4: ‘Whatever Happened to the Digital Natives? Disruptive
Innovation in the Higher Education Community of Practice.’ This chapter
uses Lave and Wenger’s (1991) and Wenger’s (1998) work on the Com-
munity of Practice to understand how Disruptive Innovation impacts on
higher education communities. The chapter also engages with more recent
critique of the Community of Practice in order to offer a nuanced reading of
the Community of Practice theory in relation to Disruptive Technology
Enhanced Learning in higher education.
New entrants to a university can be adept users of technologies, but
universities may not welcome the new technologies and practices users
bring with them. Moreover, students and lecturers may not wish to use
the technologies they use to support their social lives to support their
learning and teaching lives too. The chapter as a whole locates the role
and activity of Disruptive Innovation in higher education communities of
practice and analyses the impact of Disruptive Innovation on the higher
education sector. The chapter also identifies the periphery of a learning
community as a significant locus for innovation.
Chapter 5: ‘Bidding the Waves Go Back: Engaging with Disruptive
Innovation.’ The book is interested primarily in practice with technologies
rather than in technologies per se. Universities seek to direct technology
usage through technology enhanced learning strategies (a number of which
will be surveyed in the chapter), but this book argues that practice is
primary, and practice is shaped by a range of factors, including many beyond
universities’ control, such as marketing, constraints effected by assessment-
driven higher education systems and rival demands on the time of both
students and lecturers. The conclusion therefore argues for the recognition
of Disruptive Innovation in higher education and suggests means by which
Disruptive Technology Enhanced Learning can be incorporated within
institutional approaches to learning, teaching and assessment. These
means include technology enhanced learning strategies based on practice
rather than on technologies; the rethinking of institutional technologies to
14 M. FLAVIN

see if they can be reconfigured in line with Disruptive Innovation; and the
welcoming of innovative practice, using non-institutional technologies to
accomplish educational goals.
The chapter takes Massive Open Online Courses (MOOCs) as a case study
and argues MOOCs are not disruptive technologies as, in practice, MOOCs
are only simple and easy to use for people who have undertaken higher
education study previously; the UCISA report of 2014, for example, indi-
cated that MOOCs had, to date, made little impression (2014, p. 3). The
chapter argues that MOOCs are more akin to Second Life, a virtual world
which failed to change higher education because, the chapter argues, it failed
to conform to Christensen’s core criteria, though MOOCs may find a market
in Continuing Professional Development courses (Laurillard 2016). The
chapter argues for Christensen’s core criteria as a practical starting point for
the design and application of technologies in higher education.
The conclusion also proposes means by which to enhance learning and
teaching in higher education by accommodating the use of disruptive
technologies, recognizing that students and lecturers often by-pass institu-
tional resources in their construction of knowledge. The conclusion argues
that universities will benefit from engaging with disruptive technologies,
recognizing that disruptive technology use happens and that an accommo-
dating approach based on known aspects of practice will enable disruptive
technologies to contribute to and enhance learning and teaching in higher
education.
The book as a whole offers a fresh perspective on technology enhanced
learning by using a range of approaches to investigate the uses of technol-
ogies to support learning and teaching in higher education. Previous works
have used Disruptive Innovation, Activity Theory or the Community of
Practice theory separately, but this book is distinctive in using all three
theories in an integrated and coherent approach, to illuminate and analyse
technology enhanced learning. The conjoining of Disruptive Innovation
with Activity Theory and the Community of Practice theory means that
disruption is not just observed, but analysed, too. Disruptive Technology
Enhanced Learning applies a contemporary and relevant lens to technology
enhanced learning, offering new insights and new approaches to the appli-
cation of technologies for learning, teaching and assessment. Disruptive
Technology Enhanced Learning is a ground-breaking study of how and
why technologies succeed or fail in higher education.
This chapter has introduced the book’s area of interest and its core
arguments, while also offering a chapter by chapter summary. The next
 INTRODUCTION 15

chapter explores in more detail the foundational theoretical framework for

this book, Disruptive Innovation.

REFERENCES
Baer, L., & Campbell, J. (2012). From metrics to analytics, reporting to action:
Analytics’ role in changing the learning environment. In D. G. Oblinger (Ed.),
Game changers: Education and information technologies. Louisville: Educause.
Bayne, S. (2015). What’s the matter with “technology enhanced learning”? Learn-
ing, Media and Technology, 40(1), 5–20.
Bok, D. (2003). Universities in the marketplace: The commercialization of higher
education. Princeton/Oxford: Princeton University Press.
Burd, E. L., Smith, S. P., & Reisman, S. (2015). Exploring business models for
MOOCs in higher education. Innovative Higher Education, 40, 37–49.
Christensen, C. M. (1997). The innovator’s dilemma: When new technologies cause
great firms to fail. Boston: Harvard Business School Press.
Christensen, C. M., & Raynor, M. E. (2003). The innovator’s solution: Creating and
sustaining successful growth. Boston: Harvard Business School Press.
Christensen, C.M., Horn, M.B., Caldera, L., & Soares, L. (2011). Disrupting
college: How disruptive innovation can deliver quality and affordability to
postsecondary education. Mountain View: Center for American Progress and
Innosight Institute. Retrieved from https://cdn.americanprogress.org/wp-con
tent/uploads/issues/2011/02/pdf/disrupting_college_execsumm.pdf
Cohen, A., & Nachmias, R. (2006). A quantitative cost effectiveness model for
web-supported academic instruction. Internet and Higher Education, 9, 81–90.
Colon-Aguirre, M., & Fleming-May, R. A. (2012). “You just type in what you are
looking for”: Undergraduates’ use of library resources vs. Wikipedia. The Journal
of Academic Librarianship, 38(6), 391–399.
Danneels, E. (2004). Disruptive technology reconsidered: A critique and research
agenda. The Journal of Product Information Management, 21, 246–258.
Danneels, E. (2006). From the guest editor: Dialogue on the effects of disruptive
technology on firms and industries. The Journal of Product Information Man-
agement, 23, 2–4.
Engestr€om, Y. (1987). Learning by expanding: An activity-theoretical approach to
developmental research. Helsinki: Orienta-Konsultit Oy. Retrieved from http://
lchc.ucsd.edu/MCA/Paper/Engestrom/expanding/toc.htm
Engestr€om, Y. (2001). Expansive learning at work: Toward an activity theoretical
reconceptualization. Journal of Education and Work, 14(1), 133–156.
Ferguson, R., Clow, D., Macfadyen, L., Essa, A., Dawson, S., & Alexander,
S. (2014). Setting learning analytics in context: Overcoming the barriers to
large-scale adoption. LAK14: Proceedings of the fourth international conference
16 M. FLAVIN

on learning analytics and knowledge (pp. 251–253). http://dl.acm.org/citation.

cfm?id¼2567592
Flavin, M. (2016). Technology-enhanced learning and higher education. Oxford
Review of Economic Policy, 32(4), 632–645.
Gasevic, D., Dawson, S., & Siemens, G. (2015). Let’s not forget: Learning analytics
are about learning. TechTrends, 59(1), 64–71.
Gikas, J., & Grant, M. M. (2013). Mobile computing devices in higher education:
Student perspectives on learning with cellphones, smartphones and social media.
Internet and Higher Education, 19, 18–26.
Gordon, N. (2014). Flexible pedagogies: Technology-enhanced learning. York: Higher
Education Academy.
Head, A. J., & Eisenberg, M. B. (2010). How today’s college students use
Wikipedia for course-related research. First Monday, 15(3). Retrieved from
http://firstmonday.org/ojs/index.php/fm/article/view/2830/2476
Hemmi, A., Bayne, S., & Land, R. (2009). The appropriation and repurposing of
social technologies in higher education. Journal of Computer Assisted Learning,
25, 19–30.
Henderson, M., Selwyn, N., & Aston, R. (2015a). What works and why? Student
perceptions of “useful” digital technology in university teaching and learning.
Studies in Higher Education. doi:10.1080/03075079.2015a.1007946.
Henderson, M., Selwyn, N., Finger, G., & Aston, R. (2015b). Students’ everyday
engagement with digital technology in university: Exploring patterns of use and
“usefulness”. Journal of Higher Education Policy and Management, 37(3),
308–319.
Higher Education Funding Council for England (HEFCE). (2009). Enhancing
learning and teaching through the use of technology: A revised approach to
HEFCE’s strategy for e-learning. Bristol: HEFCE.
Hillis, K., Petit, M., & Jarrett, K. (2013). Google and the culture of search. Abingdon:
Routledge.
Horrigan, J.B. (2016). Lifelong learning and technology. Pew Research Center.
Retrieved from http://www.pewinternet.org/2016/03/22/lifelong-learning-
and-technology/
Jelfs, A., & Richardson, J. T. E. (2013). The use of digital technologies across the
adult life span in distance education. British Journal of Educational Technology, 44
(2), 338–351.
JISC. (2009). Effective practice in a digital age: A guide to technology-enhanced
learning and teaching. Bristol: JISC.
Jisc. (2011). Emerging practice in a digital age: A guide to technology-enhanced
institutional innovation. Bristol: Jisc.
Johnson, L., Adams-Becker, S., Cummins, M., Estrada, V., Freeman, A., & Hall,
C. (2016). NMC horizon report: 2016 higher education edition. Austin: The New
Media Consortium.
 INTRODUCTION 17

