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4

FIRST LESSONS

IN IMK

i

Scientific Principles
OF Agriculture.

FOR SCHOOLS

AND

PRIVATE INSTRUCTION.

BY SIR WM. DAAVSOX, C.M.G., LL.D., F.U.S.

I>ATK IKINCIHAI. OK m'(;ii,|, UNIVERSITV.

'P^

New Edition, revised and enlarged, with the permission of the

author, l)y

PKINCIHAL OF THE M'uILL NOK.MAL SCHOOL.

li

MONTREAL :

W. DRYSDALE & CO,

932 St. James Street.

/ 2:9 7

f

Entered according to tho Act of the Parliament of Canada in the year
one thousand eight hundred and ninety-seven, by William Drysdftle
& Co., in the office of the Minister of Agriculture at Ottawa.

Til ■•y

Printed by The Hrrald Poblishino Company,
603 Craig Street, Montreal.

CONTENTS.

A

INTRODUCTORY CHAPTER.

The Sciencb of Agriculture.

§ I. The Relations of Theory and Practice ^ I

§ 2. Agriculture in Schools 4

§ 3 What may be taught by the School Teacher 6

§ 4. Order to be pursued 8

§ 5. Uses of Agriculture in Schools 10

♦CHAPTER I.
Forms of Matter.

§ I. Gases 14

§ 2. Liquids 24

§ 3. Solids 30

CHAPTER n.
Heat.

* § I. Temperature 34

i * § 2. Expansion 36

* § 3. The Unit of Heat 39

«^ * § 4- Specific Heat 40

* § 5. Latent Heat of Water and of Steam 42

I • § 6. Dew, Rain and Snow 46

CHAPTER HL
Chemical Principles.

§ I. Laws of Combination 51

* § 2. The Aim of the Chemist 54

* § 3* Chemical Symbols and their Connotation 54

» § 4. Acids, Alkalies, Salts 59

IV

TAHLE OF CONTENTS.

'/

•CHAPTER IV.

ClIKMICAL PROCEMSKS.

§ I. Tests and Testing 62

§ 2. Separation of Mixtures 65

§ 3. Analysis of Compounds 70

§ 4. Synthesis, Combination 73

{i| 5. Metathesis, Replacement, Double Decomposition 75

t CHAPTER V.

Chemical Properties of the Elements and Compounds most
Important in Agriculture.

§ I. Oxygen 80

§ 2. Nitrogen 81

§ 3. Hydrogen, Water, Ammonia, Nitric Acid 83

§ 4. Chlorine, Hydrochloric Acid 87

§ 5. Carbon, Carbon Dioxide 88

§ 6. Sulphur, Sulphur Dioxide, Sulphuric Acid 92

§ 7. Phosphorus, Phosphoric Acid 94

§ 8. Sodium, Sodium Oxides, Chloride of Sodium, other

Sodium Salts 95

§ 9. Potassium, Potassium Oxides and Salts 97

§ 10. Calcium, its Oxides and Salts 100

§ 1 1. Magnesium 102

§ 12. Silicon, Silica, Silicates, Glass 103

§ 13. Aluminum, Clay, Earthenware 103

§ 14. Iron 104

§ 15. Manganese 104

CHAPTER VI.

Plants, their Functions and Structures.

« § I. Living Things 105

• § 2. The Vegetable ic6

t § 3. The Root no

§ 4. The Stem ..114

t § 5- The Leaves 115

§ 6. The Bark 120

TAULE OF CONTEXTS.

V

•-^o

CHAPTER VII.
Orc.anic Compounds Produckd by Pi ants.

§ I. Organic and Inorganic Substances ,22

§ 2. Organic Part of the Plant * ' | " ^ ,23

§ 3. Organic Substances arranged in (houps j^a

§ 4. Carbohydrates ,

§ 5. Vegetable Acids \

* § 6. Oils and Fats ',',]]], ,,,

§ 7. Nitrogenized Substances , ,-

* § 8. Proximate Analysis of PI ints , ,7

§ 9- Conclusions as to the Food of Plants ,30

CHAPTER VIII.
Thk Asiiks of Plants.

* § I. Table of Plant Analysis , ^2

* § 2. General Deductions from the Table ,.2

* § 3. Essential Ash-Ingredients , . ,

* § 4. Occasional Ash-Ingredients , . .

* § 5. The Purpose of each Ash-Ingredient j^^

* § 6. The Distriimtionof Ashes in the Plant in Different Parts

and at Different Stages of Growth 146

§ 7. Accidental Ash

§ 8. General Conclusions

• M9

^CHAPTER IX.
The Atmosi'hekic Food of Plants.

§ I. The Plant Creates Nothing ,.j

§ 2. The Composition of Air j - .

§ 3- Air as Food for Plants , -^

CHAPTER X.
The Soil, Origin and Classification.

§ I. Nature and Origin of the Soil , .5

^ § 2. Classification of Soils according to Mechanical Tex-

^"•"^•••' 158

VI TABLE OF CONTENTS.

g 3. Classification of Soils according to their General

Chemical Characters 159

i 4. Classification of Soils according to Details of Composi-
tion and relative Fertility 160

CHAPTER XI.

TiiR Relation of thk Sou, to Plants.

* § I. The Soil as an Anchorage for Plants 162

* § 2. The Soil as Supplying Moisture to Plants 164

* § 3. The Soil as a Storehouse of Nitrogen 166

t § 4. The Soil as a Storehouse of Inorganic Food for Plants 173

t § 5. The Soil in Relation to Heat 178

CHAPTER XH.

Exhaustion ok thr Soil.

§ I. Causes of Exhaustion 181

§ 2. Exhausted Soils of Canada. ... .... 188

CHAITER XIII.

Improvkmrnt of the Soil by Mechanical Mkans.

t§ I. Tillage 196

t § 2. Draining 204

CHAPTER XIV.

Improvkmrnt of thr Soil by Manures.

§ I. General Nature of Manures . *. 213

§ 2. Stable Manure 214

• § 3. Green Manuring 223

§ 4. Other Organic Manures 224

§ 5. Mineral or Inorganic Manures .... 235

CHAPTER XV.
Crops.

§ I. Wheat 252

§ 2. Cits 269

§ 3. Rye ^. 272

§ 4. liarley 274

,

TABLE OF CONTENTS. vii

§ 5. Indiiin Corn 27e

§ 6. Buckwheat 277

§ 7. Beans and Peas 270

8 8. Turnips, Carrots, Mangel Wurzel, &c a8i

t § 9. Potatoes 289

§ 10. Clover and Grasses . , . 298

•CHAPTKR XVI.
Soiling and Silos.

§ I. Green Fodder ^og

§ 2. Ensilage ^og

* For these chapters and sections the editor must be held responsible.
t This chapter and these sections have been much modified by the

editor.

1

PREFACE.

FlUST EDITION.

The writer of this little hook had, in his youth,
some opportunities of becoming familiar with agricul-
tural operations ; and rea<l with eagerness and enthu-
siasm those remarkable works of Liehig and Johnston,
which in 1840 and the following years revived
throughout Britain and America the interest in the
applications of chemistry to agriculture which had
been awakened by Sir Humphrey Davy. It was
subsequently his duty, as Superintendent of Educa-
tion in Nova Scotia, to make an effort to introduce
the teaching of agricultural chemistry into the schools
of that Province ; and more recently it has falkn to
him to communicate some knowledge of the subject to
the teachers in training in the McGill Normal School
in Montreal.

From these labors has grown the present work,
which is intended as a text-book for teachers desirous
of introducing the studv of Scientific Ai'riculture
into their schools, and also as a manual for young
men who may be pursuing the subject as a brancli of
private study. It is designed to place before such
persons the facts and principles which the experience
of the writer has shown to be most important in
relation to the existing state of agriculture in British
America.

PREFACE.

The writer has ventured to deviate from the plan
of ordinary school text-books, and to throw the
matter into the form of a series of reading lessons
adapted to the use of a senior class. It is proposed
that the pupils shall, either in school or at home,
read a few pages daily, or as often as may be
convenient, and shall then answer questions thereon,
and recei\'e such further information as the teacher
may be able to give. In this way any intelligent
pupil may so master the elements of the subject as to
be able to reduce its principles to practice in farming
operations, and to enter with advantage on the study
of larger works.

It is to be observed that this work is strictly ele-
mentary. It makes no pretension to completeness,
either in chemical science or practical agriculture. It
is not intended to finish the studies of the pupil on
this subject, but to render them more easy and profit-
able ; and the writer would advise both the teacher
and the practical farmer desirous of obtaining a more
full acquaintance with the subject, to add to their
libraries as many as possible of the larger agricultural
books, of which so many are now accessible.

The writer acknowledges with thanks his obliga-
tions to Dr. T. Sterry Hunt, Professor of Applied
Chemistry in McGill University, and to Prof.
Robins, of the McGill Normal School, for many
valuable suggestions and corrections.

McQill College, 2nd January, 1364.

• fl

Preface to the New Edition.

fOF.

my

Thirty years ago the little work of which this
recension is offered to schools, especially to the schools
of the Province of Quebec, was an admirable, succinct
presentation of those parts of agricultural science of
which it treated, as then understood. Since that time
chemical science has undergone a remarkable develop-
ment, and within a very few years agricultural
science has been profoundly modified by the discovery
of new relations of nitrogen to the soil and, in conse-
quence, of the soil to plant life. To maintain the
usefulness of the book by bringing it up to date, it
has been necessary to make some alterations and
many additions. As it would be unfair to hold the
eminent author responsible for these, it might, per-
haps, have been better by the use of parentheses or
of different type to have kept distinct the changes
made by the editor. But it was found that such an
arrangement would interfere with the usefulness of
the book in the hands of elementary pupils, and no
such typographical distinctions have been made. It
must suffice to say that, besides the accommodation
of chemical terminology and formulae to modern
usage, the editor is responsible for those chapters and
secticms of chapters which in the table of contents
are marked with asterisks, for the experiments which
are suggested and for the arithmetical exercises which
constitute an important feature of the book.

Xll

PREFACE TO THE NEW EDITION

If it should appear desirable, the editor will provide
simple apparatus and a supply of chemicals for the
performance of the experiments referred to in the
text, on being authorized so to do by the Protestant
Committee of the Council of Public Instruction, under
whose authority this little book is issued.

Practical teachers will at once recognize the value
of the arithmetical exercises which are provided.
They will furnish profitable employment for pupils
in the intervals of actual instruction by the teacher ;
they will serve to test the accuracy of each pupil's
conception of the ideas presented ; and they w^ill
firmly fasten on the mind the truths taught. Exact
calculation is incompatible with vague, ill -defined
notions of things.

Some of the arithmetical exercises are open to this
criticism : — farm practice, the use of machinery, the
value of land, the cost of labour, the price of artificial
manure, and many other data of the problems pre-
sented differ, sometimes widely, in different localities ;
hence the data of many problems respecting the cost
of raising crops wull be more or less unsuitable to the
district in which the school using the book is situated.
Let teachers or pupils supply more appropriate data
in additional problems of similar character. A dis-
cussion of differences will add interest to the work,
and enhance the value of the instruction given. The
methods of procedure will be similar although the
data and the results will differ. The main thing is
to teach the young generation of farmers to calculate,
and to calculate in view of all the elements of the
calculation. The editor believes that no young person
can work out the examples in this book, and when he
becomes a farmer, fail, as the pioneers of our country

PREFACE TO THE NEW EDITION.

XUl

failed, to remember that with every bushel of grain,
with every ton of hay, he sells a part, a valuable part,
indeed an indispensable part of his farm, a part that
must be replaced by purchase from outside, if the
fertility of the soil is to be maintained. In the
examples furnished attention is directed to three
substances only — nitrogen, phosphorus and potassium
— because these are of the highest practical import-
ance. It begins to be evident that by judicious treat-
ment of the soil, by a wnse rotation of crops, by
carrying a sufficient amount of live stock, and by a
painstaking husbanding of manures, the farm may be
made to manufacture its own nitrogenous manures,
and make good from its own resources the nitrogen
sold in crops removed from the soil, although average
Canadian farming fails to do this ; but it is certain
that every pound of phosphates and of potash sold
must be brought back again from outside sources of
supply, or the farm w^ill surely deteriorate, and this
the faster, the larger the immediate returns. It is
hoped that the numerical examples will receive due
attention in the schools, and will prove of great value
in the instruction of young farmers.

Let nothing stated in this book be taken for
granted, if in any w^ay it can be brought to the test
of actual experiment or calculation. In some respects
it is better for a pupil to err as the result of his owm
inquiry, than to be right by a blind, uncritical recep-
tion of the conclusions of others. Properly used this
book, while it would be absurd to suppose that it can
teach practical farming, will help to raise up a genera-
tion of farmers accustomed to observe nature, to
experiment, to think, to calculate, to trust themselves
and to be successful. S. P. R.

FIRST LESSONS

IN

Scientific Agriculture

INTRODUCTORY CHAPTER.

THE SCIENCE OF AGllICULTURE.

§1. T^ relations of Theory and Praclicc.

In our time all useful arts are more or less closely
connected with scientific facts and principles, and it is
to this connection that these arts mainly owe their
present high perfection and progressive improvement.
The votary of abstract science niay in his researches
regard only the laws of nature, without reference to
the arts of life ; yet his discoveries necessarily bear on
those arts, since the laws of nature are those under
which the artisan or the farmer must work. They
surround him on every side. They have fixed the
properties of all the things he uses for his purposes,
and have determined the steps of every process which
can be successful.

It is the business of physical science carefully to
explore nature, to ascertain the properties of every
object, the laws which regulate every change and pro-
cess, the conditions, in short, of existence and of

■ii!

2

action which the Creator lias imposed on the things
which He has made. Sucli knowledge must Ije
eminently practical ; it is truly power, inasmuch as it
brings to bear upon matter that which is the grand
agent of our mastery over it — enlightened thought.
All the great forces of nature — heat, electricity, light,
the various laws and properties of solids, of liquids,
and of gases, and of the different kinds of matter —
have been searched out by scientific investigation, and
broken in and harnessed for the use of the practical
man ; and every day new uses of substances, improve-
ments of processes, adaptations of machines, are being
carried out ; while every new fact or principle utilized
brings in its train the uses of others.

Much popular misconception exists as to the rela-
tion of theory to practice in the industrial arts.
There is a tendency to decry theory, as if it were
mere speculation, while, on the other hand, the more
learned sometimes sneer at mere practical skill, as if
it were wholly empirical and destitute of any sound
reason. The truth lies between these extremes, and
may be illustrated by a familiar example from an-
other art. A practical seaman must be able to per-
form all the active duties required of him in the
ship — to steer, to go aloft, to reef sails ; and a mere
landsman may be quite helpless in these matters,
however much he may know of the theory of naviga-
tion. But the ship may be well manned with able-
bodied and skilful seamen, and may yet lie helpless in
mid-ocean, if there is no one on board capable of
working out its reckoning and determining its
course ; and a landsman, a boy or a woman may be
able to do this by means of the learning taught in the
schools, though quite unable to perform any of the

duties of the practical seaman. The sliip is equally
helpless without practical skill and without science.
Both must he present. It is just so with farming.
The farmer must know the practical operations of his
art — how to plouj^^h, to harrow, to sow, to reap ; hut
he may know and industriously practice all these, anil
yet may l)e running his farm to ruin as surely as the
seaman would his ship, if he knew not his course and
distance. Here science comes to the aid of the farmer.
It teaches him the nature and composition of his soil ;
the materials of which he exhausts it in cropping ; the
various re([uirements of different cultivated plants ;
the nature and uses of manures ; the causes of sterility
and impoverishment, and the cheapest and hest modes
for remedying the one and avoi<ling the other ; and
the materials necessary to renovate lands that have
been already exhausted.

Further, these teachings of science are not merely
clever guesses and conjectures, but the results of long
and patient enquiry into facts, made by the practical
chemist or physiologist, who, each in his several way,
is just as much a practical man as the farmer.

None of the arts have derived greater benefits from
science, and especially from chemistry, than agri
culture. Soils, manures and plants have been
analyzed ; the causes of fertility and barrenness, of
running out and impoverishment, the means of supply
of tlie most valuable constituents of crops, the
enemies and diseases of cultivated plants, and many
similar subjects, have been investigated ; and the
result has been that agriculture has become a
scientific art, and has been brought to a pitch of
profitable perfection that our grandfathers would
have deemed chimerical. But knowledge of this kind

is yet only partially diffused. While in some conn-
tries, by the application of scientiHc knowledge, land
that has been cultivated for ages is being brought
back to its original fertility, and its produce vastly
increased ; in others, through neglect or ignorance, the
most fertile regions are gradually becoming unpro-
ductive.

In our own country there can be no question that
much has to be learned in this respect. The history
of many, if not of most Canadian farms, is that of
deterioration by exhaustive cropping — a process
which, if not checked by agricultural improvement,
leads to failure of crops, to poverty, to discontent, and
to emigration of the farming population to other
countries. Every one feels that to effect a cliange in
this, the mind of the farmer nmst be reached in order
that his practice may be improved. But that this
may be effectually done, tlie rudiments of agricultural
science must be taught to youth ; and the question
for the educator is — How, and to what extent, can this
be done ?

§ 2. Agriculture in Schools.

It must be admitted that it is not the province of
the common school teacher to give instruction in
trades or professions. It is his vocation to give that
elementary training which is more or less useful in all
walks of life, while special professional training
belongs to schools established for such purposes, or to
the practical man in his field or workshop; still it is a
legitimate part of the business of the teacher, to
connect, as far as may be, the subjects of his instruc-
tion with the practical work of life, and especially
with those portions of it wdiich are very generally

pursued. He cannot tench the practice of agriculture,
— that must be done in the fieUl, — but he can explain
its theory, or, to speak more strictly, the natural laws
on which its operations depend.

It is this scientific aspect of farming which can be
taught in the schools. We can teach the bearing of
modern scientific discoveries on the improvement of
the art, and we can therel)y elevate the profession
itself, make it more attractive to young persons, and
contribute not a little to the industrial wealth of the
country. And let it be observed that while on the
one hand agricnltural education tends to the improve-
ment of this important art, on the other it tends to
the elevation of the school and the teacher, by more
closely connecting education with the practical busi-
ness of life, and improving and rendering more pro-
ductive an art on which education mainly depends
for its pecuniary support.

For such reasons as these, while in all the more
enlightened countries there are special agricultural
schools and colleges, and model farms, where the
science of agriculture may be prosecuted in all its
detnils, efforts are also made to introduce the elements
of the subject into the Connnon Schools ; and this
more especially by directing the attention of teachers
to its study in the Normal Schools, in which their
professional training is received.

We must, however, carefully avoid encouraging
delusive hopes or professing to do that which we can-
not satisfactorily accomplish. We cannot, in the
ordinary schools, train practical chemists or practical
farmers. Practical chemistry is a profession to be
studied by itself, and requires a long and careful
apprenticeship for its successful pursuit. The

6

practical labor of the fanner can he learned only on a
farm. The teacher must propose to himself the more
humble task of instillinj^ into the min<ls of the young
the rudiments of the science of farminjjj, and therel)y
preparing them better to understand its practical
processes. Though the amount of agricultural know-
ledge communicated in this way is confessedly
slender ; though only the merest rudiments can be
taught ; yet the wide diffusion of even a small amount
of knowledge of principles, and the thought and inquiry
which this engen<lers, may be of incalculable value to
the country. Admitting, then, that the elements of
this great subject may thus be taught, let us inquire,
1st, what may be taught by the school teacher ? and
2nd, what order shall he pursue in teaching it ?

^ § 3. What may he taught by the School Teacher.

1. He may teach of the Plant ; of the elements of
which it is composed ; of the sources, in the earth and
in the air, whence these are derived ; of the kinds and
proportions of food required by different plants, and
the best means of supplying them ; of the wonderful
structure of the vegetable fabric, and the manner in
which it forms from the material on which it subsists,
the various pix)ducts which it affords. On these
subjects the discoveries of chemistry and physiology
will enable him to impart much valuable and practical
information.

2. He may teach of the Atmosphere ; of its composi-
tion ; of the stores of plant food which it contains,
and from which the plant dei'ives so important a part
of its substance ; and of its relations to the moisture
which it holds in solution, or which is precipitated
from it, as cloud, mist, dew, rain or snow.

X

3. He may teach of tlie S(dl ; of its <lerivation from
tlie rocks of tlie earth ; of its womlerful and complex
composition ; of its acti(m on manures, in retaininj^
them within it, and in partin<( with them to tl\e roots
of phints ; of tlie causes of its fertility and barrenness ;
of its impoverishment by croppinjjf ; of its improve-
ment by tillage, by draining, and by the application
of manures. Here he will consider the decay of dead
vegetable and animal matter, and its resolution into
food for plants ; the losses to which the richer organic
uianures are liable ; and the nature and uses of
mineral manures, with their various effects, whether
directly as food for plants, or indirectly through the
chemical changes which they induce in the soil

4. He may teach of the several Cidtivated Crops in
<letail, noticing their history, their modes of culture,
their preferences in relation to soil, treatment, and
manure ; their produce — its uses to man and animals
— and their enemies and diseases. He may, in like
manner, proceed to apply the principles learned under
these heads to the various modes of tillage, manuring
and rotation.

5. He may teach of DoDwstic Aniimih ; of the
treatment needful for their health and comfort ; of
their labour and of its profitable development and
employment, and of their marketable products, — milk,
butter, cheese, eggs, wool and young or fatted stock
of all kinds.

All these topics lie at the very threshold of agri-
cultural knowledge and practice. They may be
pursued to any extent, and the highest culture and
mental powers may be applied to them ; but their
elements may be learned by young persons at school,
and a foundation may be laid on which they may

8

build thci hi<^h(^st ami most successful prosecution of
the most useful of all arts. In the discussion of every
point prtisented, (juestions of cost, of economical
arlministraticjn, of due remuneration for labour, of
interest on capital and of sufficient returns for skill
nmst he predominant, for men do not engage in farm-
ing as an interesting and complex experiment in
science, hut as a means of livelihood, and of profitable
and stable investment of money.

§ 4. Order to he pursued.

In studying any scientific subject, more especially
in its practical applications, it is necessary to follow
some regular order of procedure ; and there are usually
different plans which may be pursued, and which may
severally have their special advantages and disadvan-
taj^es. It is sometimes best to befjin with (general
principles and rules, and illustrate them hy examples;
sometimes best to \y"x\\\ with kir)wn facts, and follow
these up to general [)rinciples. Further, in any com-
plex subject it may often be difficult to explain one
part of the subject without reference to others with
which the learner may not l)e acquainted. Now,
that we may ascertain the best order for proceeding
with our present subject, let us consider the things
with which we have to do. The objects of agriculture
are to obtain from the soil the largest possil)le amount
of valuable food for men and animals ; to preserve the
soil in such a condition that it will produce other
crops in future years, and to apply the food produced
in the most economical and useful manner. In attain-
ing these ends, the farmer has to do principally with
cultivated plants, with soils, with manures, with
domesticated animals, and with destructive vermin
and diseases.

All these siil»j(»cts tli(^ fanner naturally ri-t^anls in
the lij^ht of experience, and with reference to practical
operations. What we have to <lo is to hrini^ to hear
on their explanation the facts and principles ascer-
tained hy chemistry, physiolo(;;y, and natural history,
and more especially hy the first of these? sciences.
Agricultural chemistry, in short, is of more importance
than a<;ricultural physioloj^y, hotany, zoology, or

)]<

tl

h all of th

'ful. We sh

<^eoioi^y, tnougn an or tnese are useiui. >ve siiai .
therefore, make this our hasis, an<l hrin^if in the other
suhjects as we proceed. Havini^ laid for the learni^r
a foun<lation of such physical and chemical knowledire
as may appear indispensahle, we shall consider the
Plant, the Atmosphere, the Soil, and Manui'cs ; and
havin<^ discussed these, shall proceed to apply the
knowledge thus ac(|uired, to the Crops cultivated hy
the farmer, leaving for treatment in a .suhse(|Uent
work all questions respecting Domestic Animals.
Our arrangement may thus l»e as follows:

I. We shall notice; such general principles of Physics
and of Chemistiy as may he ahsolutely necessary for
our purpose : —

Chapter 1. Forms of matter.

2. Heat.

3. Chemical principles.

4. Chemical processes.

5. Properties of substances most import
ant in relation to agriculture.

II. We shall consider the Plant in the following
aspects : —

Chapter 6. The structures and functions of plants.

7. The organic products of plants.

8. The ashes of plants.

«

t(

((

10

((

((

III. We sliall consider in

Chapter 9. The atmosphere as a source of plant
food.

IV. We sliall consider the Soil in the following
particulars : —

Chapter 10. Its origin and classifications.

" 11. Its composition and relation to plants.

" 12. Its exhaustion by cropping.

18. Its inij^rovement by mechanical means.

14. Its renovation by manures.

V. We shall consider the chief cultivated crops
with their various habitudes and diseases, their man-
awment and their storaw.

Chapter 15. Wheat, Oats, etc.
" IG. Soiling and Silos.

We shall postpone for fuller separate treatment
Fruit Trees, their cultivation and produce ; and Do-
mestic Animals, whether as working animals, or as
furnishing dairy products, wool or animal food.

Accor<ling to this arrangement the more theoretical
part will come first ; but the reader interested in the
practice of agriculture should l)ear in mind that the
earlier parts, though apparently less practical, never-
theless contain the principles necessary to the under-
standing of the rest.

A

5. Uses of Agriculture in Schools.

The advantages of sucli a course, to the young
mind, are many and great. It leads to the considera-
tion of all those processes by which the great Hus-
bandman above produces out of the earth food for
every living thing, as well as to those humble imita-
tions of them by which man seeks to effect similar

11

results on a smaller scale. In this point of view, as a
means of enlarging the miiRl, and enabling it to rea-
son on natural causes, the subject well deserves the
study even of those who have no direct connection
with practical farming. It is, in short, an important
branch of learning in natural science.

Such a course will, further, enable the vounsr farmer
to read with advantage the best works on his art, and
to judge for himself as to thti application of their
statements to any particular case. Book farming is
little respected by many good farmei's, and, to some
extent, deservedly so. Too often afjricultural books
and articles in agricultural periodicals state facts or
experiments without appreciation of the conditions on
which success or failure depends. They thus give, as
truths generally applicable, special facts which are
of limited value, or perhaps apply to exceptional cases
only. They in this way mislead the simple practical
man who trusts to them. Even good agricultural
works require a certain amount of knowledge in those
who read them. The plainest statements may be mis-
apprehended by a reader not acquainted with the
precise meaning of the terms in which they are ex-
pressed. The most carefully guarded explanations
may be misunderstood and misapplied by similarly
unlearned readers. It thus happens that for want of
scientific precision in those who write or those who
read, the book farmer often incurs the loss and dis-
grace of costly failures, which most unjustly bring
scientific farming into disrepute, being caused, not by
the errors of science, but simply by the want of
science. The intelligent young farmer should have
enough of scientific culture to enable \\un on the one
hand to distinguish the half truths so often presented

12

from a complete statement of tlie facts and principles
bearing on any particular case, and on the other to
appreciate and understand the best scientific works
on his profession.

The knowledge even of the elements of agricultural
education will be sufficient to enable the farmer to
decide as to the application of artificial manures, and
to avoid the losses cause<l by error and fraud in the
use or manufacture of such materials. It will enable
him to consider the composition and properties of the
soils with which he has to do, and to avail himself of
the services of the practical chemist in their preserva-
tion and improvement. It will teach him to appre-
ciate the requirements of the difierent crops and
domesticated animals, the special uses of their varie-
ties, and the disea.ses to whicli they are liable. It will
give him enlarge<l views on agriculture as practised
in various countries and under difierent circumstances,
as susceptible of a vast variety of methods more or
less valuable, and as intimately connected with natural
laws. It will thus not only add to the productive
value of his labor, but will make him love his art,and
realize its true position as no mere mechanical
drudgery, but a scientific and even learned profession.
For the farmer is not a mere manual laborer, He
has to do with soils of complex composition, liable to
ruinous deterioration and susceptible of great im-
provement. He has to tend and rear vegetable and
animal organisms of complicated and varied structures
and habits. He is brought in every part of his work
directly into contact with nature and its laws. He is,
in short, the true alchemist, whose task it is to bring
out of the earth, and of things cast aside as worthless
by other artists, that most valuable of all products

13

— human food His skill and knowlcrl^e make
of the desert a fruitful field ; his iu-norance and care-
lessness may reduce the most fertile fields to <les()la-
tion. Aljove all. the farmer is an in<lependent work-
man. Isolated on his farm, he has to jud^^e for him-
self in many cases of doubt,— has to plan his own pro-
cesses, and to adapt them to his own circumstances.
In ohier countries, farming, like great manufactures,
may have its planning done by a few heads, while the
details may be carried out by hands skilled only in a
few mechanical movements: but the independent
small farmers of a country like this nmst hnve the
intellio-ence to manage as well as the skill to work.

! i'

CHAPTER I.

B^OllMS OF MATTER.

§ 1. Gases.

Experhnent 1. Instead of the glass top of a gem
jar of one pint capacity, tit in a sound wooden plug of
the same size and shape ; and tlirough the plug pass
a tube of glass or metal, of a quarter of
an inch bore and four inches long, so
that it will project nearly two inches
on each si<le of the plug, cementing it
in air tiglit with sealing wax or glue.
Insert an inverted test tube half full of
water in a bottle of water ; lower it
into the gem jar, and screw the wooden
top on tightly. Then blow through the
tube into the jar. Then suck air out of
the jar
Why does the water in the tube rise and fall ?
Air is a gas. All bodies whose physical properties
resemble those of air are called gases. Gases expand
as the limits which confine them expand. If a closed
pint bottle full of water could be suddenly doubled
in size, the water would not expand, it would still
fill only one half of the bottle ; iDut if a closed pint
bottle filled with air, or any other gas, could be sud-
denly doubled in size, the air would expand, it would
be found in every part of the bottle ; — it would still
fill the bottle. If tlie bottle, remaining tightly closed,
could be repeatedly doubled in size, the air contained

Fig. I.

15

in it would continually expand so as to till it. This
great expansibility of air and of all gases is associated
with a corresponding compressibility. It is not
possible to pump into a pint bottle tilled with water
another pint of water ; but it is possible, if the con-
taining vessel be strong enough, to pump many pints
of air at the ordinary pressure, into a pint bottle.
Air thus compressed presses outward on every side
and, if the additional pressure were removed, it would
expand again to its original volume. A steel spring
kept constantly bent will, after the lapse of a very
long time, lose its elasticity, it will not spring back
when the pressure is removed ; but air and all gases
are permanently elastic.

More definitely we may say that the volume of a
gas is inversely proportional to the pressure on each
square inch of its surface, it being supposed that the
temperature does not change. If then the pressure
on each square inch of the surface of a gas be doubled
or tripled, the volume of the gas will shrink to
one-half or one-third of its former amount ; and if the
pressure on each s((uare inch of the surface be reduce<l
to one-half, one-third or one-fourth of what it was,
the gas will expand to twice, three times or four times
its hrst volume.

However, the elasticity of a gas is nut unbounded.
Its expansibility is very great, but theoretically it
has its limits. Its compressibility is very great, but
almost every gas by the combined influence of very
great pressure and very intense cold has been reduced
to the liquid form, and then the law of compressibility
is profoundly modified.

3

16

A rithrnet leal Exe > 'c Ises.

1. Under a pressure of 10 lbs. on the square inch, a
certain amount of gas fills two cubic inches ; what
space will it till under a pressure of 20 lbs. on the
s(|uare inch ? of 25 lbs. ? of 40 lbs. ? of 5 lbs. ? of 1
lb. ? of J lb. ?

2. One cubic foot of air, under an initial pressure
of 15 lbs. on the square inch, is successively com-
pressed into the space of 432 cubic inches, lOcS cubic
inches, 100 cubic inches, 50 cubic inches and 12 cubic
inches ; what pressure is exerted on each square
inch of surface at each of these stages of compres-
sion ?

3. One cubic inch of gas under a pressure of 2,000
lbs. per s(juare inch is permitted to expand to 4, 5, 10,
20, J)0 cubic inches ; to one-fourth, one-third, one-
half of a cubic foot ; to one, two, three cubic feet.
What is the pressure per square inch at each stage of
expansion ?

Air like every other material substance has weight.
At a temperature of 60^ F., and under a pressure of
14715 lbs. on the s(]uare inch, one cubic inch of air
weighs '31 grains. Some gases are heavier than air,
some are lighter. The following numbers give the
weights of a few of the principal gases, air being 1 ;
oxygen 11088, hydrogen '0693, nitrogen 0702, chlorine
'9A^, carbon dioxide 15240. These numbers are
( ali( d ^:iio specific gravities of the several gases. To
iTid J'he weight of any volume of either of these gases,
iiufl tlu^ weight of an equal volume of air in the given
circumstances, and multiply by the specific gravity as
given above.

17

H

Experiment (ind Examples.

Expt^riment 2. Make a cylindrical paper Im^f large
eiiougli to hold about a pint, and counterpoise it in a
delicate balance. Then pour into it some carl)()n
dioxide as prepared in experiment 71.

4. H(^\v many times heavier than hydrogen is air ?

5. What is the weight of a cubic foot of air at
stan<lard temperature and pressure ?

N.H. — Standard temperature and pressure are stated
above ; ()0 F., and 14715 lbs. on the scpiare inch.
Unless otherwise stated all subsecpient (|Uestions pre-
suppose standard temperature and pressure.

(). How many cubic feet of air weigh one pound ?

N.B — 7,000 grains make a pound.

7. What is the weight of a cubic foot of each of the
following gases ; oxygen, hydrogen, nitrogen, carbon
dioxide and chlorine ?

8. If a volume of air weigh one ounce, what would
one such volume of oxyoen weiiih ? two such volumes
of hydrogen ? three of nitrogen ? four of chlorine ?
five of carbon dioxide ^

9. How many cubic inches of air, of oxygen, of
hydrogen, of nitrogiin, of chlorine and of carbon

Hoxide weiMi one ixrain ?

10. If one volume of air weigh one ounce, how
many equal volumes of oxygen, of hydrogen, of nitro-
gen, of carbon dioxide and of chlorine would weigh
one ounce ?

) The specific gravity of a gas may be determined by
comparing either the weights of (upial volumes of that
gas and of air, or the volumes of ecpial weights of that

gas and of air.

18

1^

i f

<^rains

Y

Examples.

11. What is the specific gravity of a^gas of which
one cubic incli weighs Cyl grains ? What if one cubic
inch weighs '35 grains ? iiJSS grains ? •5820 grains ?
What if one cubic foot weiglis 870 grains i ()8(S

? 1,000 grains?

12. WHiat is tlie specific gravity of a gas of which
one grain fills 1 cubic inch < 2 cubic inches ? 322o'S
cubic inches ? 20098 cubic inclies ( 1 3118 culjic
inclies ? 4()'r)4cS4 cubic inches i

18. A certain weight of air fills one cubic foot : the
same weight of hydrogen fills 14? cubic feet. What
is the specific gravity of hydrogen ?

14. One pint of air weighs- 174257 grains, and of
\ carbon dioxide 2()'5G72 grains. The weight of 1,000

cubic feet of air is 7(J526 lbs., and of hvdroo^en is
•5804 lbs. Find the specific gravities of carbon dioxide
and hydrogen.;: \^^ v V ^ ^ t

15. If ono volume of air weigli one, what would one
volume of a mixture of equal vohimes of oxygen and
hydrogen wx'igh, and what one volume of a mixtuie
of two volumes of oxygen with three of nitrogen ?

N.B. — These answers will give the specific gravities
of the several mixtures.

16. What is the specific gravity of a mixture of two
volumes of liydrogen and one of oxygen ? of equal
volumes of ox^^gen and nitrogen ? of one-fifth by
volume oxygen and four-fifths nitrogen ? of ten
volumes oxygen and thirty-seven volumes nitrogen ?

17. How many cubic inches are there in a mixture
of one grain of ox^^gen and one grain of hydrogen ?
How many in two grains of air I Wliat then is the
specific gravity of the mixture ( See questicm 9.

19

two
hnal

ten
tn?
Hire

in ?
he

In. What is tlie specific gravity of a mixture t)|-
tlirre parts l»y weight ot* oxyi^m with two ])arts of
hydrogen i ot" one ])art of oxygen with three parts of
nitrogen i* of four parts of carbon dioxide and Hnc
paits cldorine ?

J I). Sometimes it is said tliat air consists of tivo
parts by weight of oxygen and sixteen parts nitrogen.
Find the specific gravity of the mixture, and from it
state whether more oxygen or more nitrogen should
be introduced into the mixture in oi'der to reihice the
specific gravity to that of air.

Air at the surface of the earth is pressed down by tlie
weight of all the air above it. It is, therefore, inider a
pressure of about 14-4 lbs. to the s(|uare inch, which
acts e(jually in every direction.

Experiments. "

Exp. 3. Fill a tumbler quite full of water ; cover it
with a piece of paper larger every way than the top
of the tumbler. Take the tumbler in your left hand,
place the palm of your right hand (m the paper, and
turn the tumbler upside down. What would happen
if you were to remove your right hand ? Remove it
and see. The pressure of the aii* on the lower side of
the paper is greater than the weight of the water on
the other side : therefoi'e the paper is sustained.

Exp, 4. While the tumbler is still inverted and full
of water dip it into a saucer full of water ; then with-
<lraw the paper. What prevents the water from run-
ning out now ? The pressure of the air ow the surface
of the water in the saucer, for evidently the water in
the tumbler cannot run out without pushing up the
surface of the water in the saucer.

20

Exp. 5. Lift the cd^jjo of the tuinhlrr a little, Imt
not ciiouixh to niisc it rIionc tlie surface of the water
in the sauci-r. I*ut one end of an open pipe, a stiuw,
for instance, muler the e(ltr(. of the tunihler an<l blow
into it. You can thus till the tunil)ler with air from
th(^ lun^s hy the (lis[)laceni«'nt of the walei*. Would
it he easier or hai'der to hlow air into the tund>ler,
inverted and full of water, if the tunihler wei*e taller !*
Consider the subject carefully and answer for your-
self.

T

M

The pressure of the air varies a little from time to
time with the varying states of the weather. It may
increase in very tine settled weather to as much as
15 Ihs. on the scjuare inch, or sink in stormy weather
to 14 J lbs. 'J he varying pressure of the air is
measured by the barometer, an instrument in which
the wx'ight of a column of mercury in a glass tube is
balanced against the pressure of the air. When the
top of the column of mercury in the tube is 80 inches
above the level of the mercury in the reservoir, and
the temperature of the air is 00" F., the pressure of
the air is 14'7l51bs.on the square inch ; and the pressure
is greater or less by "49 lb., nearly half a pound, on
the square inch for every inch that the mercury rises
or falls. Because the pressure of the air is greatest
in tine settled weather, and least in stormy weather,
the barometer is often used as an indicator of chanofe of
weather, and is, therefore, sometimes called a weather
glass. A rising of the mercury shows increasing
atmospheric pressure, and, therefore, indicates a
tendency to tine w^eather ; a falling 1)arometer shows
diminishing atmospheric pressure, and indicates
approaching storms, with the fall of rain or snow.