Jones, C. (2012). Networked learning, stepping beyond the net generation and
digital natives. In L. Dirckinck-Holmfeld, V. Hodgson, & D. Mc Connell (Eds.),
Exploring the theory, pedagogy and practice of networked learning (pp. 27–41).
New York: Springer.
Jones, C., & Healing, G. (2010). Net generation students: Agency and choice and
the new technologies. Journal of Computer Assisted Learning, 26, 344–356.
Jones, N., Blackley, H., Fitzgibbon, K., & Chew, E. (2010). Get out of MySpace!
Computers and Education, 54(3), 776–782.
Kirkwood, A., & Price, L. (2014). Technology-enhanced learning and teaching in
higher education: What is “enhanced” and how do we know? A critical literature
review. Learning, Media and Technology, 39(1), 6–36.
Laurillard, D. (2007). Modelling benefits-oriented costs for technology enhanced
learning. Higher Education, 54, 21–39.
Laurillard, D. (2016). The educational problem that MOOCs could solve: Profes-
sional development for teachers of disadvantaged students. Research in Learning
Technology, 24. http://dx.doi.org/10.3402/rlt.v24.29369
Lave, J., & Wenger, E. (1991). Situated learning: Legitimate peripheral participa-
tion. Cambridge: Cambridge University Press.
Lawton, W., Ahmed, M., Angulo, T., Axel-Berg, A., Burrows, A., & Katsomitros, A.
(2013). Horizon scanning: What will higher education look like in 2020? The
Observatory on Borderless Higher Education. http://obhe.ac.uk/documents/
view_details?id=929
Leontiev, A. N. (1978). Activity, consciousness and personality (trans. Hall, M.J.).
Englewood Cliffs: Prentice Hall.
Leontiev, A. N. (1981). Problems of the development of the mind. Moscow: Progress.
Lepore, J. (2014). The disruption machine: What the Gospel of innovation gets
wrong. The New Yorker, 90(17), 30–36.
Littlejohn, A., Beetham, H., & McGill, L. (2012). Learning at the digital frontier: A
review of digital literacies in theory and practice. Journal of Computer Assisted
Learning, 28, 547–556.
Madge, C., Meek, J., Wellens, J., & Hooley, T. (2009). Facebook, social integration
and informal learning at university: It is more for socialising and talking to friends
about work than for actually doing work. Learning, Media and Technology, 34(2),
141–155.
Margaryan, A., Littlejohn, A., & Vojt, G. (2011). Are digital natives a myth or
reality? University students’ use of digital technologies. Computers and Educa-
tion, 56, 429–440.
O’Reilly, T. (2005). What is Web 2.0: Design patterns and business models for the next
generation of software. O’Reilly. Retrieved from http://www.oreilly.com/pub/
a/web2/archive/what-is-web-20.html
Another random document with
no related content on Scribd:
the parts protected from the laboratory fumes.[119] The details of the belt system are shown in the small
diagram in the lower central part of the figure. The apparatus is mounted on a substantial wooden box,
200 centimeters long, thirty centimeters high, and eighteen centimeters wide. The driving pulleys, ten
centimeters in diameter, are enclosed in the upper part of the case. The shafts on which these pulleys
are mounted extend through the bottom of the enclosing box and carry a wooden disk, eleven
centimeters in diameter, to prevent particles of foreign matter from falling into the beakers. The shafts
extend two centimeters below these disks, and to the end of the shafts the bent stirring rods are
attached by rubber tubing.
The board forming the support of the driving pulleys is extended two centimeters in front of the
apparatus, and in this extension twelve notches are cut, in which are held the corks carrying the tubes
which contain the solution to be used in precipitating the material in the beakers.

Figure. 9.
Huston’s Mechanical Stirrer.

The ends of these tubes are drawn out to a fine point so as to deliver the liquid at the rate of about
one drop per second.
The front of the apparatus is hinged and permits the whole to be closed when not in use, or during
the precipitation.
The apparatus has proven extremely satisfactory in the precipitation of ammonium magnesium
phosphate. The precipitate is very crystalline, and where the stirring is continued for some minutes, after
the magnesia solution has all been added, no amorphous precipitate is observed on longer standing.
132. The Citrate Method Applied to Samples with Small Content of Phosphoric Acid.—It is well
established that the citrate method does not give satisfactory results when applied to samples
containing small percentages of phosphoric acid, especially when these are of an organic nature, as for
instance, cottonseed cake-meal. In this laboratory attempts have been made to remedy this defect in
the process so as to render the use of the method possible even in such cases.[120] Satisfactory results
have been obtained by adding to the solution of the cake-meal a definite volume of a phosphate solution
of known strength. Solutions of ordinary mineral phosphates are preferred for this purpose. The
following example will show the application of the modified method:
In a sample of cake-meal, (cottonseed cake and castor pomace) the content of phosphoric acid
obtained by the molybdate method, was 2.52 per cent.
Determined directly by the citrate method, the following data were obtained:
Allowing to stand thirty hours after adding magnesia mixture, 1.08 and 1.53 per cent in duplicates.
Allowing to stand seventy-two hours after adding magnesia mixture, 2.17 and 2.30 per cent in
duplicates.
In each case fifty cubic centimeters of the solution were taken, representing half a gram of the
sample.
In another series of determinations twenty-five cubic centimeters of the sample were mixed with an
equal volume of a mineral phosphate solution, the value of which had been previously determined by
both the molybdic and citrate methods. The fifty cubic centimeters thus obtained represented a quarter
of a gram each of the cake-meal and mineral phosphates. The filtration followed eighteen hours after
adding the magnesia mixture. The following data show the results of the determinations:
Per cent P₂O₅ Per cent P₂O₅ Per cent P₂O₅ Per cent P₂O₅
mineral in organic found in in organic
phosphate. sample. mixture × 2. sample.
1 15.37 2.52 17.90 2.53
2 29.16 2.52 31.68 2.52
3 31.37 2.52 33.83 2.45
4 31.58 2.52 34.20 2.62
Mean content of P₂O₅ in organic sample 2.53
It is thus demonstrated that the citrate method can be applied with safety even to the determination
of the phosphoric acid in organic compounds where the quantity present is less than three per cent. It is
further shown that solutions of mineral phosphates varying in content of phosphoric acid from fifteen to
thirty-two per cent may be safely used for increasing the content of that acid to the proper degree for
complete precipitation. In cases where organic matters are present they should be destroyed by moist
combustion with sulfuric acid as in the determination of nitrogen to be described in the next part.
133. Direct Precipitation of the Citrate-Soluble Phosphoric Acid.—The direct determination of
citrate-soluble phosphoric acid by effecting the precipitation by means of magnesia mixture in the
solution obtained from the ammonium citrate digestion, has been practiced for many years by numbers
of European chemists, and the process has even obtained a place in the official methods of some
European countries. Various objections have been urged, however, against the general employment of
this method in fertilizer analysis on account of the inaccuracies in the results obtained in certain cases,
and it has, therefore, been used to but a very limited extent in this country. Since it is impracticable to
effect the precipitation with ammonium molybdate in the presence of citric acid the previous elimination
or destruction of this substance has been recognized as essential to the execution of a process
involving the separation of the phosphoric acid as phosphomolybdate.
It is evident from the data cited in the preceding paragraph, that great accuracy may be secured in
this process by adding a sufficient quantity of a solution of a mineral phosphate and proceeding by the
citrate method.
Ross has also proposed to estimate the acid soluble in ammonium citrate directly by first destroying
the organic matter by moist combustion with sulfuric acid.[121] He recommends the following process:
After completion of the thirty minutes’ digestion of the sample with citrate solution, twenty-five cubic
centimeters are filtered at once into a dry vessel. If the liquid be filtered directly into a dry burette,
twenty-five cubic centimeters can be readily transferred to another vessel without dilution. After cooling,
run twenty-five cubic centimeters of the solution into a digestion flask of 250-300 cubic centimeters
capacity, add about fifteen cubic centimeters of concentrated sulfuric acid and place the flask on a piece
of wire gauze over a moderately brisk flame; in about eight minutes the contents of the flask commence
to darken and foaming begins, but this will occasion no trouble, if an extremely high, or a very low flame
be avoided. In about twelve minutes the foaming ceases and the liquid in the flask appears quite black;
about one grain of mercuric oxid is now added and the digestion is continued over a brisk flame. The
operation can be completed in less than half an hour with ease, and in many cases, twenty-five minutes.
After cooling, the contents of the flask are washed into a beaker, ammonia is added in slight excess, the
solution is acidified with nitric, and after the addition of fifteen grams of ammonium nitrate, the process is
conducted as usual.
In case as large an aliquot as fifty cubic centimeters of the original filtrate be used, ten cubic
centimeters of sulfuric acid are added, and the digestion is conducted in a flask of 300-500 cubic
centimeters capacity; after the liquid has blackened and foaming has progressed to a considerable
extent, the flask is removed from the flame, fifteen cubic centimeters more of sulfuric acid are added,
and the flask and contents are heated at a moderate temperature for two or three minutes; the mercuric
oxid is then added and the operation completed as before described.
 Following are some of the advantages offered by the method described:
(1) It dispenses with the necessity of the execution of the frequently tedious operation of bringing
upon the filter and washing the residue from the ammonium citrate digestion, while the ignition of this
residue together with the subsequent digestion with acid and filtration are also avoided.
(2) It affords a means for the direct estimation of that form of phosphoric acid which, together with
the water-soluble, constitutes the available phosphoric acid, thus enabling the latter to be determined by
making only two estimations.
(3) In connection with the advantages above mentioned it permits of a considerable saving of time,
as well as of labor required in manipulation.
In addition to the tests with mercuric oxid, both potassium nitrate and potassium sulfate were used in
the digestion to facilitate oxidation. With the former, several additions of the salt were necessary to
secure a satisfactory digestion, and even then the time required was longer than with the mercury or
mercuric oxid digestion. With potassium sulfate, the excessive foaming which took place interfered
greatly with the execution of the digestion process.
134. Availability of Phosphatic Fertilizers.—There is perhaps no one question more frequently put
to analysts by practical farmers than the one relating to the availability of fertilizing materials. The object
of the manufacturer should be to secure each of the valuable ingredients of his goods in the most useful
form. The ideal form in which phosphoric acid should come to the soil is one soluble in water. Even in
localities where heavy rains may abound, there is not much danger of loss of soluble acid by
percolation. As has before been indicated, the soluble acid tends to become fixed in all normal soils,
and to remain in a state accessible to the rootlets of plants, and yet free from danger of leaching. For
this reason, by most agronomists, the water-soluble acid is not regarded as more available than that
portion insoluble in water, yet soluble in ammonium citrate.
In many of the States the statutes, or custom, prescribe that only the water and citrate-soluble acid
shall be reckoned as available, the insoluble residue being allowed no place in the estimates of value. In
many instances such a custom may lead to considerable error, as in the case of finely ground bones
and some forms of soft and easily decomposable tricalcium phosphates. There are also, on the markets,
phosphates composed largely of iron and aluminum salts, and these appear to have an available value
often in excess of the quantities thereof soluble in ammonium citrate.
As a rule the apatites, when reduced to a fine powder and applied to the soil, are the least available
of the natural phosphates. Next in order come the land rock and pebble phosphates which, in most
soils, have only a limited availability. The soft fine-ground phosphates, especially in soils rich in humus,
have an agricultural value, almost, if not quite equal to a similar amount of acid in the acid phosphates.
Fine-ground bones also tend to give up their phosphoric acid with a considerable degree of readiness in
most soils. Natural iron and aluminum phosphates, have also, as a rule, a high degree of availability. In
each case the analyst must consider all the factors of the case before rendering a decision. Not only the
relative solubility of the different components of the offered fertilizer in different menstrua must be taken
into consideration, but also the character of the soil to which it is to be applied, the time of application,
and the crop to be grown. By a diligent study of these conditions the analyst may, in the end, reach an
accurate judgment of the merits of the sample.
135. Direct Weighing of the Molybdenum Precipitate.—It has already been stated that many
attempts have, been made to determine the phosphoric acid by direct weighing as well as by titration, as
in the Pemberton method. The point of prime importance in such a direct determination is to secure an
ammonium phosphomolybdate mixture of constant composition. Unless this can be done no direct
method, either volumetric or gravimetric, can give reliable results. Hanamann[122] proposes to secure
this constant composition by varying somewhat the composition of the molybdate mixture and
precipitating the phosphoric acid under definite conditions. The molybdate solution employed is
prepared as follows:
Molybdic acid 100 grams.
Ten per cent ammonia 1.0 liter.
Nitric acid (1.246 sp. gr.) 1.5 liters.
 The precipitation of the phosphoric acid is conducted in the cold with constant stirring. It is complete
in half an hour. The ammonium phosphomolybdate is washed with a solution of ammonium nitrate and
then with dilute nitric acid, dried, and ignited at less than a red heat. It should then have a bluish-black
color throughout. Such a body contains 4.018 per cent of phosphoric anhydrid.
Twenty-five cubic centimeters of a sodium phosphate solution containing fifty milligrams of
phosphoric acid, treated as above, gave a bluish-black precipitate weighing 1.249 grams, which,
multiplied by 0.041018, equaled 50.018 milligrams of phosphorus pentoxid. The method should be tried
on phosphates of various kinds and contents of phosphorus pentoxid before a definite judgment of its
merits is formed.

CHEMISTRY OF THE MANUFACTURE

OF SUPERPHOSPHATES.
136. Reactions with Phosphates.—In this country the expressions “acid” and “super” phosphates
are used interchangeably. A more correct use of the terms would designate by “acid” the phosphate
formed directly from tricalcium phosphate by the action of sulfuric acid, while by “super” would be
indicated a similar product formed by the action of free phosphoric acid on the same materials. In
Germany the latter compound is called double phosphate.
The reaction which takes place in the first instance is represented by the following formula:

3Ca₃(PO₄)₂ + 6H₂SO₄ + 12H₂O = 4H₃PO₄ + Ca₃(PO₄)₂ + 6(CaSO₄·2H₂O);

and 4H₃PO₄ + Ca₃(PO₄)₂ + 3H₂O = 3[CaH₄(PO₄)₂·H₂O].
A simpler form of the reaction is expressed as follows:

Ca₃(PO₄)₂ + 2H₂SO₄ + 5H₂O = CaH₄(PO₄)₂·H₂O + 2[CaSO₄·2H₂O].

If 310 parts, by weight, of fine-ground tricalcium phosphate be mixed with 196 parts of sulfuric acid
and ninety parts of water, and the resulting jelly be quickly diluted with a large quantity of water, and
filtered, there will be found in the filtrate about three-quarters of the total phosphoric as free acid. If,
however, the jelly, at first, formed as above, be left to become dry and hard, the filtrate, when the mass
is beaten up with water and filtered, will contain monocalcium phosphate, CaH₄(PO₄)₂.
If the quantity of sulfuric acid used be not sufficient for complete decomposition, the dicalcium salt is
formed directly according to the following reaction:

Ca₃(PO₄)₂ + H₂SO₄ + 6H₂O = Ca₂H₂(PO₄)₂·4H₂O + CaSO₄·2H₂O.

This arises, doubtless, by the formation, at first, of the regular monocalcium salt and the further
reaction of this with the tricalcium compound, as follows:

CaH₄(PO₄)₂ + H₂O + Ca₃(PO₄)₂ + 7H₂O = 2[Ca₂H₂(PO₄)₂·4H₂O].

This reaction represents, theoretically, the so-called reversion of the phosphoric acid. When there is
an excess of sulfuric acid there is a complete decomposition of the calcium salts with the production of
free phosphoric acid and gypsum. The reaction is represented by the following formula:

Ca₃(PO₄)₂ + 3H₂SO₄ + 6H₂O = 2H₃PO₄ + 3[CaSO₄·2H₂O].

The crystallized gypsum absorbs the six molecules of water in its molecular structure.
137. Reactions with Fluorids.—Since calcium fluorid is present in nearly all mineral phosphates,
the reactions of this compound must be taken into consideration in a chemical study of the manufacture
of acid phosphates. When treated with sulfuric acid the first reaction which takes place consists in the
formation of hydrofluoric acid: CaF₂ + H₂SO₄ = 2HF + CaSO₄. Since, however, there is generally some
silica in reach of the nascent acid, all, or a portion of it, combines at once with this silica, forming silicon
tetrafluorid: 4HF + SiO₂ = 2H₂O + SiF₄. This compound, however, is decomposed at once in the
presence of water, forming hydrofluosilicic acid: 3SiF₄ + 2H₂O = SiO₂ + 2H₂SiF₆. The presence of
calcium fluorid in natural phosphates is extremely objectionable from a technical point of view, both on
account of the increased consumption of oil of vitriol which it causes, but also by reason of the injurious
nature of gaseous fluorin compounds produced. Each 100 pounds of calcium fluorid entails the
consumption of 125.6 pounds of sulfuric acid.
138. Reaction with Carbonates.—Most mineral phosphates contain calcium carbonate in varying
quantities. This compound is decomposed on treatment with sulfuric acid according to the reaction:
CaCO₃ + H₂SO₄ = CaSO₄ + H₂O + CO₂. When present in moderate amounts, calcium carbonate is not
an objectionable impurity in natural phosphates intended for acid phosphate manufacture. The reaction
with sulfuric acid which takes place produces a proper rise in temperature throughout the mass, while
the escaping carbon dioxid permeates and lightens the whole mass, assisting thus in completing the
chemical reaction by leaving the residual mass porous, and capable of being easily dried and
pulverized. Where large quantities of carbonate in proportion to the phosphate are present the sulfuric
acid used should be dilute enough to furnish the necessary water of crystallization to the gypsum
formed. For each 100 parts, by weight, of calcium carbonate, eighty parts of sulfuric anhydrid are
necessary, or 125 parts of acid of 1.710 specific gravity = 60° Beaumé.
In some guanos a part of the calcium is found as pyrophosphate, and this is acted upon by the
sulfuric acid in the following way: Ca₂P₂O₇ + H₂SO₄ = CaH₂P₂O₇ + CaSO₄.
139. Solution of the Iron and Alumina Compounds.—Iron may occur in natural phosphates in
many forms. It probably is most frequently met with as ferric or ferrous phosphate, seldom as ferric oxid,
and often as pyrite, FeS₂. The iron also may sometimes exist as a silicate. The alumina is found chiefly
in combination with phosphoric acid, and as silicate.
Where a little less sulfuric acid is employed, as is generally the case, than is necessary for complete
solution, the iron phosphate is attacked as represented below:

3FePO₄ + 3H₂SO₄ = FePO₄·2H₂PO₄ + Fe₂(SO₄)₃.

When an excess of sulfuric acid is employed, the formula is reduced to the simple one:

2FePO₄ + 3H₂SO₄ = 2H₃PO₄ + Fe₂(SO₄)₃.

A part of the iron sulfate formed reacts with the acid calcium phosphate present to produce a
permanent jelly-like compound, difficult to dry and handle. As much as two per cent of iron phosphate,
however, may be present without serious interference with the commercial handling of the product. By
using more sulfuric acid as much as four or five per cent of the iron phosphate can be held in solution.
Larger quantities are very troublesome from a commercial point of view. The reaction of the ferric sulfate
with monocalcium phosphate, is as follows:

3CaH(PO₄)₂ + Fe₂(SO₄)₃ + 4H₂O = 2(FePO₄·2H₃PO₄·2H₂O) + 3CaSO₄.

Pyrite and the silicates containing iron are not attacked by sulfuric acid, and these compounds are
therefore left, in the final product, in a harmless state. If the pyritic iron is to be brought into solution
aqua regia should be employed.
With sufficient acid the aluminum phosphate is decomposed with the formation of aluminum sulfate
and free phosphoric acid:

AlPO₄ + 3H₂SO₄ = Al₂(SO₄)₃ + 2H₃PO₄.