L>l

a

ivs

es

P)iit it i'(M|uir('s SOUK! cxpcritMJce uiul skill to r«';ul
arii^lit the iii<lieution.s of the luiromctcr.

If t\ barometer 1)0 carried to a ]iei<^lit above the
surface of the earth, the column of mercury falls as
the lieight increases ; because thei'e is a less and less
weiglit of air above the instrument, as it is carried
upward, and so tlie air around it is less and less com-
pressed. The atmospheric pressure on each scpiare
inch becomes less. Hence the barometer is often
used to measure the heij^dit of mountains.

KrAUuplcN.

20. Show that if a lieight of 30 inches of mercury
iu'licates a pressure of 147 15 lbs. on the square inch,
one inch indicates a pressure of '4005 lb. on the
square inch.

21. What atmospheric pressure on each square inch
is indicated by each of the followinf]^ heights of the
mercurial column in a barometer ; 31 inches / 30".5 ^
29() ? 28-4 ?

22. In the hurricane of November 29th, 1836, at
9 a.m., the barometer stood in London at 293 inches ;
it then began to fall rapidly, and at noon stood at
2882 inches. In half an hour the stoi'm broke with
great gusts of wind and heavy rain. At 2 p.m. the
barometer had risen to 2935, the storm began to sub-
side, and was soon succeeded by a calm. What was
the pressure on the scjuare inch at 9 a.m., at noon, and
at 2 p.m. ?

23. In the midst of a typhoon, at Hong Kong,
the barometric height was 285 inches ; what was
the atmospheric pressure on a square foot of sur-
face ?

24. On the suniuiit of S>ini-l'rcu Mr. Whimper
found the liei^^lit of the hjirometer to he 172IJ inches;
what was the pressure of the air on the scjuare inch ?

It must he rememhered that as any ^ovs l)eeomes
denser, when compressed, in proportion to tlie pressure,
proper allowance for the effect of harometric variation
must he made, wlien calculating the weight of any
volunje of air. Allowance for change of temperature
must also l)e made ; but this is a point to be afterwards
considererl.

E.i'amph's.

25. What is the weight of the air in a room 2.") feet
long, 15 feet wide and 10 feet high, at a temperature
of 00^ and under a barometric pressure of 295 inches ?

20. Under a pressure of 8 lbs. to the s(^uare inch
more than the barometric pressure, which at the time
is 80 inclies, and at a temperature of CO", a bubble of
air containing one cubic inch is formed ; what is its
weight and to wliat dimensions would it expand, if
the extra pressure were removed ?

27. A balloon contains 1 0,000 cubic feet of hydrogen
wlien it has ascended to such a height that the baro-
meter has fallen to 20 inches. What weight can it
sustain at that elevation, the temperature being 60° ?

N.B. — It can sustain the difference of the wx^ight of
10,000 cubic feet of air and 10,000 cubic feet of hydro-
gen, under the given conditions.

One gas expands into the space occupied hy another
gas in the same way as it w^ould into an empty space,
but more slowly. If for example a quart bottle of

23

cjU'Imhi tlioxidc \v»'n3 connected l>y im open tn)»e \vitl»
an empty (juai't Ijottle, the carbon dioxide would
instantly expand irito tlie empty l)ottle so as to shan'
the gas ecjually h(;tvveen the two hottles, the pressiu'e
an<l the (Kaisity l)ein<^ half as great in each
hotth> as it was in the first hottle in the Ixginning.
Hut it* two hottles ecpial in size, one tilled with carhon
dioxide at a pressure ot* l.') Ihs. per s([uare inch an<l
the othei* witli oxyocn at a pressui'e ot* ()() Ihs per
s(juare incli, were placed in comnnuiication with each
other, tlie carhon dioxi<le, somewhat more slowly than
in the former case, would expand into the oxygen
bottle, an<l the oxygen into the carbon dioxide bottle,
so as to become completely intermixed. Tin; pressure
of carbon dioxi<le in each b(jttle would be 7J lbs. p( r
S(iuare inch, and that of oxygen in each .SO lbs., so
that tlie total pressure of gas in each l»ottle wouhl be
7), + 30 = li7h Ib.s. The ilensitv of the mini^le<l j^ases
will be found by an obvious calculation to be 11919
times that of air at the same temperature and pres-
sure ; for the volume of oxygen in the mixture is
evidently four times that of the carljon dioxidt^ it
contains.

28. Two volumes of carbon dioxi<le at a pi'essure of
80 lbs. per s(|uare inch, are permitted to expand into
four volumes of hydrogen at a pressure of 50 lbs ;
what is the resulting pressure i*

29. What w^ould be the weight of one cuV)ic foot of
the mixture in the preceding example, the temperature
being 00' F. ?

30. Four volumes of nitrogen are mixed with one
of oxygen under a pressure of 35 lbs. p(U' S(juare inch.
What pressure does each gas exert ? and what is the
weight of each gas in a cubic foot of the mixture ?

f

m

Water is a li(|iiitl. Li(|uids arc unable to inaiiitain
a definite shape. Tlieir particles are moved about by
the slightest i'ovcv, so that when a licjuid is poured
into any vessel, it arranges itself into a mass of which
the ipper surface is parallel to the surface of the
earth, and the sides and lower surface take the shape
of the containing vessel. This is true whatever niay
I)e the shape of the containing vessel, and no matter
of how many parts, communicating at the bottom,
that vessel may consist. Therefore, if two cups re-
moved from each other by any distance be joined by
a pipe, every part of which is lower than the tops of
the cups, and if water or any liquid be poured into one
of the cups, it will run through the connnunicating
pipe, and stand finally at the same level in each of
the cups.

Experiment.

Experiment 6. Insert glass tubes air tight into
the open ends of a rubber tube full of water, raise the
glass tubes and lower them variously and observe the
levels of water in them.

At different depths in a liquid the pressure which
it exerts on a square inch of an innnerscd surface will
be different. That pressure is always equal to the
weight of a column of the liquid as high as the <lepth
of the submerged surface and standing on a base one
inch square. If there be any pressure exerted on any
part of the surface of a liquid completely enclosed in
a full vessel, an equal pressure additional to that due
to the depth of the li((uid will be transmitted to every
part of the vessel and its contents.

25

E.nuiqtlex.

81. One cubic iiicli of water at a tt'inperature of
60' weiglis 252i grains ; how many cubic inches are
there in an imperial gallon of watt r, which weighs
10 lbs. ?

82. What does a colunni of water 88 feet high, and
one square inch in section, weigh :*

88. If the inverted tumbler in experiment 8 were
three inches high, and cylindrical in shape,* and the
area of its mouth four scjuare inches, what would be
the downward pressure due to the water i what wouhl
be the upward pressure due to the atmosphere ^ and
what is the excess of upwar<l pressure that keeps the
paper up (

84. If the tumbler were 8 feet () inches high, what
would be the difieicnce of pressures ?

85. Had the tumbler been 80 feet high, what pres-
sure wxmld liave sustained the paper i

8(3. Had it been 85 feet high, what would the
dilf«*rence of piessure have l)een, in which direction
would it have acted, and what wouM have been the
result ?

87. What is the pressure per square inch of a
cohunn of water 85 feet hii-h, when there is no
atmospheric pressure on t'^e surface of the water ^
What is the height of the barometer when the pres-
sure of the. air just (Mjuals that of such a coUnnn of
water? What is the pressure on a surface one foot
scjuare sunk 88 feet in water, on the surface of which
the atmospheric pressure is 14iJ lbs. per .square inch i

* The shape of the tumMer is of no importance: but. if it he cylindrical,
pupils readily see that the downward pressure is equal to the weight of
water.

■ I

2(>

t]H. The sides of n liox arc so sti'oiiu; tliat fi pi'cssun;
of 50 11)S. on tlie S(|nare iiicli will just crush it; if it
be full of air at a pic ssure of 15 lbs. on the square
inch, how <leep must it be sunk in order to crush it
by the pressure of water at 00 F., when the lieight
of the barometer is 2975 inches ? and how far when
the height of tlu^ barometer is l]Oli inches ?

N.B. — When full of air at a pressure of 15 lbs. on
the square inch, it will require an outside pressure of
05 lbs. per scjuare inch to crush it.

39. If the box in the preceding exercise had been
empty of air before sinking, and the height of the
barometer had been 30 inches, at what depth would
it have been crushed /

From the surface of almost all licpiids vapour is
given off. The amount of vapour that arises into a
given space from any liquid is determined partly by
the nature of the licjuid itself, partly by the tempera-
ture. It is the same in amount whether the space
into which it rises is empty, or is filled with other
gases or vapours. When the definite amount of
vapour which can rise into a given space has been
formed, no more vapour can ascend from the exposed
surface of the liquid, and the space above it is said to
be satui'ated with vapour. If then the li(|uid be
removed, an<l the space saturated with vapour be
increased in volume, the temperature remaining con-
stant, the vapour will expand to till the enlarged
space precisely as a gas would do. But if the space
saturated with vapour be contracted, that amount of
vapour which before filled the space lost by contrac-
tion, will be deposited in droplets of licjuid, either as
a fine mist suspended in the air filling the space, or

27

settling as a tlew on the sides of the containing
vessel. The particles of a vapour rising into a con-
f!ne<l space tilled with other gases or vapours crowd
in between other particles, and add their own density
and })ressure to the density and pressure of the gases
and vapours previously occupying tlie space.

Expcriinent.

Experiment 7. Seal up in a gem jar a lump of
quicklime half as lai-ge as an egg, and also an
uncorked bottle containing a teaspoonful of water.
After a few davs examine it. Where has the water
gone / Is the lime heavier than it was ? How nmch
heavier ?

gi ven

Some liquids absorb some gases. At a
temperature one volume of a given liqui<l will absorl)
a definite inind)er of volumes of a given gas. Tlie
number of volumes of gas absorbed remains the same
hovvever the pressure to which the gas is subjected,
increases or diminishes. At the freezing point, 82^ F.,
one volume of water absorbs '02 volumes of nitrogen,
•041 of oxygen, IS of carbon dioxide and 10496 of
aunnonia.

Examiples.

40. How many quarts of nitrogen, oxygen, carbon
dioxide and ammonia will be dissolved by one gallon
of ice-cold water ?

41. How many cubic inches of nitrogen, of oxygen
and of carbon dioxide can be absorbed by one cubic
foot of ice-cold water ?

42. If the barometric pressure be 30 inches, what
weight of oxygen, of nitrogen and of carbon dioxide
will be absorbed by 100 cubic inches of ice-cold
water i

' 1

'J

2S

y

N.B. — The wei^^lit of 100 cubic inches of air at 30
inches pressure and 82 ' temperature is 32*7() grains.

43. It' in tlie preceding question the barometric
pressure were to be halve<l, doubled, to become 29
inclies and 31 inches respectiv^ely, wliat in each case
woukl be tlie weights of the absorbed gases ?

In a mixture of gases each exerts tiie pressure due
to its volume, and is absorbed independently of the
other gases present. Thus, if a mixture of one
volume of carbon dioxide and one of nitrogen exert
togcsther a barometric pressure of 30 inches, each
exerts a pressure of 15 inches, and the amount of each
gas absorbed by ice-cold water will be the same as if
it alone wei*e pressing on the surface of the water.

44. At a pressure of 30 inches how much carbon
dioxide, and how much nitrogen, will be absorbed
from a mixture of equal volumes of these gasrs, by a
cubic foot of ice-cold water ? Give the answer both
in cubic inches at standard pressure and in grains.

45. In a mixture of four volumes of nitrojjen and
one of oxygen, at a barometric pressure of 30 inches,
how much of each gas will be absorbed by 100 cubic
inches of ice-cold water i

The specific gravity of a liipiid is its weight com-
pared with the weight of an equal bulk of water at
60*^ F. It is expressed by the number which multi-
plying the weight of the water gives the weight of
an «(|ual bulk of the li(|uid. It is frequently found by
weigiiinga bottle when empty, again when full of dis-
tilled water at 00 , and a third time when full of the

29

/

li(|uid under consideration ; tlien tlie weight of the
bottle full of that liquid less the weight of the bottle, JX^
divided by the weight of the l)ottle full of water less
the weight of the bottle, gives the specific gravity of _
the linu

Example.

4(3. A bottle which when empty weighs 25 oz.,
when full of distilled water weighs 45 oz., full of
alcohol 41 oz., of sulphuric acid (il oz., of glycerine
5 oz., of mercury 2!)0 oz. ; what is the specific gravity
of each liquid ?

/^

The specific gravity of a liquid is sometimes found
l)y taking advantage of the principle that a soli<l
immersed in a liquid loses of its weight an amount
precisely ecpial to the weight of an eijual bulk of the
liquid ; e.g., since (me cubic inch of water weighs 252^
grains, one cubic inch of some substance which out of
water would weigh 750 grains, would under water
weigh only 750-252i = 497^ grains.

Example and Experiment.

47. A glass stopper which weighs one ounce in air,
weighs '58 oz. when immersed in water, 06 oz. when
inunersed in a certain sample of alcohol, "25 oz. in
sulphuric acid, and ^cS oz. in glycerine ; find the
specific gravity of each of the liquids mentioned.

Exp. 8. Find the specific gravity of a sample of
coal oil in both ways describ(Ml al)ove, an<l see if your
methods give concordant results ? Y(^ur answer
should be nearly 8.

I;

i'V'V I

I

80

§ 3. Solids.

Solids resist change of form. Their particles cohere
more or less tenaciously. It requires considerable
force to dri\' a ploughshare through the earth. It
requires a mucii greater force to break asunder solid
rock. 'J'he farmer has to do with soils which consist
of solid particles more or less connriinuted, of sand,
clay, gravel and vegetable debris, of which the several
fragments i.U> lui ^orongly adhere to one another.

Solids in a div icd state have special relations to
liquids and gases. Th' "?;rfaces of many solids attract
both gases and Ih nidi;:. Since a finely divided solid
exposes a far greater sui' fr/ ' I^han the same solid in a
compact state, many granulated, porous or cellular
solids absorb considerable (juantities of both gases
and licjuids. Thus, one cubic inch of box-wood
charcoal absorbs 90 cubic inches of annnonia, 85 of
c:irbon dioxide, 92 of oxygen, 7'5 of nitrogen, and
1*75 of hydrogen. Cocoanut charcoal, doubtless
because of its minuter cells and therefore more
exten(hMl surface, is almost twice as absorbent as
box- wood charcoal.

Experi/inent.

Exp. 9. Fill a gem jar, prepared as in Exp. 1, with
CO^ as in experiment 71. Slip a piece of rubber tube
over the end of the tube in the plug. Drop about a
cubic inch of charcoal that has been recently strongly
heated, into the jar ; quickly seal up the jar, letting
the end of the rubber tube dip into some water. Why
does the water rise in the rubber tube ?

Some solids have a surface attraction for some
liquids. A piece of wood or of stone immersed in

di

water is wetted by it ; some of the water clings to it
when withdrawn from tlic water. Water creeps a
little way up the surface of a clean glass cup in which
it is contained. It rises a considerable distance in u
tine glass tube. In the same way if one end of a chip
of wood or the corner of a porous brick be dipped into
water, the chip or the brick will soon become wet at
a noticeable height above the water level. Tins sur-
face attraction of solids for liquids is called capillary
attraction.

ExperimentK.

Exp. 10. Weigh a thin piece of thoroughly clean
glass, dip it in water, take it out, shake it well and

w^eich it again. Do the

tl

same thinef wi

th

a

piece

of

glass which you have wiped with a slightly greasy

raof,

»•

Exp. 1 1. Lay a strip of thick pasteboard, one-quarter
of an inch wide, along one edge of a clean pane of
glass. Lay another similar pane of glass on it. The
two panes will touch at one edge and be separated by
the pasteboard at the other edge. Wrap some thread
around the two panes to bind them together. Lay
them down in a little coloured water. Then tilt them
up so that the pasteboard strip is upright while the
lower edges of the panes stand in the water. Observe
the level of the water between the two panes.

Exp. 12. Fill a cup with w^ater. Wet a strip of
cotton an inch wide and six inches long, put one end
into the w^ater in the cup and let the other end hang
down outside three or four inches. See how long
before the cup will be empty.

Many solids are dissolved by liquids: especially by

! I

A

32

water, which slowly corrodes and wastes away even
rocks and stones. The solvent action of water is often
much aided by the j^ases and solid substances dissolved
in it. Limestone is almost insoluble in pure water,
but water holding carbon dioxide in solution dissolves
limestone in relatively lai'ge amounts. Many of the
great caverns of the world have been excavated in
lim(3stone rock by the solvent action of water charged
with carbon dioxide.

When water holding a solid in solution evaporates
slowly, the solid left behind frequently arranges itself
into masses sometim')s very small, sometimes of con-
siderable size, of definite form, bounded by fiat sur-
faces. These dennitely shaped masses are called
crystals. Thus if we throw common salt into water,
it is dissolved. If a drop of this solution of salt be
placed on a piece of glass, as it dries the particles of
salt unite, and become regularly arranged, forming
little transparent cubes. This is crystallization, and
it may take place either in bodies which have been
dissolved in water, or in those which have been melted
or dissipated by heat. |

Experimevt.

Exp. 13. Dissolve half an ounce of alum in two
tablespoonfuls of boiling water. Let two or three
twigs dip into the solution and set it aside to cool
slowly. When cold lift the twigs out.

/

The specific gravity of a solid is expressed by the
number which multiplying the weight of an equal
bulk of water gives the weight of the solid. As
already stated on page 29, a body innnersed in water
loses of its weight an amount precisely equal to the

• >,>

wi'iglit ot* an ecinal Imlk oi' water. TluTet'orc to find
the specific gravity of any substance heavier than
water and insoluble in it, weigh first in air, tlien when
innnersed in water, and divi<le the weij^ht in air l»v
(jljXL tUu~weigl»tr i+vw«4«ii'".

Ex<()nplef< and E,ij)('ri Dtents.

4«S. A mass of (juartz weighed 65() 5 grains in air
and 404 grains in water ; what was its volume, and
what its specific gravity ^ -^JjC* .

40. A piece of marble w^eiglied 41() grains in air and
2()2 grains in water ; what was its volume, and what
its specific gravity :* 20
X Exp. 14. Arrange a little scale, beneath the scale
pan of a balance, hanging by a fine wire or horse hair
into some water in a tumbler. Weifjh a fraonient of
limestone in air in the upper scale, then transfer it to
the lower scale under w^ater and w'eiMi again. Then
calculate the specific gravity. It should be about 27.
y Exp. 15. Find the specific gravity of some iron wire
and of a twenty -five cent piece. You should get very
nearly 7 8 and 10.

the
ual

As
ter

CHAPTER 11.

§ 1. HEAT.

TemperiUitre.

Un<]er almost all circumstances bodies expand with
heat. Gases, liquids and solids swell as they grow
warmer, and shrink as they cool.

Experiments.

Exp. 16. Drop a cold iron ring on to the smaller
end of a round rod which tapers very slightly and
w^hich the ring tits ; mark how far down it goes; take
it oft'; heat it quite hot, but not red hot, and drop it
on again ; mark how far it goes ; let it cool on the
rod ; try to draw it ott* again. Why does the black-
smith make a wagon tire hot, before he puts it on the
wheel ?

Exp. 17. Through the cork of a bottle pass air tight,
a long, small glass tube open at both ends ; fill the
bottle with inky water and cork it with the cork and
tube. Let there be enough water to rise a little way
in the tube. Warm the bottle ; cool the bottle.

Exp. 18. Empty almost all the water out of the
bottle, and turn it upside down so that the end of the
tube dips into another bottle of water. Then alter-
nately warm and cool the upper bottle, while the end
of the tube is immersed. Gases expand much more
than liquids.

\J

If a small bottle with a long narrow neck be nearly
filled with mercury, quicksilver, and be placed in a

..L-

85

10

pail of water containinf^ linnps of ico, the morciiry,
contractin'jj in bulk, will shrink ilown to a certain level
in the neck of the hottle, ami will staiul at that leNcl
as long as any ice I'eniains imnielted in the pail. If
we were to mark that level hy a scratch, we should
have the means of <letenninin<^ tliat particular tem-
jx'rature at any future time. If we wen; to plun<^e
the same hottle with the same amount of mercury in
it into freezing water at any time, weshouhl find that
the mercury would shrink down to the same mark
exactly. If we were to leave the l)ottle in the open
air on a chilly day in autumn, and the mercury were
to sink to the marked level, we should say that the;
air was just freezing cold. If it sunk helow that
level, we should know that the day was colder than
mere freezing, and if it did not shrink ([uite so far
down, we should know that the weather was not (piite
cold enough for frost. For obvious reasons our bottle
would give us more exact indications, if its neck were
made very small and very long ; and if the air were
pumped out of the neck, and the top of the bottle were
tiijhtlv^ sealed, dust could not enter nor mercurv
escape. Such a very long necked bottle, nearly full
of mercury and hermetically sealed, is called a tj^er-
mome^er, and is used for the purpose of recording
temperature. So far as yet described our thermont-
eter would mark accurately only one temperature,
the freezing point ; but, if we plunged it into boiling
water, the mercury would rise far up in the neck, or
as w^e shall call it in future, the tube of the thermom-
eter. We might then mark this second height by
another scratch, and should then be able to find out
by our thermometer whether a hot liquid was as
hot as boiling water, hotter or less hot. In the

80

ilKTiMoinctcr conniionly usrd licrc, the FalinMiluit
tlH'rni(>m('t<'r, tlu' (listaufc lictwcni tlic iVrcziui^aiid tlic
l)(>ilii»<^ points is (lividcd 'nto l«SO equal ])ai'ts called
d«'Ol•('(^s, and an iMjual graduation is continui'ij alu.""*
and lu'lovv these ])()ints. Tliirty-two of these denrr
below the iVeezini^ ])oint is marked 0, and is calle(i
zero. l)e«;rees ot* temperature lower than this are
sai<l to l)e below^ zero, and decrees of temperature
lii^her than this are said to he above zero. To
distin<^uish degrees above from thosi^ below zero
the lattia* are printed with the minus sign before
them ; so -15 means a temperatui'e 15 <legrees
below zero. The freezing point of water then is
marked .S2 , and th(i boiling point (;}2^ + ISO ) is
necessarily 212'. Many other definite degrees of
temperature have been ol)served and recorde«l. ¥
cury freezes at ->ii)^. It is not certain that a lo»,
temperature than -()() has ever been obsei'ved in the
open air, or a higher than 118 . The temperature of
the inside of the closed mouth of a healthy man is
from 1)8"' to 100°. Lead melts at 504" Mercury boils
at 0()2 '. Iron becomes red hot a little under 1,000'',
and cast iron melts at a temperature less than 3,500'.

§ 2. Expani^ion.

Gases expand with great regularity as the tem-
perature I'ises. For every degree above or below the
freezing point the volume of any gas under constant
pressure increases or contracts by 1-401 part of its
volume at the freezing point, which is the same as
1-510 part of its volume at 60 \ It will be readily
inferred that the pressure of a gas contained in a con-
fined space will diminish or increase in the same
proportion with fall or rise of temperature.

37

Let pupils verily l»y calcMilatioii tlw statciiinit tliit
l-4<!n part of t\\v noIuiih' of a pis at the frccziiii;- point
is ii(\\m\ to one 1-512 part of its volume at (10 .

Exam 1*1 f».

50. To wluit volume would *} cu])ic inches of air at
a temperature of .S2' expainl, under constant j)ressure,
if raised to the temperature of boiling water ( to the
meltin(( point of lead !* to the boiling- point of mercurv J*
to 1,000 ? to 8,500 ?

51. At wliat temperature would any volume of oas
become twice, tliree times, four times its volume at
32", if the barometric pressure remained constant ^.

52. At what t<!mperature, pressure remainintj^ un-
changed, would five ciil)ic inches of air at 00 shrink
to three cubic inches. Verify your answer by finding
what volume three cubic inches would give if raised
from the tempei' 'ture found in your answer, first to
32", and then to (iO .

53. Air is introduced to the heater of a hot air
engine at a temperature of 00 and a barometric
pressure of 30 inches : to what temperature must that
air be raised in order to exert a pressure of 10 lbs.
per .s(|uare inch above the pressure at which it was
introduced :*

54. What barometric pressure w^ould be exerted by
air vvhicli, having been sealed up in a. bottle, at a tem-
perature of 32^ and a pressure of 30 inches of mercury,
is then raised to a temperature of 100 {

As all gases expand equally with e(|ual increase of
temperature, the specific gravity of gases, compai-ed
with air or with hydrogen is the same at all tempera-
tures; for, although the gas to be compared grows

as

liorhfcfH* with inareaso of tonipenitiire, th(5 stainlanl gas
with which it is cijinparo 1 grows lighter proportion-
ally. But tlie weight of a given volume of any gas
varies with the temperature. Thus, that volume of
air which weighs 491 grains at 82' expands to 4?fi of
that volume when heated to 60^ ; therefore a volume
at GO^ equal to the first volume will weigh only f.Vj of
491 grains ; i. e. 4G4.5 grains.

Example.

55. Find the weight of 100 cubic inches of air under
a barometric pressure of 80 in., at 82 , at 40^, at 60°,
at 70", at 80; at 100 , at 212".

f

!!
P

Liquids in general contract and expand much less
than gases, when subjected to similar changes of tem-
perature. They differ greatly from one another in
this respect, and the laws governing their change of
volume are very complex. Water for example is
densest at a temperature of 89 . Both in cooling below
and in being warmed above that temperature it ex-
pands, and so becomes lighter. Therefore the layers
of water at 89"^ sink to the bottom of the containing
vessel, whether other layers are colder or warmer than
they, so that in fresh water the depths are at a tem-
perature of 89^ both in summer and in winter.

Water suddenly expands in the act of freezing ;
100 cubic inches of water at 89° become 109 cubic
inches of ice. Hence alternati^ thawinjx and freezinjj
disintegrates clods of earth, and even p ;ou.s stones;
in the same way the formation of ice in a pitcher of
water bursts it.

no

§3. The Unit of Heat.

While a tlierinonietor shows how hot any body is,
it does not tell us how much heat there is in that body.
If a thermometer be immersed in a pint of boiling hot
water, or in a gallon of such water, it will indicate the
same temperature, namely, 212^. But clearly a gallon
of hot water contains eight times as much heat as a
pint of water at the same temperature. The thermo-
meter tells us how hot the water into which it is
plunged is in any case, but it gives no direct inform-
ation about the amount of heat present, as that
depends partly on the quantity of water. In measur-
ing amounts of heat the unit adopted is the amount
of heat required for raising one pound of ice-cold
water one degree in temperature. The amount of lieat
needed to raise one pound of water one degree in tem-
perature is r early the same at all ordinaiy tempera-
tures, and may for practical purposes ])e reckone<l as
precisely the same. It follows that to raise two pounds
of water one degree in temperature would recpiire two
heat units, and to raise five pounds of water 10 in
temperature would recpiire 50 heat units.

Examples and Experiment.

56. How many heat units are required to raise 15
lbs. of water from ()0 to 75 ?

57. Ten lbs. of boilino- water cool to the freezinc"
point ; how many heat units are given out ?

58. Twenty lbs. of ice-cold water are mixed with 10
lbs. of boiling water : what is the temperature of the
mixture ? How many heat units are lost by the
boilins: water and i^ained by the icy water i

50. What weight of boiling water must b(» poured
into 20 oz. of water at GO , in order that the mixture

40

may bo Jit a tojupcratinv of 100 , and liow man y heat
units will ha translVrrod tVom the hotter to the colder
water ?

()0. If 12 lbs. of water be put on a stove where it
^ains two heat units per second, how \o\v^ wdll it take
to rise from 40 to the boiling temperature ?

(jl. A tub containing; 12 gallons of boilinij water
loses 150 heat units a minute ; in what time will it
CO >1 to 120 ? See example »M.

U2. An iron pot containing 12 lbs. of water at a
temperature of 40^ is set on a stove wdiere it gains tw^o
heat units a second ; how \ouiX before the w^ater will
be boiling hot, if the pot recjuires as much heat to
warm it as lialf a pound of water ?

O.S. A cubic foot of water w^eiijjhs G2.1 lbs. ; half
a cul)ic foot of w\'iter set on a lire, ice-cold, rose to
100' in ten minutes ; how many heat units did it gain
per minute ;*

Exp. 11). Mix known volumes of boiling water with
known volumes of ice-cold water ; o))serve the tem-
peratures, and compare with the results of calculation.

§ 4. Specific Heat.

E((ual weiglits of difl'erent substances require differ-
ent amounts of heat to raise them equally in tempera-
ture. Water r(M|uirt^s more heat than an equal weight
of any otlser li(|ui<l or solid sul)stance to raise it one
degree in temperatur(\ One heat unit, as w^e have
seen, will raise one pound of water one degree ; but it
will raise one pound of iron 0 \ or nine pounds of iron
1°, and it will raise .S4 lbs. of lead \\ or 1 lb. of lead
34". Th(^ capacity of water for heat, or, as it is
generally expressed, the specific heat of water, is 9
times that of iron and 34 times that of lea<l. Water

41

*

beinq," made tlie standjinl =iu»l its specific liejit iiidicatrtl
by unity, tlie specific heat of iron is, thent'ore, 1111,
and that of lead is "0294. The specific heat of watei-
])eing tlie greatest of all substances except hydi*(>gen,
it absorbs more heat in getting warm, and gives out
more heat in cooling, than any li(pii<l or solid. Hence
on the afteiiioon of a hot day at the seaside the sea
is cool(!r than the land, and early in the moi-ning of a
cool nii^ht the sea is warmer than the land. Early
frosts that may do considerable damage a mile or two
inland, are not felt neai' the shores of large rivers or
lakes. The climate of the interior of continents
experi(>nces more extreme temperatures both of heat
and cold than islands and peninsulas in the same
latitude. Arable land, by reason of the water it abs(jrbs,
heats up and cools <lown much less <juickly than bare
dry rock or arid sands.

E.i'((mi)le)^ and Exporimciit.

(j4. Five pounds of iron at a temperature of 200" are
immers(Ml in 10 lbs. of ice-cold water ; to what tem|)(.'r-
ature will the water be raised i

N.B. — As the specific heat of water is 9 times that
of iron, five lbs. of iron contain as nuich heat as '. lb
of water. The questicm then is ecpiivalent to this : —
if ii lb. of water at 200 ' be poured into ti^n ]iounds of
ice-cold water, what will be the resulting temperature ?

Qij. A mass of lead weighing -SI lbs. and beinn" at a
temperature of 40 is heate«l to 10<S ; how many heat
units are absorbed ?

()G. An iron kettle weighing 9 lbs. is emptied of
boilinir water ; then 10 lbs. of water at 5S" are at once
poured into it : what will the temperatui'e of the water
become, an<l how many heat units will the kettle
impart to the water i

4t

G7. If tliivo vessels each contain three ounces of
water at a temperature ut' 65 , and one ounce of water
at a tenipei'ature of 212° be poured into one vessel,
one ounce of iron at 212 immersed in another, and
one ounce of lead at 212 in the third, what will be
the resultino^ temperature in each case ?

Exp. 20. Test the correctness of the foregoing answer
by experiment thus : tie strings to an ounce of iron
wire coiled tightly, to an ounce of sheet lead and to a
corked bottle containing an ounce of water. Then
innnerse all three in boilinj^ watt^r lon<2: enou2fh to
become of the same tempei-ature ; lift them out by the
strings and empty the water and plunge the iron and
lead into separate vessels each containing three ounces
of water at the temperature of 65 . When time
enough has been given for the equalization of temper-
ature of the contents of each vessel take the tempera-
tures.

§ 5. Ldteni Heat of Water and of Steam.

If one pound of ice at 18 below zero be exposed to
a source of heat that furnishes one heat unit per
second, since the specific heat of ice is only one half
that of water, the ice will be warmed up to 32' in 25
secon<ls. Then the ice will begin to melt, and the
mingled ice and water will for 142 seconds cease to
get warmer, all the heat being expended in melting
not in warming the ice ; for at the end of the 142
seconds, that is after receiving 142 heat units, the ice
will have been changed into water just as cold as the
ice was when it bei^an to melt. The amount of heat
consumed in melting without warming one pound of
ice is called the latent heat of one pound of water. If
the same amount of heat has been employed in raising

43

the temperature of an equal weight of water it would
have increased its temperature by 142" ; this is what
is meant by saying that the latent heat of water is
142".

As soon as the ice is all melted, the temperature will
again begin to rise, the supply of heat remaining
constant, at the rate of 1 per second ; and in three
minutes from the melting of tlu; last particle of ice,
the water will have reached the boiling point, 212 .
Steam will then form and escape in bubbles, and the
w^ater will cease to grow hotter. For 960 seconds the
ebullition will continue without increase of tempera-
ture, and at the end of that time the last drop of
water will have disappeared in steam. The amount
of heat, 966 heat units, which was expended in chang-
ing one pound of water into steam, without increasing
the temperature, is caHed the latent heat of one poun<l
of steam. The fact just stated is often thus expressed,
the latent heat of steam is 966 . This statement is
exact only when the steam or vapour of water has
been formed at a temperature of 212 . At lower
temperatures the latent heat of vapour is somewhat
greater. It will be observed that the total amount of
heat consumed in raising one pound of water from the
freezing to the boiling point, and then boiling it aw^ay
w^as 180 + 966 - 1,146 heat units. If the water had
been raised to the temperature of 60 only and then
allowed to evaporate slowly, until it had wholly
disappeared in the air, the total of heat units thus
used w^ould have been 1,100, something less than in
the former case. But for practical purposes it is
sufficiently near the truth to say that the amount of
heat required to heat one poinid of water at 32 F. to
a moderate temperature and then to evaporate it at

44

that temperature is 1,125 heat units, bein^ 1,091 at the
freezing point and 1,140 at tlie boiling point. Hence,
if a pound of water be evaporated from wet elotlies
on a line, or from the sui-faee of wet land on a windy
day, or from the damp clothing of one who has been
walking in the rain, as much heat nmst be abstracted
from the air and from suiTounding bodies as would
suffice to raise 45 ll)s. of water 25 in temperature.

All the statements made above respecting a mass of
ice which first becomes less cold, then melts, again grows
warmer, r. .d rinally boils away, nwiy be read conversely.
That is CO say, one pound of steam at 212 , in condens-
ing t( hot water at the same temperatiu'e, liberates
9(>0 iieat units which are absoi'bed by surrounding
obje ;ts, and raise their teirv^erature proportionately.
Tlif a the condensed water as it cools, gives up one
her.t unit for every degree of fall in temperature till
?2" is reached. Then if the abstraction of heat still
continues, the water U'gins to freeze, parting with
heat, yet getting no colder, until it lias evolved 142
heat units, by which time it has become a solid mass
of ice at 32 . After it is frozen, it yields up one heat
unit for evoy two degrees of fall in temperature.

Examples a ml E.i'pcvi m cut.

68. In a cold room four gallons of water at GO" lose
one heat unit per second ; what weight of ice will
have formed in an hour ?

GO. One pound of steam is condensed by ten lbs. of
ice-cold water; what is the resulting teniperature ?

70. A mass of dry earth, of which the specific heat
is one-fifteenth that of water, and which weighs 30
lbs., is moistened with 5 lbs. of water, and. beini^ at a
temperature of GO , is exposed to cold in such

45

of

circumstances that it loses one heat unit a second.
When will the mass be^in to freeze, and when will
it be completely frozen ?

71. The specific heat of a sani])le of sand is one-fifth
tliat of water ; 10 lbs. of it are moistened by 2 lbs. of
w^ater, frozen hard, and cooled down to K) below zero.
It is placed where it will gain 20 heat units per min-
ute ; how long before the mass will be quite dry at a
temperature of 212' ?

N.B. — Reckon that each pound of water <lried away
after the ice is thawed costs 1,125 heat units.

Remark that in a still, cold rooui water will sink
considerably below the freezing point without freez-
ing ; but, if ngitated, will then form as much ice as
w411 give out enough latent heat to raise the tempera-
ture of the whole to 82 .

72. A pound of water has sunk to the temperature
of 20' without freezing ; how much ice will form, if
it be shaken ?

78. One cubic foot of a certain soil, when dry,
w^eighed 80 lbs. and had a specific heat { that of water.
Having been saturated with 40 lbs. of water, its tem-
perature one morning was found to be 85 . It
was exposed to the sun so that it received 10,700 heat
units in the day. Under the influence of the wind it
lost 9 lbs. of water by evaporation during the day.
What was its temperature at the close of the day ?

74. Other things being as in the last example, what
would the temperature of the soil have been, if
it had contained only 80 lbs. of water, and had lost
only 8 lbs. by evaporation :'

From the results of the two preceding examples it
is evident that, although water is essential to the
grow^th of plants, its presence in too great quantity

Ad

'

lit'
I)

I!

is injurious to those which are usually cultivated.
Too much moisture makes a soil cold.

Exp. 21. Put one ounce of ice into three ounces of
boiling water and observe the temperature just as the
ice is melted ; compare with the results of calculation.
Try with different amounts of ice and of w^ater at
difibrent temperatures.

§ 0. Deiv, B(tln and Snoiv.

The evaporation of water, however, like every other
natural process, is of the highest utility. To it we
owe the refreshing dew and fertilizing rain, and the
kind covering of snow which protects our fields from
the intensity of the frosts in winter. Its relations to
plants are so important and so beautifully adapted to
the purposes which they serve, that no apology will
be necessary for devoting a little time to their con-
sideration.

It was before stated that heat is necessary for the
evaporation of water, — and when this heat is removed
from the invisible vapour thus produced, it is again
reduced to the state of water. Thus, if in summer a
pitcher of cold water be placed upon a table, in a short
time the outside of the vessel becomes moist or covered
with globules of water. This shows that the air
always contains the vapour of water, and tliat this
vapour, wdien it touches a cold body, is reduced to the
liquid state. These simple facts will enable us to
understand tlie general causes of dew and rain.

In clear weather, the earth's surface and the air in
contact w^ith it, are warmed by the rays of the sun.
But every warm body has a tendency to radiate or
send forth its heat, until it becomes as cold as the sur-
rounding ol)jects. After sunset, therefore, the earth's

47

in
|in.

or
11 r-

I's

sui't'iic'j rapidly cools, until, at length, it becomes so
col<l that the vapour of the air in contact with it, be-
comes condensed in the form of deiv, or if the cold be
more intense, in that of hoar frost. But different sub-
stances, when allowed to cool, lose their heat with
(liferent degrees of rapidity ; and of course, those
which cool most quickly and thoroughly, must collect
the greatest quantity of water from the air. I'his
property also forms the basis of an arrangement bene-
ficial to vei^etation ; for grass anrl other herbam) radi-
ate their heat more rapidly than most other bodies;
and hence, " in the cool of a sunnner's evening, the
grass plat is wet when the gravel walk is dry ; and
the thirsty pasture and every green leaf are drinking
in the descending moisture, while the naked land and
the barren highway are unconscious of its fall."

When the sky is covered with clouds, these return
the heat which the ground loses by radiation ; and
when the air is agitated by the wind, its vapour is
usually insufficiently cooled for condensation, hence
in cloudy and windy nights, there is no dew.

The early frosts of autumn depend on causes similar
to those of dew. In autumn, plants are cooled to a
temperature below the freezing point, by the radiation
which takes place during a clear night ; in such cases,
a very slight covering, even a thin cloth, may impede
radiation, and save a plant ; and exposure to a slight
current of air, or even facing a cloudy spot of the sky,
or smoke in the air, may save particular parts of a
field.