140. Reaction with Magnesium Compounds.—The mineral phosphates, as a rule, contain but little
magnesia. When present it is probably as an acid salt, MgHPO₄. Its decomposition takes place in slight
deficiency or excess of sulfuric acid respectively as follows:
 2MgHP₄ + H₂SO₄ + 2H₂O = [MgH₄(PO₄)₂·2H₂O] + MgSO₄
and MgHPO₄ + H₂SO₄ = H₃PO₄ + MgSO₄.
The magnesia, when in the form of oxid, is capable of producing a reversion of the monocalcium
phosphate, as is shown below:

CaH₄(PO₄)₂ + MgO = CaMgH₂(PO₄)₂ + H₂O.

One part by weight of magnesia can render three and one-half parts of soluble monocalcium
phosphate insoluble.
141. Determination of Quantity of Sulfuric Acid Necessary for Solution of a Mineral
Phosphate.—The theoretical quantity of sulfuric acid required for the proper treatment of any phosphate
may be calculated from its chemical analysis and by the formulas and reactions already given. For the
experimental determination the method of Rümpler may be followed.[123]
Twenty grams of the fine phosphate are placed in a liter flask with a greater quantity of accurately
measured sulfuric acid than is necessary for complete solution. The acid should have a specific gravity
of 1.455 or 45° B. The mixture is allowed to stand for two hours at 50°. It is then cooled, the flask filled
with water to the mark, well shaken, and the contents filtered. Fifty cubic centimeters of the filtrate are
treated with tenth normal soda-lye until basic phosphate begins to separate. The excess of acid used is
then calculated. Example: Twenty grams of phosphate containing 28.3 per cent of phosphoric acid, 10.0
per cent of calcium carbonate, 5.5 per cent of calcium fluorid, and 2.4 per cent of calcium chlorid were
treated as above with sixteen cubic centimeters of sulfuric acid containing 10.24 grams of sulfur trioxid.
In titrating fifty cubic centimeters of the filtrate obtained as described above, 10.4 cubic centimeters of
tenth normal soda-lye were used, equivalent to 0.0416 gram of sulfur trioxid. Then 10.24 × 50 ÷ 1000 =
0.5120 = total sulfur trioxid in fifty cubic centimeters of the filtrate, and 0.5120 - 0.0416 = 0.4704 gram,
the amount of sulfur trioxid consumed in the decomposition.
Therefore the sulfur trioxid required for decomposition is 47.04 per cent of the weight of the
phosphate employed. One hundred parts of the phosphate would therefore require 47.04 parts of sulfur
trioxid = to 73.6 parts of sulfuric acid of 1.710 specific gravity or 92.1 parts of 1.530 specific gravity.
A more convenient method than the one mentioned above consists in treating a small quantity of the
phosphate, from one-half to one kilogram, in the laboratory, or fifty kilograms in a lead box, just as would
be practiced on a large scale. A few tests with these small quantities, followed by drying and grinding
will reveal to the skilled operator the approximate quantity and strength of sulfuric acid to be used in
each case. The quantities of sulfuric acid as determined by calculation from analyses and by actual
laboratory tests agree fairly well in most instances. There is, however, sometimes a marked
disagreement. The general rule of practice is to use always an amount of sulfuric acid sufficient to
produce and maintain water-soluble phosphoric acid in the fertilizer, but the sulfuric acid must not be
used in such quantity as to interfere with the subsequent drying, grinding, and marketing of the acid
phosphate.
For convenience the following table may be used for calculating the quantity of oil of vitriol needed
for each unit of weight of material noted:

One Part by Weight of Each Substance Below Requires:

Sulfuric Acid by Same Unit of Weight.
At 48° B. At 50° B. At 52° B. At 54° B. At 55° B.
Tricalcium phosphate 1.590 1.517 1.446 1.382 1.352
Iron phosphate 1.630 1.558 1.485 1.420 1.390
Aluminum phosphate 2.025 1.930 1.839 1.756 1.721
Calcium carbonate 1.640 1.565 1.495 1.428 1.411
Calcium fluorid 2.006 2.010 1.916 1.830 1.794
 Sulfuric Acid by Same Unit of Weight.
At 48° B. At 50° B. At 52° B. At 54° B. At 55° B.
Magnesium carbonate 1.940 1.860 1.775 1.690 1.660

Example.—Suppose for example a phosphate of the following composition

is to be treated with sulfuric acid; viz.,[124]
Moisture and organic 4.00 per cent.
Calcium phosphate 55.00 “
Calcium carbonate 3.00 “
Iron and aluminum phosphate
nearly all alumina 6.50 “
Magnesium carbonate 0.75 “
Calcium fluorid 2.25 “
Insoluble 28.00 “
Using sulfuric acid of 50° B., the following quantities will be required for
each 100 kilograms.
Kilos of acid
required.
Calcium phosphate, fifty-five kilos 83.44
“ carbonate three and a half kilos 5.48
“ fluorid, two and a quarter “ 4.52
Aluminum and iron phosphate, six and a half kilos 12.55
Magnesium carbonate, three-quarters of a kilo 1.40
Total 107.39
142. Phosphoric Acid Superphosphates.—If a mineral phosphate be decomposed by free
phosphoric in place of sulfuric acid the resulting compound will contain about three times as much
available phosphoric acid as is found in the ordinary acid phosphate. The reaction takes place according
to the following formulas:

(1) Ca₃(PO₄)₂ + 4H₃PO₄ + 3H₂O = 3[CAH₄(PO₄)₂·H₂O].

(2) Ca₃(PO₄)₃ + 2H₃PO₄ + 12H₂O = 3[Ca₂H₂(PO₄)₂·4H₂O].
In each case the water in the final product is probably united as crystal water with the calcium salts
produced. The monocalcium salt formed in the first reaction is soluble in water and the dicalcium salt in
the second reaction in ammonium citrate. Where fertilizers are to be transported to great distances there
is a considerable saving of freight by the use of such a high-grade phosphate, which may, at times,
contain over forty per cent of available acid. The phosphoric acid used is made directly from the mineral
phosphate by treating it with an excess of sulfuric acid.

AUTHORITIES CITED IN
PART FIRST.