Other causes may condense vapour at various
heights in the air. Moist and warm air ascendintj
from the earth s surface, and entering cooler regions,
will begin to relinquish the moisture which it contains;

48

and a cloud will be formcMl which may either descend
in rain, or be wafted to some distant locality. The
more usual explanation of the formation of clouds is
founded on the fact, that if two ecjual portions of air
differently heated, and both containing as much vapour
as they can retain, are mixed, the temperature of the
mixture will be the mean of that of the two portions
of air ; but this intermediate tempei-ature will not be
sufficient to maintain, in th(i state of vapour, all the
water of both portions, and consecpiently water must
be deposited. When therefore, in our atmosphere, a
current of warm air becomes intermixed with one that
is colder, a (juantity of fog, mist, or cloud is produced,
proportioned to the excess of the watery vapour con-
tained in both currents, above the quantity which they
can retain when mixed. Lastly, electricity, whose
agency is so manifest in thunder storms, acts, in ways
not yet well understood, in accumulating clouds, and
precipitating their contents to the earth in the form
of rain, or, more rarely, as destructive showers of hail.
The subjoined table gives the weight of water
contained as invisible vapour in every cubic foot of
air saturated at each of the temperatures mentioned :

20°.
25°.
30^
35".
40°.

Grains.
.. 1.5
.. 1.6
.. 1.8
.. 2.1
.. 2.0

(j rains.
^' p ...... «>.«.

♦ 10 ...... T".^

Grains.
.. 8..S
.. 9.t)
..ll.()

60^
65^

5.8
7.0

70°.
75°.

SO".

Of) ■•••••ii'S**)

00^

,15.0

Grains.

95' 18.0

100" 20.5

105" 23.0

110' 20.4

1 lo"......30.5

Examples.

75. How many tons of water are contained in a
cubic mile of saturated air at 70^ ?

76. How many tons of water in a cubic mile of
saturated air at 30° ?

m.!t:^

49

lescend
r. Tlie
ouds is
of air
vapour
I of the
ortions
not be
all the
r must
here, a
ne that
►duced,
r con-
h they
whose
[ ways
s, and
form
hail,
water
oot of
oned :

Grains.
.18.0
.20.5
28.0
..2(5.4
..1)0.5

m a

le of

77. How many tons of water in two cubic miles of
saturat(Ml air at 50 ;*

Kcmark that for the purpose of the next (juestion
we may reckon that il' (Mpial (juantities of air at <lit'-
ferent temperatures be mingled the mixture will bo
of the av^era^e temperature.
\^ 7N. How many tons of water would be deposite<l as
^ rain if a cubic mile of saturated air at a temperature
of 70' were mixed with (me cubic mile of saturate<l
air at :^0 ? ^

Air is seld(jm saturated with vapour, but the actual
amount pi'esent at any time may be easily deter-
mined by obscH'ving at what temperature moisture be-
(•ins to be deposite<l from it. For the air is saturated
at that temperature. The temperature at which
moisture begins to be deposited is called the dew-
point.

Examples and Experiment.

79. On a hot day, temperature 90' in the shade, a
glass jug of well-water at a temperature of 50' was
just dinnned by the deposit of moisture on the out-
side. At that time how many grains of water were
there present in one cubic foot of air ? What per
cent, of the moisture necessary to saturation was pre-
sent ? What per cent, of the weight of the air was
moisture, the barometric pressure being 30 inches ?

80. At 8 o'clock in the evening the temperature of
a grass plat and of the air above it is 65^ ; the tem-
perature of the grass continues to fall at the rate of
l"" every 15 minutes until four o'clock in the morning,
when it ceases to fall. The air contains 2.6 grains of
moisture per cubic foot. At what time will dew begin

1'^

50

to form ? Will tliorc lit' hoju' frost? What will be
the lowest tcinperaturc of the nl^lit ^

(Si. The toinpei'ature is 75 and the dew-point 5"
lower ; what per cent, of the nioisture necessary to
saturation is present, an<l what per cent, of the mois-
ture present wouM he rleposited if tlie temperature
wen^ to fall 20^ ^

Exp. 22. Hang up a tin of very cold water in a
room on a hot day. Take the temperature of the
room, and also of tlu^ water when the moisture at first
condensed on the outside disappeais. From the data
so obtained calculate the amount of moisture present
in each cubic foot of air in the room and the addi-
tional amount which it is capal»le of absorbing.

in

n\

will be

K)int 5'
"isai'v^ to
Hi mois-

cr m a
of the
at first
lie (lata
present
e addi-

CHAPTKR III.

CHEMICAL 1MIINCII'M<:S.

§ I. Laiv.-i of CuinJ)i nation.

Instead of expUiininj^ the <(eneral principles of
chemistry in a formal mannei-, we shall illustrate
them hy a familiar example. If we take 100 pounds
of pure limestone, and expose it for some tin»e to a
red heat, as is done in lime-kilns, an invisihle air or
j^as «'sca[)es from it, and at length we have only 50
pounds of (piick lime remaining. If we have collected
the gas which has been given out, its weight will be
found to be 44 pounds, or as much as the limestone
has lost. This gas is known to chemists as carbon
dioxide Limestone therefore is a eompoinid sub-
stance, and may be dccon^poxcd or separated into two
other substances. But this process may be carried
still farther, The skilful chemist can obtain from the
44 pounds of carbon dioxide, 1*2 pounds of carbon or
cliarcoal, and i'}2 pounds of a gas named oxyg(in ; and
from the 50 pounds of (|uick lime, called by the
chemist calcium oxide, 10 pounds of oxygen and 40 of
a metal named calcium. Here then we have :

12 Curboii and ^2 Oxyj^en, fonuiii*^ 44 Carbon Dioxide
40 Calcium " Ki OxV<'en, " 5<> Calcium Oxide

Formin<r, wlion united.
Calcium Carbonate.

100 Limestone or

E. I' per in tent.

Exp. 2'}. Weigh a fragment of limestone as big ns
a pea : heat it on charcoal before the blowpipe with a

52

ji^entle blast till it has beon red hot for half a ininuto.
(See exp. 82.) Weigh again when cold, and see what
proportion of the weight has been lost. Compare
witli the foregoing statements.

m

First, it is evident thao such a union is not a mere
mixture of carbon, calcium and oxygen ; it is that
more intimate union ternusd CombindfioK, and we
see that ivJien two bodies thus comhine, the result is (t
third substance very diffeveid from either.

Secondly. If we take any nuniber of specimens of
^nire limestone we shall tind them all to consist of
the same substances, and in the same propoition ; or if
we form cai'bon dioxide or lime by causing their
ingredients to unite, it will be found that weights of
these corresponding to those wdiich are found in lime-
stone, are alone capable of combining to form these
substances. These ingredie ts, therefore, coinbine in
uniform and definite proportions.

Experiment.

Exp. 24. Try experiment 28 with several different
bits of limestone and of marble.

Thirdly. If we put some pounded limestone i:^to a
glass, and pour upon it a little hydrochloi'ic acid, aii
ejfervescence or boiling up will take place, in conse-
quence of the carbon dioxide of the limestone escap-
ing; and, after this has subsided, we shall find that
the hydrochloric acid has combined with the lime,
forming calcium chloride. In this case, then, the
hydrochloric acid has expelled the carbon dioxide in
order that it miyht itself combine with lime. The

53

111 ere

that;

1 v\'e

tendeywies of bodies to combine with each other, fhev,
are 7iot equally powerfid, so that previously existinf]^
combinations may be decomposed by the addition of
new substances.

Experivient. '

Exp. 25. Weif^li a bit of limestone as big as a pea.
Then weigh a test tube with half a teaspoonful of
hydrochloric acid in it, put the limestone into the
hydrochloric acid, and, sometime after it is dissolved
weigh again. What has become of the lost weight ?
How does the proportion of lost weight compare with
the proportion lost in experiment 23 ^

Fourthly. After having decomposed limest(me, and
obtained carbon, calcium, and oxygen separately, we
cannot decompose these three substances, or separate
an^'thing further from them ; they are therefore
termed siinj>le or eleDientar}) bodies.

Fifthly. It is found that these principles apply to
nearly all the objects known to us ; that these are,
like limestone, compoun<l bodies, and that they are all
composed of a limited number of simple substances,
or elements, which ma}'' be arranged as follows :

(3 Gases — Oxygen, Hydrogen, Nitrogen, Argon,*
Chlorine, Fluorine.

10 Nonmetallic liquids or solids at coynmon
teniimraAwres — Sulphur, Selenium, Phosphorus, Bro-
mine, Iodine, Carbon, Boron, Silicon, Arsenic, Tellu-
rium.

u?

m
m

*Arfr«)n is a lecently discovered constituent of the utmosplioro, present in
.'■mall (iiiaittity and havinf? no known rolations to iniimnl or to vegetable
life. It is: therefore, not referred to again in this work-

f ''

It .•stheV'■'^''"^''""^''"'^''-"^-'•
P7n^k tt fc^IeSl'-^'y to analy,. eon.

substances, wj.ethe • o £ n^rf"" ""•■ p4" Hies of
"'''"••e or in the ,i '^'"-"""^'^' P'-oce.ss.s „","i,tt

:^ «/• t>>e greatest S , 'e eonf '"" ^'^ '^>''"bol.s whici.

J 'lie 1 are pi-oLabJy i„ ' "'" "* ■''>''"Iiv;,li„„ an.l
fmple substance, espec ,11? l >"'P'''=^-^ '^'"ke in'eac

55

iir-

naines of the substances. 80 the three simple sub-
stances which constitute lime-stone are thus repre-
sented : — One atom of carbon by C, one of calcium by
Ca and one of oxy i^en by O. Further, as the weights of
these atoms are supposed to be quite definite, C
stands for an invariable though exceedingly minute
weight of carbon. Similarly, Ca and O stand for
dirterent though quite detinire weights of calcium and
of oxygen respectively. No one knows with any ap-
proacli to accuracy just what the weight of any atom
is as compared with our ordinary weights like the
iiniin or the ])ound. But chemists have ixood irrounds
for affirmino- that the relative weij^hts of the atoms of
different elementary substances are known, and this
with great exactness. When compared with one atom
of ]iv(h'0(jcen, the liofhtest substance known, one atom
of carbon weighs 12 times as much, one of calcium 40
times as much antl one of oxvixen 10 times as much.
It is, tlierefore, customary to repi'esent the weight of
one atom of hydrogen, H, by 1, making it the stan-
dard of comparison, and to say that the weight of one
atom of C is 12, of Ca 40, and of O 10. These num-
bers are called the atomic weiij^hts of hv<lrown,
carbon, calcium and oxygen respectively.

Each compound body again is supposed to b;^ mido
up of molecules, tliat is of small definite grou[)s of
atoms, each molecule being like every other in the
compound, l)eing made U[) of thr same nund)er of
atoms similarly arranged, and having, therefore, the
same aiif<{re<»ate wei<xht. The chemist's view of the
molecular constitution of compound bodies is indi-
cated by formuhe in which arci combined the symbols
of their elements. So he ix'])i'esents carbon <lioxide
by CO2, meaning to indicate thei'eby that each

66
molecule of cai4,rm j; -j .

-l.o„ unitc^ulXTtoms^^^^^^ of

ahso therel,y the fact tha CwL P" / "-^Pr^^^ting
of ca,.bo„ and oxygon t nit",) „ h "'■''■'^•' '« composed
parts by weight of mrl^n f I " "*'' Proportions of 12
»f oxygen. 5t w° Ue reLmf"' '5 ""** '" 32, Utl
'"V'f for ,j„ick li,„e .Z'/f'Z ""'^ CaO, the for-
ox„ e, represents thaUh s siS„"'^'"'*'""'«* «*Icium
parts of calcinn. united o 16 1,k' '.• '"""^^ "P "^ 40
chemist represents li<nesto„e i^tfn, ,"* °-^>»'-n- The
carbonate, by CO + P..n *^'' ''«* "'""es calcium

pressions ^tl! r.^by '8,S:6'="'t""f '''' *-« «
''"efly tj.e fact that ca^eimn ^^ "*" *''"« expresses
parts calcium, 12 mZ oV^ carbonate consists of 40
combined tog^the.f '^'''"" *"'' « P'^rts oxygen

Exwrnplea.

82 In one pound of ptrl^r.,. i- • ,
^ve.|ht of C, a,Kl what of O r" '''"''■"'^ ^'''at is the

eaching.^^die^t'r- '"" "'' '"»^'' CaO, how n.uch of

^'i-^In^l'l ltn/°" '"-'¥'« 2.240 lbs.

^'■•<'xi.Ie, Ca T '^^ <=""'P°«fon of ,s« lbs. carbon

«6. In ft charcoal fire ciul,.,., r • . •
the „n,o„ of the charcoal el !'''•," '' *°""<^'' ^v
tl>e air; how many lbs of ov', ' "",'', "'^yS*^^" froia
burn up a pound^and a half^o'Vr"''' Y" "^"^ed to

of the J. to ?,,."'' ;■;■"! "" t- with the oxygen

"----^;o. wiro.:: ;s, of c^^^^^

57

how

•bon

bv

H'oiii

to

JOW

fen
of
is

l)urno(l, with how iiuicli oxygen does it unite, and
how much water is formed ?

(SS. What is tlie weight of each ingredient in 75
lbs. of wliite niarbh', pure calcium carbonate ?

iS9. There are 20% of impurities in a piece of lime-
stone weighing: '^75 lbs.; how much carbon dioxide,
and how much calcium are there in it ?

90. When charcoal burns with an insufficient supply
of oxygen, a gas named carbon monoxide, of which the
fornuda is ('(), is formed ; how nnich C, and how^ much
0 are there in il2 lbs. of it ?

91. Carbon mo>i')xide will burn : it maybe some-
times seen burning with a Hickering bluetlame on the
top of a coal fire. In burning it unites with O to
form CO2. What weight of O is required to consume
14 lbs. of CO, and what Aveight of CO2 is formed ?

92. In the processes of digestion and respiration of
an animal one ounce of glucose, CeH.aOe, is made to
unite with O so as to produce carbon dioxide and
watt^r. How nnich oxygen, in a<ldition to that which
the gluc(jse already contains, will be required, and
how much carbon dioxide and water will be formed ?

The w hole significance of these symljols and formuhe
Cfiiniot here be shown ; but one point more must be
mentioned. It is held that each molecule of matter
in tlie gaseous state occupies the same space as any
otlicr molecule of gas of wdiatever kind, under the
same conditions of temperature aud pressure. It
follows that under the same con litions e(}ual volumes
of diflVrent substances when in the o-aseous form con-
tain the same number of molecules. For exampl(% at
a temperature of 00", and under a barometric pressure
of oO inches one pint of one gas contains the same

ri

I I

58
r>f of ^'^P^^a^^ecl atoms buf nf ? ^ ^^^' nude un

O.. vveighs twice 7fiT ^'^'^ molecule of n .
atoms of r,v„ • o«cause it is ™„ f oxygen,

the moleculf o? f"^ ^•^'■•gl'ing ic' Tnl^^ ^^ ^^o

">e ^oleSof oA^^"8^n, ,< 4hs"ttVrT

<^he molecule of l3^ ^^'^^« ^^ fchnes m. 7 i ^"^

59

To

finer
So
as
tint
>int
ice.
as

•

IS

lile
of

lat
le

la

volume of carbon dioxide is 22 times, and that of the
same vohmie of oxygon is l(j times that of an ofjual
volume of hydrogen, the pres-jures and temperatures
being also equal. Remember that the specific gravity
of hydrogen is .0093. (See page 16.)

Examples.

93. What at 60' and barometric pressure 30 inches
is the weiglit of one cubic foot of hydrogen ? (See
page 16.)

94. If the weiglit of a certain volume of hydrogen,
be one ounce, what in the same circumstances would
be the weight of an equal volume of each of ^he
following gases, — oxygen, carbon monoxide and carbon
dioxide ?

95. What is the weight of one imperial gallon of
each of the following gases, — H, O, CO, CO2, at the
freezing point, when the barometric pressure is 29.4
inches? (See page 25.)

96. The barometric pressure being 30 inches and
the temperature 60°, what would be the weight in
pounds of a room full of CO2, the room being 14 feet
long, 10 feet broad and 9 feet high ?

97. In the same circumstances as in the preceding
example, what is the weight of air in a room 34 feet
by 21 feet by 15 feet ?

§ 4. Acids, Alkalies, Salts.

Acids have a sour taste, redden blue litmus paper
and vegetable blues generally. Alkalies are highly
soluble in water, have a caustic and soapy taste, com-
bine with acids to form salts, and with fats to form
soaps ; change vegetable red to blue, and yellow to
brown ; and tend, when strong and pure, to corrode

Wr

Ml

f

In

11

r

60
l-vo a peculiar tl«t lif ^t;; "" '''■•''='' '^"'-•; ti.ey

cabbage bright rod v,!hl?\!- f ,^" P"'"!''*-' "'' ••'-"'I

acrid taste; asiarletTr,? "'"'•'""' '"'■" '^ b"r„i„g
tion of cau tic 2 i In «i '!" l""""''^^''' '" '^ ""l"-
taking place outcklv^f '.,''""'>' *""' '''"«■ "'« change
tile ihJevs ■ c ,,,S;7' 1 , *^"''''-''' ''« fi'-st crusliod m

>^'-<'wn. But if it" •""■?.'■ "'^ * t^uttei-cup dark

l>oth the caustic taste ,ftl'^ ^''"^'ar be pourcl,

">o vinegar will d tj^ '^^I t" ''"^ "'Y'*;' ''
sahne taste • and H„. ,. u' . '* replaced by a

effi^ct upon vcH Ota 'T """" "'"' '>*'^''' "°

stancesVlicfunite vvir?w'^''^'"''^^ "^"^I -" -'l^-
their acid proper es I T"'' "^ '''^ *° "outrali;.e
with the.nl'arrcaS bt " '"C^'^^f ^f eon,bi„atio„
slight V or nof af nil i i i . ^*^^"y ^t tliein beinij but
suc\ cfus ic"ty Ir io "^r " --'-•> do not exhibit
colours as thecal alies iuT^ "'' ''°'!"'" °" vegetable
proportional to Swiity ^'°^'''^"'' ^''""^ '^''""'^t

wal?a'fra^;reS' r ^'^P'^'-^l^ tablespoonfuls of
calcium oxide el^h f. 1„° ""' hydroxide, a bit of
a drop of anmSa fe ^' ^f ^''''" °^ ^'"'^*' ''"d

write on reddened litmn^ '''''*'" .P''" '" '^^e'l and
itaacned litmus paper. Put a bit of red

61

litmus paper into each. Try the effect of each on the
crushed petals of red flowers, and of yeHow flowers.

Exp. 27. Into separate tablespoonf uls of water drop
one drop of sulphuric acid, one of hydrochloric acid,
two of vinegar. Write with the solutions on blue
litmus paper. Put a bit of blue litmus paper into
each. Try the eflect of each on the crushed petals of
blue flowers.

Exp. 28. Collect your acid liquids together in one
glass, and drop your alkaline liquids in cautiously
until the resulting mixture will neither turn blue
litmus red, nor red litmus blue. Then the acids and
alkalies will have neutralized each other, and the
solution is said to be neutral.

CHAPTER IV.

CHEMICAL PROCESSES.

5 1. Teds and Testhui.

A most important practical (juostion for chemists is
this : How shall we reco<jjnize witli certainty the
various substances, simple or compound, with which
we deal ?

It is of course easy to recognize by their physical
properties many elementary substances. Quicksilver
cannot be confused with anything else. But it is not
eiiually easy to distinguish many substances from one
another, especially when present in small quantities
and largely admixed with other substances, or com-
bined with them.

Chemists have noted a large number of peculiar
phenomena which, under certain conditions, show the
presence of particular substances. When they seek to
determine the presence of some substance, they repro-
duce the conditions under which the peculiar pheno-
mena should result if the substance sought were
present ; and, as these phenomena appear, or do not
appear, the presence or absence of that particular
substance is demonstrated. This process is called
testing ; and, inasnmch as the testing usually depends
on brinfjinof two chemical substances too^ether which
forthwith produce some notable appearance, ea^h sub-
stance is said to be a test of the other. Substances
thus used as tests receive the common name of
reagents.

m

\ > to- — -

1">
U.I

leinists is
inty the
:h which

physical
icksilver
it is not
from one
uantities
or corn-
peculiar
how the
seek to
y repro-
pheno-
were
do not
rticular
called
epends
which
3h sub-
stances
ame of

it

Some of tlie tests used by tlie chemist are j^jeneral,
servintr to indicate classes of substances. Thus a
solution of blue litmus is a sensitive test for acids,
which in very small ([uantity turn it red ; and red-
dened litmus is a test for alkalies which change it
back to blue. See Exps. 26 and 27.

Exp. 29. Into a test tube put a bit of iodine as large
as a pin's head and warm the tube over a spirit lamp.
Smell cautiously.

The appearance of this beautiful purple vapour
proves the presence of iodine. No other substance
presents such an appearance. No other substance
smells ([uite like iodine. The appearance and the smell
are tests of iodine ; by these properties the chemist re-
cognizes it. But these properties are not always avail-
able ; iodine in solution gives no purple vapour ; iodine
in combination has no characteristic smell. And these
tests are not sensitive ; for exceedingly small quanti-
ties of iodine cannot be thus discovered.

Exp. 30. Smear a piece of paper with starch paste
and dry it. Put a drop of water on the starchy side
of the paper and into the water a bit of potassium
iodide as large as a pin's head. Near the water draw
a line of nitric acid like a pen stroke, and run the
rlrop of water into the nitric acid. Observe the color-
ation.

No substance but iodine colours starch in this way.
Iodine and starch are tests for each other ; they are
used by the chemist as reagents ; they are very sensi-
tive tests each for the other ; they can be used when
the iodine is in solution ; and, with the help of a little
nitric acid, when the iodine is condaned with a metal.

6

(>4

Kxp. .SI. Dissolve n l)it of almn as Imt^c us ji <^rain
of wheat in a teasj)()onful of Nvater. Divide the sohi-
tion into two parts. Into one part (h'op one (h'op of
ammonia ; into the (jther (nie (hop of sohition of
barium nitrate, an<l a minute later one (hop of nitric
acid.

The white gehitinous precipitate foniRMl in the first
solution sliows the presence of alumina : and the white
cloud ins(jluhle in nitric acid, which is formed in the
other case, demonstrates the presence of sul})huric acid.

Exp .S2. With a blow-
pipe maintain a steady,
well-defined flame from
an oil(not coal oil)lamp.
To learn to do this, 1st,
keep the cheeks dis-
tended while breathing
throuo-h the nose ; 2nd,
with the blow-pipe be-
tween the lips do the
same thing, but, as the
air will escape from
the blow-pipe, the
mouth must be from
time to time refilled
from the lungs, with-
out interruption to
the stream of air through the blow-pipe ; 3rd, direct
the blast into the flame of the lamp, or into a candle
flame, and keep the flame steady in form and size.
Try to get a sharp point of flame directed downward
with an inner luminous cone. The point of this cone
is called the reducing flame, (h), and the outer scarcely
visible flame is called the oxidizing flame, (a).

tig.

(ir>

y as ji <^min

ide tin: solii-

Diit: drop of

solution of

rop of nitric

mI in the first
lud the white
ornied in the
dpliuricacid.
With a hlow-
^ain a steady,
Ml tlame from
2oaloil)hunp.
) do this, 1st,
cheeks dis-
Jle breathing
e nose ; 2nd,
low-pipe be-

lips do the
', but, as the
jscape from

pipe, the
st be from
me refilled
lungs, witli-
Iruption to
8rd, direct

ito a candle
|ii and size.

downward

►f this cone

ter scarcely

a).

Exp. .*^'^ At the end of a tliin copper wire, four
inches long, make a loop about i'., in. in diameter: heat
it red hot in the oxidizing Hanje, put on it a bit of
microcosmic salt as large as a grain of wheat, and boil
all moistui'e away in the blow-pipe Maine ; then dip
the ••lassv bead of .salt while still hot into some finely
powdercil eounnon salt and once m<>i«' heat in the'
oxidizing flame, '^i'he magnificent blue colour ))ro-
dueed is eharaetei'istie of coj)per chloride, and in the
])resent instance demonsti'ates the presence of chlorine
in the common salt.

Otlu'r examples of tests and testing will be found
in the next chapter.

§ 2. Separation ({f riiirtarfs.

In all the experiments that follow weigh carefully
the substances operated upon and the results of the
operations, when possible. Before weighing, thoroughly
dry the substances to be weighed, if they are at all
damp, by exj)()sing them for s(jme time to tin? tem-
])erature of boiling water. Com])are the weights of
the (juantities of matter operated on, and of the result-
ing (juantities and endeayour to account for all the
matter employed, ay.oiding loss. Use the smallest
(juantities of the materials employed that will enal)le
the results to be clearly noted.

Ejcperhnents.

Exp. t]4). Mix fine sand and sawdust; divide into
halves; separate half of the mixture b}* ivi n lunvhig,
and the other half by shaking up in water and skim-
ming off the sawdust, that is by floatation.

Grain and chafl'are separate*! by wianoiving.

r.f)

Exp. ']o. Mix iron tilings and sand. Put a tea-
s])uont'ul of the mixture in a heap at one si<le of a
diinK-r phite ; pour enough water into tlie plate to be
one-eighth of an incli deep, and by rolling the plate
gently make a current of water sweep over the mix-
ture ; try to wasii away the sand from the tilings.

Gold dust is separated from sand by waf<lriur/; for
a gentle current of water will sweep away the lighter
grains of sand and leave behind the heavier grains of
gold. In nnich the same way the wash of waves, cur-
rents and tides carries the finer particles of the shore
out to sea, and deposits them in b(Hls of clay, while
san<ls are deposited nearer t'le shore and boulders and
pebbles constitute the shore itself.

Exp. 86. Mix half a teaspoonful of salt with ten
times its bulk of sand and divide into equal portions ;
put (me-half into a test tube with water and shake
for some time ; then pour oft the brine and repeat the
process ; put the remaining half into a tube open at
both ends and stand on a board ; let water drop
gently in on the top of the mixture; brine at first
strong, but becoming weaker and weaker will ooze
out under the bottom of the tube and maybe caught :
clean sand ^vill be left behind ; see in which way you
can best clean the sand, and in which way 3^ou can
niost perfectly collect the salt, wliich may be. recovered
from the brine by boiling the water away. The chemist
calls the secjnd process li.i'iriafioi} ; the farmer
calls it leaching. So he leaches ashes in making potash,
and the rains leach a heap of manure when tliey soak
out and wash awa\' its solul)le and most valuable
ingredients.

Exp. 87. Divide a spoonful of tea into three equal
parts ; steep one part in water for a day ; pour hot

I

67

Put a tea-
lie side of a
e plate to be
iii<^^ the plate
ver the niix-
le tilings.
vaslthicf ; for
y the li<rhter
ier grains of
t' wavx's, cur-
of the shore
" clay, while
boulders and

dt with ten
lal portions ;
r an<l shake
d repeat the
J be open at
water drop

ine at first
tv will ooze

be cauf^-ht :
ch way you
ay you can
)e recovered
The chemist
the farmer

ino' potash,

1 tliey soak
<t valuable

three equal
i pour hot

1

i

water on another part, and let it stand a few minutes ;
boil the remaining part in water for a minute or two.
Observe the differences in appearance and taste of the
three liquids when poured off* the tea.

The first mode of dealing with the tea is called
digest ion, the second in/as ion, und the third (Iccoctiim.
If digestion is prolonged until deca}^ begins, the pro-
cess is called maceration.

Exp. 38 At a gentle heat melt a little lard in a
teaspoon. Let it cool slowly, and just as it looks opa(jue
put a drop of it on some blotting paper that has been
l)lackene(l with ink and drie<l. The lard will be
divided into two parts, a more easily fusible fat or oil,
lard oil, which will spread in a greasy blotch into the
blotting paper, and a more solid fat, stearine, which
will remain at the middle of the circle of grease.

The stearine and the lard oil are separated b^- differ-
ence of fusibility. This method of separation is used
on a larw scale in the manufacture of lard oil : nu'lted
lard is allowed to cool toal)out 100 F. At this temper-
ature stearine solidifies in small particles disseminated
through the more liquid portions of the fat, and wlu'ii
the pasty mass is envelope(l in cloths and subjeelcd to
pressure, the oil is s([ueezed out and the less fusible
stearine is retaine<l in the rloths.

Exp. 3f). Mix a bit of ivxline as large as a grain of
wheat with half a teaspoonful of sand in a long test
tube ; heat the mixture over a spirit lamp.

Tlie sand and the iodine Nvill V)e separated by niih-
hmation of the iodine. In a similar way camphor is
separated from tlie wood of the camphor tree, and
native sulphur is separated from the earthy matters
with which it is mixe<l.

H

ns

Ex]). 40. Pold a circle of filter paper, Mutting ])apei',
into a (piadraiit : open it out into a cone so as to leave
tliree thicknesses of paper on one side and one on the

other side ; fit it into a glass
fnnnel, wet it with a little clean
water; pour muddy water into
the filter, taking cai*e that the
water does not lise above the
edge of the filter paper. The clear
water that drops through is called
the liltrate ; you have jilteird the
water.

Exp. 41. Stir up a little clay
in water. Let it stand aside, a?id
when it has setth'd pour off the
water to the last drop without
disturhnif*; i^he sediment. This is
ih'C(nii<iH(nt.

Exp. 4-. Repeat Exp. LS, and
see what proportion of the alum
vou recover l)\' cn/sfall iztftum.

Exp. 4!i. Jioil away the x^uter fr<^m which you have
removed the crystals oi a! inn in the foreiifoini*" experi-
ment, and weigh "^Ve residr.e Sre if you have
recovered the w iiole of the alum by the crapordtioti
of the water.

Exp. 44. Fill a test tub»^ one-thii'(l full of water,
colored re(l witli dve, and one thii'd full of sweet oil.
Shake them well together. 'I'he opa([Ut' piidv licpiid
produced is caUtMl an emulsion. Let the tube stand
til! the contents hav<' again separated and decant the
olive oil.

Exp. 45. Make a similar emulsion, and pour it into
a hlter wet with water. Thus li«|uids which do not

Fie

GO

utting })apoi*,
so as to leave
\(\ one on tlie
into a fi^lass
a little clean
water into
re that the
! above the
'r. The clear
►ugh is called
' ^filteviul the

\ little clay
(l aside, a?id
pour off' the
I'op without
'ut. This is

xp. LS, and
i* the alum

eh vou have
>ini'' ex])cri-
you have
capuriftiini

1 of watei*,

t* sweet oil.

[)ink li(|uid

tuhe stand

decant the

)our it into
ieh do not

mix may he separated by dccantation or hy filtration.

Exp. 4(). Half fill a test tube four inches long witfi

beer. Cork the tube with a cork that has a loncf tube

"<^

cZ^

throuoh it bent nearlv at ri^i^ht an<dos. Set the test
tul)e ovrr a spirit lamp so that the exit tube may
slant sHjihtlv downward to a f^lass. Lav wet blottinii
papt'r on the exit tube and keep it wet so as to cool
the tube. F'resently a coloi'less li(juid will drip into
the glass. When a few (h-o]>s are collected, smell it;
set it on fire ; it is alcohol.

The boiling ])oint of water is 212 , that of alcohol
is 173'. Li([uids who.se boiling points differ consider-
ably miy b(? separated hy iUsfUljifiou.

Exp. 47. C'olh'ct a bottle full of carbon dioxide as
in experiment 71. Pour into it, in a cool place, a
little watci and shake well, covering the mouth of

%
II

m

70

the bottle with your thumb. Repeat the process until
the bottle is halt" full ot* water. Divide the water,
saturated with gas, into equal parts in two glasses.
Put one in a warm place, put the other into the gem
jar of experiment one, and suck air out of the jar.
Observe the formation of bubl>les in each case. The
bubbles are bubbles of carbon dioxide.

Gas may be removed from liquids in which they
are dissolved by heating the liquid or by diminishing
the pressure on the surface.

Exp. 48. Having prepared some chlorine, as in Exp.
68, pour some into a bottle by the aid of a funnel
until the bottle is half full ; then pour in lialf as much
water and immediately close the mouth with your
thumb and shake the bottle. Why is your thumb
sucked into the bottle ?

Exp. 49. Half till a bottle with chlorine. Cover
the mouth with your thumb. Invert the bottle ; dip
the mouth under water and remove your thumb ;
soon the chlorine will be absorbed by the water and
the air in the bottle will remain. Gases may be
separated from one another by means of the greater
solubility in some licjuid ot* one ingredient of the
mixture.

§ 3. Analynifi of Compounds,

All the separations considered in the preceding
section have been merely mechanical and physical.
No permanent change of properties of the substances
operated upon has been produced. In Exp. 86, for
example, the sand and salt operated on remain sand
and salt throughout the operation. But in Exp. 28
the heated calcium carbonate breaks up into two
distinct substances, CcJcium oxide and carbon

)Coss until
he water,
o glasses.
^ the gein
f the jar.

se.

^1^

The

liich they
niiiishiiid*

IS m Exp.
a funnel
f as much
ith your
ir thumb

Cover

)ttle ; (lip

thumb ;

ater and

may be

3 (greater

o

f the

receding
physical.
)stances
'^6, for
I in sand
Exp. 28

to tM'( )

carbon

dioxide differing materially in their properties from
the calcium carbonate fi'om which they were derived.
The calcium carbonate is in this case detunnposed by
the heat, and if we carefully weighed the original
substance and collected and weighed the results of
the operation, so as to be sure that we had lost noth-
ing, we should say that we had analysed the calcium
carbonate.

One or more ingredients of a mixture may oftim l)e
removed by chemical means.

Exp. 50. Mix some filings of zinc and copper and
pour sulphuric acid, diluted with ten times its bulk of
water, on them ; ol)serve that the zinc is dissolved
and that the copper remains undissolve<l.

N.B. — In diluting the acid drop the acid slowly
into the water.

Exp. 51. Observe the effect of pouring dilute
sulphuric acid on brass filings.

Exp. 52. Put two drops of sulphuric acid in a wine
glass of water. Observe its sour taste and its action
on blue litmus paper. Put into it a half teaspoonful
of litharge and shake well. Let it settle and again
taste it, and try it with blue litmus paper.

Exp. 58. Seal up a stick of phosphoi'us in the gem
jar of experiment 1, having a piece of I'ubber tube
slipped over the glass tube that passes tlirough the
sto])pei'; let the free end of the rubber tube dip into a
pail of water and set the whole aside to stand for 24
hours. Olxserve with great care what h.as taken
place, for the results are very important. Was there
any watei- in the jar wlien it was first seale<l u|) !*
How much is in it now ( Is the jar one-fiftli full of

t ,:

f

H

il

72

U

water ? Witlioiit much (listurl)iiig the jar uiLseal it,
([uietly remove the stick of pliosphorus and drop it
into water. Now h)wei* a burning- bi^X'r into the air
in the jar. Wliy does it <fo out ! WouM it go out as
cpiickly if lowered into a jai- full of ordinary air {
Why is the air in the jar different from ordinary air ?
What has become of the air tliat has oone from the
jar, the place of which was supplied by water.

The answers to these questions are that air is a
mixture of two gases, very distinct in pi'operties, cme
of which is removed by the action of tlie pliosphorus,
and the other of which is not. The part removed by
the phosphorus is the part of the air which supports
combustion ; it amounts to about one-fifth of the
volume of the air and is called oxygen. The part
which is not removed by the phosphorus, and wliich
will not support coml)Ustion, is called nitrogen. Phos-
phorus is capable of slowly uniting with the oxygen
of the air at a low temperature, to form a compound
which readily unites with water an<l is dissolved in it.
The result of thn union is an acid, and in con.sequence
the water in the jar reddens blue litnuis.

Exp. r)4. Into a long test-tube of hard glass put
enough red precipitate, mercuric oxide, to rice a
quarter of an inch in the tulx'. Cork tlie tube with a
cork through which passes a long, small tube, open at
both ends nnd bent as in the figure. Let the tube be
so supported that the free end of the delivery tube
may dip into water under the mouth of an inverted
tube filled with water. Then strongly heat the
mercuric oxide by a lam]^, as in tlie maiginal
fiLiUi-e. The red oxide of mercury will blacken and
(lecomnose. Mercury wdl condense on the cooler

4/

upper part of the tii-st test tube and bubbles of gas

rs

unseal it,
I droj) it
bo the air
go out as
ary air f
lary air ?
from tlie
I'.

air is a
I'ties, one
)sphorus,
loved \)y
suppoi'ts
^ of tlie
'lie part
• 1 wliicli
. PIios-

oxv(»-en
inpoiUKl

ed in it.
ecjuence

ass put
:'ise a
with a
open at.
tube be
■y tube
merted
at the
ai'o'inal
en and
cooler
of gas

will be collected in the second test tube. When the
action ceases, or wlien the second test tal)e is full of

gas, tliis tube may be withdi*awn, stoppe<l with the
thumb and turned mouth upward. Then a glowing-
match end inserted into the gas will bi-ighten up
and be rekindled.

N.B. — Take care to remo\e the bent tul)e from the
water before you remove or extinguish the lamp.

The red precipitate, Hg O, has been resolved by
heat into metallic mercury, Hg, and oxygen, (). Other
decompositions can be similarly eflected by the appli-
cation of lieat : and still others are broui^ht about l»v
the passage of cui'rents of electricity, or by the' action
of liii'ht.

§ 4. Sf/iifhrsi.'^, ( <))nh'tnaf\on.

Chemical changes of every kind are o-ivatlv facili-
tated bv minute division and close contact of the sub-
stances acting on each othei*. Two masses of sulphur,

74

11

']i

S, and of copper, Cu, produce no efiect on each other,
althou<(h permitted to lie in contact with eadi other
for an indefinite time. But if tliey he re<luced to an
impalpahle powder and fj^round t()<^ether in a mortar,
they unite into copper sulphide, CuS, with the evolu-
tion of nuich heat

Gases readily mix with each other, hut in the
gaseous state particles of matter though exceedingly
finely divided, do not conje into such close contact with
each other as in the licpiid state. Hence the gaseous
condition of matter is not so favoui'able to chemical
reactions as the liquid. But when gases do combine,
the combination is frequently effected with suddenly
explosive violence.

Experiments.

Exp. 55. Fill a small rubber bag with a mixture of
two volumef5 of hydrogen and one of oxygen. A^yi a
nozzle to the bag, and, by squeezing out some of its
contents while the nozzle is beneath the surface of
some strong soap-suds in a little tin dish, l)low up a
froth of soap-bul)bles. Remove the bag a few feet off,
and touch the froth with a liofhted match : a violent
explosion will ensue as a result of the combination of
the oxygen and hydrogen with each other, in accord-
ance with the ecjuation 2H + O = H2O, i.e., water.

When gases condjine with licpiids the union is faci-
litated by causino'a stream of the tras to bubble throu^^h
the liquid.

Exp. 5(). Blow air from the lungs by means of a
straw through lime water. The carbon dioxide, CO 2,
in the air expired, unites with the calcium hydroxide,
CaO.Ha, dissolved in the water, to form a white
precipitate which is calcium carbonate CaC03.

t-'l

2 1

N.B. — Liine water is made by .stirrinc" a tablcspoon-
t'ul of ({iiick or slaked lime in a pint of water, lettino-
it settle and then pouring oft' the clear licpiid. It must
he kept in a well-corked hottle.

The union of gases with solids is aided by forcing a
current of the gas over and between the particles of
the solid. So a charcoal tire is kept alight by the draft
which causes the oxygen, (), of the air to come in
contact with the glowing coals, C, forming CO 2 by
the union.

In most instances of chemical combination heat is
generated, as in many of the examples of condjination
given above. In some instances the application of
heat is necessary to initiate chemical combination, and
then the act of combination itself .supplies enough
heat to continue the action. To light a charcoal fire,
fire mnst be applied ; but when the action has once
begun, it is not necessary to supply extraneous heat
in order to maintain it.

§ 5. Mefathesw, Replacement, Doable Deroniposition.

Comparatively few chemical transformations are
either mere decompositions or mere combinations. By
far the ixreater number result from inefathe.sis which
is either the replacement of one atom or molecule of a
compound by another atom or molecule ; or an inter-
change of atoms or molecules l)etween two compounds,
where, two compounds being broken up, doable decom-
poHition takes places. Metathesis involves both decom-
p jsition and combination.

E.i'periments.

Exp. 57. Dissolve a bit of copper sulphate as large
as a pin's head in a drop of water. Put the solution

'iM

7<)

on a knife Miulc. Oljsurvu the C()j)|)ery stain wliero
tlui solution rests.

In tliis case co])j)or sulphate, (hi SO^, is hrou;.;ht
into contact with ii'on, Fe. Tlu; iron replaces, takes
the place of, the cop[)er ; ferrous sulphate, Fe S(J^, is
f(>nne(l and copper, Cu, is set free, and forms acoatino-
on the knile hiade. The whole as rej)resented hy tlie
ecpiation Cu SO, + Fe ^ Fe SO, + Ou.

Exj). r)(S. Fill a test tuhe with water, invert it
under watei* in a hasin and raise it until its mouth is
just undei' the level of the water in the ])asin. Plunij;e
under the mouth of the test tube a hit of sodium as
lari^-e as a ^rain of wheat wrapped up in a fragment
of paper. The sodium will rise in tlie test tube,
accompanied by a torrent of bub])les, wdiich will dis-
place the water and till the tube. If, when full of pis,
its mouth ])e closed with the thumb, the test tube
may be lifted from the water. Li«^ht a match, approach
it to the mouth of the tube and remove the thumb.
The pis in the tube will catch lire. It is hydrogen
that has been set free from the water by the sodium
according to the equation, H2 O -f- Na = NaOH -f H.
The NaOH, sodium hydroxide, formed has dissolved
in the w^ater and will reveal its presence by changing
the colour of a bit of reddened litnuis paper back to
blue.

In this examj)le one atom of hydrogen has been
replaced by one atom of sodium. Other substances,
of which we shall name onl}- potassium, are able to
replace hydrogen, atom by atom. Certain other
substances combine with hydropen atom with atom ;
wo name only chlorine. Hy<lrogen, sodium, potassium

77

^11

wl

K'l'O

', takes
.S(\ is
L'oatino-

l>y the

ert it
')uth is
Plunyo
urn as
ginent

tube,
II dis-
jf pis,
; tube
roach
luinb.
ro^eii
diuni

+ H.
!)l\'ed

iofilio-

ft in

ik to

been
ices,
e to
tlier
0111 ;
ium

and eliloriiic are ealle(l monads, or are said to be
univalent.

Into some dilute sulpliui'ie aeid drop a slii'ed of zinc.
Hubbies will speedily pitlieron tile zinc, detach them-
selves, an<l rise throu;^h the li(|uid. IF collectecl an<l
examined they will l»e found to consist of liydi'oecn.
In this case one atom of zinc has replaced two atoms
of hydrooen, H, SO, + >^n = Zn SO, + H., Some
substances, as calcium and maL;nesium, I'eplace two
atoms of hydrop'n by one atom, and some substances,
as oxy<^en and sulphur, condtine one atom with two
of hydro<;en. Calcium, magnesium, oxyeen and sulphur
ai'e called dyads, or are said to be bivalent.

Aluminum, nitrooen and phosphorus are triads, are
ti'ivalent : carbon and silicon are tetrads, are (piadri-
valent.

Oroups of atoms, molecules, are often univalent,
bivalent, trivalent, etc., and replace or are replaced
by atoms or other UK^lecules accordin<^ly. Such <^roups
of atoms are called radicals, an<l often retain their
identity, replacing atoms or other radicals atid being
themselves replaced as wholes through long series of
chemical changes.

Experiment..

Exp. 5fJ. Dissolve a crystal of silver nitrate,
Ag NO^^ as large as a pin's head in a half wine glass
of water, and in another glass of water dissolve a pinch
of common salt, Na CI. Let a drop of the solution of
salt fall into the solution of silver nitrate, and watch
the white cloud that forms.

i i if:..

The white cloud is silver chloride ; the reaction
that has taken placid is indicated by the equation

IMAGE EVALUATION
TEST TARGET (MT-3)

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^ **;^

1.0

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■ ii£ IIIIIIO

1.8

1.25

1.4

1.6

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Photographic

Sciences
Corporation

33 WEST MAIN STREET

WEBSTER, NY. 14580

(716) 873-4503

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Aj( NO, -f Na CI = Na NO, + Ag CI. Both the
silver nitrate and tlie s(Kliuni chloride liave been
decomposed and their constituents luive interchan^e<l
with one another. Fence the action is caUed double
decomposition.

Experiment 5f) illustrates a very important law of
metathesis which may be thus stated. If by any
rearrangement of the substances present together in a
solution an insoluble substance can be formed, it will
be formed and precipitated.

Silver nitrate, Ag NO,, is readily soluble in water ;
so also is sodium chloride Na CI. But if solutions of
these salts be mixed, as much silver chloride, Ag CI,
a very insoluble salt, as can be formed, is at (mce
formed, and is deposited as a hea^ y precipitate. If in
the mixed solutions the Na CI and Ag NO, be present
in equivalent amounts, that is molecule for molecule
each atom of silver will find its ecjuivalent atom of
chlorine, will unite with it and will be precipitated,
the whole of the silver and the whole of the chlorine
disappearing from the solution and only sodium nitrate
Na NO, remaining dissolved. If there be an excess
of the silver nitrate, all chlorine will be precipitated
as Ag CI and the water will hold both Na NO, and
Ag NO, in solution. If, on the other hand, there be
an excess of sodium chloride, all the silver will be
deposited and the supernatant water will contain both
Na NO, and Na CI, and only these.

A snuilar law holds good in case of fusion ; but in
this case substances are removed from the influence
of other substances present by volatilization. If in
the fusion of any number of substances together, any
rearrangement could give rise to a substance volatile
at the temperature of the fusion, that substance will
l»e formed, and will escape in the gaseous state.

?.)

oth tlie
^e been

double

law of
by any
licr in a

it will

water ;
ions ot*
A« CI.
it once
. Kin
present
olecule
torn of
)itated,
ilorine
nitrate
excess
iitated
O3 and
lere be
sill be
n both

Snch considerations explain tlu; apparent inversion
of the order of affinities which is observed in certain
instances. Thus in water potassium carVionate is
decomposed by acetic acid ; potassium acetate is formed
and gaseous carl)on dioxide escapes. Here the vola-
tility of the carbon dioxide aids the reaction. liut if
through a solution of potassium acetate in alcohol a
stieam of carbon dioxide be passed pota.ssium car-
l»onate will be formed and precipitated, for it is
in.soluble in alcohol, and acetic acid will be set free.
Her<j the insolubility of the potassium carbonate
determines the action.

In like manner we may explain tin* inHuence of
mass in determining decompositions. If steam be
passed over iron tilings heated red hot in a tube oxide
of ii'on will be forme(l and hydrogen will be liberate*!
and .swept on ly the atmosphere of steam. But if
h^ilrogen be passed over the saire oxidized tilings,
heated to the same ttnnperature in the same tube,
the filings will be deoxidized, vapo\ir of water will
be formed and will be swept onward by the atmos-
phere of hydrogen.

Tables of the strength of affinity of diffi'rent sub-
stances for each other have been fornuMl which are
u.seful when the circumstances are accurately and
full}' stated, but which are apt to be nnsleading if
applied in changed con<liti()n.s.

Jut in
luence
If in
r, any
olatile
will

M

i

CHAPTER V.

CHEMICAL PROPERTIES OF THE ELEMENTS MOST IM-
PORTANT IN AGRICULTURE, AND OK THEIR
SIMPLE COMPOUNDS.

These elements are four ^ases — oxygen, nitrogen*
hydrogen and chlorine ; four non-metallic solids —
carboDj sulphur, phosphorus and silicon ; and seven
metals — potassium, sodium, calcium, magnesium^Jron,
manganese and aluminum.

§^1. Qxygen. Symbol, O ; ajbonyc weigh t,_.LCL As
this gas constitutes nearly one-fourth of the air we
breathe, it will be readily seen that it is destitute of
smell, of taste and of colour. To its presence air owes
its power of supporting combustion and respiration.
When unmixed it may be distinguished from common
air by two remarkable properties. If a vessel be filled
with it, and a lighted taper introduced, the flame is
greatly increased in size and brilliancy, and if an
animal be introduced, its vital functions are stimulated
and excited to such an extent that fever and death in
a short time result. Oxygen is very abundant in
nature, combining with a greater range of substances
than any other element, fluorine perhaps excepted. It
constitutes 23 per cent, of the weight of the atmos-
phere. It exists in still larger proportion in water,
nine pounds of which contain eight of it. If iron be
exposed to air and moisture, it rusts and increases in
weight. This rust is a combination of iron with the
oxygen of the air, or of water ; and is identical with
some of the ores from which iron is obtained. Many

81

lOST IM-

nitrogen*

solids —

ul seven

uirijjran,

JUL As
e air we
titute of
air owes
jpirai^jon.
common
1 be filled
flame is
nd if an
imulated
death in
ndant in
ibstances
epted. It
le atmos-
in water,
: iron be
reases in
with the
ical with
]. Many

of tlie ores of otiicr metals, and the majority of rocks
and earths comprising' the surface uf our j^dobo, are
similar compounds of metals and other substances with
oxygen, so that this gas, in its pure state invisible,
and only a little heavier than common air, is capable,
when combined with metals and other substances, of
assuming the liquid and solid states, and in these
forms constitutes nearly one-half of the weight of the
crust of our globe, an<l of the bodies of its animal and
vegetable inhabitants.

The most striking property of oxygen, its power of
supporting combustion, which has been already illus-
trated in Exp. 54, may bo further shown as follows: —

Experimp/nt and Exmnple.

Exp. 60. Into an open test-tube four or five inches
long put half a teaspoonful of powdered chlorate of
potash mixed with half its bidk of clean san<l. Heat
the mixture over a spirit lamp, (ias will soon be
given off in C(msiderable (piantity. Hold in the mouth
of the test-tube an extinguished match, of which the
tip is still glowing. It will be rekindled anJ burn
vividly. By arranging the experiment, as in Fig. 5,
the gas given off may be collected.

This property of rekindling into flame a bit of glow-
ing wood is used as a test of oxygen gas ; but it is by
no means a sensitive test, as it is applicable only when
uncombined oxygen predominates in a gaseous mix-
ture.

98. Find the specific gravity of oxygen compared
with hydrogen and with air.

§ 2. Nifi'ivfpn. Syml>()l, X ; atojnic J^eight 14. As
nitrogen constitutes 77 per cent of the vv'elgliT jot the.

^ii

r ■'

82

fitinosphore, it will l>o ri;;litly iiifcrnMl that it is a^as
without color, taste, or siiioll. It does not itself burn,
neither will it support the comhustion (»f othei* luxlies :
and animals and plants die when confined in it Nitro-
gen enters into conihination with dirtieulty and readily

lisenjjfages itself from niaiiy of its combinations.

riiei'efore compounds containin<( nitrogen are unstable,
apt to <lecompose, sometimes with explosive viohmce.
In air it is merely mixed with an«l serves to dilute
oxygen and to prevent it from acting on both living
beings and dead matter, with too great violence and
rapidity.

E.rperlmenf (ind E.ramph'.

Exp. ()1. Collect and examine nitrogen thus : Make
a little stool with legs of wire three inches \nn<f and
a top of thin wood one inch scjuare. Set it to stand in
a soup plate full of water. On the top put a V>it of
phosphorus as lirge as a pea ; .set fire to it, and invert
over it a quart gem jar with the mouth dipping into
the water. First air will escape from the jar, because
it expamls with the heat. White fumes of phosphoric
anhydride, P, O5, will fill the jar. Water will rise
in the jar showing that a part of the air is consumed.
The phosphorus will be extinguished before it is all
consumed, and liefore the air has disappeared. Let
the whole stand for a while. Water will continue to
rise in the jar as it cools, and care nmst be taken to
supply water to the plate so as to keep the mouth of
the jar alwa3^s covered. The white fumes will gradu-
ally disappear dissolved in the water : slip a piece of
paper under the mouth of the jar, while still under
water ; fold it up around the mouth of the jar, lift the
jar out of the water while wrapped in the paper, and

88

keeping th<' paper over th«3 mouth set tlic jar upri<(]it.
Ilan^ an cml of liglittMl caiulle on a wire and <lip it
into the Jar, rtMnovin^ the paper lor that purpose. The
eandle will ^^o out. Tlie «.,^as in tlie jar is nitnij^en ; it
lo(>ks like air, I ait it will not sup])ort conihustion.

There is no easy direct test for free nitro^in. It is
recognized hy its negative ])i()]>erties. A cohairless
oas which has no smell, which does not hum, nor sup-
])ort comhustion, nor pro<hice a pn^cipitate in lime
water, is prohahly nitro<;en.

90. Calculate the specific gravity (»f nitro<(en com-
pared with liydro^i'en an<l with air.

§ '^- ILUlh'^'U^-M- ^y^^^l^^l H- y t^tomic wei<;ht 1.
Kj'IK'viincntH.

Exp. ()2. Throw a hit of sheet zinc, one inch S(piare,
and two or thi*ec iron tacks into a mixture of four or
five parts of water to one of sulphuric aci<l. Ohserve
the formation and rise of huhhlrs.

Exp. 68. Invert a test tuhe filled with water over
the ascending;* stream of huhhles till it is tilled with
the j^as ; remove the test tuhe n»outh downward and
a])proach a li«j;hte<l match to the mouth. If the arran<jfe-
ment like that of Fi^. 5 without the lamp he use<l
witli zinc, iron and sulphuric aci<l in the corked test
tuhe, the hydrogen may he collected in the inverted
test tuhe. When full cover the mouth of the tuhe
with your thund), turn it miaith upward, hold a
li<;;hted match three inches ahove the mouth and
remove your tlunuh.

Like oxygen, nitrojjjen, and their mixture, air, hydro-
•en is a colorless gas, without taste or smell ; it is
however Uiore than 14 times lighter than air, an<l will

-

l\i

//"

84

not support life or coiiil)\i.stion, Imt on the other hand
is itself very combustible; forming water H a O, by
union witli oxygen^

jThe presence o^ ny(h'o|»'rn in any substance is recoj^-

nized by the formation ot water, wJien the substance

Js sufficiently heated in contact with oxygen.

Exp. 64. Bury a bit of tallow as lar^e as a pea m
half a teaspoonful of copper oxide in the l)ottom of a
long test tube. Take care that the test tube, tallow and
co;)per oxide are quite dry ; holding the test tube
nearly horizontal, heat the end of it strongly by a
spirit lamp. Observe the moisture that will condense
in the cool en<l of the tube, proving that tallow con-
tains hydrogen.

' k

U

As mercury is a licjuid metal, so hydrogen is a
gaseous metal, and by the united influence of great
pressure and extreme cold it has of late been reduced
to the metallic form.

As stated above, hydrogen is combined with oxygen
to form water, ot which the fornmla is H^O- With
nitrogen it forms annnonia, of which the formula is
H3N. Another very important compound is nitric
acid, of which the formula is H N O^. These coni-
pounds will be presently considered.

Example.

100. What information respecting the vapour of
water and the gas ammonia is given by the statement
that their formulae are H /) and H^N ?

Water ; H 2 O^ The physical properties of water
have~been already mentioned, page 24. Here it will

l)e nt*ces.sary to advert to one or two of its chemical
properties.

When hy(h'oj]jen is burned, or wlicn substances
eontaininj^ hyih'o^Ton are burned, or decay in air,
water is formed by the union of tlie liydrogen with
nxyfjfen. Sometimes water is decomposed in nature's
chemistry ; especially when animal or vegetable
substances are decaying, or when some metals, as iron,
are rusting under water. In such circumstances many
complicated reactions take place, one i-esult of which
is that a part of the hydrogen of the water is some-
times, though rarely, set free. More frequently it
unites with other substances that may be present, as
with nitrogen to form ammonia, N H3, with carbon
to form marsh gas, methyl hydride, CH^, with
sulphur to form hydrogen sulphitle, HjS, or with
phosphorus to f oi-m hydrogen phosphide, H 3 P.

Water unites chemically with many substances, as
with (luick-lime to form slaked lime. Quick-lime, as
stated before, is Ca () ; but if water be poured on it,
heat is evolved, the lime absorbs water, and crumbles
into a fine powder which has the chemical composi-
tion Ca HaOa. The chemical reaction is indicated by
the cijuation Ca O -|- H20 = Ca H^ O2.

Exper'nnent and ExiOnple.

Exp. (55. Pour on an ounce of (juick-limo an ounce
of water. Observe the effect. Dry the resulting
powder thoroughly and see how nearly the weight
corresponds to the theoretical weight.

101. Find the theoretical weight of slaked lime
resulting from the precerling experiment.

Again water unites with many substances in the
act of crystallization. The cubes of common salt

86

refri'iHMl to on page '.V2 are free from water ; but
crystals of blue vitriol, copper sulphate, contain more
tluin one-Ht'th of their wei<(ht of water, and water
constitutes two-thirds of the weight of soda crystals.

Experiments.

Exp. ()(). On a hot stove put a pinch of common
salt, a crystal of alum, one of hlue vitriol and one of
washing soda ; note their behavior.

Animonid ; H3N. Exp. G7. Mix a small pinch of
.sal-ammoniac with an equal quantity of slaked lime,
slightly damp, an<l heat the mixture gently in a test
tube over a spirit lamp. Smell it. Hold a \t\t of
damp, retl litmus paper in the fumes.

The .smell is due to ammonia, H3N, a compound of
nitrogen and hydrogen. Though composed of two
gases destitute of taste and smell, and itself a gaseous
substance, it has a burning taste and a pungent
smell. Water aUsorbs niore than 1,000 times its bulk
of anunonia at a temperature of 32', the amount
diminishing with increase of temperature. Water
holding ammonia in solution constitutes the common
spirit of hartshorn, whose taste and smell are those of
the ammonia which it contain.s. Ammonia dissolved
in water has alkaline properties, combining with acids
to form salt.s.

Anunonia is easily recognized by its smell conjoined
with its power of changing to blue the color of a bit
of damp, red litmus paper. Anunonia in cojnbina
tion is set free by calcium hydrate and is then
recognized as in Exp. 67. (See page 99).

Nitric Acid is a liquid compound of hydrogen,
nitrogen and oxygen, HNO,. When somewhat

kiV

; ::,rft-:sr::awtrew'w*- ■*

87

diluted with water it is the substance known ns
iKjuafortis. It is a strong acid. It may )>e reco^mized
even in combination by the magnificent red colour
produced when nitric acid or any nitrate is brouj^lit
into contact with a solution of brucine in concentrated
sulphuric acid.

102. How much O, ami how mucli H, in 9 lbs.
water ? in one imperial pxllon :* in one cubic foot i in
one ton ?

103. What are the proportions by volume and by
weight of hydrogen, nitrogen and oxygen in nitric
acid.

104. What weight of O, of N and of H is contained
in 504 lbs. nitric acid ?

§ ^- .Q!iU^h\&^- Symbol, CI ; atomic weight 85.5^
E.rpermients.

Exp. 68. Put a tablespoonful of chloride ofjlime
into a tall narrow jar, pour on it an equal bulk of
hydrochloric acid, and loosc^ly cover the jar with a
card. Effervescence will ensue an<l the jar will be
filled with a transparent yellowish gas, chlorine,
which is so heavy that it will remain in the jar,
if large enough to hold it all. The odour is peculiar
and powerful, but it must be smult at a distance, as
the gas is dangerously irritating to the lungs.

Exp. 09. Sprinkle filings of antimony into the jar.
They will take fire and burn as they fall.

Exp. 70. Dip the end of a strip of blotting paper
into spirits of turpentine and then insert it into the
jar of chlorine. The turpentine will take fire and

In

burn witli a dull red flame, emitting dense clouds of
unconsunied carbon.

Chlorine is a greenish yellow gas, heavier than air,
of a powerful odour and (juite irrespirahlc. In it
nmny metals and hydrogen may be burned, but car-
bon cannot. Exp. 83 furnishes a test for chlorine.

Hydrochloric Arid, HCl. The result of the com-
bustion of hy^lrogen in chlorine is hydrochloric acid
gas, which is higldy soluble in water. At a tempera-
ture of GO", one volume of water dissolves 450 volumes
of this gas. The solution is sold under the names of
hydrochloric acid, muriatic acid and spirit of salt.

Examples.

105. Find the specific gravity of chlorine compared
with hydrogen and with air.

106. The fornnila of spirits uf turpentine is C,oH,6;
how many molecules of hydrochloric acid are formed
by the combustion in chlorine of one molecule of
turpentine ?

107. What weight of chlorine is needed for the
combustion of one ounce of turpentine, and what
weight of carbon will be set free ?

108. What is the composition by volume and by
weight of hydrochloric acid gas ? and what is its
specific gravity compared with air ?

§ 5. Carbon. Symbol, C^ atomic weight, 12. This
substance is most familiarly known as common wood
charcoal, which consists of carbon with a small mix-
ture of potash and earthy and other matters ; it also
exists in large quantity in mineral coal ; black-lead is

80

almost pure carbon ; and the diamond exhibits it in
its pun.*st form. The diamond differs from wood
charcoal only in hoinp^pure and crystalline. Carbon is
infusible and insoluble, and enters into more complex
forms of combination than any other substance. It
is an essential component of every animal and vej^e-
table profluct. Hecatise of its surface attraction dry
porous charcoal, as that of wood or bones, possesses
the reniarkable property of al)sorbin^ from the air
larj^re (piantities of gases and (,»ther exhalations; hence
its use in depriving putri<l meat an<l other <lecaying
substances of their ofi'ensive smell ; it also absorbs
from water many organic .sul>stances which it may
contain, and even some of the inorganic saline
substances.

When charcoal is burned it combines with oxygen,
forming carbon dioxide, C 0^, a gas which disappears
in the atmosphere ; and when animals breathe, the
oxygen of the air which enters their lungs, ccnnbines
with carbcm derived from the blood, an<l is returned
to the atmosphere in this same form of carbon dioxide.

The fact that carbon, when exposed at a high
temperatun; to an abundant supply of oxygen, unites
with it to form carbon dioxide, enables the chemist to
<letect the presence of carbon in any other form than
that of carbon dioxide itself. (See Exp. 77 below.)

Ej'perhnents.

Carbon Dioxide : CO.,. Exp. 71. Pour dilute
hvdrochloric aciTt HTT^Jils of limest(me in a tall,
loDsely covered glass. A brisk efi Tvescence will
ensue, and the air in the glass will be <lisplaced
l)y a heavy invisible gas, the presence of which may
be de.uonstrated by lowering into it a lighted end

11 \

i

i

i

t

i
1

90

of candle, wliich will l)e iniintMliately extinguished,
while the gas itself does not take fire.

Exp. 72. .Pour this gas from the jar into a tunihler,
and show that the tumbler has been tilled, bv lower-
ing a lighted match into it.

Exp. 78. Pour the gas from the jar on a lighted
candle, so as to extinguish it.

Carbon dioxide is a heavy, colorless gas which
extinguishes Hame, is not itself combustible, and which
speedily sullbcates animals that iidiale it. When
dissolved in water it forms carbonic acid, C O. +
H^ O = H2CO3 , a weak aci<l which r;Hldens
vegetable blue colors, has a sour taste, and is capable
of cond)ining with aUidlics such as potash and soda,
with alkaline earths such as lime and with other
bases.

Two of the modes in which carbon dioxide is
produced in nature, namely, condmstion and animal
vespiration, have been already mentioned ; but it may
be formed in many other ways. It exists in large
(juantity in limestone and other rocks, and is given
out by volcanoes, and brought to the surface by springs ;
it is also sometimes disengaged from tissures, etc., in
mines, and accumulates in deep cellars, Wells, etc., form-
ing the "choke damp" which occasionally proves fatal
to persons incautiously entering such places. When
wood, straw, or similar substances, are exposed to air
and moisture, a kind of slow combustion, which we
call decay, commences, part of their carbon and
hydrogen condnne with the oxygen of the air, and
form carbon dioxide and water, until at length noth-
ing remains but a coaly mass capable of little further
change.

01

her

In couse(|U('nce of tlu'se processes, it is evident that
carbon dioxide must he constantly produced and added
to tlie atuiospliere ; and, if this proceeded uncliecked,
it would at lengtli accumulate in so i^reat (|uantity,
that animal life would l)e <lestroyed. But it is found
that the (juantity of carbon dioxide in the air does not
e(|ual the one -thousandth part of its wei<^ht, and is not
increasing. It is also known that water is capable of
dissolving more than its own bulk of carbon dioxide,
an<l conseijuently that rain and surface water are
always impregnated with it ; and it is found by ex-
periment, that plants supplied witli the air an<l water
containing this gas, apply its carbon to the formation
of wood and other vegetable products. It thus appears
that the carbon dioxi<le produced by burning, breath-
ing, decay, and other processes, and which would otlier-
wise contaminate the atuK^sphere, is employed as the
food of plants, and is thus, by the wise arrangement
of a beneficent Providence, ma<le a source of supplying
the most valuable substances which the earth affords
to man.

Expfr line ii ts am f E.n trn/ flcs.

Exp. 74. Dissolve a little baking soda in water
and let a few drops fall into a clear solution of lime
water. Observe the white cloud that is formed. Drop
in two or three drops of hydrochloric acid, and watch
the disappearance of the cloud. The cloud is com-
posed of calcium carbonate, which is dissolved by the
hydrochloric acid.

Exp. 75. Dissolve a little potassium nitrate in water,
and drop a little into lii.ie water ; if the potassium
nitrate be pure no cloud will be formed. The absence
of carbonic acid is demonstrated.

p

i

«' i' SI

f if

I i

Exp. 76. Fuse a little of the potassium nitrate in a
KJiort wide tube of hard <^lass, held over a spirit lamp
by a liandle of twisted wire, and throw into it a bit
of charcoal as lar^e as a grain of wheat. Brilliant
deflrj^ration will take place. Let the tul)e and its
contents cool. Dissolve a little in water and drop the
solution into lime water, A wdiite cloudiness will show
that carbonic acid is now present foi*med by the union
of the carbon with oxygen derived from the fused
potassium nitrate.

Exp. 77. Repeat this experiment with a bit of
wood, of starch, of sugar, of Hnger nail, of beef, or of
any part of any vegetable or animal, and demonstrate
th(i truth of the universal presence of carbon in
animal and vegetable structures.

109. How nmch carbon dioxide is formed by the
combustion of 10 lbs. caibon ?

110. What is the specific gravity of carbon dioxide
compared with hydrogen and with air ?

111. Till.' amount of carbon dioxide in the air is
about four ten-thousandths of its volume, what pro-
portion is that of its weight ?

112. If the weight of the air on every square inch
of surface be 147 lbs., and if six ten-thousandths of
its weight be carbon dioxide, how many tons of carbon
dioxide hang over an acre ?

118. The conditions being as in the preceding ques-
tion, how many tons of carl)on are afloat over an acre
of land ?

§ 6. Sulphur. _ Syndtnl Si ; ntpmiV weight ^^ This
is a w^ell-know^n, brittle, yellow solid. When heated it
undergoes a series of of interesting changes.

93

Experiments,

Exp. 78. Put a toaspoonful of sulphur into a test
tube, heat it over a spirit lamp and watch it. First it
melts into an amber colored, thin liquid. Its tempera-
ture is now 285^, and if cooled at this sta^e it appear.*
a^ain as ordinary yellow sulphur. If still turther
heated it grows darker and thicker, so that at 445° it
can scarcely be poured out of the tube. Heated still
more highly it again becomes thin, but is of a dark
brown color. If at this stage poured into cold water, it
becomes a soft, tough, elastic, dark brown mass.

Exp. 79. Put a part of this brown mass into boiling
water and observe what takes place.

Exp. (SO. Put the rest of the dark brown mass aside
for a month or two and then examine it again.

Exp. 81. Heat some more sulphur in a test tube un-
til it boils, the temperature is then 825 . Observe the
color of the vapour. Pour out some of the vapour on
a cold slate. Flowers of sulphur, as the tine yellow dust
is called, will be formed.

Exp. 82. Set fire to a little heap of sulphur. Ob-
serve the colour of the tlame ami the suffocating
odour. Hold a damp bit of blue litnms paper in the
fumes, and see it first turn red, then white.

The fumes produced in the last experiment are a
gas, sulphur dioxide, S O^, which when dissolved in
water forms sulphurous acid; 8O2 -h H2 O = H^ 8O3 in-
dicates the reaction. Sulphurous acid destroys most
veiretable colors. The solution of this acid in water
slowly absorbs more oxygen from the air ; thus
H2 SO3 + O becomes H^ SO^, sulphuric acid. This in
a concentrated form is a dense, oily, intensely sour and
most strongly corrosive liquid, exhibiting all acid

•■Jvfil

94

properties in tlieir liifj^liest th'^ree. In commerce it is
calleil oil of* vitriol

h\r(t inplcx.

114. With what weijiiht of oxymMi will (SO Ihs. of
sulphur combine in hurnin^- ^

115. A certain sjimple of commercial sulphuric acid
contains two per cent of water, the rest heinii; pure
acid, how much sulphur, hydrogen an<l oxygen are in
each 50 lbs.

116. What is the specific gravity of sulphur dioxide
compared with hydrogen and with air :'

Substances containing sulphur when heate<l by the
blowpipe on charcoal give the odour of burning sul-
phur. Soluble sulphates give, with barium chlori<le,
a white precipitate, which is (piite insoluble in the
strcmgest acids.

§7. Phosij)h()ru.9. SyndK)l, P : atomic weight 81.
Phosphorus is a solid substance, in appearance some-
what resembling bees-wax. It is highly inflammable,
taking fire at ordinary temperatures, so that it must
be kept under water and handled with extreme caution.
It burns with an intense light, evolving dense clouds
of white smoke, Pa O5, phosphoric anhydride. Phos-
phoric anhydride dissolves readily in water, forming
a strongly acid solution, according to the following
reaction, P2 O5 +3 (H2 0) = 2 (H3 P O^ ) ; one molecule
of phosphoric anhydride, together with three molecules
of water, foi* vo molecules of phosphoric acid.

Free phos^ .jrus is never met with in nature. The
phosphates, when they are fused with a bit of mag-
nesium in a closed tube and after cooling are moistened,
give a characteristic odour like decaying fish.

Uo

1.

117. \Vl»,'it wuij-lit of ()X\Li('n is rt'iiuii-cil for tlu'
C()ni[)k'to coiiil>n.sti«>n of 1 II). 15 oz. of phosplionis :*
Wliut wt'i^^lit of phosphoric aiihy<li'i(l(' will he foi-iiurcW

lis. Find the weight of water rucrssarv to ciiana'c
4 Ihs. 7 oz. of ])hosphoric aiihydridi' into phosphoric
acid !* How much ])hos])hoi'i(* acid will he |)roduccd (*

S (S. Soi/ltf)!). Sviiihol Na ; atomic . wcmht, 2*3.
Sodium IS a silver-white metal, so soft as to he readily
cut with a knife or HatteniMl hetween the tincrtTs so
light as to float on water, and so r^sidily acted on hy
oxvufen as to tarnish immcdiat'lv when exposed to
air, and to d' omposo water with great rapidity,
replacing o^ .df (jf its hydrogen. These reactions
are indicatetl hy the following e(|uati(jns : 2 Na + 0 =
Na2 O, so<lium monoxide: and Xa+ H^ () = 11 -|- Na
HO, the last suhstance is called sodium hydroxide or
caustic soda. Sodium monoxide ahsorhs water with
great avidity and with the evolution of much heat,
forming with the w^ater sodium hydroxide, according
to the e(]uati(mNa O+H, 0 = 2 (Xa OH,). Sodium

hyd]

d

roxKie IS an a

Ikal

1 and, as such, is very so

)luhl

e HI

water,and unites with acids toform highlv soluhle salts.
Sodium takes lire in chlorine, forming sodium
chlori<le, connnon salt, an important adjunct to the
foo<l of men and of animals. Xa + CI = Na CI.
Sodium chloride is also foi-med hy the interaction of

d

either sodium monoxide or sodium

h

di

hvd

di

roxide wi

th

hydrochloric acid : thus, Na, 0 + 2 II CI = 2 Na C1 +
H, O, or Na O H + H CI - Na CI + H, O. Similarly
nitric acid acting on either the UKJiioxide or the
livdroxide forms sodium nitrate: thus, Na2 0 +
211 NO, = 2 Na NO, + H.O, or NaOH -\- HNO, =
NaNO, +H^ O, sodium nitrate and water.

■-iJ

I

i^

06

With carbonic acid sodium forms two salts, the
sodium, carbonate and the hydrogen sodium carbonate
commonly called sodium bicarbonate. The reactions
are indicated by the following equations : Na^ O H-
H, CO3 = Na, CO3 + H, O ; and Na OH + H, CO3 =
Na 11003+ Ha O. Similarly with sulphuric acid
are formed sodium sulphate and hydrogen sodium
sulphate or sodium bisulphate, as by the following
equations : Na^ O -|- H, SO^ = Na, SO^ + H, O, and
Na OH + H, SO, =Na HSO, -f H, O.

With phosphoric acid, H3 PO, , sodium forms three
salts according as one, two or three atoms of the
hydrogen are replaced by sodium, the monosodium
phosphate, Na H2PO,, the bi-sodium phosphate,
Na, HPO4 , and the ter-sodium phosphate Na3 PO 4 .

Sea-salt, Na CI, whether directly derived from the
sea, or from the residue of dried-up ancient seas,
rock-salt, dug out from beneath the accumulated
sands, clays and limestones that in the course of
geological ages have been heaped over it, is the source
from which most of the salts of soda used in the arts
are derived.

Another sodium salt, sodium nitrate, Na NO 3, con-
stitutes extensive beds in the rainless districts of Peru
and Chili. This substance, often called in commerce
Chili saltpetre, is extensively used as a manure.

Examples

119. How much sodium and how much oxygen are
contained in 1 lb. 15 oz. of sodium monoxide ? and
how much hydrogen is there in 350 grains of sodium
hydroxide ?

120. In 117 lbs. common salt how many pounds of
sodium and how many of chlorine are there ? and if
the chlorine were liberated at the temperature of 60^,

\)'t

and the pressure 30 inches of mercury, how high
must a room 7 feet square be in order to hold it all ?
121. Find what weight of each of the following
substances contains one ounce of sodium : a. sodium
carbonate, b. hydrogen sodium carbonate, c. sodium
sulphate, d. hydrogen sodium sulphate, e. sodium
nitrate, /. monosodium phosphate, g. bi-sodium phos-
phate, h. ter-sodium phosphate, i. sodium chloride.

§ 9. Potassium. SymljoL-K ; atomic weight 89^
The description of sodium and its compouncis given
above is precisely applicable to potassium, except
that potassium imparts a violet colour to colourless
flames, that potassium chloride is not common salt,
is not used as a condiment, and is not the chief
source of potassium salts, nor is potassium nitrate
found like sodium nitrate in extensive beds in
America, but in South Africa. With these excep-
tions read all that is said under the head of scdium
again, substituting the words potassium and potash
for sodium and soda, and in all the formulao and
equations of reaction inserting the symbol K instead
of Na. Any substance which imparts to a colourless
flame a hue that appears purple when seen through
thick cobalt-blue glass, contains potassium.

Example,

122. Write out the equations which show the mode
of formation of a. potassium monoxide, h. caustic
potash, c. potassium chloride, d. potassium nitrate, e.
the two potassium carbonates, /. the two potassium
sulphates, and g. the three potassium phosphates.
Give the names of the carbonates, the sulphates, and
the phosphates.

\)<

Wood ashes contain nnich potash which is extracted
as lye by lixiviation. The lye is boileil down until all
the water is evaporated ; the solid residue is fused at
a red heat and forms the potash of connnerce. Further
purification produces pearlash, which, however, le-
(piires further ti'eatnu'nt in order to derive from it
pure potassium cai'honati', K2 CO, Most of the salts
of potash are thus derived from tho ashes of trees and
other land plants.

For about .'35 years past a new source of sujiply of
potash has been opened up in Stassfurt, in Saxony,
where thick beds of minerals containin*:^ much potash
have been discovered overlying a deposit of rock salt.
From this locality very lar^^e quantities of minerals
containinjj^ a high percentage of potash are exported
in a crude or in a partially purified state, to be u.sed
as manure under the names of kainit, abi-aum salt,
muriate of potash and sulphati^ of potash. Very re-
cently beds of nitrate of potash have been discovered
in South Africa. *

123. If three ounces of potassium be burned in air,
how much potassium oxide will be formed ?

With how much water will 47 grains of K2 O unite,
and what will be the weight of the resulting potas-
sium hydroxide ?

124. In 101 lbs. of potassium nitrate how much
nitrogen, and how much potassium are there ?

125. If potassium in a manui'e be worth 6c a
pound, and nitrogen 15c a pound, what is the value
as manure of one ton, 2,000 lbs., of potassium nitrate ?

12G. If its value as a manure be estimated by the
potassium it contains at Gc a pound, what is the value

^
^

0\)

of 100 \hH. of potassium monoxide ^ of potassium
hy<lroxido ^ of potassium chloride if of j)otassium car-
bonate ^ of potassium sulpliate ?

127. A certain sample of potashes rjave 44 /, of
potassium carlKmatc and 40 " ., of potassium hydroxide.
What was its value per ion as manure, this bein^
determined solely l>y the potassium present, at Oc a
pound ^

12tS. What is the wei»^]it of eaeh constituent in 1,000
grains of each of the following substances: a. potas-
sium monoxide, h. potassium liydroxide, c. potassium
chloride, d. potassium nitrate, e. potassium sulphate,
f. hydrogen potassium sulphate, g. potassium carbon-
ate. It. hydrogen potassium carbonate, i. mono-potas-
sium phosphate, /'. bi-potassium phosphate, A*, ter-potas-
sium pliosphate.