[1] Day, Mineral Resources of the United States 193, pp. 703, et seq.
[2] Massachusetts Agricultural Experiment Station, Bulletin 51, March, 1894.
[3] Brown, Manual of Assaying, p. 24.
[4] Bulletin de l’Association des Chimistes de Sucrèrie, No. 2, pp. 7, et seq.
[5] Proceedings of the Twelfth and Thirteenth Meetings of the Society for the Promotion of
Agricultural Science, p. 140.
[6] Chemical Division, U. S. Department of Agriculture, Bulletin 43, p. 341.
[7] Rapport adressé par le Comité des Stations agronomiques au sujet des Methodes à suivre dans
l’Analyse des Matières fertilisantes.
[8] Die Landwirtschaftlichen Versuchs-Stationen, Band 38, S. 303.
[9] Vid. op. cit. 6, p. 341.
[10] Zeitschrift für analytische Chemie, 1890, S. 390.
[11] Vid. op. cit. 6, p. 342.
[12] Chemisches Centralblatt, Band 2, S. 813.
[13] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 165.
[14] Phosphates of America, p. 144.
[15] Vid. op. et loc. cit. 13.
[16] U. S. Geological Survey, Bulletin No. 47.
[17] Vid. op. et loc. cit. 14.
[18] Vid. op. et loc. cit. 13.
[19] Vid. op. cit. 14, p. 147.
[20] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 168.
[21] Phosphates of America, p. 153.
[22] Die Landwirtschaftlichen Versuchs-Stationen, Band 34, S. 379.
[23] Zeitschrift für analytische Chemie, 1892, S. 383.
[24] Zeitschrift für angewandte Chemie, 1894, Ss. 679 und 701.
[25] Vid. op. cit. supra, 1889, p. 636.
[26] Vid. op. cit. 24, 1891, p. 3.
[27] Rapports presentèes au Congrès International de Chimie Appliqué, Bruxelles, Août, 1894, p.
26.
[28] Vid. op. et loc. cit. 20.
[29] Le Stazioni Sperimentali Agrarie Italiane, Vol. 23, p. 31.
[30] Crookes’ Select Methods, p. 538.
[31] Journal of Analytical and Applied Chemistry, Vol. 5, p. 671. For additional authorities on these
methods consult Meyer and Wohlrab, Zeitschrift für angewandte Chemie, 1891, Ss. 170 und 243.
Gruber, Zeitschrift für analytische Chemie, Band 30, S. 206. Shephard, Chemical News, May 29,
1891, p. 251. Vögel, Zeitschrift für angewandte Chemie, 1891, Band 12, S. 357.
[32] Journal of the American Chemical Society, April, 1895.
[33] Vid. op. cit. 21, p. 150.
[34] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 170.
[35] Vid. op. cit. supra, p. 173.
[36] Comptes rendus, Tome 54, p. 468.
[37] Crookes’ Select Methods, p. 500.
[38] For details of method see Fresenius quantitative Analysis.
[39] U. S. Department of Agriculture, Chemical Division, Bulletin 43, p. 341.
[40] Letter to B. W. Kilgore, Reporter for Phosphoric Acid to the Association of Official Agricultural
Chemists.
[41] Die Landwirtschaftlichen Versuchs-Stationen, Band 38, S. 304.
[42] Communicated by Dr. Solberg.
[43] From the Official Swedish Methods; translated for the author by F. W. Woll.
[44] Methoden van Onderzock aan de Rijkslandbouw-proefstations, 1893, p. 4.
[45] Zeitschrift für analytische Chemie, 1893, S. 64.
[46] Journal of the American Chemical Society, Vol. 16.
[47] Zeitschrift für angewandte Chemie, 1894, S. 678.
[48] Journal für Landwirtschaft, Band 30, S. 23.
[49] Vid. op. cit. 47, p. 544.
[50] Vid. op. cit. 46, Vol. 16, p. 462.
[51] Vid. op. et loc. cit. supra.
[52] Die Agricultur-Chemische Versuchs-Station, Halle a/S., Ss. 56, et seq.
[53] Chemische Industrie, 1890.
[54] Vid. op. et loc. cit. 52.
[55] Chemiker Zeitung, 1890, No. 75, S. 1246.
[56] Vid. op. cit. 43.
[57] Glaser, Zeitschrift für analytische Chemie, 24, 178 (1885). Laubheimer, Ibid, 25, 416 (1886).
Müller, Tagebl. d. Naturforscher-Vers. zu Wiesbaden, 1886, 365. Vögel, Chemiker Zeitung, 1888,
85. Stutzer, Ibid, 492. Seifert, Ibid, 1390. v. Reis, Zeitschrift für angewandte Chemie, 1888, 354.
Loges, Reportorium für analytische Chemie, 7, 85 (1887). Kassuer, Zeitschrift für
Nahrungsmitteluntersuchung und Hygiene, 2, 22 (1888). C. Müller, Die Landwirtschaftlichen
Versuchs-Stationen, 35, 438 (1888).
[58] L’Engrais, Tome 9, p. 928.
[59] Vid. op. et loc. cit. 44.
[60] Journal of the American Chemical Society, Vol. 16, p. 462.
[61] Die Landwirtschaftlichen Versuchs-Stationen, Band 41, S. 329.
[62] Journal of Analytical and Applied Chemistry, Vol. 5, p. 685.
[63] Vid. op. cit. supra, Vol. 3, p. 413.
[64] Zeitschrift für angewandte Chemie, 1886, S. 354.
[65] Vid. op. cit. 52, p. 61.
[66] Vid. op. cit. 55, Vol. 18, p. 1153.
[67] Chemiker Zeitung, 1894, No. 88, p. 1934.
[68] Op. cit. supra, 1892, p. 1471.
[69] Vid. op. cit. 60, p. 721.
[70] Zeitschrift für analytische Chemie, Band 29, S. 408.
[71] Mitteilungen der deutschen Landwirtschafts Gesellschaft, 1890-’91, No. 11, S. 131.
[72] Zeitschrift für angewandte Chemie, 1888, S. 299.
[73] Vid. op. cit. 70, p. 409.
[74] Vid. op. cit. 72, 1890, p. 595.
[75] Vid. op. cit. 61, Tome 43, p. 183.
[76] Chemiker Zeitung, Band 18, S. 565.
[77] Chemical News, Vol. 1, p. 97.
[78] Archive für Wissenschaftliche Heilkunde, Band 4, S. 228.
[79] Journal für praktische Chemie, Band 70, S. 104.
[80] Sutton’s Volumetric Analysis, p. 237.
[81] Bulletin de la Société des Agriculteurs de France, 1876, p. 53.
[82] Manual Agenda des Fabricants de Sucre, 1889, p. 307.
[83] Journal of the American Chemical Society, Vol. 15, p. 382, and Vol. 16, p. 278.
[84] Chemical News, Vol. 47, p. 127.
[85] American Chemical Journal, Vol. 11, p. 84.
[86] Vid. op. cit. 83, Vol. 16, p. 282.
[87] Bulletin 43, Chemical Division, U. S. Department of Agriculture, p. 88.
[88] Vid. op. cit. supra, p. 91.
[89] Repertoire de Pharmacie, 1893, p. 153.
[90] Revue de Chimie Analytique Appliqué, 1893, p. 113.
[91] Chemiker Zeitung, 1894, S. 1533.
[92] Blair, Analysis of Iron and Steel, p. 95.
[93] Journal of Analytical and Applied Chemistry, Vol. 7, p. 108.
[94] Journal of the American Chemical Society, Vol. 17, p. 129.
[95] Vid. op. cit. 92, p. 99.
[96] Eighth Annual Report of Purdue University, p. 238.
[97] Receuil des Travaux Chimiques, Tome 12, pp. 1, et seq. Journal of the Chemical Society
(Abstracts), Vol. 64, p. 496.
[98] Zeitschrift für angewandte Chemie, 1891, Ss. 279, et seq.
[99] Le Stazioni Sperimentali Agrarie Italiane, February, 1891.
[100] Journal of the American Chemical Society, Vol. 17, p. 43.
[101] Vid. op. et loc. cit. supra.
[102] L’Engrais, Tome 10, p. 65.
[103] Journal of Analytical and Applied Chemistry, Vol. 5, p. 694. Zeitschrift für analytische Chemie,
Band 18, S. 99.
[104] Vid. op. cit. 92, p. 103.
[105] Journal of the Chemical Society (Abstracts), Vol. 58, p. 1343.
[106] Comptes rendus, Tome 114, p. 1189.
[107] Vid. op. cit. 24 and 25.
[108] Report communicated to author by W. G. Brown.
[109] Chemisches Centralblatt, 1895, p. 562.
[110] Wiley, Report on Fertilizers to Indiana State Board of Agriculture, 1882.
[111] Proceedings of the Association of Official Agricultural Chemists, Atlanta, 1884, p. 19. Report of
Indiana State Board of Agriculture, 1882, p. 230, and Proceedings of the Association of Official
Agricultural Chemists, Atlanta, 1884, p. 30. Huston and Jones. (These gentlemen are now
investigating all materials used as sources of phosphoric acid in fertilizers; their results here quoted
are from unpublished work, and include but a small part of the work so far done.) American
Chemical Journal, March, 1884, p. 1. Proceedings of the Association of Official Agricultural
Chemists, Atlanta, 1884, p. 23. Ibid, p. 28. Ibid, p. 38. Ibid, p. 45. U. S. Department of Agriculture,
Chemical Division, Bulletin No. 7, p. 18. Ibid, Bulletin No. 28, p. 171. Ibid, Bulletin No. 31, p. 100.
Ibid, Bulletin No. 31, p. 99.
[112] Manuscript communication to author.
[113] Pamunky phosphate is the so-called “olive earth” found along the Pamunky river, in Virginia. It
is almost all precipitated iron and aluminum phosphates, and the product is peculiar in that the iron
is almost all in the ferrous condition.
[114] In the work of T. S. Gladding only fifty cubic centimeters of citrate were used.
[115] In the work of T. S. Gladding only fifty cubic centimeters of citrate were used.
[116] Zeitschrift für analytische Chemie, Band 10, S. 133.
[117] Lehrbuch der Düngerfabrication.
[118] Bulletin 54, Purdue Agricultural Experiment Station, p. 4.
[119] Vid. op. cit. supra, p. 7.
[120] Runyan and Wiley; Paper presented to Washington Section of the American Chemical
Society, April 11, 1895.
[121] Bulletin 38, Chemical Division, U. S. Department of Agriculture, p. 16.
[122] Chemiker Zeitung, 1895, S. 553.
[123] Die Käuflichen Dungermittel Stoffe, dritte Auflage, 1889.
[124] Wyatt, Phosphates of America, p. 128.
 PART SECOND.
NITROGEN IN FERTILIZERS.

143. Kinds of Nitrogen in Fertilizers.—Nitrogen is the most costly of the essential plant foods.
It has been shown in the first volume, paragraph 23, that the popular notion regarding the relatively
great abundance of nitrogen is erroneous. It forms only 0.02 per cent of the matter forming and
pertaining to the earth’s crust. The great mass of nitrogen forming the bulk of the atmosphere is
inert and useless in respect of its adaptation to plant food. It is not until it becomes oxidized by
combustion, electrical discharges, or the action of certain microorganisms that it assumes an
agricultural value.
Having already, in the first volume, described the relation of nitrogen to the soil it remains the
sole province of the present part to study it as aggregated in a form suited to plant fertilization. In
this function nitrogen may claim the attention of the analyst in the following forms:
1. In organic combination in animal or vegetable substances, forming a large class of bodies, of
which protein may be taken as the type. Dried blood or cottonseed-meal illustrates this form of
combination.
2. In the form of ammonia or combinations thereof, especially as ammonium sulfate, or as amid
nitrogen.
3. In a more highly oxidized form as nitrous or nitric acid usually united with a base of which
Chile saltpeter may be taken as a type.
The analyst has often to deal with single forms of nitrogenous compounds, but in many
instances may also find all the typical forms in a single sample. Among the possible cases which
may arise the following are types:
a. The sample under examination may contain nitrogen in all three forms mentioned above.
b. There may be present nitrogen in the organic form mixed with nitric nitrogen.
c. Ammoniacal nitrogen may replace the nitric in the above combination.
d. The sample may contain no organic but only nitric and ammoniacal nitrogen.
e. Only nitric or ammoniacal nitrogen may be present.
144. Determination of the State of Combination.—Some of the sample is mixed with a little
powdered soda-lime. If ammoniacal nitrogen be present free ammonia is evolved even in the cold
and may be detected either by its odor or by testing the escaping gas with litmus or turmeric paper.
A glass rod moistened with strong hydrochloric acid will produce white fumes of ammonium chlorid
when brought near the escaping ammonia.
If the sample contain any notable amount of nitric acid it will be revealed by treating an aqueous
solution of it with a crystal of ferrous sulfate and strong sulfuric acid. The iron salt should be placed
in a test-tube with a few drops of the solution of the fertilizer and the sulfuric acid poured down the
sides of the tube in such a way as not to mix with the other liquids. The tube must be kept cold. A
dark brown ring will mark the disk of separation between the sulfuric acid and the aqueous solution
in case nitric acid be present. If water produce a solution of the sample too highly colored to be
used as above, alcohol of eighty per cent strength may be substituted. The coloration produced in
this case is of a rose or purple tint.
Nitric nitrogen may also be detected by means of brucin. If a few drops of an aqueous solution
of brucin be mixed with the same quantity of an aqueous extract of the sample under examination
and strong sulfuric acid be added, as described above, there will be developed at the disk of
contact between the acid and the mixed solutions a persistent rose tint varying to yellow.
To detect the presence of organic albuminoid nitrogen the residue insoluble in water, when
heated with soda-lime, will give rise to ammonia which may be detected as described above.
145. Microscopic Examination.—If the chemical test reveal the presence of organic nitrogen
the next point to be determined is the nature of the substance containing it. Often this is revealed
by simple inspection, as in the case of cottonseed-meal. Frequently, however, especially in cases
of fine-ground mixed goods, the microscope must be employed to determine the character of the
organic matter. It is important to know whether hair, horn, hoof, and other less valuable forms of
nitrogenous compounds have been substituted for dried blood, tankage, and more valuable forms.
In most cases the qualitative chemical, and microscopic examination will be sufficient. There may
be cases, however, where the analyst will be under the necessity of using other means of
identification suggested by his skill and experience or the circumstances connected with any
particular instance. In such cases the general appearance, odor, and consistence of the sample
may afford valuable indications which will aid in discovering the origin of the nitrogenous materials.