Note. — Compounds of ammonia arc most readily
understood by assuming that when one molecule of
ammonia meets one molecule of water, the atoms
rearrange themselves as by the following equation :
NH3 4-H, O = (NH, ) HO. The molecule NH, to
which chemists crive the name ammonium, has never
been isolated, but it seems to play in many reactions
the same part as one atom of sodium or one of potas-
sium would <lo. Thus (NH, )H(3, like NaHO or
KHO, is a caustic alkali ; and as these are respectively
named so«lium hydroxide and potassium hydroxide,
so that may be named ammonium hydroxide. Again
as there are sodium and potassium chlorides, nitrates,
carboiiates, sulphates and phosphates, there are
ammonium chloride, commonly called sal annnoniac,
(NH^ )C1 ; ammonium nitrate, (NH^ )^^3 j animon-

il

1(10

iunicarl)oiiato, 2(XH^ )C()^ ; aiinnonium hydrot^cn car-
bonate, (NH^ )H0()3 ; aininoniuin sulphate, 2(NH^ )
SO3 ; and three phospliates,the niono-amnioniuin phos-
phate, (N H^ ) Hj P O^ ; the bi-aninioniuin phosphate,
2(NH^)HP0^; and the ter-auinionium phosphate,
^(NH^ )^0^^ A comparison of the fonnuhe oi these
salts with those of the correspond in <^ sodium and
potassium salts will show the correspondence of the
molecule NH^ to the atoms Na and K.

§ 10. Calcium. Symbol Ca ; atomic wei^it 40
This is a light, yellow metal which oxidizes readily in
air, and wlien heated burns with a bright red light,
producing abundant white clouds of (|uick-liine,
calcium oxide, Ca O. Calcium oxirle readily combines
with water, evolving great heat in the act of combi-
nation ; Ca O -f H2 O = Ca O2 Ha , calcium hydroxide,
slaked lime. Calcium hydroxide is an alkaline earth
soluble in w^ater to some extent, but much less so
than the alkalies, and entering into combination with
acids to form an interesting series of salts.

The alkaline earths are distinguished from the
alkalies by the comparative insolubility of their
carbonates as already exemplified in Exp. 56, and
again in Exp. 88 below.

Experimenti*.

Exp. 83. Into a weak solution of sodium carbonate
drop a drop of lime water. The white cloud produced
is calcium carl»onate as indicated by the equation
Na,,C03 +CaO,H, =CaC03 4-2NaOH.

Exp. 84. Blow air from the lungs into the water
holding the calcium carbonate in solution. After a
while the white cloud of calcium carbonate will

J

101

4lisapp(*ar, for it is soluhlc in water holding car)x)nic
acid in solution.

Calciina carbonate is found ^abundantly in nature
in different states of aggregation as marl, chalk, lime-
stone. When raised to a red heat these calcium
carbonates lose their carbon ^lioxide and quick-lime
remains ; Ca C O3 = Ca O -f- C O, As pointed out
above, quick -lime absorbs water, and becomes slaked
lime, which is mixed with more water and with sand
to make mortar. Mortar hardens chiefly because the
lime absorbs carbon dioxide from the air, and returns
to the state of calcium carbonate.

Quick lime and slaked lime hasten the decomposi-
tion of many organic substances and set free the bases
of many salts by combining with their acids.

Sulphuric acixl and calcium oxide unite to form
calcium sulphate ; H, S O^ -|-Ca 0 = Ca S O^ -f H, O.
One molecule of calcium sulphate united to two
molecules of water constitutes gypsum, Ca S O4 +
2H2 O. When moderately heated, gypsum loses the
two molecules of water and falls into a dry powder,
plaster of Paris, but when again moistened it
reabsorbs the water it had lost and becomes solid once
more. For this reason it is much used in making
plaster casts and ornaments.

There are three compounds of calcium and phos-
phoric acid whose relations to each other are cf great
interest to the farmer. They are :

Name.
Tercalcium Phosphate
Bicalcium *'

Monocalcium "

Formula.

Ca3 l\ O,

Common Name.
Bone-ashes

Reverted Phosphate Cag H
Superphosphate Ca H4 Pg Og

2 P2 0,

102

T«*rcalciiini phospliatr cniistituics tlic i-iN-Mtcr part
of tht' nslu's of hui'ut lioiu's and cnnstitiiti's lari»v IkmIs
of a stony mineral named apatite. It is ahnost
insolul)lo in pure water, lait is very slowly solulile in
water hoUlin^r carbon dioxidi^ in solution. l^icalcium
phosphate is known in trade as revei-tcMl p]ios[)liate.
It is more soluble than'tlu^ ter-calcium phosjihatt', but
very much less scjluble than super})hosphate.

Examples.

129. In 100 lbs. of quick lime, calcium oxide, how
mucli calcium and liow much o.xyp'ii are there; ?

l.'iO. What weight of phosphoric aidiydri<le is there
in 117 lbs. of monocalcium phosphate ^

181. 74 lbs. slaked lime, calcium hydroxide, are
exposed to a current of dry air containin;^ caibon
dioxide until all change ceases ; what amount of
CO2 will be absorbed, of H2 () evaporated, and of
Ca COj producetl ?

132. Twenty pounds anhydrous gypsun), Ca SO ^,
are mixed with seven pounds of water, making
a damp cast; how many pounds of water will be
evaporated in drying the cast ?

§ 11. Afaqnettiu m. Symbol IMg ; ilioiuc_wt'it<''ht 24.
This is a silvery looking metaT which slowdy tarnishes
in the air. When strongly lieated it takes fire, burning
with an exceedingly bright white light, giving oft'
dense clouds of magnesia, Mg O. Magnesia is an
alkaline earth, scarcely soluble in water, uniting
with acids to form salts.

Example.

133. In 100 pounds of magnesia, how mucli magne-
sium, and how much oxygen ^

ion

5 12. SKlcnii. SviiiljulSi : atniiiic \V(>i^lit2H. This is
kiinwn to the clit'iiiist as a lunNvii j)()\\<lri',jH('pai'«'«l w itii
<litKculty, ami of no \isr when prepared ; l»iit its oxide,
silicon dioxide, Si ()^ is most alunidant in nature;
<iuartz, rock crystal, flint, sand aic t'<>rnis in wlncli it
occurs/ [t unites with alkalies, with alkaline earths,
/md with hases nem. rally. \ o-|vat pai-t of the i-ncks
of th(3 earth, especially of the? ])riiimry nxdvs, are
mixtures of silica and the silicates. For e\ani})lc,
<;ranite is plaiidy seen to he a mixture of thrt?e
minerals, one glassy and transpai'ent, (piart/: one
somewhat poi'Ci'lain-liki' in appearanc, felspar, an«l
on<' in tile form of scales intermixed with the others,
nnca. (^)uaitz is silica : ft'lsj)ar is j)otassium alumi-
num silicate : and nnca is in the main a complex
silicate (>f aluminum, potassium an<l iron.

The silicates of the alkalies and alkaline earths are
fusible and melt into transparent j^jlass. (dass is
tinted of various colours, some of them of ori^it
l)eauty, by various metals and their compounds.

E.rampJf.

184. In one ton of sharp sand, pui'o silica, how
many ptanids of oxyi^cn.and how many of silicon are
there i*

§ 18. Alirm'uni'ii.. Symbol Al : atomic vei^dit^2.7^
This is a li;:^]it metal not much hea\ iei' than ;;1jiss. white
and brilliant, intermediate in appearance between sih'er
and polished steel, now used for various piu'poses in
the arts. It unites with oxy^^en, fornjin<.,f a white
powder, alumina, AI2 O3 . This acts as a weak base ;
it unites with silica, forming- aluminum silicate, the
principal ingredient of many minerals. Clay is a
mixture of many substances in varying proportions,

5 1,

f I
• I

5»

.

^

,

1

*

'l

104

Ijut in which aUnninuin silicate and silica priMlouiin-
ate. When a lump of clay is exposed to great heat,
among other changes some of its particles undergo
fusion, and bind the rest into a firmly coherent mass.
According to the character and amount of other
substances mixed in the clav, bricks, earthenware and
porcelain are produced.

Exa^nple.

135. In 1,000 grains of alumina, how much
aluminum is there ?

1 14. Iron. Symbol Fe ; atomic weight 56.

§ 15. Mcmganese^ Symbol Mn ; atomic weight 55.

These "are heavy metals occurring int-Tie ashes of
plants. The common metal iron everyone knows.
On exposure to air and moisture it rusts, that is it
combines with oxygen, and constitutes an oxide
known as ferric oxide, Fca O3 , of which the yellow or
brown rust of iron and red ochre are examples. This
substance occurs in most soils, and gives to them a
reddish or brownish color. There is another oxide of
iron, ferrous oxide, Fe O, having less oxygen, which
occurs in some wet soils and bog waters. It has
a greenish or greyish color, and when exposed to air
passes into the ferric oxide. Common green vitriol is
ferrous sulphate, Fe S O^ . The oxides of iron occur
in very small quantity in the ashes of plants.

Oxide of maganese occurs in still smaller quantity
in plants, and is sometimes absent. It is hence not
supposed to be essential to th'ir healthy growth.

f

\\J^' CHAPTER VI.

PLANTS, THEIR FUNCTIONS AND STRUCTURES.

§1. Living Tlvlngs. Living tilings are distinguished
from things destitute of life by two fundamental
peculiarities. Living things have definite active func-
tions to perform ; and they cease to be when these
are performed — they die. From the fact that they
have active functions to perform arise two peculiari-
ties ; they are organized, that is, they have parts
specially fitted to discharge their functions, and, since
force is necessary for the performance of function,
and since nothing creates force, every living thing re-
quires that force shall be supplied to it from without.
Organization implies parts subordinate to, but together
constituting, a whole, an individual. Again, because
individuals perish, preparation for the perpetuation of
the race is made by processes of reproduction. New
individuals begin life small in size, and incapable at
first of performing all their functions, that is, they
are immature. Hence living things both grow and
develop. They grow by changing substances, more or
less unlike themselves, into their own proper sub-
stance, and in doing this they add the new material
between and among the minutest particles of their
substance ; that is they grow by interstitial assimila-
tion. A necessary geometrical result of interstitial
growth is a tendency to rounded forms in the outlines
of living things. Living things, beginning immature,
acquire with lapse of time increasing complexity of
structure and of function, until maturity is attained.

106

II

H

m

i

After a f,n*cat<u' or loss period of full vigour, decay of
tlie organism aiKl diminution of power progress, until
death closes the life-cycle of the individual. Repro-
duction tends to the renewal of the parental forms.
Hence living things that are related to each other by
a common ancestry are in all important respects alike.
The sum total of livinj^ thin<js that resemble one an-
other, as nmch as the descendants of a known conmiou
ancestry resemble each other, constitutes a species.

The following conspectus exhibits the most import-
ant peculiarities of living things and the relation of
their peculiarities to each otlier : —

LIVING THINGS.

1 Discliargt3
fiiiictiuiis

f me organized as individuals;
I. re

quire supplies offeree from "without.

I at the cost of food ;
f grow -^ by interstitial assimilation;

2 Die .•. reproduce .-. ■{

( and.*, have rounded forms ;

devplon / ^''^^"^ infancy to maturity,
j ac\eiop I ^j^j .^,^^^ ^^^^ ^j^^^jj .

[ constitute species.

Living things, on the ground of difference of func-
tion, are divided into two kingdonis, vegetable and
animal.

§ 2. The Vcgetahle. A vegetable is an organism
designe<l to store up force, an animal to utilize force
while dissipating it. The force which the vegetable
stores up is sunlight: the work that is done by sun-
liirht in the vefretable ororanism is the deoxidation of
various compounds, chietly carbon dioxide and water,
the liberation of a part of the oxygen and the synthesis
of the residues into the various combustible substances
of which the plant is built up. Just as coal is a store
of force utilized in the steaui engine, so is the plant a
store of force utilized in the animal that feeds upon it.

1(»;

)!'

The power of tlie plant to employ sunlight in the
deoxidation of the compounds on which it feeds, is
absolutely dependent on the presence of chlorophyll,
the green coloring matter of leaves ; hence only the
green parts of plants prepare their nutriment, and
these act only in daylight.

Every plant uses up some (jf its own material in
the work of organization. The seed in germinating,
the bud in unfolding, the flower in developing, the
fruit in ripening, absorl) oxygen, erhale carbon dioxide,
in fact undo a little of the work which the green parts
of the plant have l)een doing at the expense of sun-
light. This work of organization proceeds independ-
ently of sunlight, while the w^ork of preparing material
by deoxidizing carbon dioxide, etc., always demands
sunlight.

Some plants have no chlorophyll, and so prejiare
none of their own material. All tliese are dependent
on material previously prepared by other plants. Some
of them are parasitic on other plants as the dodder
which infests flax fields. Some develop in the interior
of living plants, as the rust and the smut which
invade the wheat plant, or as the fungus which
destroys the potato.

Some of them develop in the bodies of animals, and
are the cause of many painful and fatal diseases.
Many of them, from the microscopic mouMs that
develop in decaying bread or cheese or jam, to the
mushrooms that flourish in rich pastures or the gigantic
woody excrescences that grow upon the boles of
decaying trees, are saprophtes ; they arrest the progress
of dead organized matter on its way to decomposition,
consuming a part in or<ler to organize the remainder
into new forms of life.

It

l!!

lOS

The substances which constitute the food of plants
when taken into the system of a vegetable, have
entered into a chemical and vital laboratory, where
they are destined to undergo a scries of changes, end-
ing in their assuming forms and properties very
ditterent from those which originally belonged to them.
It is therefore necessary that we should consider the
organs of plants ; the vessels or utensils as it were,
which nature employs in converting the unorganized
matter of the soil and air into food for men and
animals.

The f/eneral struct itre of all plants is nearly the
same. The wood of the hardest tree, as well as the
stem of the most delicate herb, is composed of an
immense number of very small tubes and cells, whose
sides consist of woody matter, enclosing cavities suited
for containing or transmitting sap or other fluids.
These cells and tubes assume many different forms,
varying from those of nearly round bags or bladders,
to those of long pipes, sometimes extending through
the whole length of a plant. They also differ very
much in dimensions, direction and mode of arrange-
ment ; and it is to these differences that we must
ascribe the various degrees of coarseness and fineness,
toughness and brittleness, hardness and softness, which
we observe in the w^ood of diflerent trees, as well as
the various kinds of texture which appear in the
organs of every individual plant. To examine these
varieties of structure, and the purposes which they
serve, is a pursuit full of interest and instruction ; for
the present, however, we must content ourselves with
a very general outline of the subject, taking for our
example the structure of trees, which are the largest
and most perfect specimens of vegetation.

109

The trunk and branches of a tree may be viewed
as consisting of three parts — Bark, Wood and Pitli.
The true Bark consists of a tissue of cells, closely em-
bracing the tree, of a white or brownish c )lour on the
older parts of the trunk, and green on the young
extremities of the twigs. This inner or true bark is
covered and protected from the air by an outer skin
or covering, which in some trees, as the white bircli,
consists of numerous thin and tough layers. In some
plants, as the grasses, this outer bark is the only
external covering which appears, and in these plants
it often consists in part of dense inorganic matter, con-
stituting the strongest part of the stem. The Wood
is principally composed of cells and vessels of various
forms and sizes, arranged lengthwise in the stem, and
crossed by bundles of cells placed horizontally, and
extending from the centre of the wood to the bark, so
as to form thin plates stretching across the wood, and
called the silver grain, or 'medullary rays. The office
of these is supposed to be that of conveying fluids from
the bark to the heart of the tree. The Pith, which is
present only in young branches and small stems,
consists of large cells placed horizontally, and it
probably serves to store up superabundant sap till it is
required by the plant. These structures, though most
obvious in the trunk, are continued into the branches,
and, in some degree, into the leaves. Though the
structure which we have noticed prevails in trees, and
in a great number of herbaceous plants, there is a
large proportion of the vegetable kingdom which shows
no regular arrangement of bark, wood and pith ; and
the whole of the grains and grasses are of this last
kind. In these plants, however, the parts discharging
the different functions of wood and bark are no

: i

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wanting, l»ut ratln-r iiitiiiiat<'ly unite*.! instead of being
separated into different portions. We may now con-
sider tlie functions of those ormxns which belonor to
nearly all plants.

§ 3. The Boot

The larger branches of the I'oot, like those of the
trunk, consist of bark and wood ; but in their smaller
ramifications both bark and wood become soft, porous,
and easily peneti'ated by water; and these minute
and greatly divided extremities of the roots, penetrat-
ing to every part of the soil around a plant, are its
true mouths or feeders. The spongy rootlets arc
capable of taking only fluid f(K)d ; no particle of clay
or other undissolved matter can enter them ; thev
absoi-b water, and this in so large a (piantity that a
sunflower three feet high has been stated to draw
from the soil thirty ounces of water in tweb'e hours
of a sunn\' day. fhit the water of the soil is not
pure ; it contains a great variety of mineral and other
substances in solution, and these it nmst carry to the
roots of every plant which grows upon it.

That growing plants absorb water by the roots,
and that the water so absorbed carries with it
substances held in solution, may be easily demon-
strated bv raisinuf from the soil a \'im)rously ucrowino-
succ\ilent plant, washing the earth gently from its
roots, and innnersing them in a bottle of water
containing cosine, red diamond dye, in solution. The
^y^».^e^ - ill disappear, and that it is passing upward
mi() tlic piiint will be shown by the red coloui'inn;:
M ^^t' f* creeping slowly up into the stem and leaves.
Do ill plan •; thi^n. which can grow on the same soil,
re(]uire from it the same kinds of food ? Experiment

Ill

'1*

e

t

shows that this cannot be the case. If a pea and a
plant of wheat grow side by side, and if both be
gathered and burned, the ashes of the wheat will be
found to contain a large proportion of silica or flint,
which served to strengthen its straw, while those
of the pea will be found to afford scarcely any of this
earth. The water of the soil must have brought a
certain quantity of silica to the roots of the pea as
well as to those of the wheat, but by the former plant
it was rejected as useless, while to the latter it was
absolutely necessary. It becomes therefore an in-
teresting question whether the roots themi>elves have
the power of selecting from the soil what is required
by the plant, or whether they absorb all matters
indifferently, and leave to the other parts of the plant
the office of selecting the most proper kinds of food.

A brief discussion of the manner in which sub-
stances dissolved in water pass through animal and
vegetable membranes will throw some light on this
question.

If in a bag of animal membrane, say the lining
membrane of a turkey's crop, a mixture of sugar, salt,
dissolved gelatine and thin, boiled starch, be tied up
rnd the whole set to float in a pail of water, it will be
found, after the lapse of some hours, (a) that the
membranous bag is fuller than at first, water having
entered it ; (b) that some salt and some sugar have
passed out through the membrane so that the water
on the outside has become just as sweet and just as
salt as the liquid within the bag ; but (c) that no
gelatine and no starch can be detected outside the
bag. From the results of many such experiments,
varied in countless ways, it is now known that
crystalloid substances, such substances as will

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crystallize, e.g., sugar and salt, will pass through a wet
membrane to mix with water on the other side, while
water will come through in the opposite direction to
dilute the strong solution, and that this will continue
until the solutions on opposite sides of the membrane
are of equal strength. It is also known that colloid
substances, such as form a jelly with water, e.g.,
gelatine and starch, will not pass through a membrane.
This passage through the membrane, called osmose,
does not depend on the vitality of the membrane,
which, indeed, in the case supposed, is dead, and which
might be inorganic ; and the membrane exercises no
selective power, all crystalloids pass through it
indifferently, and colloids never pass.

So the roots of plants, apparently of all plants
indifferently, transmit to the interior of the plants
whatsoever crystalloid substances the soil waters
bring, and continue to do this until each crystalloid is
of equal strength of solution in the sap and in the
soil water. If the plant removes one ingredient by
consuming it, the soil water continues to provide it,
as fast as removed, until the soil itself is exhausted.
If the plant uses none of it, equilibrium is soon
established between the sap within and the soil water
without, and no further interchange of that particular
substance is effected. The selective power, then, lies
not in the thin membranes that constitute the walls
of the delicate cells at the extremities of the roots,
but in the whole economy of the growing plant.

Similar considerations throw light on the excretive
power of roots. Plants produce various crystalloid
substances that are dissolved in their sap. Such sub
stances will be transmitted outwardly, to be retrans-
ferred inwardly when they have been chemically

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changed l»y acting on suUstancis outside the plant.
A demonstration ci tlie excretion of organic matter is
furnished l>y the f »ct, tlmt when grain is ma<le to sprout
in powdered clialk, after germination lias taken place,
a part of the chalk (calcium carhonate) is found to be
converted into calcium acetate ; acetic acid (vinegar)
having been produced in the young plants and given
out by their roots to combine with the lime. Rootlets
growing on litmus paper mark it with red lines, and
plants growing in a layer of sand on a marble slab
etch a tracing of such roots as reach it on the polished
surface.

In strict accordance with the laws of osmotic trans-
fer is the fact that chemical substances which have
entered the plant in combination with other substances,
and have been separated from them in the plant, may
be then transferred outwardly, and there undergo
such chemical changes as may lit them to be re-trans-
ferred inwardly. Silica alone cannot be dissolved in
water, but when it combines with potash, suda, or
other alkaline substances, in certain proportions, it
becomes soluble, and in this state it enters into the
vessels of plants. Silica however requires nearly half
its weight of potash or soda to render it soluble, and
on examining the ashes of ripe wheat, it is found that
the quantity of silica which they contain is four times
that of their alkaline matt(^r ; or that there is present
in the ripe plant only half the quantity of alkali re-
quired for the solution of the silica which it contains.
It is evident therefore that a portion of potash or soda
has been sepai*ated from the silica w^ith which it w^as
combined, and has been expelled, and perhaps this
process may take place repeatedly, so that a small
quantity of alkali may be the means of introducing
much silica into the straw of wheat.

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An explanation of the well known benelits of a
rotation of crops has been attempted on the supposition
that the excrements disengaged from the roots of a
plant, must be hurtful to others of the same kind if
planted in the same soil, while on the other hand they
might be nutritive to plants of other kinds. Thus if
the roots of a pea be placed in water, they communi-
cate to it in time a brown color, in consequence of
gummy secretions being thrown oft' from the plant ;
and if, after the water has thus been filled with ex-
crements, another plant of the same kind be placed
in it, it will not flourish ; but if, instead of a second

f)ea, we place in it a plant of wheat, this will grow
uxuriantly and take from the water a part of the
matter previously deposited in it. In the same manner,
the soil in which any species of vegetable has long
been cultivated may become surcharged with its ex-
crements and the substitution of some other crop,
which can free the soil from these, may be rendered
necessary. But the latest experiments and observa-
tions on this subject seem to show that the organic
excretions of plants have practically little effect on
their culture, and that the extent to which they re-
move mineral matter from the soil is really the
principal cause which renders the soil unsuitable to
them. This we must consider under another division
of our subject.

§ 4. The Stem.

That the water absorbed by the roots is carried
upwards into the stem, is evident from a consider-
ation of what takes place when a plant is grown
in a solution of eosine as before described. This
water in its progress becomes more or less mixed

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with the fluids existing in the plant. In consequence
of this interiFUxture, and probably also of changes
effected by the agency of the cells and vessels through
which it passes, the sap of trees, even in the lower
part of the trunk, differs much from the water which
the roots are sucking from the soil. Thus in spring,
the sap of the maple is rich in sugar, a substance which
it could evidently not obtain from the water in the
ground. The presence of this sugar is due to the fact
that many trees store up in autumn a quantity of
starch, and possibly other substances, in the cells of
their stems and roots ; and in order that the starch
thus prepared may be rendered useful in advancing
the growth of the young leaves, the first process
necessary is its conversion into sugar, a change, as will
afterwards be seen, very easily effected. In spring,
before the leaves are developed, growth is going on
very slowly, and the sap not being used in the forma-
tion of wood and leaves, is allowed to accumulate in
the wood, and when the tree is stimulated by the light
and heat of the sun, may be obtained by tapping it.
But as soon as the leaves are formed, the sap is rapidly
withdrawn to furnish materials for their growth, and
for the formation of wood ; and for this reason it can-
not then be obtained in the same quantity or of the
same quality as in early spring.

§ 5. The Leaves.

A leaf, as it appears to the unaided eye, consists of
a framework of tough fibres, proceeding from its stalk,
and branching over it in every direction ; on these are
stretched two skins or membranes forming its upper
and under sides, and the space between these is filled
with soft and pulpy matter. When examined with

I

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the microscopo, otlu^* structures upiuMir. Tlw surfaces
of the leaf, especially the lower one, are found to ho
perforated with nuim^'ous minute- opi^nings, connnuni-
catin«jf with small cavities in its interior; the j^roen
matter is found to consist of cells tilled with a soft
l^reen suhstance; and tlu^ fihres are found to he formed
of vcsstds similar to thost; of the wood. Into tlui leaves
thus constructed, the sa]) is convt^yed from the stem
hy m(;ans of tlu^ stalk and tihres; from these it i)ass(;s
into the cells of the <j;reen matter, where it is exposed
to the action of th(5 external air, and of the light and
heat passing through the outer mend>ranes. Under
the influence of these powerful causes of chemical
change, the leaf becomes the seat of important pro-
cesses.

1 A large portion of the water of the sap escapes
trom the leaves by evaporation and perspiration.
Water contained in a vessel in which the roots of a
growing plant are placed is gradually drawn up and
given out by the leaves, until at length, if not renewed,
it becomes altogether exhausted ; and then the plant
droops and withers, because the leaves are rapidly
exhaling its Hinds, while the roots are receiving no
new supplies. This emission of water proceeds with
the greatest rapidity when the plant is exposed to the
direct ravs of the sun, and in darkness it becomes
veiy slow or ceases altogether. Thus the sun-tlower,
which, in a sunny day, can give off 30 ounces of
water, emits only 3 in a dry night, and none in a dewy
one. In* consecpience of this rapid escape of water,
the substances which it held in solution are left in a
more ctmcentrated state, and ready to be deposited
wherever they are required. The large ({uantity of
water which thus passes through their system also

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i'niil)l«js plants to obtain from tin; soil alannlanco of
many suljstances which are containt'd in it in very
small quantity, or arc with <lirticulty soluhlo in water.

E.rpcriwrtifti.

Exp. (S.5. Invert a tumbler over some thickly j,^row-
in<^ herhaf^e on the ground, as a mass oi duckweed or
some turf. Observe the amoiuitof moistiuv condensed
in the tund)ler.

Exp. 80. Pinch a fi^rowing leaf gently between two
pieces of glass in the .sunshine for twenty minutes.
()bserv(^ the gi'eater amount of moisture given oiYhy
the lower side of the leaf, because the lower side has
more pores than the upper side.

It is not easy to determine just how great the
amount of water exhaled by the growing plant i.s.
Investigators have been led to discordant results,
probably because the amount of transpiration is
influenced by many conditions, — by temperature, by
the amount of moisture in the .soil, by the humidity
of the air, and by the amount of sunlight, as well as
by the nature, the vigour and the degree of maturity
of the plants investigated. As an approximation to
the truth it may, perhaps, be said that for every
pound of dry material formed by the growing plant
it transpires 350 to 400 pounds of water, and that,
perhaps, 10 tons of water are evaporated daily from
an acre of ground covere<l with vigorous vegetation.

The powers of the leaves, w^ith reference to water,
are not limited to exhalation; in some cases they can
also absorb it from the atmosphere, or from the rain
and dew which fall upon them. It is thus that
drooping plants may be revived by watering their

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leaves, and thus that the air plants of China and
Buenos Ayres flourish when suspended from the walls
and balconies of liouses, without any connection with
the ground. But the amount of water thus imbibed
by such plants as the farmer cultivates is very small.

2. The leaves absorb and decompose carbon dioxide,
which, as before stated, exists in small quantity in
the atmosphere, and is the principal source of the
carbon in plants. If a vegetable be confined in a
glass vessel containing air, with the usual proportion
of carbon dioxide, or having a little more artificially
added, and then placed in the sun, after some time it
will be found that a part of the carbon dioxide has
disappeared, and that a corresponding quantity of
oxygen occupies its place. This change is eflected by
the leaves, and other green parts of the plant, which,
therefore, have the power of absorbing carbon dioxide,
decomposing it, retaining the carbon, and expelling the
oxygen.

If a handful of parsley be bruised, squeezed into a
cup and covered with alcohol for a few hours, an
alcoholic extract of olilorophyll will be made, which
will appear green by transmitted and reddish brown
by reflected light. It is to the presence of this sub-
stance, chlorophyll, that leaves owe their colour, and,
as before remarked, their power of decomposing carbon
dioxide.

This decomposition of carbon dioxide proceeds with
rapidity in sunlight; it goes on much more slowly in
the shade, and ceases altogether in darkness. Accord-
ingly, during the prolonged sunshine of the summer
in arctic and subarctic regions, vegetation advances
with extraordinary rapidity. At A I ten, in Norway,
lat. 70® N., peas have been known to grow in length

119

3 J inches in 24 hours, and some of the cereals 2 J
inches in the same time. At the same place barley
ripens twenty days earlier than at Christiana, 10*^
further south, where also the average temperature of
the summer is 6° F. higher.

While leaves absorb and decompose carbon dioxide
in the sunlight only, all developing parts of the plant
are constantly absorbing oxygen and emitting carbon
dioxide ; relatively in much smaller quantity, it is
true, during daylight, so that this process is then apt
to be oveHooked. As the latter process goes on in
darkness, when the former is wholly arrested, it then
attracts attention, but in 15 or 20 minutes of direct
sunshine a plant will decompose as much carbon
dioxide as it exhales during a whole night.

The decomposition of carbon dioxide by the leaves
of plants is most important to their growth, because
upon the carbon thus fixed in their structures their
strength and solidity in a great measure depend ; and
as this decomposition can only proceed in the pre-
sence of air and light, plants cultivated where these
are deficient, become blanched, slender and watery.
For the same reason, potatoes and other vegetables,
cultivated for the starch and similar substances con-
tained in their roots, are unable to obtain the neces-
sary quantity of carbon, and in consequence produce
a crop of inferior quality, when cultivated in the
shade or too thickly crowded. It is thus also that
where plants can obtain light only in one direction,
they grow toward it ; for the side next the light being
able to fix more carbon, becomes firm and woody,
while the other, being soft, extends more rapidly, and
hence the stem bends toward the light. From the
same cause the wood of trees which have grown in

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open ground, ivS more hard and durable than that of
those which have lived in thick forests.

3. The leaves absorb and emit other gaseous bodies
beside carbon dioxide. Experiment shows that the
leaves cannot absorb nitrogen directly from the air,
but that they readily absorb the ammonia and nitric
acid floating in it, and, by decomposing these obtain
the nitrogen recjuired by the sap. The various odors
and perfumes exhaled by many leaves and flowers
are all volatile matters, formed in their cells and
vessels, and which would probably be injurious if
retained.

In the leaves, then, the sap loses much of its water,
receives an additional quantity of carbon, and is
subject to other changes afterwards to be considered ;
thus altered it passes into the vessels of the bark.

§0. The Bark.

"■^The pi-incipal office of the inner bark is to apply to
the formation of new tissues the substances contained
in the thickened sap which it receives from the
leaves. For this purpose this fluid is carried down-
war<l, adding new matter to the outer surface of the
wood and the inner surface of the bark, and pene-
trating by the me<lullary rays to nourish the interioi-
of the tree. In this manner it returns to the roots,
by whose extremities its waste and useless portions
are probably returned to the soil ; and the remainder,
becoming mixed with the ascending sap, is aj^in
carried upward to the leaves. In some plants, such
as the grasses, which have no true bark, the descend-
ing sap probably passes through a particular set of
vessels, which are mingled among those which carry
the ascending sap.

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Frcmi the very short and general view whicli we
have taken of the nutrition of vegetables, it appears
that their food IS obtained from the water contained
m the soil and by the leaves from the atmospheric
air; that the substances obtained from both these
sources are united in the leaves ; and that they there
undergo changes fitting them for being converted
into the various matters which are found in the roots
stems and fruits of plants. The nature of those
changes, and of the substances which result from
tliem, are next to be considered

CHAPTER VII.

ORGANIC COMPOUNDS PRODUCED BY PLANTS.

§1. Organic and Inorganic Substances.

All the forms of matter which we observe on the
globe, may be divided into two great classes,
Organized and Unorganized matter. To the latter
belong all those rocks, waters, metals, and other
substances, which neither are nor have been the seat
of life, and which constitute the mass of our earth.
To the former belong the bodies of animals and plants,
and the various substances composing them, such as
flesh, blood, starch, wood, etc. These compounds
being produced by organized bodies, those possessing
life and organs for its maintenance, are hence
properly named organic substances.

Organic substances are all compound, and when
exposed to air and moisture, they decay and, except a
small quantity of fine dust, gradually disappear into
the air. When burned or exposed to heat, they are
decomposed, and some, such as fat, gum and sugar,
are entirely dissipated in a gaseous state, while
others, as wood and lean beef, leave a small quantity
of ash. This ash, as will be afterwards seen, is an
essential and necessary part of vegetable structure,
and consists of substances w^hich the plants have
taken from the soil, and which are distinguished as
inorganic. By the mere application of heat in
presence of air, or by burning, we can thus separate
the mass of any organized body, a plant for instance,

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fty

Ian
Ire.

las
lin
]te

into two groups of substances, — the organic, wliich
usually constitutes the greater part of the mass, and
which burns away, and the inorgnnic, or earthy part,
which remains as the ashes. The inorganic matter
contained in the ashes of plants, though by no means
of secondary importance in agriculture, may be left
for the present unnoticed, while we attend more
particularly to their strictly organic part, reserving
the ashes for a subsequent chapter.

§2. Organic Part of the Plant.

It was before stated that all the known varieties of
matter consist of between sixty and seventy simple
substances ; but it is a still more remarkable fact, that
plants of every description, with all their endless
variety of appearance and properties, consist for the
most part of but four of these elements, carbon,
oxygen, hydrogen, and nitrogen. The same remarks
apply, with ecjual truth, to animal substances.

The proportions of the constituents of plants vary
somewhat widely in different plants, and even
more widely in different parts of the same plant.
Tobacco contains three times as mu'ih ash as an equal
weight of hay, and the grain of wheat six times as
much nitrogen as the straw. But a first rough
approximation tojbhe truth is made by the statement
that the plants cultivated by the farmer, when
thoroughly dried, consist of about 47% C, 40% O,
5% H, 2% N, and 6% ash. More exact statements
will be found in the table page 141.

It will be observed that carbon preponderates in
the composition of the vegetable. This substance is
never absent from organic compounds. It is to its
presence that these substances owe that liability to

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char when exposed to heat, by which tlie chemist
often distinguishes organic from inorganic substances.
Carbon, as ah'eady stated, is neither volatile nor
fusible at the highest temperatures of combustion,
consequently ^' hon a substance containing much
carbon is exposed to a high temperature with limited
access of oxygen, the associated substances are burned
or volatilized, leaving some or all of the carbon behind
to reveal itself by its intensely black colour.

It thus appv-Ars chat three of the four elements
which chiefly con ih'ii ..o the solid structure of animals
and plants, are, in theii pare state, invisible gases,
and the remain' "^g one '. identical with ordinary
charcoal ; yet into how greu' :>, variety of beautiful
forms and valuable products are they transmuted by
nature, and how interesting and instructive must be
the study of the ways in which these wonderful
processes are effected. This becomes still more
remarkable when we add that by far the larger part
of the mass of vegetables consists of substances
composed of three of these elements only — carbon,
oxygen and hydrogen. Of this nature are wood,
starch, sugar, etc. The substances containing nitrogen,
or the nitrogenized substances, are in comparatively
small quantity in plants, though of vast importance,
since they are those on which the subsistence of
animals chiefly depends ; for while the organic part of
the plant consists chiefly of non-nitrogenized matter,
that of the animal consists principally of the
nitrogenized.

§ 3. Organic Substances Arranged in Groups.

We have seen that carbon dioxide, water, ammonia
and other substances, which form the food of plants,

125

ful
liore
art
ces
on.
od,
en,
ely
ce,
of
tof
ter,
Ithe

iia

its,

are taken into tlieir cells and vessels, and constitute
the raw material wliicli afi'()r<ls the carbon, oxygen,
hydrogen an<l nitrogen required for the formation of
their tissues and products. Nothing in nature is more
wonderful than the processes of organic chemistry,
by which the plant succeeds in forming out of so few
elements that almost endless variety of woods, resins,
oils, gums, acids, sugars and other matters which are
contained in plants.

It is to the presence of different compounds of
these descriptions that vegetables owe the diversity of
tastes, odours, colours, and of nutritious, poisonous, or
medicinal properties, which we find in different plants
and in different parts of the same plant ; a diversity
so great that we can scarcely help considering every
vegetable to be endowed with the power of arranging
in ways peculiar to itself, the simple substances con-
tained in its food. .

To examine in detail all this vast variety of vege-
table products, and endeav^our to discover the causes
of their production, would form an interesting study ;
but it would lead us far from the applications of
chemistry to common agriculture, and would involve
us in some of the most difficult questions in the
science; questions, many of which are yet unanswered,
or but very imperfectly understood. There are, how-
ever, some of these substances so generally diffused
among plants, or so valuable to man, that they must
receive our attention, if we would wish to know of
what the produce of our fields consists, how it is pre-
pared, or how it can be best obtained. We may for
our present purpose divide these substances into two
groups, the Non-nitrogenized and the Nitrogenized,
a<xain subdividing the Non-nitrogenized into three

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subordinate groups, viz., carbohydrates, acids and fatty
or oily substances.

§4. Carbohydrates.

The greater part of the substance of vegetables
consists of compounds destitute of nitrogen, contain-
ing, therefore, only three of the four organic elements.
Of these substances we may notice :

1. Cellulose or Woody Fibre, so named because wood
is almost wholly composed of it. It is present in the
stems, roots and leaves of nearly all plants, forming
the sides of their cells and vessels ; and hemp, flax
and cotton consist of cellulose nearly in a state of
purity. When the wood of different trees is analyzed,
it is found to vfvy somewhat in its composition, pro-
bably because the cells and vessels of wood become
incrusted or partially tilled with other matters which
cannot be easily separated from the true woody fibre.
It fs, perhaps, for the same reason that the composi-
tion of cotton, pith and the cellular matter of soft
vegetables is found to differ slightly from that of the
wood of trees.

In pure cellulose, however CeH.oO., the quantity
of oxygen is 8 times that of the hy irogen ; or, in
other words, these two elements are in the proportions
required to form water ; HO th&t woody and cellular
matter may be viewed as composed of charcoal and
water ; though it is evident that the water or its ele-
ments, which thus compose more than half the weight
of wood, must be in a very different state from that
in which this fluid is usually found. For this reason
it is that this group of substances is designated by
the term carbohydrates.

2. Starch. — This substance is, like wood, contained

127

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llular
and
ele-

leight
that

jason

by

lined

in nearly all plants, but, while wood is the mat(;rial of
the cells and vessels, starch is at particular seasons
stored up as a reserved stock of food, to be employed
when other supplies fail, or when a growth more
luxuriant than ordinary is required Many plants
whose stems die in autumn, form larfje roots or under-
ground stems, containing matter fitted to send forth
and nourish vigorous shoots in spring, and this matter
very frequently consists in great part of starch. The
tubers of the potato, for instance, are constructed of
cells, each of which contains several littk^ grains of
starch, destined, if not used as food by animals, to be
drawn off by the vessels of the sprouting " eyes " in
spring. Grains of all kinds, and many other seeds,
contain large (juantities of starch, destined to furnish
the first food to the seedling plant. Thus wheat con-
tains from 59 to 77 per cent, of starch ; barley 67 to
70 ; oats, 70 to 80 ; rice 84 to 85. Starch therefore
forms a large part of bread, and most other kinds of
vegetable food ; in using which we are applying to the
promotion of our growth w^hat plants have prepared
for theirs.