SOURCES OF NITROGENOUS FERTILIZERS.

146. Seeds and Seed Residues.—The proteid matters in seeds and seed residues, after the
extraction of the oil, are highly prized as sources of nitrogenous fertilizers either for direct
application or for mixing. Typical of this class of substances is cottonseed-meal, the residue left
after the extraction of the oil which is accomplished at the present time mostly by hydraulic
pressure. The residual cakes contain still some oil but nearly half their weight consists of
nitrogenous compounds. The following table gives the composition of a sample of cottonseed-meal:
Ash 7.60 per cent.
Fiber 4.90 “
Oil 10.01 “
Protein 51.12 “
Digestible carbohydrates, etc. 26.37 “
While the above shows the composition of a single sample of the meal it should be remembered
that there may be wide variations from this standard due either to natural composition or to different
degrees of the extraction of the oil.
The composition of the ash is given below:
Phosphoric acid, P₂O₅ 31.01 per cent.
Potash, K₂O 35.50 “
Soda, Na₂O 0.57 “
Lime, CaO 5.68 “
Magnesia, MgO 15.19 “
Sulfuric acid, SO₃ 3.90 “
Insoluble, 0.69 “
Carbon dioxid and undetermined, 7.46 “
The cakes left after the expression of the oil from flaxseed and other oily seeds are also very
rich in nitrogenous matters; but these residues are chiefly used for cattle-feeding and only the
undigested portions of them pass into the manure. Cottonseed cake-meal is not so well suited for
cattle-feeding as the others mentioned, because of the cholin and betaïn which it contains; often in
sufficient quantities to render its use dangerous to young animals. The danger in feeding increases
as the total quantity of the two bases and also as the relative quantity of cholin to betaïn, the former
base being more poisonous than the latter. In a sample of the mixed bases prepared in this
laboratory from cottonseed cake-meal the cholin amounted to 17.5 and the betaïn to 82.5 per cent
of the whole.[125]
The nitrogen contained in these bases is also included in the total nitrogen found in the meal.
The actual proteid value of the numbers obtained for nitrogen is therefore less than that obtained
for the whole of the nitrogen by the quantity present as nitrogenous bases.
In the United States cottonseed cake-meal is used in large quantities as a direct fertilizer but not
so extensively for mixing as some of the other sources of nitrogen. Its delicate yellow color serves
to distinguish it at once from the other bodies used for similar purposes. No special mention need
be made of other oil-cake residues. They are quite similar in their composition and uses, and
manner of treatment and analysis to the cottonseed product.
147. Fish Scrap.—Certain species of fish, such as the menhaden, are valued more highly for
their oil and refuse than for food purposes. But even where fish in large quantities are prepared for
human food, there is a considerable quantity of waste matter which is valuable for fertilizing
purposes. The residue of fish from which the fat and oil have been extracted, is dried and ground
for fertilizing uses. The fish scrap thus obtained is used extensively, especially on the Atlantic
border of the United States, for furnishing the nitrogenous ingredient in mixed fertilizers, and also
for direct application to the fields. In fish flesh deprived of oil and water, the content of phosphoric
acid is about two and one-half per cent, while the proteid matter may amount to three-quarters of
the whole.[126]
The use of fish for fertilizing purposes is not new. As early as 1621 the settlers at Plymouth
were taught to fertilize their maize fields by Squanto, an Indian. According to Goode, the value of
nitrogen derived from the menhaden alone was two million dollars in 1875.[127] In 1878 it is
estimated that 200,000 tons of these fish were captured between Cape Henry and the Bay of
Fundy. The use of fish scrap for nitrogenous fertilizing has, since then, become an established
industry, and the analyst may well examine his samples for this source of nitrogen when they are
manufactured at points on the Atlantic coast, in proximity to great fishing centers.
148. Dried Blood and Tankage.—The blood and débris from abattoirs afford abundant sources
of nitrogen in a form easily oxidized by the microorganisms of the soil. Blood is prepared for use by
simple drying and grinding. The intestines, scraps, and fragments of flesh resulting from trimming
and cutting, are placed in tanks and steamed under pressure to remove the fat. The residue is
dried and ground, forming the tankage of commerce. Dried blood is richer in proteid matter than
any other substance in common use for fertilizing purposes. When in a perfectly dry state, it may
contain as much as fourteen per cent of nitrogen, equivalent to nearly eighty-eight per cent of
proteid or albuminoid matter. Tankage is less rich in nitrogen than dried blood, but still contains
enough to make it a highly desirable constituent of manures. Naturally, it would vary more in its
nitrogen content than dried blood.
149. Horn, Hoof, and Hair.—These bodies, although quite rich in nitrogen, are not well suited
to fertilizing purposes on account of the extreme slowness of their decomposition. Their presence,
therefore, should be regarded in the nature of a fraud, because by the usual methods of analysis
they show a high percentage of nitrogen, and therefore acquire a fictitious value. The relative value
of the nitrogen in these bodies as compared with the more desirable forms, is given in paragraph 5.
150. Ammoniacal Nitrogen.—In ammonia compounds, nitrogen is used chiefly for fertilizing
purposes as sulfate. The ideal nitrogenous fertilizer would be a combination of the ammoniacal and
nitric nitrogen found in ammonium nitrate. The high cost of this substance excludes its use except
for experimental purposes.
151. Nitrogen in Guanos.—The nitrogen in guanos may be found partly as organic, partly as
ammoniacal, and partly as nitric nitrogen. The high manurial value of guanos and bat deposits in
caves, is due not only to their phosphoric acid, but also to the fact that part of the nitrogen is
immediately available, while a part becomes assimilable by nitrification during the growing season.
The content of nitrogen in guanos is extremely variable, and depends largely on the climatic
conditions to which the deposit has been subjected. The state in which it exists is also a variable
one, but with a constant tendency to assume finally the nitric condition.
The well-known habits of birds in congregating in rookeries during the nights, and at certain
seasons of the year, tend to bring into a common receptacle the nitrogenous matters which they
have gathered and which are deposited in their excrement and in the decay of their bodies. The
feathers of birds are particularly rich in nitrogen, and the nitrogenous content of the flesh of fowls is
also high. The decay therefore, of remains of birds, especially if it take place largely excluded from
the leaching of water, tends to accumulate vast deposits of nitrogenous matter. If the conditions in
such deposits be favorable to the processes of nitrification, the whole of the nitrogen, or at least the
larger part of it, which has been collected in this débris, becomes finally converted into nitric acid,
and is found combined with appropriate bases as deposits of nitrates. The nitrates of the guano
deposits, and of the deposits in caves, arise in this way. If these deposits be subject to moderate
leaching, the nitrate may become infiltered into the surrounding soil, making it very rich in this form
of nitrogen. The beds and surrounding soils of caves are often found highly impregnated with
nitrates.
While for our purpose, deposits of nitrates only are to be considered which are of sufficient
value to bear transportation, yet much interest attaches to the formation of nitrates in the soil even
when they are not of commercial importance.
In many soils of tropical regions not subject to heavy rainfalls, the accumulation of these nitrates
is very great. Müntz and Marcano[128] have investigated many of these soils, to which attention
was called first by Humboldt and Boussingault. They state that these soils are incomparably more
rich in nitrates than the most fertile soils of Europe. The samples which they examined were
collected from different parts of Venezuela and from the valleys of the Orinoco, as well as on the
shore of the Sea of Antilles. The nitrated soils are very abundant in this region of South America,
where they cover large surfaces. Their composition is variable, but in all of them calcium carbonate
and phosphate are met with, and organic nitrogenous material. The nitric acid is found always
combined with lime. In some of the soils as high as thirty per cent of calcium nitrate have been
found. Nitrification of organic material takes place very rapidly the year round in this tropical region.
These nitrated soils are everywhere abundant around caves, as described by Humboldt, which
serve as the refuge of birds and bats. The nitrogenous matters, which come from the decay of the
remains of these animals, form true deposits of guano, which are gradually spread around, and
which, in contact with the limestone and with access of air, suffer complete nitrification with the
fixation of the nitric acid by the lime.
Large quantities of this guano are also due to the débris of insects, fragments of elytra, scales
of the wings of butterflies, etc., which are brought together in those places by the millions of cubic
meters. The nitrification, which takes place in these deposits, has been found to extend its products
to a distance of several kilometers through the soil. In some places the quantity of calcium nitrate is
so great in the soils that they are converted into a plastic paste by this deliquescent salt.
152. Nitric Nitrogen.—In its purer forms, and suited to manurial purposes, nitric acid exists in
combination with sodium as a compound commonly known as Chile saltpeter.
The existence of these nitrate deposits has long been known.[129] The old Indian laws originally
prohibited the collection of the salt, but nevertheless it was secretly collected and sold. Up to the
year 1821, soda saltpeter was not known in Europe except as a laboratory product. About this time
the naturalist, Mariano de Rivero, found on the Pacific coast, in the Province of Tarapacà, immense
new deposits of the salt. Later the salt was found in equal abundance in the Territory of
Antofagasta, and further to the south in the desert of Atacama, which forms the Department of
Taltal.
At the present time the collection and export of saltpeter from Chile is a business of great
importance. The largest export which has ever taken place in one year was in 1890, when the
amount exported was 927,290,430 kilograms; of this quantity 642,506,985 kilograms were sent to
England and 86,124,870 kilograms to the United States. Since that time the imports of this salt into
the United States have largely increased.
According to Pissis[130] these deposits are of very ancient origin. This geologist is of the opinion
that the nitrate deposits are the result of the decomposition of feldspathic rocks, the bases thus
produced gradually becoming united with the nitric acid provided from the air.
According to the theory of Nöllner[131] the deposits are of more modern origin, and due to the
decomposition of marine vegetation. Continuous solution of soils beneath the sea gives rise to the
formation of great lakes of saturated water, in which occurs the development of much marine
vegetation. On the evaporation of this water, due to geologic isolation, the decomposition of
nitrogenous organic matter causes generation of nitric acid, which, coming in contact with the
calcareous rocks, attacks them, forming calcium nitrate, which, in presence of sodium sulfate, gives
rise to a double decomposition into sodium nitrate and calcium sulfate.
The fact that iodin is found in greater or less quantity in Chile saltpeter is one of the chief
supports of this hypothesis of marine origin, inasmuch as iodin is always found in sea plants, and
not in terrestrial plants. Further than this, it must be taken into consideration that these deposits of
sodium nitrate contain neither shells nor fossils, nor do they contain any calcium phosphate. The
theory, therefore, that they are due to animal origin is scarcely tenable.
Lately extensive nitrate deposits have been discovered in the U. S. of Columbia.[132] These
deposits have been found extending over thirty square miles and vary in thickness from one to ten
feet. The visible supply is estimated at 7,372,800,000 tons, containing from 1.0 to 13.5 percent of
nitrate. The deposits consist of a mixture of sodium nitrate, sodium chlorid, calcium sulfate,
aluminum sulfate, and insoluble silica. It is thought that the amount of these deposits will almost
equal those in Chile and Peru.

METHODS OF ANALYSIS.
153. Classification of Methods.—In general there are three direct methods of determining the
nitrogen content of fertilizers. First the nitrogen may be secured in a gaseous form and the volume
thereof, under standard conditions, measured and the weight of nitrogen computed. This process is
commonly known as the absolute method. Practically it has passed out of use in fertilizer work, or
is practiced only as a check against new and untried methods, or on certain nitrogenous
compounds which do not readily yield all their nitrogen by the other methods. The process, first
perfected by Dumas, who has also given it his name, consists in the combustion of the nitrogenous
body in an environment of copper oxid by which the nitrogen, by reason of its inertness, is left in a
gaseous state after the oxidation of the other constituents; viz., carbon and hydrogen, originally
present.
In the second class of methods the nitrogen is converted into ammonia which is absorbed by an
excess of standard acid, the residue of which is determined by subsequent titration with a standard
alkali. There are two distinct processes belonging to this class, in one of which ammonia is directly
produced by dry combustion of an organic nitrogenous compound with an alkali, and in the other
ammonium sulfate is produced by moist combustion with sulfuric acid, and the salt thus formed is
subsequently distilled with an alkali, and the free ammonia thus formed estimated as above
described. Nitric nitrogen may also be reduced to ammonia by nascent hydrogen either in an acid
or alkaline solution as described in volume first.
In the third class of determinations is included the estimation of nitric nitrogen by colorimetric
methods as described in the first volume. These processes have little practical value in connection
with the analyses of commercial fertilizers, but find their chief use in the detection and estimation of
extremely minute quantities of nitrites and nitrates. In the following paragraphs will be given the
standard methods for the determination of nitrogen in practical work with fertilizing materials and
fertilizers.
154. Official Methods.—The methods adopted by the Association of Official Agricultural
Chemists have been developed by more than ten years of co-operative work on the part of the
leading agricultural chemists of the United States. These methods should be strictly followed in all
essential points by all analysts in cases where comparison with other data are concerned. Future
experience will doubtless improve the processes both in respect of accuracy and simplicity, but it
must be granted that, as at present practiced, they give essentially accurate results.
155. Volumetric Estimation by Combustion with Copper Oxid.—This classical method of
analysis is based on the supposition that by the combustion of a substance containing nitrogen in
copper oxid and conducting the products of the oxidation over red-hot copper oxid and metallic
copper, all of the nitrogen present in whatever form will be obtained in a free state and can
subsequently be measured as a gas. The air originally present in all parts of the apparatus must
first be removed either by a mercury pump or by carbon dioxid or by both together, the residual
carbon dioxid being absorbed by a solution of caustic alkali. Great delicacy of manipulation is
necessary to secure a perfect vacuum and as a rule a small quantity of gas may be measured
other than nitrogen so that the results of the analyses are often a trifle too high. The presence of
another element associated with nitrogen, or the possible allotropic existence of that element, may
also prove to be a disturbing factor in this long-practiced analytical process. For instance, if
nitrogen be contaminated with another element, e. g., argon, of a greater density the commonly
accepted weight of a liter of nitrogen is too great and tables of calculation based on that weight
would give results too high.
First will be given the official method for this process, followed by a few simple variations
thereof, as practiced in this laboratory.
156. The Official Volumetric Method.—This process may be used for nitrogen in any form of
combination.[133]
The apparatus and reagents needed are as follows:
Combustion tube of best hard Bohemian glass, about sixty-six centimeters long and 12.7
millimeters internal diameter.
Azotometer of at least 100 cubic centimeters capacity, accurately calibrated.
Sprengel mercury air-pump.
Small paper scoop, easily made from stiff writing paper.
Coarse cupric oxid.—To be ignited and cooled before using.
Fine cupric oxid.—Prepared by pounding ordinary cupric oxid in a mortar.
Metallic copper.—Granulated copper, or fine copper gauze, reduced and cooled in a current of
hydrogen.
Sodium bicarbonate.—Free from organic matter.
Caustic potash solution.—Make a supersaturated solution of caustic potash in hot water. When
absorption of carbon dioxid, during the combustion, ceases to be prompt, the solution must be
discarded.
Filling the tube.—Of ordinary commercial fertilizers take from one to two grams for analysis. In
the case of highly nitrogenized substances the amount to be taken must be regulated by the
amount of nitrogen estimated to be present. Fill the tube as follows: (1) About five centimeters of
coarse cupric oxid: (2) Place on the small paper scoop enough of the fine cupric oxid to fill, after
having been mixed with the substance to be analyzed, about ten centimeters of the tube; pour on
this the substance, rinsing the watch-glass with a little of the fine oxid, and mix thoroughly with a
spatula; pour into the tube, rinsing the scoop with a little fine oxid: (3) About thirty centimeters of
coarse cupric oxid: (4) About seven centimeters of metallic copper: (5) About six centimeters of
coarse cupric oxid (anterior layer): (6) A small plug of asbestos: (7) From eight-tenths to one gram
of sodium bicarbonate: (8) A large, loose plug of asbestos; place the tube in the furnace, leaving
about two and five-tenths centimeters of it projecting; connect with the pump by a rubber stopper
smeared with glycerol, taking care to make the connection perfectly tight.
Operation.—Exhaust the air from the tube by means of the pump. When a vacuum has been
obtained allow the flow of mercury to continue; light the gas under that part of the tube containing
the metallic copper, the anterior layer of cupric oxid (see (5) above), and the sodium bicarbonate.
As soon as the vacuum is destroyed and the apparatus filled with carbon dioxid, shut off the flow of
mercury and at once introduce the delivery-tube of the pump into the receiving arm of the
azotometer just below the surface of the mercury seal, so that the escaping bubbles will pass into
the air and not into the tube, thus avoiding the useless saturation of the caustic potash solution.
Set the pump in motion and when the flow of carbon dioxid has very nearly or completely
ceased, pass the delivery-tube down into the receiving arm, so that the bubbles will escape into the
azotometer. Light the gas under the thirty centimeter layer of oxid, heat gently for a few moments to
drive out any moisture that may be present, and bring to a red heat. Heat gradually the mixture of
substance and oxid, lighting one jet at a time. Avoid a too rapid evolution of bubbles, which should
be allowed to escape at the rate of about one per second or a little faster.
When the jets under the mixture have all been turned on, light the gas under the layer of oxid at
the end of the tube. When the evolution of gas has ceased, turn out all the lights except those
under the metallic copper and anterior layer of oxid, and allow to cool for a few moments. Exhaust
with the pump and remove the azotometer before the flow of mercury is stopped. Break the
connection of the tube with the pump, stop the flow of mercury, and extinguish the lights. Allow the
azotometer to stand for at least an hour, or cool with a stream of water until a permanent volume
and temperature have been reached.
Adjust accurately the level of the potash solution in the bulb to that in the azotometer; note the
volume of gas, temperature, and height of barometer; make calculation as usual, or read results
from tables.
156. Note on Official Volumetric Method.—The determination of nitrogen in its gaseous state
by combustion with copper oxid, has practically gone out of use as an analytical method. The
official chemists rarely use it even for control work on samples sent out for comparative analysis.
The method recommended differs considerably from the process of Jenkins and Johnson, on which
it is based. The only source of oxygen in the official method is in the copper oxid. Hence it is
necessary that the oxid in immediate contact with the organic matter be in a sufficiently fine state of
subdivision, and that the substance itself be very finely powdered and intimately mixed with the
oxidizing material. Failure to attend to these precautions will be followed by an incomplete
combustion and a consequent deficit in the volume of nitrogen obtained.
The copper oxid before using is ignited, and is best filled into the tube while still warm by means
of a long pointed metal scoop, or other convenient method. The copper spiral, after use, is reduced
at a red heat in a current of hydrogen, and may thus be used many times.
157. The Pump.—Any form of mercury pump which will secure a complete vacuum may be
used. A most excellent one can be arranged in any laboratory at a very small expense. The pump
used in this laboratory for many years answers every purpose, and costs practically nothing, being
made out of old material not very valuable for other use.
The construction of the pump and its use in connection with the combustion tube will be clearly
understood from the following description:
A glass bulb I is attached, by means of a heavy rubber tube carrying a screw clamp, to the glass
tube A, having heavy walls and a small internal diameter, and being one meter or more in length.
 The tube A is continued in the form of a U, the two arms being joined
by very heavy rubber tubing securely wired. The ends of the glass
tubes in the rubber should be bent so that they come near together
and form the bend of the U, the rubber simply holding them in place.
This is better then to have the tube continuous, avoiding danger of
breaking. A tee tube, T, made of the same kind of glass as A, is
connected by one arm, a, with the manometer B, by a heavy rubber
union well wired. The union is made perfectly air-tight by the tube
filled with mercury held by a rubber stopper. The middle arm of the
tee, a′, is expanded into a bulb, E, branching into two arms, one of
which is connected with A and the other with the delivery-tube F, by
the mercury-rubber unions, MM′, just described. The interior of the
bulb E should be of such a shape as to allow each drop of mercury
to fall at once into F without accumulating in large quantity and being