Starch, when pure, is colorless and tasteless ; it is
not dissolved by cold water, but with hot water it
forms a jelly which by prolonged boiling becomes clear,
the starch havinof been rendered soluble. The com-
position of starch is indicated by the formula Ce H10O5,
the same as that of cellulose.

3. Gum. — Of this substance cherry gum and gum
Arabic are good examples. It is found in the state of
mucilage in the sap of all plants, and in nearly all the
roots and seeds used for human food. Gum dissolves
in water, forming mucilaginous solutions ; that ob-
tained from different plants differs in solubility, some

10

iljj

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varieties being soluble only in hot water, others in cold,
and others forming a kind of jelly. The composition
of gum is the same with that of starch, Ce H,o O5,

4. Sugar. — The most familiar example of this sub-
stance is common cane sugar, sucrose, which is found
abundantly in the sugar cane, maple, Indian corn, beet,
and various other plants. The composition of cane
sugar ditiers little from that of starch and gum. It is

V^,2 ^22 ^If

In a number of plants, varieties of sugar are found,
differing somewhat in chemical constitution from that
of the cane. The most important of these is grape
sugar, glucose, which contains more of the elements of
water than any of the substances before noticed, its
composition being Ce H,2 Oe. This sugar is less sol-
uble in water and less sweet than the common variety.
It is found in honey, in germinating seeds, in fermented
liquors, in the grape, gooseberry, apple, plum and most
other fruits. It is therefore especially the sugar of
fruits and of germinating seeds, as cane sugar is
especially that of the general sap.

Before proceeding further, we may pause for a little
to consider some of the Diutual relations of the four
substances which have just been described. They are
produced by vegetables in greater abundance than any
other substances, and are concerned in most of the
changes which take place by the agency of vegetation.
That they may be more readily obtained by all plants,
they are composed of carbon, oxygen and hydrogen
alone, so tliat whenever carbon dioxide and water are
present, the materials for their formation can be ob-
tained ; and these, as w^e have already seen, may be
found in f.very place where vegetation can subsist.

So simple are the isolations of these carbohydrates

V2\)

to carbon dioxide and water, tlie universal food of
plants, that it is easy to iina«^ine tlie general method
of transformation by which the deoxidation of CO^
and of Ha O gives rise to these substances. Boussin-
gault has suggested that VO.^ and H^ O are deoxidized
together, the former losing one-half of its oxygen and
the latter the whole. Thus CO, -f H, () = C()-|- H, -f
Oa of which we may suppose the 2() to be disengaged.
Then six times the resi<lue would be glucose,
C6 H.aOe . Glucose less a molecule of water would be
cellulose or starch or gum, for Ce HijOe — H^O —
Ce HioOj ; and two molecules of glucose less one of
water would be sucrose 2(C6 H.^Oe ) — H^ 0 = C,2H ;,,()„.

It must not, however, be supposed that the above
or any similar scheme certainly reveals the detailed
processes of nature ; for these are as yet (]uite
unknown.

While the carbohydrates all consist of the san:o
elements, they contain them in the same or nearly the
same proportions. In this respect we may ahiiost
regard them as only one substance, capable of assum-
ing several ditterent forms ; in its soluble states of
gum and sugar circulating in the sap and supplying
nourishment to every organ, and in its more-insoluble
forms stored up as starch for future nourishment or
fashioned into tough woo<ly walls of cells and vessels.

That these substances, thus nearly related, may be
changed from one form to another, that sugar may be
converted into wood or starch, and gum into sugar,
and vice versa, we have abundant proof in many com-
mon processes. If barley be moistened and thrown
into a heap, as in the process of malting, as soon as it
has sprouted we find a great part of its starch con-
verted into sugar ; the sugar of the beet or of maple

I

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sap, wlion these plants begin to grow in spring, soon
disappears and becomes converted into woody steni«
and leaves; and wlien a potat(; is planted and begins
to grow, its starch furnislies the material for its stems
and foliage, after having first been taken np in the
sap in the form of gum and sugar.

Sonic of these changes may be produced by art,
and by examining how this is done, we may be
better able to understand how they occur in the living
plant. They may be effected : —

1. Ji}j Heat — If sawdust be carefully washed, then
dried in an oven till it becomes crisp, and afterwards
ground, the wooden flour thus produced, if boiled in
water, forms a jelly like that from starch. By merely
applying heat and moisture, we can thus convert
woody fibre into starch. Again, starch when exposed
to a heat below 300*^F. becomes yellow or brown, and
in this state is soluble in cold water, and in other
respects has the properties of gum. Starch changed
in this way is called British gum, and forms a good
sulxstitute for gum Arabic. Chemically, British gum
is dextrin, Ce Hj^Oj . Lastly, in the manufacture of
British gum, a portion of the starch is sometimes
changc^d* into sugar. Heat, therefore, is capable of
transforming starch into gum, and gum into sugar.

2. By Acids ami Alkalies. — If to a (quantity of
fine sawdust or linen rags, we add more than its
weight of sulphuric acid, and rub the mixture in a
mortar, the wood or linen will be converted into jelly
and then into gum. If to the gum thus produced we
add more sulphuric acid, and a (piantity of water, and
allow it to stand for some time, the gum will be found
changed into grape sugar. Any of the varieties of
wood, starch, or gum, may thus be converted into

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su^ar; and in France potato starch tlnis transfonucd
is employed to some ext<'nt in tlie mannfactnre t)f
brandy and fi'rmrnted li(|Uors. 100 ll»s. of starch
mixed with GOO of water, and 10 of sidphuric aei<l,
hy hoiling for seven or eight hours, pnxhice about 112
lbs. of grape sugar.*

C(ine sugar may also by the action of acids be
readily changed into f/ntpc sugar ; and it is for this
reason that fruits preserved in sugar often become
candied. The vegetable acids of the fruit convert the
cane sugar into grape sugar, and the latter, being less
soluble, crystallizi's in little lumps.

Alkaline substances are also capable of effecting
some of these transformations. If sawdust be boiled
in a strong solution of pun pntash, a poi'tion of the
woody fibre will assume the properties of starch.

Since we can so easily, by artificial means, produce
these transformations, it cannot be doubted that they
can be still more readiij iffected within living plants.
Human art can, however, imitate only a part of the
processes of this kind which are known to take place
in vegetables. We can change wood into starch, and
starch into gum, and gum into sugar ; but chemistry
is altogether unable to reverse the process, and con-
vert sucfar back afjain into wood.

The plasticity of these compounds of carbon and
the elements of water, is not, however, limited to
mutual transformations. By various kinds of decom-
2)osition they can be clianged into other substances,
such as alcohol and vinegar. One of the most com-
mon changes of this kind is fermentation. When to
a decoction of malt, or to the juices of sweet fruit, we

nto

*A process similar to this is now extensively employed in making
glucose for the use of confectioners.

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add a little yeast, carbon dioxide begins to escape,
and in time the grape sugar contained in these liquids
is found to be changed into alcohol or spirit, C^ He O.
In this case Ce H./Oe =2 {(\ Hg 0) + 2 (CO3 ). One
of grape sugar yields two of alcohol and two of carbon
dioxide. The carbon dioxide escapes from the fer-
menting li(juid in bubbles, and the alcohol remains in
the water. By further exposure to the air the alcohol
thus produced aljsorbs a portion of oxygen from the
atmosphere, and is changed into vinegar. Thus
alcohol together with oxygen becomes acetic acid and
water ; C, He O + 20 = C, H, O, + H, O.

These artificial modes of transfoiining wood, starch
and vinegar, though they may not show us exactly
the ways in which these changes take place in plants,
are sufficient to give an idea of some of the means by
which they may be effected. We may now consider
another class of l)odies found in most plants, the acids.

§ 5. Vegetable Acids.

1. Acetic Acid or Viner/ar is one of the mdst
abundant. It is present in the juices of many plants,
is produced in the germination of seeds and by the
fermentation of dead vegetable matter. The compo-
sition of vinegar is giv^en by the formula C2 H^Oa,
so that like grape sugar it contains equal proportions
of carbon and the elements of water. In conformity
with this similarity of composition, a solution of cane
sugar with a little vinegar added to it, when exposed
to the air for some time, becomes chanijed into a solu-
tion of vinegar. Most of the vegetable acids, however,
contain oxygen in excess of the amount ru pessary to
form water with tho hydrogen present. This is the
case in the acids hereafter enumerated.

133

2. Tartaric Acid is composed of C^ Hg Oe, contain-
ing therefore proportionally more oxygen, and less
hydrogen, than the acetic. It is contained in sorrel
and in some berries, and, in combination with potash,
abounds in the grape. The hydrogen-potassium-
tartrate, HKC^ H^ Oe , obtained from the latter fruit,
is the well known cream of tartar.

8. Citric or Lemon Acid differs little in composi-
tion from the last, (Cq Hg O7 ). It gives acidity to the
lemon, orange, cranberry and strawberry.

4. Malic Acid differs slightly in composition from
the tartaric. It is i\ Hg O5. It gives their sourness
to the unripe apple and plum.

5. Oxalic Acid is found abundantly in many plants,
usually in combination with lime or potash. It exists
in the sorrels, in rhubarb, and plentifully in many of
the lichens which grow on trees and stones. Oxalic
acid consists of carbon, hydrogen and oxygen, in the
proportion of C2 H2 O^.

These and many other acids occur in greater or less
abundance in most plants ; and though they do not
constitute an important part of their l)ulk, they are
of some consequence. They communicate to many
fruits and other articles of food an agreeable acidity.
They combine with and render soluble and otherwise
suitable for plants, many of the earthy substances
which are found in them. They serve, in the modes
before noticed, to effect changes in the substances con-
tained in the tissues or sap ; for example, in convert-
ing starch into sugar. And lastly, they are them-
selves capable of being transformed into various use-
ful products, as we often see to be the case in the
conversion of a sour unripe fruit into a sweet ripe
one. In this change the acid present in superabundant

' 1

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i

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134

(|uantity in the unripe fruit, and causing it to be
unpalatable and unwholesome, is converted into grape
sugar, and the fruit is thus rendered agreeable to the
taste, and nutritive.

§ 6. Oils and Fats.

Two kinds of oils are found in plants, the volatile
and the fixed oils. The volatile oils, present usually
in small quantities in plants, and, therefore, although
important as giving odours and flavours to vegetable
products, of slight importance agriculturally, cannot
here be considered. But the fixed oils and the fats,
which are distinguished from the volatile oils by
leaving a permanent grease stain on paper, are of
greater importance, and must receive brief notice.

The oils and fats produced by vegetables are
numerous ; but thev are somewhat similar in chemi-
cal composition and may he sufficiently represented
by two of their number ; one oil, oleine, and one fat,
stearine. Oleine is the chief ingredient in olive oil ;
and stearine, an abundant constituent of many vege-
table oils and fats, is found nearly pure in mutton
tallow. Oleine is represented by the formula C^ H5
3 (C,8H3303 ); ami stearine is C3 H5 3 (C,8H350). When
these substances are distilled in a current of highly
heated steam, each molecule reacts on three molecules
of water, as indicated in the subjoined ecjuations,
C3 H5 3(C.8H,30, ) + 3(H, 0) = C3 Hs' O3 -t^CsHsfi.),
and C3 H5 3 (C,8H350) + 3 (H, 0) = C3 Hg O3 + 3
(C18H36O). The common result of the two reactions,
C3 Hs O3 , is the interesting substance glycerine, familiar
to us as a colourless, viscid, sweet liquid. The Cj^H^fi^
of the first reaction is known as oleic acid, and the
C18H36O of the second is named by the chemist

1 ''X

stearic acid, is known in trade by the designation
Belmont sperm, and is used in the manufacture of
Behnont sperm candles.

When oleine or stearine is heated with a solution of
sodium hydroxide or potassium hydroxide one mole-
cule of the oil or fat reacts with three molecules of
the alkali as by the following equations : —

C3 H5 3 (C,8H330, ) l-f 3 (Na OH) = C, Hg O3 +
3 (C,8H33Na O, ).

C3 H53 (C.8H35O) + 3 (KOH) = C3H8O3 +
3 (0,81*33 KO).

Glycerine, it will be observed, is produced in each
case ; and, in the first instance, three molecules of
sodium oleate, and, in the second instance, three mole-
cules of potassium stearate are formed. Tliese are
soaps. The first is the soap that results from boiling
olive oil and caustic soda together, and is known in
trade as Oastile soap. The second is a soft soap such
as the housewife makes when she boils together
domestic grease, consisting chiefly of stearine, and the
lye of wood ashes, which contain much K O H.
Potash soaps are soft ; soda soaps are hard. Hence,
when the housewife wishes to make hard soap from
her soft soap, she stirs into the soap, while still hot,
some salt, and interchange of elements takes place as
by the following equation : O18H35K O -|- Na 01 =
Oi8H35Na O -|-K 01. A sodium soap, or hard soap,
and potassium chloride are thus formed.

§ 7. Nitrorjnnised Siibslancef^.

These, though present in much smaller quantity
than the non-nitrogenized constituents of the plant,
are of vast importance both to the plants themselves
and to the animals which feed on them. In the plant

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they appear to deteriniiio all the vital changes by
which the other substances are produced ; and to the
animal they are the materials out of which alone its
most important tissues can be formed.

1. If we take a small quantity of the dough of
wheaten flour and wash it on a linen or muslin ra^jso
as to remove the starch which forms a large constitu-
ent of the flour, we And remaining on the cloth a
substance of a remarkably sticky and tenacious char-
acter. It is known as the (fhiten of wheat, and it is
to this substance that the flour owes its capacify for
constituting a tenacious paste and for forming raised
bread. It is a nitrogenized substance, insoluble in
water, but soluble in acids and alkalies ; and is similar
in composition with the flesh of animals. It consti-
tutes from ten to twenty per cent, of the grain of
wheat. Other grains contain this substance, but in
less quantity than that of wheat.

2. In Indian corn a similar substance, or rather a
modification of the same, occurs, and has been called
zeiv. Another similar substance occurs in consider-
able quantity in peas and beans, and is named
legaynln.

8. If the juices of many succulent plants, as of the
tubers of the potato, are heated to the boiling point,
flakes of curdled matter separate from the fluid, and
are found to consist of the substance albumen^ with
which we are familiar in the white of cg^. This sub-
stance, unlike gluten, is soluble in water, though it
curdles and becomes insoluble when heated. It is
thus suited for circulating in the sap of plants ; and
as glutinous and albuminous matters seem to be
mutually convertible, they may be regarded as related
to each other in the same manner in which starch is
related to sugar or gum.

137

All of the above mentioned nitrogenized substances
contain, in addition to carbon, hydrogen, oxygen and
nitrogen, a small portion of sulphur, which seems t(j
be a necessary ingredient in their composition.

Approximately the several nitrogenous substances
named above consist of 54*^/,, carbon, 7'7„ hydrogen,
16"/rt nitrogen, 22*-'/^ oxygen, l*^/,, sulphur. Some
of them also contain phosphorus, but in small quantity
only, seldom amounting to one-half of one per cent.

Their composition is not so well understood as to
enable us to express it in definite, generally accepted
formul}\3.

§8. Pro.rimate Analysis of PlunU.

It may be said of all plants cultivated by the
farmer that they chiefly consist of water, cellulose,
soluble carbohydrates, acids, oily or fatty matters, and
nitrogenous materials. Either essential to the com-
position of these substances, or entangled with them
in the process of growth, is a small percentage of ash,
to the consideration of which attention must be
directed in the next chapter. The proportions of
these substances differ much in different plants, and
still more in different parts oi the same plant, as will
appear clearly on examination of the table, page 141,
which gives in columns 5 to 10 inclusive, the results of
a proximate analysis of the chief agricultural pro-
ducts.

Columns 1-5 inclusive, of the same table, give the
result of the ultimate analysis of the same substances,
column 5 belonging to both analyses. An ultimate
analysis differs from a proximate analysis in this
respect, that the ultimate analysis gives tlie weight of
each element in a substance, while a proximate

i

i

138

'II 1

analysis gives the weight of each separable compound
in it.

Exiimple.

130. See what differences there are between the
ultimate analysis given in the table and the results
you could find from the proximate analysis on the
supposition that the fibre mentioned is cellulose, that
the soluble carbohydrates are starch, that the oil is
oleine and tb- ., the composition of the nitrogenous
substances \-» given correctly on page 137.

In thi 4 table the quantity of nitrogenized matter
expresst s very nearly the flesh-producing value of
the sevf ral substances when u • d as articles of food ;
and in Jiis respect such facts are not only important
in relation to the nature of plants, but in relation also
to •'j/ieir use as food for men and animals. All the
edible substances afforded by the vegetaljle kingdom
may be grouped under two heads — the heat-and-work-
producing and the liesh-producing. Under the
former come starch, sugar, gum and oil. These
substances, by their combustion in the body, keep up
animal heat, maintain muscular energy, and prevent
waste and thinness. Animals fed on such substances
and not exposed to cold, tend to accumulate fat ; on
the other hand, the consumption of such food enables
them to endure cold. To the second class belong
gluten, albumen and legumin, which afford the
material of flesh and sinew. The scientific selection of
food for animals depends in great part on the study of
the relative amounts of these two kinds of food in
different substances, and in duly proportioning these
accordingly. The relative amounts of curd and

139

cream produced by inilch cattle may also be iiiHueiiced
in the same way. But these are subjects too extensive
to be considered in this place.

We may close this notice of the organic matters
contained in plants by stating briefly the relations
which they bear to the food and structure previously
referred to.

§ 9. Conclusions as to the Food of Phods.

The organic food of plants consists in part of
gaseous or aeriform substances, and in part of
substances not aeriform, but fixed. The gaseous part
of the food may be absorbed by the leaves directly
from the air, or by the roots from the soil ; in which
latter case it is usually taken up through the medium
of water, in which it has become dissolved. The fixed
part of the food can be obtained only from the soil,
and only by the roots, and by these only in a state of
solution in water. Of the elements actually found in
the plant, those that constitute its organic or com-
bustible part may be obtained either in a gaseous or
fixed state, either from the air or from the soil ; those
that constitute its ashes oi' incombustible part, as we
shall find, only from the soil.

In respect to both these classes of substances, the root
and the soil are the most important practical subjects
of consideration ; since the air is alike in its composi-
tion, or nearly so, at all times and places, and caimot
in this respect be regulated by the farmer. Still, as
the leaves absorb food from the air, whatever gives it
the largest amount of health;)^ leaf will enable the
plant to do this most effectually, and sufficient
exposure to air and light are also absolutely necessary.
The farmer, by taking proper care of the root and the

T^

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140

soil, thus provides also for the proper action of the
leaf and the air.

In respect to the particular elements of the organic
part of the food of plants, while it is useful to have
in the soil organic matters yielding carhon dioxide, it
is more essential to have substances yielding nitrogen
either as ammonia or nitric acid. For this reason the
richer animal manures are justly held to be of great
importance in agriculture ; while it is also of the first
importance that such manures should be applied to
plants in their young state, that they may early form
large and healthy leaves and roots, and maj^^ thus he
able to avail themselves of the stores of carbon dioxide
and ammonia afforded by nature. It is thus to be
observed that while the organic part of the food of
ordinary plants may be furnished by the air and rain,
yet the more important cultivated plants require
more than this in order that they may yield large
crops ; and further, that the small and starveling
plants of a poor soil have not sufficient root or leaf
freely to avail themselves of the liberal stores of
nature. Hence, though strictly organic manures may
not be so important to plants as those which supply
ths material of the inorganic part, they are still of
great value.

In the most favorable circumstances in our climate
one acre of land under cultivation does not assin)ilate
in a year more than 3,000 lbs. of carbon, 3,000 lbs. of
oxygen, 400 lbs. of hydrogen and 100 lbs. of nitrogen.
Indeed a good crop of oats assimilates only 2,500 lbs.
of carbon, an almost equal amount of oxygen, 350 lbs.
of hydrogen, and 50 lbs. of nitrogen.

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CHAPTER VIII.

THE ASHES OF PLANTS.

§ 1. Table of Plant Analysis.

We have already seen that the combustible or
organic part of the plant, at least in the kinds culti-
vated by the farmer, largely preponderates over the
ashes. We are not on that account, however, to sup-
pose the materials of the ashes of small consequence
to the plant ; on the contrary, experience proves that
they are of the utmost importance ; and since they
can be obtained only from the soil, and not at all from
the air, their presence in the ground must be closely
connected with its fertility or barrenness. The table,
page 141, compiled from various sources, representing
the results of chemical analyses of plants and their
ashes, will enable us to illustrate these points.

§ 2. General Deductions from the Table.

An examination of the foregoing table suggests at
once several important truths.

First. — The chemical relations of the ash-ingredients
are manifold. Two are alkalies, potash and soda ;
two are alkaline earths, lime and magnesia ; two are
oxides of heavy metals, oxide of iron and oxide of
manganese ; two are acids, sulphuric acid and phos-
phoric acid ; one, silica, and one, chlorine, difter widely
in chemical relations from each other and from all
other ash-ingredients.

Secondly. — As each ash-ingredient is present in the
ashes of each plant given in the foregoing table, in

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143

plants that differ botanical ly so widely as wheat, peas,
potatoes and turnips, it is difficult to avoid the con-
clusion that each substance enumerated has relation
to the functions of plants as plants, and not merely
to the peculiar functions of each kind of plant.

Thirdly. — Yet that the varying proportions of ash-
ingredients have something to do with the peculiar
functions of each kind of plant is evident by observ-
ing the resemblances in the ashes of plants of allied
species and the differences in those of widely diverse
species. Compare, for example, the amounts of lime
and of silica in the straw of wheat, barley and oats ;
and contrast with the amounts of those substances in
pea straw.

§3. E^

sh

ngredients.

Are all the substances named above essential to the
development of plants ?

Many experimenters have shown by growing plants
in soils artificially prepared, or in water, that potash,
lime, magnesia, phosphoric acid and sulphuric acid
are essential to the growth of plants. Of soda it is
found that the proportion is very variable ; in some
cases the amount is almost inperceptible ; in other
cases, with plants of the same kind, it is present
abundantly. The conclusion to which we are driven,
as stated by Johnson (" How Plants Grow "), is " that
soda is never totally absent from plants ; that, if
indispensable, but a minute amount is requisite ; and
that the foliage and succulent portions of the plant
may include a considerable amount of soda that is not
necessary to the plant, that is, in other words, acci-
dental." A precisely similar statement may be made
of chlorine.

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Oxido of iron in iiiiiiutii (|imntity is essential to the
growth of plants, although the amount is so small as
to be discoverable in some instances only by sensitive
tests.

Silica is found in the ashes of all plants ^rown in
ordinary conditions, and is very ahmidant in the
grasses, accumulating in them centrifugal ly ; that is
to say, it is most abun<lant in the cuticle of the stem,
in the leaves, and especially in their tips, and in the
husk of the grain. But recent investigations have
seemed to indicate that much of this silica is acci-
dentally present, and Knop has gone as fai* as to say:
"I believe that silica is not to be classed among the
nutritive elements of the grasses." It is ditHcult, how-
ever, to receive this statement, in view of the invari-
able presence and comparatively stable proportions of
this ingredient in the ashes of the grasses.

We may cm the whole conclude that two alkalies,
potash and soda; two alkaline earths, lime and
magnesia ; oxide of iron, silica, chlorine, sulphuric acid
and phosphoric acid are essential to the development
of plants.

§ 4. Occasional Ash-Ingredients.

Other substances are occasionally found in the
ashes of plants. Copper, lead, zinc, arsenic, fluorine
and many other substances have been detected *
plants. Nor is this to be wondered at, \\ he
remember that the plant admits throng s

whatever crystalloid substances are di.ssoK 1 in le
soil waters. It is even found that such substances
sometimes modify physiological processes in the
plant; for special varieties of plants are occassion ally
found where unusual ingredients exist in the soil ;

145

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hut, so far as is yet known, no suhstance not enumer-
ated in the foregoing tahle is essential to tlie highest
(U'vek)pnient of plants.

§ 5. TJce Purpose of each Aah-Iin/n'dlcnt.

Our knowledge of the functions of the several asli
ingredients of plants is as yet very imperfect. It
may he stated, however, that they are useful mechan-
ically and chemically. Mechanically, some of them,
like the silica in the straw of wheat, may serve to
give strength and protection. Chemically, others may
aid the plant in the production of its organic part.
It would seem that certain earthy matters ai*e specially
related to certain kinds of non-nitrogenized matter
— for example, that all plants which produce nuich
stai'ch, sugar, or gum, require nmch potash. With
regard to the nitrogenized constituents of the plant,
as gluten and albumen, it would seem that the pres-
ence of sulphates and phosphates is of especial
importance to them. The former afford the sulphur
which these nitrogenized substances contain, and
phosphates are always plentiful in the ashes of those
parts of plants which are rich in nitrogen, phosphoi*ic
acid appearing to facilitate the transfer of albuminoids
from cell to cell. Chlorine performs the same office
in relation to starch. Without iron chlorophyll is not
formed, and without chlorophyll leaves are colorless,
and refuse to decompose carbon dioxide. What, how-
ever, may be the peculiar physiological importance of
soda, of lime, of magnesia, or of silica, it is impossil)le
definitely to say.

The relation of each ash-ingredient to growth is
modified by the nature of the plant itself. In some
species of plants, and even in some varieties of the

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same species, a much less proportion of earthy matter
suffices to enable growth to go on than in others.
Hence the well known fact that the growth of one
kind of plant on a certain portion of soil does not
prove its fitness for the growth of other kinds of
plants. A fir tree ma}^ thrive on soil quite too poor
in alkalies and other earthy matters for the healthy
growth of a maple tree.

§6. The Distribution of Ashes in the Plant, in differ-
ent Parts and at different Stages of Growth.

Two questions suggest themselves to the thoughtful
mind. First. Does every part of each plant require
the same proportionate amount of each ash-ingre-
dient ? A comparison of the composition of the ash
of each grain with that of its straw gives at once a
negative reply. In the wL^at plant, silica is the
leading ingredient of the ashes of the straw, while
phosphoric acid predominates in the ashes of the
grain. This might be inferre<l from what has been
already stated respecting the special relations of one
of these ash-ingredients to one of the most important
classes of organic substances. Phosphoric >xcid is
specially related to the nitrogenous substances whiciv
are so abundant in the grain, so scanty in the sti;:w.
There are about four times as much nitrogenous
material in the grain as in the straw , and, correspond-
ingly, almost four times as much phosphoric acid in
the one as in the oth3r. The varying composition of
the different parts of the plant in relation to organic
products necessitates a varying composition of their
ashes.

The second question is this. Does a plant show a
constant proportion and composition of its ash at all

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stages of its growth ? When we rec(jlleet that certain
organic products are predominant in the earlier stages,
others in the later stages of the growth and develop-
ment of plants, we shall anticipate the answer to tlie
above question. The absolute quantity of ash and
the proportion of the ingredients of the ash differ in
different stages of growth. Young leaves have little
ashes ; old leaves, a very large quantity.

§ 7. Accidental Ash.

So far it has been found impossible to (U'termine
with accuracy the amount of each ash ingredient
essential to the full development of each part of the
plant. But it is clearly shown that in very many, if
not in most cases, there is an additional amount
accidentally present, brought into the plant with the
soil waters absorbed by the roots, and left behind
when moisture is evaporated from the leaves, some-
times forming an incrustation or efflorescence on tlie
surface of leaves and stems ; sometimes deposite<l in
crystals in the interior of cells or in the interstices
between them ; sometimes merely dissolved in and
adding to the density of the sap, but not playing any
important part in the nutrition of plants.

It is the presence of this accidental ash that con-
fuses the results of many careful analyses. Where
particular substances, especially if readily soluble in
water, abound in a soil, plants are prone to show in
their ashes a superabundance of these particular sub-
stances. The fact that beet-root shows 17 times as
large a proportion of chlorine and eight times as
much soda in some analyses as in others is to be
accounted for, not by errors of analysis, nor by differ-
ence of variety of plant merely, l)ut largely by the

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soil in which the plants are grown being in some cases
strongly impregnated with common salt, which has
diffused itself by the rootlets into the root.

A part of the accidental ash is merely extraneous.
The alumina, the manganese and much of the iron
shown in certain analyses have been supposed to be
externally adherent to plants. These substances have
all a strong surface attraction for vegetable fibre, and
are in consequence largely used in dyeing. Young
plants, and the lower part of the stems of mature
plants, are exposed to the plash of rains which
bespatter them with the ferruginous clay forming a
part of every arable soil. Such matter on drying
adheres almost inseparably to the tissues of the plant,
and must, of course, appear in the analysis of its
ashes.

The attempt to determine how much of each ash-
ingredient is essential to the perfecting of the plant
is further confused by the tendency ef elements
belonging to the same chemical family to replace each
other in compounds. It is suspected that to a certain
extent potash and soda, lime and magnesia, iron and
manganese, can be substituted for each other in the
chemistry of life, as they certainly are in th? consti-
tution of many mineral species.

There is, therefore, wide variation in the amount
and composition of the ashes of plants of the same
species, as given by different skilful analysts; and
the foregoing table is the mean of many somewhat
widely divergent analyses. The extent of the varia-
tion for some of the substances contained in the fore-
going table is given below ; —

^

149

Tlant PjnoDUcrs.

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AVlieat Grain from "/o-

to'Vo.

Wheat Straw from "/„.

to 7„.

Peas from "/(,.

to *7o.

Pea straw from 'Vo-
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16

18

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15

§ 8. General Conclusions.

The great discrepaneies of analysis shown above,
which are as yet ([uite inexplicable, warn us to
use such results with extreme caution in deducing
rules for practical guidance. Yet there are certain
general statements in relation to these inorganic
constituents of plants, which lie at the very basis of
scientific agriculture, and should be tirndy fixed in the
mind of the farmer.

1. Most of the substances found in the ashes of
plants are not present accidentally, but are absolutely
essential to the life and health of the plant.

2. Different plants and <lifferent parts of the same
plant contain the materials of the ashes in different
proportions.

3. The absolute quantity of ashes is diflerent in

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different plants, and in different parts of the same
plant, and also in different stages of growth of the
same part.

4. The substances contained in the ashes can be
obtained by the plant only from the soil, or from the
manure which the farmer places therein. They can-
not be obtained in any degree, like the materials of
the organic part, from the air. Further, in every crop
the farmer necessarily removes a large quantity of
these ash materials from the soil ; and unless the
latter contain these in unlimited quantity, it follows
that cropping must exhaust the soil of the inorganic
food of plants.

These truths in relation to the inorganic consti-
tuents of the plant, :ire among the most valuable
results of modern chemistry iu its application to
agriculture.

,

)

CHAPTER IX.

THE ATMOSPHERIC FOOD OF PLANTS.

§1. The Plant Creates Nothing.

In discussing vef^e table life and growth it must be
constantly remembered that the plant ct'eates nothing.
If a plant under any circumstances has become one
pound heavier, then one y)()und of material has been
gathered by the plant, either from the air in which
its foliage is spread, or from the soil in which its
roots are buried. Its growth is always an assimila-
tion of pre-existent material. It is capal)le of decom-
posing certain compounds, and of rearranging their
elements into new compounds ; but beyond this it can-
not go. It cannot add to the amount of matter in the
world, and it cannot transmute one kind of ele-
mentary matter into anotlier kind. The earth is
not one grain the heavier, or the less heavy, by reason
of all the plants that in the immeasurable ages past
have grown on the land or in the sea. Nor is there
in the world, by reason of vegetable life, one atom
more or less of oxygen, of hydrogen, of nitrogen, of
carbon, or of any other elementary substance than
when this planet was first formed.

§2. The Composition of Air.

Whence then do plants derive their material ?
Speaking of land plants, from the air and from the
soil. What part of their material do they derive from
the air and what from the soil ? Speaking generally,

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they derive their organic part from the air, their
inorganic from the soil ; but for a complete reply to
this question it will be needful to enquire particularly
into the supplies of plant food furnished by the air
and by the soil. We shall in this chapter consider
the air as a magazine of food supply for plants,
reserving to the next chapter a discussion of the soil
in relation to the sustenance of plants.

As has been already stated, atmospheric air consists
of a mixture of two gases, oxygen and nitrogen, into
which is diffused variable quantities of vapour of
water, carbon dioxide, ammonia, other exhalations of
vegetable and animal life, and pnxlucts of combustion
and decay. Where animals are crowded together,
oxygen is somewhat deficient, and carbon dioxide,
annnonia and organic emanations are in excess ; while
the air is somewhat richer in oxygen where vegetation
is growing freely. But, on the whole, animal life and
vegetable life are so balanced in the world, and the
atmosphere is so thoroughly stirred up and commingled
by winds, that in the open country atmospheric air
preserves, except in relation to moisture, to carbon
dioxide, and to annnonia, a very constant composition.
If for the moment we omit these more variable com-
ponents, the air may be said to consist of 79 cubic
feet of nitrogen and 21 cubic feet of oxygen in every
100 cubic feet of air; or, which is approximr tely the
same thing, of 77 pounds of nitrogen and 23 pounds
of oxygen in every 100 pounds of air. The amount
of carbon dioxide present in air is somewhat variable.
The extreme range of 500 analyses made a few years
ago, was from 47 to 87 hundred-thousandths of the
weight of air, the average being about 6 ten-thou-
sandths. By volume this is about 4 ten- thousandths

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Ammonia V)eing very soluble in water is almost com-
pletely washed out of the air by rain ; it accumulates
in the air during dry weather. The (juantity fluctu-
ates greatly, but is always small. (3n the average its
weight in the air is nearly one part in one million.
Vapour of water may be less than \ per cent, or more
than 8 per cent, of the weight of the air. As a rough
approximation to the truth we may put its average
amount at one per cent, of the weight of the air.

§ »3. A Ir as Food for Plants.

Tlie air then surrounds the foliage of plants with
abundant imcombined oxygen and nitrogen, with a
smaller amount of carbon (lioxi<le and water and with
very minute proportions of other substances, and we
have seen page 118, that leav'es are adapted to absorb and
to appropriate to the needs of plants gaseous materials.

Are all the constituents of the air available as food
for plants ? The answer to this must be that by far
the greater part of the air is not adapted to nourish
plants. It is one impgrtant function of plants to
supply oxygen to air ; therefore they do not on the
whole absorb oxygen. It is true that under excep-
tional circumstances some parts of plants absorb
oxygen from the air. Germinating seeds, expanding
buds, and opening Howers do this ; but the net result
of the growth of plants is to return to the air at least
ten times as much oxygen as they absorb from it.
Nitrogen is necessary to the growth of plants, but it
appears to be physiologically impossible for agricul-
tural plants to feed directly on the uncond)ined
nitrogen around them. A very little they derive by
their leaves from the nitrogenous compounds that
exist in very small aniount in the air ; but by far the

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154

greater part of their supply oi nitrogen is absorbed by
the roots. Neither the oxygen nor the nitrogen of
the air is plant food. The carbon dioxide in the air,
however, is absorbed and decomposed by the foliage
of plants, and is the source from ' which by far the
greater part of the carbon of plants is derived, and is,
therefore, a most important plant food. The water
held in solution by the air does not directly minister
through the leaves of farm crops to their nourishment,
although as the source of dews, rains and snows it
supplies through their roots one of the essentials of
their life and growth.

Examples.

187. Assuming the composition by weight of the
air, on some summer day when the barometric
pressure is 29-8 inches, to be N ToO^/o, O 2298^/rt,
H, O 106^/o, CO, 0599^/,^ and NH3 0001^/^ ; what
weight each, (a) of free nitrogen, (b) of free oxygen,
(c) of water, (d) of carbon dioxide, (e) of carbon, ( / )
of ammonia and (g) of hydrogen rests on one acre of
land ? Give the answers in tons except in the case of
ammonia, where the answer may be given in pounds.

138. If in the circumstances given above, J of the
moisture in the air were to be deposited as rain, what
would be the depth of the rain fall in inches ?

139. If a plant exposes to a wind moving ten miles
an hour one square foot of surface, when the barome-
tric pressure is 30 inches and the temperature is 60*^ ;
how much carbon dioxide comes into contact with the
plant in ten hours, the proportion of carbon dioxide
being 6/10,000 of the weight of the air ?

140. If a crop of wheat has assimilated in grain
and straw 2,100 lbs. of carbon, 200 lbs. of hydrogen

155

and 56 lbs. of nitrogen, and if all the carbon has been
derived from carbon dioxide, all the nitrogen and a
part of the hydrogen from ammonia and the rest of
the hydrogen from water ; how much carbon dioxide,
ammonia and watei* must have been <lecompo.sed by
the wheat plants ? How many tons of air containing
6/10,000 of carbon dioxide would be needed to supply
the carbon of such a ci*op as is supposed in the
preceding (juestion ?

141. If one acre of oats assimihites 2,500 lbs. of
carbon, what per cent, of the amount of carbon over
an acre of land is that, when the pressure of the air
is 14| lbs. on the square inch and the proportion of
carbon dioxide is 549 millionths of the weight of
the air ?

142. If the proportion of ammonia present in the
air is one millionth and the pressure of the atmosphere
is 14| lbs. on a sijuare inch ; what weight of ammonia
rests above one acre of ground ?

143. How much ammonia Would be re(|uired to
furnish a crop with 100 lbs. of nitrogen ?

'}

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CHAPTER X.

THE SOIL.

§ 1. Nature and Orifiin of the Soil,

y^ The soil is derived from tlio waste of the rocks of
tJie earth's crust ; but it is not a mere mass of rubbish ;
on tlie contrary, it is a complex mixture of a number
of substances in which many interesting chemical
changes are constantly going on, and which possesses
many important properties in reference to the nutrition
of the plants that grow cm it.

With regard to the oriojin of soils from rocks, we
may take as an example the common and durable
rock granite. In a piece of granite we can usually
perceive three distinct minerals : 1st, (juartz or flint,
which is neai'ly pure silica ; 2n<l', feldspar, with flat
and shining surfaces of a white or reddish colour, an<l
usually the largest ingredient in the mass. It is a
compound of silica with alumina and potash, or soda,
or both ; 3rd, mica, black or silvery scales with
metallic lustre, and composed of silica, alumina, oxide
of iron, oxide of manganese, potash, and sometimes
magnesia. *

Now a mass of such granite is slowly acted cm by
the w^eather ; that is, by the rain-water charged with
carbonic acid. The latter substance gradually decom-
poses the feldspar, removing its potash and soda, and

* If the teacher can obtain a piece of granite, these minerals may be easily
shown to the pupils. The allied ruck syenite has the mineral hornblende
instead of mica. Hornblende is usually of a blackish colour, and consists
principally of silica, magnesia, lime, and oxide of iron.

157

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leaving the silica and alumina, which then become soft
and cruml)linf]f, and ultimately fall into Hne clay. The
feldspar being thus broketi up, the (juart/ and mica
fall asunder into sand and Hat scales, and a soil results,
which in its texture will be partly of a sandy and
partly of a clayey nature, and as to composition will
contain silica, alumina, soda, potash, oxide of iron, and
perhaps carbonate of lime, phosphate of lime, and
other substances contained in the minerals which may
be mixed with the granite. These substances will be
in the state of clay, which has the power of retaining
the more soluble matters in its pores, or in the state
of grains of sand, which may be themselves gradually
undergoing waste, and yielding their ingredients to
the soil.

Let now a mass of such soil be acted on by water,
and the clay may l>e washed away in whole or in
part, and deposited in valleys and flats, giving rise to
a stiff' soil. The sand may remain or be washed into
some other place, and will constitute a sandy or light
soil, and there may of course be any number of
mixtures of these two opposite kinds.

Further, let plants grow on this soil, and their roots
and fallen leaves decay in and upon it, and a certain
quantity of vegetable mould will be produced, and
mixed with the soil, constituting its organic part.

It will be observed that these statements refer to a
granitic soil only, but in the case of other rocks the
process is similar ; though it is evident that the greater
the variety of the rocks and minerals ground up to
form the soil, the more complex will be its composition.
Still as the common rocks are everywhere composed
of a few elements, it follow\s that in the main the soils
of all parts of the world are alike, differing principally

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in the />/v>/)oWio»,s of tlw nut wry numerous substances
of which th<'y are ctniipostMl.

Such bein^ the ori<;in of tlie soil, it is evident that,
regarding it from (liferent points of view, we may for
practical purposes form different chissifications or
arrangements of s(jils. Let us next consider these.

§2. C/assijic(itio7i of Soils arrordhii/ to Mechdnical

Text lire.

We may re<(ard soils as more or less coarse or tine,
and thus obtain a classification dependin<^ (m the
mechanical texture of the soil, which, for practical
purposes, is much used and of great value. In this
respect the soil may vary from coarse pebbles or loose
sand to the fincist and most tenacious clay ; and in
general, those soils are best atlapted for agriculture
which consist of mixtures of sand with a moderate
quantity of clay and a little vegetable matter. When
sand or other coarse matter predominates, the soil is
deficient in the power of retaining water and the
soluble and volatile parts of manure. When clay is in
excess, the soil is too retentive of water, is not easily
warmed, does not admit of access of air, and conse-
quently does not allow those chemical changes to take
place in the soil and manures placed in it, which are
necessary to prepare proper food for plants. The
following classification of soils in reference to these
points has been proposed.

1. Pure Clay; from this no sand can be extracted
by washing.

2. Strong Clay, or brick clay, contains less than 20
per cent. sand.

3. Clay Loam has from 20 to 40 per cent. sand.

V

or

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20

4. Loam has from 40 to GO per cent. sand.

5. Sandy Loam has from GO to 80 per cent. .sand.

6. Sand has less than 20 per cent. clay.

Examples.

N.B. — In answerln<T these questions deduct the
organic matter, and determine the percentage of sand
in the remainder.

144. A certain soil free from organic niatter con-
tains 45^ of its weight of sand. What should it he
called ?

145. A similar .soil has J}5% clay. What name
designates it '*

14G. A soil consists of 12% organic matter, 37%
sand, and the rest clay. What is its proper name i

147. What is the name of a soil of which 15% is
organic matter and G5% is sand ?

14S. What is the proper term to designate a soil
of which 20% is organic matter and 70% is clay.

§ 3. Classification of Soils accordhnj to their General

Chemical Characters.

We may cla.ssify soils according to their predomi-
nant or leading ingredients. Here we may divide soils
into organic and inorganic parts, the former consist-
ing of the remains of plants and animals mixed with
the soil, the latter of the mineral substances originally
present in it. These last again may consist of silica,
alumina, or lime in predominant quantity. Hence we
obtain such a classification as the following : —

U 1. Organic soils, or those of bogs, and the vegetable
"^ mould of the woods, consisting in great part of par-
tially decomposed vegetable matter.

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160

2. S'diciows soils, or those in which silicious sand
is the prevailing ingredient, and which are often
formed from the waste of sandstone rocks.

3. Argiltacroiis soih, or those which consist prin-
cipally of clay, and are often formed from the waste
of slates and shales.

4. Calcareous soils, or those in which lime is a
principal ingredient, and which may be produced from
the waste of limestone, chalk, or marl.

§ 4. Classification of Soils according to Details of
Coniijosition and Relative Fertility.

We may classify soils of any or all the kinds separ-
ated in the above heads, according to their fertilitv or
barrenness in relation to our cultivated crops, that is
according to the presence or absence of the materials
of the ashes of those crops. No soil, unless it contains
some substance poisonous to plants, or is a mere
shifting silicious sand, is absolutely barren ; but we
call a soil barren which will not produce such plants
as the farmer cultivates. Such a soil mav be made
fertile by adding to it the substances in which it is
deficient ; but if this cannot be done except at a cost
as great as or greater than that for which fertile soil
can be procured, the soil may be regarded as prac-
tically barren and worthless.

The mechanical texture and predominant ingredi-
ents of soils, though important to their fertility, do
not absolutely determine it. A sandy, loamy or clay
soil, or a silicious or calcareous soil mav cr mav not
contain all the materials of the ashes of our crops ;
and if it does not it will be barren. This obliVes us
to consider the composition of soils in detail. Bearing

101

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7 or
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ins

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we

nts •

ade

t is
Icost

soil

rac-

ledi-
do

Iclaj'
not

lops ;

Is us

Iring

in mind then the three classifications of soils above
explained, let us next proceed to consider* their com-
position.

This will be seen at a glance in the followini^ tablo,
from Johnston, representini;' the in^j^redients of three
difierent soils, with their relative propertit's : —

Conipo.sifioii of Soils of Dijf event Degrees of Fert Hi f j/ .

Organ ic in alter

Silica (in tlie sand and clay)

Alumina (in the clay)

Lime

Magnesia

Oxide of iron

Oxide of manganese

Potash

/^m\ ; «. >chietlv as common suit
( hlorine, j

Sulphuric acid

Phosphoric acid

Carbonic acid (comhincil with the

lime and magnesia)

Loss

Fertile
without

Fertile
with

Manure. Manure.

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14

1000

50

51

IS

8

30

trace

lOOC

Barren.

40

778

91

4

I

81

trace

4*

1000

Pi

CHAPTER XI.

THE RELATION OF THE SOIL TO PLANTS.

§1. The Soil as an Anchorage for Plants.

The soil affords the plant mechanical support. By
its roots the plant is anchored to the ground and
upheld against wind and rain. To subserve this pur-
pose the soil must have weight and coherence.

Dry Organic soils weigh about 50 lbs. per cii. ft.

" Heavy Clay " " " 75 " " "

" Silicious or Calcareous " " " 110 " " ''

From these numbers it is possible to calculate the
weight per cubic foot or per acre, to a depth deter-
mined, of soils in general, which are mixtures in
varying proportions of the substances given above.

Exam2)ley.

149. A calcareous sandy loam consists of 45y of
its bulk silicious sand, 10// colca'-eous sand, 35// clay
and 10% organic matter. vVhr.t does it weigh per
cubic foot, and winit is the ^Yeight of an acre of such
soil one foot deep ?

150. Of the bulk of a certain clay loam 60% is
clay, 25% sand and 15% organic matter. What is the
weight per cubic foot and per acre 1 foot deep ?

151. The roots of a maple interpenetrate a mass of
loam, half silicious sand and half clay, measuring 80
feet long, 25 feet wide and 4 feet deep. What weight
of soil anchors the tree ?

The weight of an acre of soil one foot deep may be

163

estimated at from .'U million to 4 million ll»s., that is
from 1,750 to 2,000 tons. In the calculations that
folloW; the last number will be employed.

152. Calculate the weight in tons of the several
inorredients that make up an acre one foot deep of the
soil fertile without manure, whose analysis is ^iven
on page 161.

158. If a cart-load of lime weighs 1,000 lbs., how
many loads of lime would be needed to give to the
soil fertile with manure as nuich lime to tiie acre one
foot deep, as is contained in the land fertile without
manure ?

154. If it cost 5c per lb. to supply phosphoric acid
to the soil in some form, what will it cost to bring up
one acre one fo3t deep of the soil fertile with manure
to the richness in phosphoric acid of the soil fertile
without manure ?

155. Manufacturers of artificial manure reckon
potash worth 6 cents a lb. in manure ; at that rate
what would it cost to bring one acre one foot deep of
soil No. 2 to the richness of potash of soil No. 1, if a
trace of potash mean 1 100 of 1^.

The cohesion of a soil, in other words its stiffness,
may be either too great or too small. The so-called
heavy clays, (which are, however, heavy, n<»t because
of the weight of the soil, but because of the
cohesion of its particles), and especially clays
which contain large quantities of alkali, when wet
form a tenacious, plastic, intractable mass ; and when
dry cohere into stony lumps, through which the
plough can scarcely force its way, and which will not
crumble down into a state of fine tilth. In ••uch soils
seeds do not readily germinate, and into tliem roots

I'h

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rlo not easily poiR'tratc. On tlii' other hand light
sands, easily <lisplaced l>y the wind, do not afford a
footdiold for plants Inicause of their lack of coher-
ence. Wh(.'n the thin vegetation that in tiie lapse of
ages has slowly crept over such surfaces of shifting
sand, and that by its rootlets binds the particles
togethei", is once broken up, it becomes a difficult task
to re-estal)lish vegetation.

§ 2. The Soil as S applying Moisfiwc to Plants.

The soil is a reservoir from which the plants culti-
vated on the farm derive almost all their supply of
that indispensable nutriment, water. Water exists in
the soil and subsoil in three fornis — ground water,
capillary water, hygroscopic water. Ground water is
that which will drip from the soil ; capUhiry^ water
is that which, like the oil in a lamp wick, creeps up
through the pores (jf the soil from tlie ground water,
and hydroscopic water is that which a dry soil can
absorb f i*om nToIsture-laden air.

If we dig dow^n a few inches in some cases, a
few feet in others, we reach a stratum of soil so
surcliarjxed with water that the moisture oozes out
more or less rapidly and collects as a pool at
the bottom of the excavation — a well is formed.
The level at which this ground-water stands
in wells is uniform over considerable areas of flat
sands and gravels, and Is called the water-table.
When the sul)soil at or below the w^ater-table is per-
meable, the water-table rises with abundant rains,
and falls in lono-coritiinied drouo-hts, so that w^dls are
filled to overflowing or run dry together over con-
siderable areas. In deep tenacious clays, however, the
wells are usually filled not by infiltration from below

I

165

but by overflow from above. They are then of the
nature of mere tanks, each independent of its neigh-
bours. Below the water-table the pores of the soil
are filled with water, air cannot penetrate, and the
roots of agricultural plants will not grow.

Water is attracted by and creeps slowly in all direc-
tions over many surfaces in contact with it. Thus a
clod of dry earth of whicli one corner is dipped in
water, will soon become damp throughout. Water so
distributed through the ])ores of the earth is called
capillary water.

From the capillary water in the soil land plants
derive their chief supply, although many plants
send down a few strong roots into the ground
water. The height to which capillary water rises
above the water table, varies with the nature
of the soil and with the state of tilth. In fertile,
well worked soil, it may be as much as six
or eight feet, so that to that height moisture
w^ill be supplied in a slow ascending current
sufficient to keep the soil damp and dark in colour,
replacing the water lost by evaporation from the
leaves of plants and from the surface of the soil. It
must not be supposed that capillarity gives rise only
to ascending curi'ents of moisture in the soil. The
texture of all cultivated soils is too close to permit
water poured on the surface abundantly to sink down
out of sight iunnediately, as if it were poured on a
pile of broken stone. It forms puddles on the surface
or runs down over it in streams. Bui the capillary
action of the soil begins at once to convey the super-
natant water downward. The water soaks into
the land. From particle to particle the moisture
slowly descends, until it has more or less completely

If

^ 1 <',(',

disappeared from the surface. After rain, capillary
currents creep downward, adding to the ground
water. In drought, capillary currents creep upward,
supplying surface evaporation. Lateral capillary
currents distribute moisture right and left from damp
to dry adjacent ground. Thus a continual slow cir-
culation of capillary moisture refreshes the rootlets
of growing plants. The same surface attraction which
distril)utes capillary water also retains it in the pores
of the soil. Soils differ greatly in their capillary
power as measured by their retentiveness. If dry
soils be thoroughly wetted and permitted to drain,
they will retain varying amounts of water. Thus
coarse quartz sand will retain 25°/ of its weight of
water, marl 30^, loam 60°/, pure clay 70%, garden
mould 90%.

Hygroscopic water is that which a dry soil is able
to absorb from damp air. The amount varies much
with the chemical constitution of the soil, with the
^caiperature and with the degree of saturation of the
t.i^. If the soils of which the power of retention is
stated above were thoroughly dried and exposed for
24 hours to saturated air, it would be found that the
quartz sand would gain nothing in weight by absorp-
tion, marl 80%, loam 35%, pure clay 50%, garden
mould 55%. Generally speaking hygroscopic povrcr
increases with capillary power. Experiment has
^hown that hygroscopic water in some soils can sup-
ply sufficient moisture to keep some kinds of plants
*'rom wiltiuiT.

y

I

§ 3. The Soil as a Store-House of Nitrogen.

The soil supplies almost all the nitrogen that
plants require. In ammonia, in nitric acid, and in

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has
sup-
ants

that
d in

comparatively inert nitroj^enous compountls of organic
origin, all fertile soils contain much nitrogen. That the
plant depends chiefly upon the soil for its nitrogen is
evident. Nitrogen abounds in the air ; but we have
seen that the plant cannot assimilate atmospheric
nitrogen. Ammonia exists in air, and some doubtful
experiments seem to indicate that the leaves of plants
can absorb and use it; but so small is the average
amount of ammonia in the air that, relatively to the
demands of the growing plant, carbon dioxide is nearly
400 times as abundant as ammonia. To make the same
statement concretely, it would require more than a
year for a plant to collect from the ammonia of the
air the nitrogen recjuired to organize with the carbon
which the plant collects from the air in a day.
Nitric acid also is found in the air, but in still smaller
quantity, so that if a plant had to collect its nitrogen
from nitric acid as diffused in the air, ten years would
scarcely suffice for gathering enough nitrogen for the
daily growth of a plant. If atmospheric nitrogen is
not availaV)le for the plant, and if the atmospheric
supply of nitric acid and anmionia together, for 350
years, would not furnish the nitrogen required for
one year's growth of plants, it is evi(lent that vegeta-
tion cannot be fed with nitrogen from the air ; it must
draw its nitr')gen from the soil.

The soil is a store house of nitrogenous food for
plants. This is evident, for three reasons. 1st.
gecausetciiLthii rains bring down the anuuonia and
mtric iuii^i-which escape into the air through <lecay or
combustion of organic substances, or which are formed
in it by the electrical disturbances or by the chemical
reactions of which the atmosphere is the tlieatre.
2nd. Because to it is restored in large part the

til

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nitrogenous compounds which arc the debris of life,
whether the excreta of animals, the falling foliage of
plants or the dead and decomposing bodies of animals
and plants. J^rd. Because in ways but imperfectly
understood the soil is the seat of an active manu-
facture of nitrogenous compounds from the nitrogen
of the air by bacterial life, more particularly' by
bacteria that are parasitic on the roots of leguminous
plants.

1st. The chief reason for the smallness of the
amount of ammonia and nitric acid in the air is that,
being both exceedingly soluble in water, they are
washed out of the air by every shower, and so, almost
as fast as they appear in air, they are transferred by
rain to the soil. ]3uring dry weather ammonia and
nitric acid accumulate in very small (quantity in the air.
When wet weather sets in, the first shoivers bring
down almost all the accumulation, and later showers
lind little or none. Hence the proportion of these
substances varies greatly in different rains.

Ammonia varies from no appreciable quantity up
to almost one part in 50,000 of rainwater, and nitric
acid from nothing to one part in 100,000 of rain-
water. Although the amount of each of these sub-
stances brouiJ-ht down to the earth bv the rain of a
year fluctuates within narrower limits than the
amount brought down by individual showers, yet it is
not possible to speak very positively even in this
regard. As a first approximation to the truth it
may be said with reserve that in our climate about
12 lbs. of ammonia and 5 lbs. oL nitric acid are
anmSTly:

l'MrirfelL,on^ an _acre of
land ; that is between 11 and 12 lbs of mlroffenln"
these two compounds. This amount, though not

](\9

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it
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unimportant to tho growtli of plants, is quite in
adequate to the recpiirenient of crops, whicli, if good,
assimilate from 50 to 100 lbs. of nitrogen per acre.

2nd. In the economy of the world but little of the
nitrogenous material prepared by plants finally
escapes con-jumption by animals, so as to go to waste
by decay. Herbage, fruits, seeds, are consumed by
various tribes of beasts and birds. Even fallen leaves,
boughs torn off by winds and tree trunks overthrown
in the forest afford food to innumerable hosts of
iavertebrate forms which, individually insignificant,
in the aggregate modify profoundly the course of
nature But animals in the act of living reduce the
food which plants have prepared for them, and wliich
they have consumed, to compounrls which either
are inorganic or closely approach to the inorganic con-
dition. The carbon of their food is almost wholly
combined with oxygen and returned as carbon dioxide
to the inorganic world in the act of respira-
tion. The nitrogen of their food is organized into
nerve and muscle. These w^aste in the act of living,
and their nitrogen is nearly all returned to the soil by
secretions in the form chiefly of urea, hippuric acid
or uric acid. Urea characterizes the urine of
mammals whose food is highly nitrogenous ;
hippuric acid abounds in that of herbivorous mam-
mals, while uric acid is characteristic of the execre-
tions of birds, reptiles and invertebrates. But.
whether in one form or another, the nitrogenous
waste of life is returned to the soil.

3rd. The attention of scientific observers begins to
be attracted to the effects produced by microscopic
forr^s of life which flourish in the organic matter of
soils. Modern research has shown how, in many

fe

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170

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!

"

ways', tlic <freatiu* lifi3 wliicli our eyes see is iiiiuls-
tered to, modified by or destroyed by swarming
forms of life tliat abound in the air, in the waters, in
dust, in the soil, everywliere ; so minute that the
known forms ahnost ehide tlie higher powers of our
best microscopcKs, and suggest irresistibly the belief
that below them exist unknown forms that quite
escape our visitm, but tliat by their numbers and by
their rapid niultipHcation work out unique but most
important results in the world of life. Dwelling in
the borderland l)etween the vegetable and animal
kingdoms they have been sometimes assigned to the
one, sometimes to the other kingdom, but, as in func-
tion they are allied to the fungi, they are now almost
universally classed with vegetables. Sometimes,
with reference to their many kinds, their vast num-
bers and their small size, they are collectively' called
microdemes, literally little populations. Sometimes^
they are called microbes, literally small living things
a term that has of late become familiar through its
special application to forms that multiplying in living
animals cause many widespread epidemic diseases,
as the influenza microbe, the cholera microbe, etc.
Some of those earliest discovered were rod-like in
form, hence the name bacteria plural of bacterium, a
latinized form of the Greek bacterion, a staff. But
other forms than statt-like abound ; some more or
less spherical, some slender threads, straight, spiral,
contorted or convoluted. All are destitute of chloro-
phyll ; they cannot therefore gather nourishment
from inorganic matter by the aid of sunlight.
Hence they consume organic food as found in the
fluids oi living plants or animals, in their dead and
decaying bodies, or in their dejecta. They are

171

the
and
are

creatures of fermentation, putrefaction, disease, death
and darkness. Vigorous lif(i and sunlight are un-
friendly to them. The products of their life, tlieir
secretions, are important and unique. Just as the
yeast plant, living in a solution of sugar, produces
carbon dioxide and alcohol, so Ijacterium lactis, living
in milk, produces carbon dioxide and lactic acid. In
the case of many microbes of disease it is suspiHited
that their poisonous secretions work more mischief
than their mere consumption of the material of
living tissues.

Many such forms prosper in rich soils. Many
kinds of fermentation occur in them. Two must be
briefly alluded to. One, or perhaps more than one,
species of microbe lives and multiplies in soils con-
taining nitrogenous matter, and produces nitrates.
Its life is most active ia darkness, at a temperature
of about 100^ F., at depths to which the oxygen of
the air can penetrate, in soils that contain car-
bonaceous matters, nitrogenous matters, phosphates,
alkalies and a due proportion of moistui'e. Light is
unfriendly to these microbes ; the absence of oxygen
is fatal ; temperatures below 40^ F. arrest their
activity ; temperatures above 180*^ F., complete desic-
cation, and various vegetable and mineral poisons
destroy them. Where they flourish, salts of ammonia,
decaying animal matters and inert nitrogenous suV>-
stances are rapidly oxidized into nitric acid, which
unites with such alkalies or alkaline earths as maybe
present, and which in combination with them forms
the most valuable because the most readily available
source of nitrogen to higher plants. Another microbe
plays a part still more important in the nitrogenous
nutrition of the higher plants. It has long been

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(716) 873-4503

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suspected that the leguminous plants such as clover,
vetches, peas and beans, add to rather than subtract
from the nitrogenous wealth of the soil, or at least
that they do not deduct from the nitrogen accumu-
lated in the soil as much as they organize in their own
structure. From recent researches it seems highly
probable that some forms of microbic life, parasitic on
the roots of leguminous plants, have the power of
assimilating nitrogen from the air, especially when
growing in soils rich in carbonaceous matter, thus
increasing the nitrogenous wealth of the soil.

Whether washed from the air, or collected from the
debris of animal and vegetable life or manufactured
Ijy bacterial ferments in the soil, certain it is that
larsje amounts of nitrofjen in various forms of
combination are stored up in the organic matter of
the soil. In the form of ammonia an average soil
may contain about 20 lbs of nitrogen to the acre ; a
rich garden soil may contain as much as 75 lbs. In
the form of nitric acid the amount of nitrogen will
vary greatly with the weather, as the nitrates are
leached out of the soil by rains, and accumulate in
dry weather. There may be in a good soil as little as
20 lbs of nitrogen in the nitrates contained in an acre
of soil one foot deep, or as much as 500 lbs. The
inert nitrogen of a fertile soil, associated with its
organic matter, vastly exceeds the amount present in
ammonia and nitric acid. It mav amount to from
2% to 5% of the organic mattoi" of the soil. The
average of fertile soils will give about '16% of the
total weight of the surface soil, or from 4,000 to 8,000
lbs. of nitrogen per acre one foot deep.

173

§ 4. The Soil as a Storehouse of Inorganic Food

for Plants.

The soil is also the storehouse from which plants
derive all their inorganic nutriment. The potash,
soda, lime, magnesia, iron, silica, phosphoric acid,
sulphuric acid and chlorine necessary to the develop-
ment of plants must be present in the soil or plants
cannot grow upon it. The percentage of any of these
ingredients may be but small, because a small per-
centage of the composition of an acre of soil one foot
deep, weighing 2,000 tons, 4,000,000 lbs, represents a
large absolute amount, one one hundreth of one per
cent, being 400 lbs ; but each ingredient must be
present. In fertile soils the constituents of the ashes
of plants are present in very different proportions
from those in which they occur in the plant ; some of
those most abundant in the plant being the rarest in
the soil, and vice versa. Hence the mass of the soil
is to be regarded not as in itself food for plants, but
only as holding and containing this food, and giving
support and protection to the plant and its roots.
The substance alumina, which we find in the soil and
not in the plant, is especially important in these
ways. It is possible to reduce a fertile soil to barren-
ness without materially altering its weight, bulk, or
mechanical texture.

The fertility or barrenness of soils does not alto-
gether depend on the quantity of organic matter, that
is of vegetable mould or humus present in the soil.
This is no doubt of great value. It is constantly
yielding by its decay, carlxmic acid and nitrates to
nourish the organic part of the plant. It is setting
free, little by little, the earthy matters of its own

174

i ,

I I

... i

ashes. It is also by its decay inducing chemical
changes, which tend to set free other matters held in
combination in the particles of the soil. It renders
clay soils more friable, and sandy soils more retentive
of volatile substances, and of substances in solution.
It darkens the color of the soil, and thus enables the
solar heat to have more effect on it. These are all
important uses. Still there are some alluvial soils
nearly destitute of organic matter, and yet of almost
inexhaustible fertility, and there are some peaty soils
very rich in organic matter, yet very barren. If or-
ganic matter has accuuiulated in a soil by the growth
of vegetation of a high order, then, conditions of heat
and moisture being favourable, the soil will be fertile,
and if the organic matter be abundant, they will be
exceedingly fertile. Such soils were formed by the
growth of the deciduous forests (»f Canada, and by
the growth of the grasses of the western prairies.
But if the organic matter has resulted from the
growth of lower forms of vegetation, as of the coni-
fers on our gravel ridges or of mosses in bogs, the soil
may be comparatively barren. Important though
the organic matter of the soil is, the mineral matter
is more so.

Not only must all the inorganic matters needed by
the plant be present in the soil, but they must be pres-
ent in an available form. Inorganic matter enters the
plant only through the tender tissues of the rootlets,
in a state of solution. Unless then these matters are
in such a state as to l)e soluble in soil-water, that is in
water which hckls in solution carbonic acid or alkalies
or other substances derived from the soil or the air
or the roots of growing plants, their presence in the
insoluble state is of no immediate value to the plant.

175

jmical
leld in
enders
entive
lution.
ies the
are all
il soils
almost
by soils

If or-
growth
of heat
! fertile,
will be

by the
L and by
prairies,
•om the
,he coni-

the soil

though
pi matter

jeded by
be pres-
iters the
rootlets,
bters are
Ihat is in
alkalies
kr the air
Lee in the
the plant.

It is true that they need not be very soluble.
Phosplioric acid in solution in soil water does not in
any case exceed one part in 50,000 ; but as the forma-
tion of every pound of dry vegetable matter is
attended by the evaportion of at least 2*50 pounds of
water, this very small proportion of phosphoric acid
in solution would account for 5 per cent, of this sub-
stance in the vegetable structure. It is true also
that the whole amount needed is not necessarily
available at once. If while a crop is growing the
chemical changes which are inc- ssant in a soil,
progressively render soluble the needed nutriment as
it is required, the crop will Hourish ; even if at no
given moment of the season the soil holds ready all
the nutriment requisite.

Chemical analysis of soils is of comparatively little
service as a guide to agricultural practice, just because
it fails to answer the question how much of the
nutrient material in the soil is available or will
readily become available for the wants of a crop. It
can accurately state the amount of each ash ingredient
present in the soil. It can dt^monstrate the absolute
barrenness of a soil b}^ proving that it is destitute of
some essential ingredient of the ashes of plants. It
can show what amount of each ash ingredient can be
leached out of the soil by water. But plants can
undoubtedly take from a soil more than pure water will
dissolve from it, just how much chemistry cannot say ;
and it cannot tell the farmer what additional amount
will be set free during the growth of the crop by
the chemical changes resulting from the development
of roots in the soil, from the operation of bacterial
life, from the influence of heat, moisture and frost,
and from the combined interactions of the many

»3

176

Ir.

ii

I :

substances contained in the soil or supplied to it as
manure.

Soils differ materially in their power of retaining
soluble substances.

The absorbent and retaining power of soil is one of
its most remarkable properties. The arable soil is
not a mere sieve through which any matter in solu-
tion can pass freely ; but, on the contrary, it has a
great power of retaining, as in a filter, all saline and
other substances that may be present in the water
permeating it. This power is very different in
different soils, and in the same soil in the case of
difierent substances. In passing through any ordi-
nary soil the dark water of a dunghill, or a saline
solution, will lose large portions of its contents, which
remain, so to speak, entangled among the particles of
the soil, or adhering to their surfaces. In light and
sandy soils this power of retaining nutritive sub-
stances is less ; in heavier soils, greater ; in soils hav-
ing much vegetable matter it is strongly marked ;
and in light soils of a red or brown color, having the
particles mixed with oxide of iron, it is greater than
in colorless, sandy Poils. Extremely light sands, and
extremely compact clays, possess this power in the
smallest degree, so that the porosity of the soil seems
to be mainly important in reference to this property.

Further, the absorptive property of the soil appears
to be connected with a chemical action upon the sub-
stances present in it ; some solutions being decomposed
in passing through certain soils, and one substance
retained while another is allowed to pass. Thus salts
of potash and ammonia sometimes part with these
bases to the soil ; the acids present entering into other
combinations.

177

it as
ining

me of

ioil is
solu-

has a

le and

water

jnt in

jase oi

y ordi-

i, saline

1, which

tides of

y]\t and

ve sub-

ils hav-

narked ;

^^ing the

ter than
ids, and
in the
)il seems
►roperty.
appears
the sub-
•omposed
jubstance
hus salts
lith these
tto other

It would seem from various experiments that the
matters thus absorbed by the soil are more readily
available to plants than those in chemical combina-
tion with its ingredients. Tlie latter are only little
by little set free by decomposition ; and this is
believed to explain the effect of tillage in improving
soils, and also the fact that chemical analysis often
shows a larger amount of nutritive substances than
experiment proves to be practically available. Thus,
if an analysis shows a large quantity of phosphate of
lime in a soil, it may yet happen that plants like
wheat, which require much of this substance, may not
be able to obtain it in time, in consequence of its
occurrence in the form of soli<l particles or sand.
Tillage, by stirring the soil and promoting the solu-
tion of these particles and their mechanical absorption
by the ground, may make them available ; and may
consequently appear to enrich the soil. The presence
of organic matter in the soil has a double influence in
these processes. First, by producing carbonic acid,
it adds to the solvent power of the water of the soil.
Secondly, by its mechanical absorbing power, it
retains the substances dissolved till required by the
roots of the crop.

Certain chemical manures also, as common salt and
lime, are highly important in the solution of inert
substances ; and the matters thus dissolved, being
absorbed by the soil, are retained for use.

This property of soils is of immense importance in
the formation of composts, and the use of bog earth
under manure heaps and stables. The earth and bog
become mechanically saturated with nutritive matters,
and thus become most valuable fertilizers.

The absorbent power of soils also serves to illustrate

178

f:

k

m

fir

Jiiii,

the advantages of subsoil ploughing and draining, as
it is of the highest importance to bring all parts of
the soil within reach of the air and water permeating
it, and that it may absorb nutritive matters instead of
rejecting them from its surface. Were it not for this
property, soluble substances present in the soil would
be immediately washed out of it, and fallowing,
tillage and draining would rapidly impoverish the
land by allowing its soluble constituents to be carried
off by water.

§ 5. The Soil in Relation to Heat.

The temperature of a given soil depends on the
amount of heat it receives from the sun and gains or
loses by the winds that blow over it, by the rains
that soak into it, or by the soil water that percolates
through it. The temperature of the winds and the
rains and the amount of sunlight are nearly uniform
over broad belts of country and determine its general
climate. But in 'broken country the climates on
opposite sides of a hill may widely differ. One farm
perhaps slopes gently to the southeast, lies open to
morning suns, and is sheltered from bleak northwest
winds. Another farm has a northern exposure, and
is swept by all the bitterest storms of late fall, winter
and early spring. The first farm enjoys a climate
more genial than that of the other by the equivalent
of several degrees of latitude.

Under the same circumstances of climate and
exposure it is well known that soils differ greatly in
temperature, because they differ in their relations to
heat. Some soils have a greater specific heat than
others, they require more heat to warm them, and
they yield up more heat in cooling than other soils.

179

r, as
s of
ting
id of
this
ould
ving,
1 the
.rried

n the
bins or
rains
solates
nd the
[liform
reneral
tes on
e farm
pen to
thwest
re, and
winter
climate
ivalent

tte and
;atly in
iions to
;at than
jm, and
ler soils.

The surfaces of some soils ahsorV) from sunlight more
heat, and radiate more in darkn»jss than otliers do.
Finally some soils c(m(hict hoat downward from the
surface into the interior more rapidly than others do.
Specific heat of Hoih. Taking tlie specific heat of
water as 1 that of dry peaty matter is 21, of (h'y
clay 14, of dry silicious sand 1, and of dry chalk '18.
From these numhers may he calcidated the specific
heat of dry soils that consist of various aihnixtures of
organic matter, clay, sand an<l lime.

Examples.

156. What is the specific heat of a dry clay loam
consisting of 25% sand, 10% organic matter and 65%
clay ?

157. What is the specific heat of a dry calcareous
loam consisting of equal parts of chalk, sand, clay and
humus ?

But wet soils differ very little in specific heat,
because water has in comparison with the dry matter
of soils so high a specific heat.

158. What are the specific heats of wet humus, clay,
sand and chalk each containing 50% of its weight of
water ?

159. What would they be if in each case the weights
of water and of soil were e(|ual ?

160. What is the specific heat of a soil consisting of
25% water, 25% humus an<l 50% silicious sand ?

AJmrrhent and rttdiafiiif/ power of soil. — The
power of the surface of a soil to absorb the radiant
heat of the sun depends largely on its colour. Dark
coloured surfaces absorb heat most readily. All soils
sprinkled over with a thin coating of lamp-black and

180

i:

exposed to the full blaze of sunlight speedily acquire
a comparatively high temperature, and nearly all the
same temperature. If whitened w'th a sprinkling of
magnesia, they soon acquire in the same circumstances
equal temperatures, but many degrees lower than when
blackened. Similarly, dark coloured soils rise in
temperature under the same exposure to sunlight
several degrees above soils naturally light-coloured.

The surfaces which absorb heat most readily also
radiate it away most readily, so that they cool most
rapidly by night as well as heat up most rapidly by
day.

Conduefinrf power of soiln. — It is evident that the
difference of temperature between the upper and
lower layers of a soil warming in the sun will be less
as the conducting power of the soil is greater. The
conducting power of soils is, however, small in any
case. It is greater in compact and in stony or

fravelly soils than in loose, friable, well-tilled soils,
rost penetrates more deeply into the soils that have
the higher conducting power. Hence in our climate,
under roads and streets the ground is frozen four or
live feet deep, while at the same time in gardens with
a light surface soil, protected by snow, the frost
descends but a few inches.

I the
ng of
ances
when
se in
[ili^ht
red
y also
I most

lat the
jr and
be less
r. The
in any
ony or
I soils.
at have
climate,

four or
ns with

e frost

CHAPTER XII.

EXHAUSTION OF THE SOIL.

The table of the composition of soils, when com-
pared with that of the ashes of cultivated plants,
throws lij^ht on the causes of exhaustion of soils, and
on the advantages of rotation of crops. Soils mani-
festly become exhausted when, by a succession of
crops requiring much of some particular substance,
that substance is removed from the soil to such an
extent that the crop can no longer obtain a sufficient
quantity; and the number of crops which a soil will
give, depends on the amount of such matter which
it originally contained. The particular substance
first exhausted will be that which was originally
most deficient in the soil, and on which the crop in
question makes the greatest demands. Further, the
exhaustion of one substance is fatal to the fertility of
the soil, especially for such crops as require much of
that substance, since the plant cannot, except within
very narrow limits, substitute one element for
another.

§ 1. Causes of Exhaustion.

Johnston gives the following estimate of the quan-
tity of matter taken from an acre by an ordinary
English four course rotation. He supposes that the
crop of turnips may amount to 25 tons, that of barley
to 38 bushels, that of clover and grass to 2 tons per
acre, and that of wheat to 25 bushels,

1«2

ll

I'l,

M '1

' I

Potasb

Soda

liime

Magnesia

Alumina

Silica

Sulphuric Acitl ....
Phosphoric Acid..
Chlorine

Turnip

Barley.

Rve

Wheat.

Roots.
145.5

Grain
5.6

Straw

4.5

Clover

Gra>s
28 5

Grain Straw

45.0

3.3

0.6

<{4.3

5.8

1.1

12.0

D.O

:s.5

0.9

45.8

2.1

12.9

030

l«.5

1.5

7.2

15.5

3.fi

1.8

7.5

2.0

1.5

1.0

2.2

0.5

3.4

0.3

0.8

0.4

2.;

23.0

23.0

90.0

8.0

«2.0

«.o

86.0

4».0

1.2

2.8

10.0

8.0

0.8

1.0

22.4

4.2

3.7

15.0

0.0

0.6

6.0

14.0

0.4

1.5

8.0

O.l

0.2

0.9

Total.
239.0

im.«j

149 0
329
10.3

299.2
72.8
61.5
25.6

Total pounds 970.9

If we were to suppose the common four years'
rotation of oats, turnips or other green crop, wheat
and hay, the result would not be very materially
different.

The table shows a loss by cropping in four years of
rather less than half a ton of mineral matter from an
acre ; and if we enquire as to the nature of this loss
we find that it might be repaired, if we except the
silica, which, being abundant in nearly all soils, may
be left out of the account, by the following quantities
of mineral manures :

325 lbs. dry Pearl Ash.
333 " Carbonate of Soda.

43 " Common Salt.

30 " Gypsum.

150 lbs. Quick Lime.
200 " Epsom Salts.
83 " Alum.
210 " Bone dust.

These substances would be required to replace those
taken away, provided that no part of the crops or the
manure derived therefrom should be returned to the
soil.

It will be observed that the green crop portion of
the rotation carries off the greater part of the mineral
substances, and consequently that grain crops are not

1«3

Potal.

..970.9

years'

wheat

.erially

ears of
rom an
lis loss
pt the
Is, may
antities

Lce those
)S or the
d to the

)rtion of
} mineral
s are not

the moat exhaustinpf to the soil. Practically, how-
ever, the <lit!erencc between a rotation .sucli as this,
and no rotation, includes the supposition that
manures are introduced with the green crops, whereas
where there is no rotation, j^rain crops are often cul-
tivated for a succession of years without manure.

Whatever the crops cultivated, it is apparent that
cropping for successive yenis without manuring, must
ultimately exhaust the soil or render it harren. A
very rich soil may long endure such cropping, owing
to the great (juantity of these substances contained
in it; a poor soil will be reduced to sterility sooner;
a shallow .soil will fail sooner than a deep one, a light
soil sooner than a .stitt'one.

Further, the more available .su))stances in the soil
will be exhausted first. The less soluble will remain,
and thus a .soil may become barren while it still retains
much of the food of plants; in this state its productive-
ness may partially and temporarily be restored by
leaving it at rest, and especially by fallowing and
tillage, or by ploughing in of green crops, all of which
processes tend to set free some of the previously insol-
uble substances.

If we compare the table of the sul)stances removed
by crops with that of the composition of the soil, it is
apparent that the exhaustion falls most heavily on
some of the substances least abundant in the soil. We
cannot exhaust any ordinary soil of silica, alumina, or
oxide of iron ; nor can a soil naturally calcareous be
exhausted of its lime ; but there are few soils which
can bear several crops without manure and not .suffer
an appreciable exhaustion of their available phos-
phates and alkalies. More preci.sely, we find that the
substances neces.sary to the plant, present in smallest

i»

I

!

'(

I I

184

quantity in fertile soils, and absent or deficient in
exhausted ones, are potash and soda, chlorine, sulphuric
acid and phosphoric acid. Of these, potash and phos-
phoric acid are both the most important to the more
valuable crops, and the most difficult and costly to
procure.

It results that in so far as inorganic matters are
concerned, potash and phosphoric acid stand first as
of practical importance in the theory of agriculture.