discharged in mass. The third arm of the tee a″ is bent upwards at
the end and passes into a mercury sealing tube, D, where it is
connected by means of a rubber tube with the delivery-tube from the
furnace. The flow of the mercury is regulated by the clamp C, and
care should be taken that the supply does not get so low in I as to
permit air bubbles to enter A. The manometer B dips into the tube of
Figure. 10. mercury H. A pump thus constructed is simple, flexible, and perfectly
tight. The only part which needs to be specially made is the tee and
Mercury Pump and the one in use here was blown in our own laboratory. The bent end
Azotometer. of the delivery-tube F may also be united to the main tube by a
rubber joint thus aiding in inserting it into the V-shaped nozzle of the
azotometer.
The azotometer used is the one devised by Schiff and modified by Johnson and Jenkins.[134]
We prefer to get the V nozzles separately and join them to any good burette by a rubber tube.
The water-jacket is not necessary, but the apparatus can be left exposed until it reaches room
temperature.
Any form of mercury pump capable of securing a vacuum may be used, but the one just
described is commended by simplicity, economy, effectiveness, and long use.
158. The Pump and Combustion Furnace.—The pump and combustion furnace, as used in
the laboratory, are shown in Fig. 10. The pump is constructed as just described, and rests in a
wooden tray which catches and holds any mercury which may be spilled. The furnace is placed
under a hood which carries off the products of the burning lamps and the hot air. A well-ventilated
hood is an important accessory to this process, especially when it is carried on in summer. A small
mercury pneumatic trough catches the overflow from the pump and also serves to immerse the end
of the delivery-tube during the exhaustion of the combustion tube.
The other details of the arrangement and connections have been sufficiently shown in the
previous paragraph.
159. Volumetric Method in this Laboratory.—It has been found convenient here to vary
slightly the method of the official chemists in the following respects: The tube used for the
combustion is made of hard refractory glass, which will keep its shape at a high red heat. It is
drawn out and sealed at one end after being well cleaned and dried. It should be about eighty
centimeters in length and from twelve to fourteen millimeters in internal diameter. The relative
lengths of the spaces occupied by the several contents of the tube are approximately as follows:
Sodium bicarbonate, two; asbestos, three; coarse copper oxid, eight; fine copper oxid, containing
sample, sixteen; coarse copper oxid, twenty-five; spiral copper gauze, ten to fifteen; copper oxid,
eight; and asbestos plug, five centimeters, respectively.
 The copper oxid should be heated for a considerable time to redness in a muffle with free
access of air before using and the copper gauze be reduced to pure metallic copper in a current of
hydrogen at a low red heat. The anterior layer of copper oxid serves to oxidize any hydrogen that
may have been occluded by the copper. When a sample is burned containing all or a considerable
part of the nitrogen as nitrates, the longer piece of copper gauze is used.
160. The Combustion.—The tube having been charged and connected with the pump it is first
freed from air by running the pump until the mercury no longer rises in the manometer. The end of
the tube containing the sodium bicarbonate is then gently heated so that the evolution of carbon
dioxid will be at such a rate as to slowly depress the mercury in the manometer, but never fast
enough to exceed the capacity of the pump to remove it. The lamp is extinguished under the
sodium carbonate and the carbon dioxid completely removed by means of the pump. The delivery-
tube is then connected with the azotometer, and the combustion tube carefully heated from the
front end backwards, the copper gauze and coarse copper oxid being raised to a red heat before
the part containing the sample is reached. When the nitrogen begins to come off, its flow should be
so regulated by means of the lamps under the tube, as to be regular and not too rapid. From half
an hour to an hour should be employed in completing the combustion. Since most samples of
fertilizer contain organic matter, the nitrogen will be mixed with aqueous vapor and carbon dioxid.
The former is condensed before reaching the azotometer, and the latter is absorbed by the
potassium hydroxid. When the sample is wholly of a mineral nature it should be mixed with some
pure sugar, about half a gram, before being placed in the tube. When bubbles of gas no longer
come over, the heat should be carried back until there is a gradual evolution of carbon dioxid under
the conditions above noted. Finally the gas is turned off and the pump kept in operation until the
manometer again shows a perfect vacuum when the operation may be considered finished. In the
manipulation our chief variation from the official method consists in connecting the combustion
apparatus with the measuring tube before the heat is applied to the front end of the combustion
tube. Any particles of the sample which may have stuck to the sides of the tube on filling will thus
be subject to combustion and the gases produced measured. Where it is certain that no such
adhesion has taken place it is somewhat safer on account of the possible presence of occluded
gases to heat the front end of the tube before connecting the combustion apparatus with the
azotometer.
161. Method of Johnson and Jenkins.—In the method of Johnson and Jenkins the principal
variation from the process described consists in introducing into the combustion tube a source of
oxygen whereby any difficultly combustible carbon may be easily oxidized and all the nitrogen be
more certainly set free.[135] The potassium chlorate used for this purpose is placed in the posterior
part of the tube, which is bent at slight angle to receive it. The sodium bicarbonate is placed in the
anterior end of the tube. The combustion goes on as already described, and at its close the
potassium chlorate is heated to evolve the oxygen. The free oxygen is absorbed by the reduced
copper oxid, or consumed by the unburned carbon. Any excess of oxygen is recognized at once by
its action on the copper spiral. As soon as this shows signs of oxidation the evolution of the gas is
stopped. Care must be taken not to allow the oxygen to come off so rapidly as to escape entire
absorption by the contents of the combustion tube. In such a case the nitrogen in the measuring
tube would be contaminated.
It is rarely necessary in fertilizer analysis to have need of more oxygen than is contained in the
copper oxid powder in contact with the sample during the progress of combustion.
162. Calculation of Results.—The nitrogen originally present in a definite weight of any
substance having been obtained in a gaseous form its volume is read directly in the burette in
which it is collected. This instrument may be of many forms but the essential feature of its
construction is that it should be accurately calibrated; and the divisions so graduated as to permit of
the reading of the volume accurately to a tenth of a cubic centimeter. For this purpose it is best that
the internal diameter of the measuring tube be rather small so that at least each ten cubic
centimeters occupies a space ten centimeters long. The volume occupied by any gas varies
directly with the temperature and inversely with the pressure to which it is subjected. The quantity
of aqueous vapor which a moist gas may contain is also a factor to be considered. Inasmuch as the
nitrogen in the above process of analysis is collected over a strong solution of potassium hydroxid
capable of practically keeping the gas in a dry state the tension of the aqueous vapor may be
neglected.
163. Reading the Barometer.—Nearly all the barometers in use in this country have the scale
divided in inches and the thermometers thereunto attached are graduated in Fahrenheit degrees.
This is especially true of the barometers of the Weather Bureau which are the most reliable and
most easy of access to analysts. It is not necessary to correct the reading of the barometer for
altitude, but it is important to take account of the temperature at the time of observation. There is
not space here to give minute directions for using a barometer. Such directions have been
prepared by the Weather Bureau and those desiring it can get copies of the circular.[136]
The temperature of a barometer affects its accuracy in two ways. First the metal scale expands
and contracts with changing temperatures: Second, the mercury expands and contracts also at a
much greater rate than the scale. If a barometer tube hold thirty cubic inches of mercury the
contents will be one ounce lighter at 80° F. than at 32° F. The true pressure of the air is therefore
not shown by the observed height of the mercurial column unless the temperature of the scale and
of the mercurial column be considered.
Tables of correction for temperature are computed by simple formulas based on the known
coefficients of expansion of mercury and brass. For barometers with brass scales the following
formula is used for making the correction:
t - 28.63
C = -h .
1.113t + 10978
In this formula t = temperature in degrees Fahrenheit and h = observed reading of the
barometer in inches.
Example:—Temperature observed 72°.5
Barometer reading observed, 29.415 inches,
from which C = 0.1165, and this number, according to the conditions of the
formula, is to be subtracted from the observed reading. The true reading in
the case given is, therefore,
29.298 inches or 744.2 millimeters.
The observed reading 747.1 “
And the correction 2.9 “
Unless extremely accurate work be required the correction for temperature is of very little
importance in nitrogen determinations in fertilizers. Each instrument sent out by the Weather
Bureau is accompanied by a special card of corrections therefor, but these are of small importance
in fertilizer work. In order then to get the correct weight of the gas from its volume the reading of the
thermometer and barometer at the time of measurement must be carefully noted. However, after
the end of the combustion, the azotometer should be carried into another room which has not been
affected by the combustion and allowed to stand until it has reached the room temperature.
Every true gas changes its volume under varying temperatures at the same rate and this rate is
the coefficient of gaseous expansion. For one degree of temperature it amounts to 0.003665 of its
volume. Representing the coefficient of expansion by K the volume of the gas as read by V, the
volume desired at any temperature by V′, the temperature at which the volume is read by t and the
desired temperature by t′, the change in volume may be calculated by the following formula:

V′ = V[1 + K(t′ - t)].