It is observed in practice, especially on those virgin
soils rich in vegetable mould, that long cropping
deprives them almost entirely of this vegetable mould,
and this is sometimes regarded as the sole cause of
their impoverishment. In reality, however, it is only
a small part of the cause ; but it is to be observed that
the vegetable mould contains within it a large amount
of the material of the ashes of leaves and other vege-
table matters which have grown upon the soil, and
these are exhausted with the disappearance of the
vegetable mould. It may even happen that the
forests growing for ages on the soil have drawn up
from it nearly its whole stores of available mineral
matter and deposited these in the surface vegetable
soil. In this case so soon as cropping has exhausted
the black mould, the fertility of the soil is gone. But
in soils of fertile character it is more usual that much
mineral food for plants remains in the soil and sub-
soil, though often in a state which requires the action
of the air for its reduction to a useful state ; hence
after the vegetable mould has been exhausted by
destructive cropping, the land will still yield some-
thing after repose or fallowing, or subsoil or trench
ploughing.

We must consider here the dilferences of the soil

jence

by

lome-
lench

soil

185

and subsoil. The upper soil may be fertile and the
subsoil Vjarren, and vice versa. In the former case,
crops which spread their roots near the surface, as is
the case with the grain crops, will thrive on it, but
will exhaust it more rapidly than if the subsoil were
fertile. In the latter case, only plants which can
send their roots deeply into the soil will succeed well.
In the former case, mixing the subsoil with the soil
may be injurious, in the latter it may be beneficial.

As the soil becomes gradually poorer under ex-
haustive cropping, the grain ordinarily becomes short
in straw, and the kernel smaller in quantity and
poorer in quality. At the same time certain weeds,
which still find enough of food in the soil, grow
with greater rankness than the crop. Various kinds
of parasitic fungi, the mildews, rusts, etc., attack the
crop and diminish still further the yield. All these
evils are aggravated if the same variety of grain is
cultivated without change of seed.* In these circum-
stances the uninstructed farmer usually holds that
the seasons have become less favorable than formerly,
and he is confirmed in this conclusion by finding that
in some unusually favorable season he still has a
fair crop. He is further confirmed in it when he finds
that ploughing in a green crop or adding stable
manure, though it increases the straw, does not much
improve the grain or rid it of its diseases and enemies ;
and unless otherwise instructed than by his own
experience, he may remain in ignorance of the fact
that the ground is exhausted by the loss of the
mineral matters he has taken from it in successive
crops, and cannot l)e fertilized except by restoring
them to it.

Indeed, his land may be in such a state that in an

I

186

unusually favorable wseason it will produce a good
crop, but not in an ordinary season, and since the
large crop exhausts it more than the small one, the
yield may be even less than usual in the following
year. Now, to be profitably cultivated, the land should
be in such a state of fertility that it will yield good
crops in ordinary years, and that failures should be
the exception, not the rule. It is also not unfrequently
the case that the urdioalthy condition of a plant, de-
pending on deficient nutriment from the soil, is the
predisposing cause of diseases and failures. If the
soil has the materials of the straw and leaves of
wheat, and has not the phosphates required for the
grain, the latter cannot be produced ; but in this case
it usually happens that the plant does not simply
wither without producing grain, but that, unable to
turn the stores of sugar and albumen it has accumu-
lated to this use, it yields them a prey to the fungi
which cause rust, hiildew and other diseases ; and the
loss of the crop is attributed to these, when the
primary cause was a partially exhausted condition of
the soil. In such a case it is even possible that the
straw may be luxuriant without the plant having the
means to perfect its seed.

This sad picture of exhaustion applies to large
portions of eastern America, and is the principal
reason why the wheat culture continually recedes to
the west, leaving the exhausted fields to^be occupied
with buckwheat or other inferior grains.

Some curious cases of special exhaustion of single
substances have been observed l)y chemists. One of
these is the removal of phosphates*], by pasturage.
Pasturage is generally supposed to improve rather
than to deteriorate the soil. Still the phosphates

187

good

•e the

le, the

owing

■should

I good

aid be

^uently

mt, de-

[, is the
If the

aves of

for the

liis case
simply

laVjle to

iccuniu-

le fungi
and the
hen the
lition of
.hat the

[ving the

|to large
principal
^cedes to
occupied

|of single

One of

[asturage.

rather

Losphates

removed in the bones and milk of cattle, gradually
tell on the quantity of these substances in tlie soil ;
and hence, in certain old pastures, beginning to fail, a
dressing of bone dust has been found to produce
almost magical effects, because it restored the one
ingredient, in this case, beginning to be deficient.

It follows from the above statements, that to know
the nature, causes and remedies of exhaustion in any
particular case, we must study the original com-
position of the soil, the substances wdiich have been
removed from it by cropping, and the best and
cheapest w^ay of supplying those which have become
deficient.

It also follows that the fertility of the land can be
maintained only l»y restoring to it an adequate amount
of the substances of which our crops deprive it, or by
rendering fresh quantities of these still in the soil
available to plants by tillage, fallowing, etc. This
last mode however leads at length to a total ex-
haustion of the soil, if pursued without recourse to
the other. Fortunately for the farmer, the produce
which he must sell oft* the farm does not take away
so much inorganic matter as that which he may keep ;
if, for instance, he disposes only of grain and animal
produce, he can keep for the sustenance of the land
all the straw, hay, roots, etc., or the manures produced
in their use by animals. By a careful economy of
these resources in a system of rotation farming,
exhaustion may in rich lands be avoided for an in-
definite period, though the introduction of additional
manures will even in this case be more or less re-
quisite. In China and Japan a scrupulous and pains-
taking economy of every kind of animal and vegetable
manure has maintained the fertility of the soil from

188

k

if;

the most remote ages, and will continue to do so, and
to support a dense population, for an indefinite period,
and this without any kn(5wledge of scientific princi-
ples. On the other hand, the neglect of manures in
soiiie districts of North America establishes a drain
upon the land, which no amount of scientific know-
ledge can remedy except at very great cost.

§ 2. — Exhausted Soils of Canada.

Many very instructive facts in relation to the exhaus-
tion of soils in Canada, are disclosed by the analyses
of Canadian soils executed by Dr. Hunt, of the
Geological Survey of Canada, and published in the
Report of the Survey for the years 1849 and 1850,
and also in the general report, in 1863. We shall
introduce here a few of these analyses in illustration
of the general statements already made.

One of the soils analyzed was a vegetable mould
from the alluvial flats of the valley of the Thames in
Western Canada, and is aaid to have yielded 40 or
even 42 bushels of wheat to the acre, and in some
instances to have been successfully cropped for thirty
or forty years without manuring. Dr. Hunt describes
this soil as follows: —

" Such is the fertility of the soils in this region
that but little need has hitherto been felt of a system
of rotation in crops ; some, however, have begun to
adopt it, and have commenced the cultivation of
'' ^er, which grows finely, especially with a dressing
* plaster, which is used to some extent.

" The natural growth of these lands is oak and elm,
with black walnut and white wood trees of enormous
size ; the black walnut timber is already becoming a
considerable article of export. Fine groves of sugar

189

, and

■»riocl,

rinci-

:es in

drain

inow-

xhaus-
nalyses
oi the
in the
d 1850,
re shall
stration

mould
tames in
id 40 or
in some
►r thirty
tescribes

Ls region

[a system

jegun to

ration of

dressing

and elm,
(enormous

jcoming a
oi sugar

maple are also met with, from which large quantities
of sugar are annually made.

" I give here an analysis of a specimen of the black
mould from the seventh lot of the first range of
Raleigh. The mould here is eight or ten inches in
thickness, and had been cleared of its wood, and used
six or eight years for pasture ; the specimen from a
depth of six inches contained but a trace of white
silicious sand.

" No. 1 consisted of —

Clay 83.4

Vegetable matter 12.0

Water 4.6

100.0

100 pf* i of it gave to heated Hydrochloric acid —

Alu ^ma 2.620

Oxide of Iron and a Utile Oxide of Manganese... 5.660

Lime 1.500

Magnesia 1.060

Potash and Soda 825

Phosphoric Acid 400

Sulphuric Acid 108

Soluble Silica 290

i)

This, it will be observed, is a soil rich in alkalies,
phosphoric acid, and soluble silica ; and on these
accounts, eminently adapted for the growth of wheat
as well as of nearly all other ordinary crops.

With this may be compared a soil from Chambly,
in Lower Canada, respecting which the following
remarks are made :

" The soils of this Seigniory are principally of a
reddish clay, which, when exposed to the air, readily
falls down into a mellow granular soil. In the places
where I had an opportunity of observing, it is under-
laid at the depth of three or four feet by an exceed-

«'f

100

ingly tenacious blue clay, which breaks into angular
fragments, and resists the action of the weather. The
upper clays constitute the wheat bearing soils, and
were originally covered with a growth of maple, elm
and birch ; distinguished from them by its covering
of soft woods, principally pine a)id tamarack, is a
gravelly ridge, which near the church is met with
about fourteen acres from the river; it is thickly
strewn with gneiss and syenite boulders much worn
and rounded. The soil is very light and stony, but
yields good crops of maize and potatoes by manuring."

" The extraordinary fertility of the clay is indi-
cated by the fact that there are fields which have, as
I was assured by the proprietors, yielded successive
crops of wheat for thirty and forty years, without
manure and almost without any alternation. They
are now considered as exhausted, and incapable of
yielding a return, unless carefully manured ; and
such, for the last fifteen or twenty years, have been
the ravages of the Hessian fly upon the wheat, which
is the staple crop, that the inducements to the im-
provement of their lands have been very small ; so
that the Richelieu valley, once the granary of the
Lower Province, has for many years scarcely fur-
nished any wheat for exportation. But the insect,
which for the last three or four years has been
gradually disappearing, was last season almost
unknown, and the crops of wheat surpassed any for
the last ten or twelve years."

" Of a number of soils collected at Chambly, oijly
three have as yet been submitted to analysis ; they
are — one of the reddish clay taken from a depth of
sixteen inches, from a field in good condition, and
considered as identical in character with the surface

51- The
lis, and
3le. elm
iovering
,ck, is a
jet with
thickly
ch worn
.ony..hut
anuring.
J is indi-
i have, as
successive
s, without
on. They
capable ot

^red; a^^
hiave heen
leat, which
|to the im-
small; so
lary oi the
freely ^^^"
the insect,
s has been
5on almost
ped any ^or

Lmbly. only

lalysis ; they

\ a depth o«

ludition, and

the surface

191

soil before tillage, No. 2 ; and one at a depth of six
inches, from a field closely adjoining, but exhausted
by having yielded crops of wheat for many succes-
sive years without receiving any manure, No. 3 ; the
latter supported a scanty growth of a short, thin,
wiry grass, which is regarded as indicative of an im-
poverished soil, and known as herhe a cheval ; both
were from the farm of Mr. Bunker ; the third. No. 4,
is a specimen of the gravelly loam above mentioned,
from an untilled field upon the farm of Mr. Yule."

No. 2 contained a small amount of silicious sand and
traces of organic matter, and gave 5.5 per cent. of water.

100 parts of it yielded to heated Hydrochloric Acid:

Alumina IVIOO

Oxide of Iron 8.080

Maganese t(>0

Lime 711

Magnesia 2.810

Potash r,:\6

Soda ;J40

Phosphoric Acid 418

Sulphuric Acid 020

Soluble Silica 180

No. 3 consisted of —

Silicious sand with a little feldspar 9.0

Clay 7U.2

Vegetable matter 08

Water o.O

100.0

100 parts of it gave —

Alumina not determined

Oxide of Iron 4.o00

Lime ^^7

Magnesia S88

J^i»s^\ m

Doda }

Phosphoric Acid 126

Sulphuric Acid 031

Soluble Silica 080

14

1«2

n : ■

k

ilf

By the action of water, a solution containing
minute traces of chloride and sulphates of lime,
magnesia and alkalies is obtained. 100 parts of the
soil give in this way, of chlorine, .0018; sulphuric
acid, .0005.

No. 4. This soil contained about 20 per cent, of

pebbles, and 12 of coarse gravel : that portion which

passed through the sieve consisted of —

Gravel 75.0

Clay 13.7

Vegetable matter 6.1

Water , 5.2

100.0

The soil was very red, and the sand silicious and

quite ferruginous, consisting of the disintegrated

syenitic rocks which make up the coarser portions.

100 parts gave —

Alumina 2.935

Oxide of Iron 5.505

Lime 156

Magnesia 409

Potash 109

Soda 144

Phosphoric Acid 220

Sulphuric Acid 018

Soluble Silica 080

The first of these soils, (No. 2) that which had not
been exhausted, closely resembles in its proportions of
inorganic plant-food that first noticed. It is further
to be observed, that while one of these soils, that from
Raleigh, is very rich in vegetable matter, and the
other, that from Chambly, contains very little, both
are equally fertile as wheat soils. This is a striking
evidence of the great importance of the mineral
riches of the soil.

If now, we compare the fertile soil No. 2, with the

lori

ining
lime,
i the
)liuric

snt. oi
which

75.0
13.7

6.1

5.2
100.0

)\is and
.egrated

tions.

2.935
5.505
.156
.409
.109
.144
.220
.018
.080

with the

exhausted soil No. 8, we see at once that the latter
ha.s parted with the greater part of its alkalies and
phosphoric acid, and probably with the more available
part of these substances. The exhaustion of potash
and phosphates is, in truth, the cause of its present
sterility ; and when we consider that the straw and
grain of thirty crops of wheat have been taken from
it without return, we have sufficient reason for fche
change.

The third soil. No. 4, characterized as of light
quality, is, in comparison with No. 2, poor in lime,
phosphates, alkalies, and soluble silica, but it has
nearly twice as much phosphoric acid as the worn out
soil, No. 3, and is not behind it in soluble silica. An
equal (juantity of ordinary manure would probably
produce more effect on it than on the exhausted soil
No. 3.

Another tferm of comparison is afforded by a soil
from the farm of Major Campbell, at St. Hilaire,
which is said to have been reclaimed from compara-
tive exhaustion by manuring and draining. It is a
heavy clay, and afforded, on analysis, in 100 parts :

Alumina 12.420

Oxide of Iron 7.320

Lime 697

Magnesia 1.490

Potash 591

Soda 231

Phosphoric Acid 390

Sulphuric Acid 022

Soluble Silica ia5

This soil, it will be observed, rises very nearly to
the level of the unexhausted soil from Chambly ; and
the difference between it and the exhausted soil. No. 3,
is, no doubt, due to the manures added by the

104

N,.'

proprietor, and to the admixture of unexhausted sub-
soil by draining and deeper ploughing.

That this last cause had some share in this result
is indicated by an analysis of subsoil, taken from the
same field, but at a depth of thirty inches from the
surface. No manures penetrate a clay soil to such a
depth as this, so that this analysis gives the natural
(juality of the soil. It shows in 100 parts :

Alumina 4.380

Oxide of Iron 6.245

Lime 980

Magnesia 1.080

Potash 753

Soda 355

Phosphoric Acid 474

Sulphuric Acid 024

Soluble Silica 210

It thus appears that the subsoil is far richer than
the improved surface soil in alkalies, phosphates, and
soluble silica. The subsoil is a vast store of mineral
manure, ready to be applied to use by under-draining
and subsoil ploughing. It would seem that this applies
very generally to the exhausted clay soils of Canada,
which, having been undrained, ploughed in a shallow
manner, and cropped by plants which feed in these
circumstances only on the surface soil, might be
renovated by tile draining and the use of the subsoil
plough more easily than by the application of manurial
substances. This is a fact which holds forth a gleam
of hope for all the impoverished farms of the older
and exhausted districts.

It is to be observed, however, that the material of
the subsoil probably requires some tillage and aeration
to make its constituents available for plants, so that
it should be very gradually mixed with the surface

105

jub-

jsult

the

the

ch a

tural

m

45

80
i80
'53
$55
174
024

no

than
^s, and
lineral
•aining
ippUes
Janada,
Ihallow
these
rht be
subsoil
murial
gleam
le older

soil. It would also require the addition of some organic
matter, as, for instance, peat or bog mu«l.

In leaving these Canadian soils, it is deserving of
remark, that even the richest of theui are rather poor
in sulphuric acid, and would, therefore, probably bo
benefited by the use of gypsum.

It nmst also be observed that the exhaustion of
soils is not to be accounted for simply by the removal
of mineral matters. The soil, as already stated, is the
storehouse from which many plants derive the greater
part of that indispensable substance nitrogen. In the
husbandry of nature which carefully returns to the
soil the debris of life, and which mingles on each foot
of ground in proportions determined by the needs of
the case, plants of many divers species continually
supplanting each other in a ceaseless rotation, the store
of nitrogen is constantly replenished, but when a
farmer removes from the same Held the same crop of
grain year after year without adequate manure, he
not only exhausts the soil of its mineral wealth, but
he reduces it to infertility by depriving it of available
nitrogen.

jrial of
leration
so that
surface

CHAPTER XIII.

ITi I-

r 5' '

f

i I

IMPROVEMENT OK THE SOU. HV MECirANICAL MEANS.

Amelioration of the soil may be mechanical, l»y
acting on its texture and its relations to water aiul the
air, or chemical, by adding to it nutritive substances.
The former only will be consi<lei*ed in this place. The
latter will cointi more naturally under the head of
manures.

§1. imiiita^

Several methods of improving the mechanical con-
dition of the soil are within tht; reach of the farmer.

One of these is the ancient and most important
expedient of tlllafje. The stirring and loosening of the
soil by the plough, Dm spadcN the harrow, the subsoil
plough, and other implements, are not merely neces-
sary preparations for the se«xl, but important means
of ameliorating the soil. The chemical changes pro-
ceeding in the soil, by which food is prepared for
plants, require the presence both of air and water.
The larger pores of the soil must be filled with air, the
smaller with water. This is the condition of a mellow,
well prepared soil. It is the condition most favourable
to the germination of seeds and the penetration of
roots, as well as to the complex chemistry of the soil
itself. The roots of a crop exhaust the soil in their
vicinity, while other portions remain untouched ; but
tillage mixes the whole again, and gives the roots of
the succeeding crop a better opportunity of extracting
nutriment.

id;

ANS.

1(1 the
ances.
. The

\\ con-
Lriner.
portant
VoUUc
su\)S()il
neces-
mcans
es pro-
rod for
water,
air, the
mellow,
curable
tion oi
the soil
m their
ed; but
roots of
tracting

Again, tliere are in most .soils Hniall fragments of
vegetable and mineral matter, which, if exposed to the
action of the air and moisture, would yieM up their
constituents as food for plants. Tillage enables them
to do so. Hence the maxim of some farmers that
nmch and careful tillage is etjuivalent to manure.
Hence also the benefit of fallowing, which not merely
allows the soil to rest, but brings into use its reserve
stores of nutriment.

We must, however, beware of supposing that tillage
actually enriches the ground, or ot falling into the.
error of those writers who maintain that nothing else
is necessary to fertility. The manurial value, so to
speak, of tillage, depends essentially on its power of
rendering serviceable the insoluble portions of the
soil ; and when these are exhausted by a long course
of cropping, tillage or fallowing will fail to be of
service any longer in this respect. Even in this case,
however, if the surface soil only is exhausted, subsoil
and trench ploughing may bring a new soil within
reach of plants, and by rendering its stores accessible,
prolong for some time, though not for ever, the fruit-
fulness of the soil.

The chief implements of manual tillage are the
spade or the digging fork, the rake and the hoe. The
spade or the digging fork are employed to loosen and
to invert the top layer of the soil, to form beds, to
throw up ridges of soil, or to trench the land more or
less deeply. The loosening of the soil admits air and
moisture to it, and enables the rootlets of plants to
penetrate it more easily in all directions. The in-
verting of the soil buries weeds, turns under the
upper more highly oxidized layers of the soil, and
brings up the lower layers to be acted on more

If

its

m

198

IV^

immediately by the air. Beds elevated above the gen-
eral surface of the garden are thereby rendered some-
what drier than the general mass of the soil, and are
most frequently resorted to in rainy climates, and in
low undrained soih. Ridges are frequently thrown
up at the approach of winter in order that the clods
may be disintegrated, and the soil rendered friable by
frost. The trenching of land, which is essentially a
disturbance of the subsoil two or three spades deep,
. may be so conducted as merely to loosen the subsoil and
make it accessible to the roots of plants. Or, again,
it may be so managed as to bring up from beneath
and mingle with the upper soil more or less of the
subsoil. Whether it is wise to do this or not will be
determined by the character of the subsoil. The
digging fork penetrates hard ground more easily than
the spade, and it loosens wet ground more effectively,
not compacting it so much. The use of the rake is to
follow the spade, removing weeds and stones, break-
ing up clods which have escaped the pulverizing
action of the spade, and levelling the minute inequali-
ties of surface. The common hoe and the scuffle hoe,
or Dutch hoe, especially the latter, are excellent
exterminators of weeds, and both loosen the topmost
layer of the soil. But the common hoe is the more
serviceable in hilling up potatoes and corn.

No farm implements for the purpose of tillage,
operated by horses or by steam, can quite equal in
effectiveness the hand tools just df^scribed. But
ploughs, harrows, horse-hoes and rollers are no mean
substitutes for them.

The common plough consists essentially of a, the
beam, to which all other parts are fastened ; b, the
coulter, a sort of perpendicular knife, which cuts the

^11

199

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oreU-

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l are

id in

•own

clods

lie by

lly a

deep,

iland

igain,

neath

)f the

^rill be
The

Y than

tively,

e is to

break-

jrizing
quali-
Q hoe,

Icellent
»pmost
more

Itillage,
Liual in
But
mean

a, the

h, the

luts the

furrow-slice off vertically ; c, the share, a triangular
i horizontal knife, set at the deepest part of the plough
i to cut off the sole oi' the furrow slice ; d, the mould
board, or breast, a twisted surface Vjehind the coulter

which gradually turns

the furrow slice over ; e,

the head of the plough,

to which the draft-chain

is fastened to pull the

plough through the

/, the stilts or handles, by which the plough-

rtian guides it, regulating both the depth and the

width of the furrow.

Many refinements of design and make, not above
descril)ed, tend to the perfecting of this most import-
ant of agricultural implements. An adjustable wheel
or wheels sometimes carry the front of the beam and
serve to govern the movement of the plough so as to
secure the cutting of a fnrrow slice constant in width
and depth. The brake or clevis at the head of the
plough, to which the draught chain is attached, admits
a right or left and an up or down adjustment so as to
cause the plough to cut a wider or a narrower, a
deeper or a shallower furrow. Sometimes a skim-
coulter, which is like a miniature plough, is fastened
to the beam in front of the coulter. Its purpose is to
turn the top layer of the soil with weeds and manure
that has been spread on the surface, into the bottom
of the furrow, to be buried under the furrow slice.

Ploughs are modified for special purposes, as the
ridging plough and the side liill plough. Most im-
portant of all the special purpose ploughs is the
.subsoil plough. This plough is intended to run
behind a common plough in the .same furrow, splitting

1

'^'dl

I'

200

and slightly raising but not throwing up to the
surface nor inverting the subsoil. One of the best
forms of the subsoil plough consists of a beam with
its clevis in front and handles behind, to the under
side of which is fastened, by two perpendicular steel
standards, an arrow head of steel laid flat, with its
point set in front. The forward standard presents a
cutting edge. The arrow head is flat on the under
side, but rises backward into a convex wedge. Such
an arrow head, 12 inches long, 8 inches broad, and
rising to 3 inches thick in the middle of the back,
forced through the subsoil at a depth of from 6 inches
to 18 inches beneath the bottom of an ordinary fur-
row, has an extraordinary effect in breaking up hard
pan, in loosening the subsoil and in deepening the
available soil without throwing the raw subsoil up to
mingle with the surface layers.

The horse hoe or cultivator appears in farm prac-
tice under many forms. It is essentially a frame
work, partly or wholly carried on wheels, armed
beneath with long perpendicular standards ending in
teeth or in cutting blades that scarify the earth from
one to four inches deep, cutting oflf weeds and loosen-
ing tlie very surface of the earth so as to admit air
and hinder evaporation. In order to fit the cultivator
for many uses it is often provided with many forms
of interchangeable teeth or blades.

Harrows in field culture serve the purposes for
which the rake is used in gardening. The harrow
consists of a frame-work of one piece, or preferably
of more than one piece hinged together, so as to be
somewhat flexible and capable of accommodating
itself to inequalities of surface, furnished with many
spikes projecting beneath. As this implement is

201

the

best
with
inder

steel
th its
nts a
under

Such
1, and

back,
inches
y tur-
p hard
tig the
I up to

1 prac-
frame
armed
ling in
1 from
oosen-
nit air
tivator
forma

Jses for
larrow
terably

to be
)dating

many
bent is

<lragged over ploughed land it combs off the project-
ing edges of the furrows as left by the plough ; it
levels the surface ; it breaks down clods ; it teases
out wee«ls ; it raises stones to the surface ; and leaves
the ground mellowed and pulverized to tlie depth of
two or three inches. Also after the broadcasting of
seed, it buries the seed just beneath the surface, hid-
ing it from the light and from birds, and bringing it
within the influence of capillary moisture rising from
the deeper moist layers of the earth. A good harrow
has a very flexible frame, as light in weight as is
consistent with covering a sufficient width of ground
and sinking the harrow deep enough for its work,
and its teeth are so disposed in the frame that no
tooth follows in the track of another, and that the
ground passed over by the harrow is combed by many
little e(iuidistant furrows.

The roller most freijuently used is specially
designed for smoothly compressing the surface of the
soil about the seed when newly sown, and is usually
a smooth cylinder of cast iron revolving on an axle ;
but it is better made in sections as though built up
of four or more very broad -faced cast iron wheels of
equal size revolving on a common axle.

The plough is used to invert the soil in preparation
for a new crop. When sod is broken up it is desir-
able to turn under the upper layer which contains
grass, weeds and their seeds, in order that the ve^i^eta-
tion that is to be replaced may be destroyed. For
this purpose the breaking plough is]employed, making
the breadth of the furrow-slice at least twice its
depth ; the sod is then inverted, its grass side rots,
and the roots turned upward die, killed by the action
of the sun and wind. In fall ploughing with the

i

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Bill

ill

'^r

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i

202

;

i^'

I:

I

in"

■ f :

common plough, preparatory to spring work, it is best
to throw up the furrows in little ridges that may
crumble down in the frost. This is best done by
making the depth of the furrow-slice about two-
thirds of its breadth. The furrow-slice will then be
turned through one right angle and a half, (135^,
three fourths inverted), and the angle formed by the
meeting of the inner face, and the bottom of each
furrow-slice will be thrown directly upward, so as to
cover the field with longitudinal right-angled ridges,
exposing to the action of the weather the largest
possible amount of surface, and admitting air freely
to the corresponding longitudinal hollows left empty
between and under the furrow-slices. It must be
remembered, however, that in a field ploughed in this
manner, if the soil be so coherent that the furrow-
slices retain their form, the capillary connection
between the ploughe<l layer and the subsoil is to a
great extent cut off. Water will rise very slowly
from the subsoil into the ploughed layer, so that the
latter is dependent for moisture on showers. Such
ploughing is more suitable, therefore, in fall than in
spring. The winter rains and frosts will crumble
and compact the ploughed layer, so a« to restore
capillary contact with the subsoil before the seed is
sown in the spring. But if ground be so ploughed in
the spring and immediately sown, and dry weather
follow, germination is delayed and young plants are
stunted in jSfrowth throuijh lack of moisture. Of
course cross ploughings, and the use of the cultivator
and the roller, crumble the soil, fill in the hollows
underneath the ploughed land, and restore capillary
connection.

Ploughing, and indeed every kind of tillage, is

203

best

may

3 by

two-

n be

135^,

J the
each

as to

idges,

irgest

■reely

inpty

ist be

n this

irrow-

ection
to a

lowly
t the
Such

Ian in
iiuble
istore
iC'l is
led in
father
are
Of
Ivator
jUows
fllary

je, is

injurious to tenacious soils while so wet as to be in a
plastic condition. Then the trampling of horses and
of men and the compressive action that necessarily
attends the use of every instrument of tillage, knead
the soil into resistent clods that long refuse to admit
the entrance of rootlets. Heavy clay lands, although
usually rich in the inorganic food of plants, have this
great disadvantage, especially when undraincd, that
they are accessible for tillage during a much smaller
part of the year than lighter soils. When the weather
is dry, they are so hard as to be all but impenetrable
by the plough ; when it is wet, the soil if worked
kneads into bricks ; and, besides, after being soaked
by rains they retain the water with which they are
charged so tenaciously that it is long before they
come into condition for working. In these heavy
soils the constant traverse of the sole of the plough
at a nearly uniform depth forms a hard pan of great
compactness, which neither moisture nor roots can
easily penetrate. The use of the subsoil plough is
here indicated.

Before seed is sown implements of tillage are used
to reduce the soil to a state of tine tilth ; that is to a
loose, granular condition, in which there are innumer-
able pores filled with air; the granules neither
crumbling down into a fine compact dust that the
first rain will make into an air-proof mortar, nor adher-
ing to each other in stony clods ; the capillary connec-
tion with the subsoil being maintained so that with-
out having the air contained in it replaced by water,
the upper soil may nevertheless be kept moi.st.

When seed is sown by hand, the harrow is used to
cover it and the roller to restore the capillary connec-
tion broken by the harrow.

'ill

I

1 i

i 1

N'.ii

'J

1 i

1 :

: 1 (
P ■

204

When seed is broadcast or drilled in close drills, so
that tho crop covers the ground, tillaore ceases till the
crop is harvested. But when the crop is sown in
wide drills or hills, as root crops and corn, as soon as
the young plants can bo distinguished, or even earlier,
shallow cultivation with the horse hoe or cultivator
begins. The stirring of the upper layers of the soil
between the rows of plants contributes greatly to the
luxuriance of vegetation, especially in dry weather ;
this for two reasons, first, the weeds which compete
with the crop for nourishment from the ground are
destroyed ; secondly, the capillary connection between
the lower and the topmost layers of the soil is inter-
rupted, so that moisture is not evaporated from the
unoccupied surface, and that part of the land from
which the crop derives its nourishment is kept both
moist and warm. Such cultivation must, however,
be shallow, or it will destroy many spreading rootlets
of the crop.

One most important mode of ameliorating the soil
is under-draining by tiles and similar contrivances.
No expedient has proved so serviceable in improving
the mechanical qualities of the soil ; and even in warm
and dry climates like that of Cannda, it has been
found most profitable by all who have skilfully
employed it. Its various beneficial effects may be
'•hortly summed up as follows : —

It makes the soil warmer, by draining off the water
v^'hich otherwise would keep the ground cold by its
evt)*r»oration. Land under-drained is sometimes from
li)" to 15° warmer than similar undrained land lying
adjacent to it. For this reason, and because the soil

20ry

)Ving

^arin

jbccn

fully

|y be

^ater
its
[from

soil

being sooner rid of surface water, is more quickly
ready to endure the trampling of men and horses
without poaching, it enables the ground to be worked
earlier in spring and later in autunm, and renders the
growth of crops more rapid.

It tends to prevent the surface from being too much
washed by rain ; as it enables the water to penetrate
the soil, carrying downward the substance of rich
manures, instead of washing it to lower levels. It
thus, in connection with that absorbing power of the
soil already described, saves the riches of the soil from
waste.

It allows the roots of plants to penetrate deeply
into the soil, instead of being stopped, as they often
are, at the depth of a few inches, by a hard subsoil, or
by ground saturated with water, or loaded with sub-
stances injurious to vegetation. For this reason,
drained lands stand drought better than undrained,
and their crops are also larger and more healthy.
Hence also it often happens that draining benefits
even light lands, if they happen to have an imperme-
able subsoil.

It permits free access of air, thus preventing the
" souring " of the soil, and bringing manures of all
kinds into a fit state for absorption by the roots.

It prevents injury to the soil from the water of
springs coming from beneath by capillary attraction.
It also prevents baking in dry weather, and causes
the ground to crumble more freely when ploughed.

It tends to diminish the effect of frost in throwinc:
out the roots of clover and grasses, by enabling the
roots of these plants to take a deeper hold of the soil.

In short, it renders land easier and more pleasant
to work ; makes crops more sure and heavy ; prevents

■ a
1.1

T'

SB

(

I A

*

I-

.!

j i

206

alike injuries from drought and excessive moisture ;
economizes manures ; and is equivalent to the deepen-
ing of the soil, and the lengthening of the summer.

The following short summary of the methods of
under-draining is taken from " Norton's Elements of
Scientific Asrriculture."

" First, as to depth ; where a fall can be obtained,
this should be from 30 to 36 inches. The plants can
then send their roots down, and find to this depth a
soil free from hurtful substances. The roots of
ordinary crops often go down three feet, when there
is nothing unwholesome to prevent their descent. The
farmer who has a soil available for his crops to such
a depth, cannot exhaust it so soon as one where they
have to depend on a few inches, or even a foot of
surface. Manures, also, cannot easily sink down
beyond the reach of plants. On such a soil, too, deep
ploughing could be practised, without fear of disturb-
ing the top of the drains. The farmer should not, by
making his drains shallow, deprive himself of the
power to use the subsoil plough, or other improved
implements that may be invented, for the purpose of
deepening the soil. There are districts in England,
where drains have had to be taken up and relaid
deeper, for this very reason. It would have been an
actual saving, to have laid them deep enough at the
first.

" Second, as to the way in which they should be
made, and the materials to be used."

" The ditch should, of course, be wedge-shaped, for
convenience of digging. The bottom of it need only
be wide enough to receive the tiles. The upper part
of the earth is taken out with a common spade, and
the lower part with one made quite narrow for the

207

be

J for

^art
ind
Ithe

purpose, being only about four inches wide at the
point. The bottom is finislied clean and smooth, with
a peculiar hoe or scoop. This is necessary, because
the tiles must be laid on an even smooth foundation."

Of all materials that have been used in the con-
struction of drains it is now found that tiles, made of
clay and burned, are cheapest. These have been
made of various shapes.

" The first used was the horse-shoe tile. This was
so named from its shape ; it had a sole made as a
separate piece to place under it, and form a smooth
surface for the water to run over.

"Within a few years this tile has been almost
entirely superseded by the pipe tiles (which are
merely earthenware pipes, of one inch bore or larger,
and made in short lengths). These tiles have a great
advantage over the horse-shoe shape, in that they
are smaller, and are all in one piece ; this makes
them cheaper in the first cost, and also more econom-
ical in the transportation.

" All these varieties are laid in the bottom of the
ditch, it having been previously made quite smooth
and straight They are simply placed end to end,
then wedged a little with small stones, if necessary,
and the earth packed hard over them. Water will
always find its way through the joints. Such pipes,
laid at a depth of from 2 J to 8 feet, and at proper
distances between the drains, will, in time, dry the
stiffest clays. Many farmers have thought that
water w^ould not find its way in, but experience will
soon show them that they cannot keep it out. The
portion of earth next the drain first dries ; as it
shrinks on drying, little cracks begin to radiate in
every direction, and to spread until at last they have

J

m

15

i J
i

U

u

208

penetrated through tlie whole mass of soil that is
within the influence of the drain, making it all, after
a season or two, light, mellow and wholesome foi*
plants."

" They form a connected tube, through which
water runs with great freedom, even if the fall is
very slight. When carefully laid, they will dis-
charge water, where the fall is not more than two or
three inches per mile. If buried at a good depth,
they can scarcely be broken; and if well baked, are
not liable to moulder away. There seems no reason
why well-made drains of this kind should not last
for a century. The pipe tiles are used of from 1 to
IJ inches diameter of bore for the smaller drains,and
for the larger, up as high as 4 or 5 inches. They are
all made in pieces of from 12 to 14 inches in length.
An inch pipe will discharge an immense quantity of
water, and is quite sufficient for most situations.
These small drains should not ordinarily be carried
more than 400 to 500 feet before they pass into a
large one, rurniing across their ends. Where a very
great quantity of water is to be discharged, two
large-sized horseshoe tiles are often employed, one
inverted against the other.

"Third, as to the direction in which the drain
should run. The old fashion was to carry them
around the slopes, so as to ciU off the springs ; but it
is now found most efficacious to run them straight
down, at regular distances apart, according to the
abundance of water and the nature of the soil. From
20 to 50 feet between them woulp probably be the
limits for most cases. It is sometimes necessary to
make a little cross-drain, to carry away the water
from some strong spring. In all ordinary cases, the

209

drains running straiglit down, and discharging into a
main cross-drain at the foot, are amply sufficient."

For connecting the consecutive lengths of pipe
collars are sometimes used. These are very short
pipes, in which the diameter ot* the bore is eijual to
the outer diameter ot* the pipes to be connected. The
adjacent ends of these pipes are thrust into the collar,
which serves to prevent, almost completely, the
entrance of silt at the junction.

As, however, silt cannot be completely excluded,
the pipes used in drainage should be as small as will
carry oft* the water, in order that
they may be effectively scoured by
the current through them ; they
must be most carefully laid with a
uniform fall, and should be joined
with the larger pipes at a small
angle, by the use of junction pipes,
in order that there may be no places
of slack current in which the silt
may be deposited ; and where una-
voidable abrupt changes of direction or of slope take
place, there silt basins should be established. These
silt basins may be constructed of wood, of brick or of
stone, or they may be merely larger earthenware pipes
set on end, the general plan of construction Ljing
readily understood from the marginal figure, which
represents two drain pipes, one entering and the other
leaving the silt basin. It is clear that much of the
earth brought down by the entering pipe will settle
in the silt basin, which must be cleared out from
time to time. The silt basin may be built up to the
surface and there carefully covered, or it may be
covered at about the level of the drain with a board

I

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or a atone, and the earth rilled in above it, its position
bein<]f, of course, exactly noted. The exit of the
whole Kystem of draina<^e should be carefully binlt,
and the mouth covered with an iron grating to pre-
vent the entrance of vernun.

Before commencing to lay drains, the wliole laml
to be drained should be carefully mapped out, with
contours of elevation drawn. The system of drainage
should then be determined, fully and accurately
marked on the plan with the position of every smaller
and larger drain and silt basin carefully laid down.
The plan should then be exactly followed and pre-
served for future reference.

With regard to these mechanical modes of im-
proving the soil, it may be stated with truth —

1. Tiiat except in some cases of naturally deep an<l
well-drained soils, no soil has a fair chance of showing
its capabilities without deep ploughing and draining.

2. That many partially exhausteil soils may have
their fertility restored by these processes.

3. That the deepening and loosening of the soil
occasion no waste of manures, but the reverse.

4. That when judiciously conducted these improve-
ments have proved themselves to be among the
cheapest and most profitable that can be attempted.

In estimating the cost of underdraining, it will be
borne in mind that the price of tiles will differ in
different localities and that their cost to the farmer
will depend on his distance from the kilns. Again
the cost of laying will be less where skilled labour
can be secured, even at much greater daily wages.
In the examples that tV)llow the cost of tiles without
collars is reckoned at 25 cents a rod, with collars at
30 cents a rod. The cost of laying is estimated at

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50 cents a rod four fci't flcop, 47 cents tlireo feet six
inches <lecp, 4.S cents three feet (U-ep, and '38 cents
two feet six inches deep.

Exam j ties.

161. How many rods (jf <]rain will he required to
drain a ten acre s(juare field, the Hrst drain heing one
rod from and parallel to one side and the other drains
parallel to it and two rods apart ?

1()2. How manv, if the Hrst drain be 15 feet from
one side, and the otliers 80 feet apart ?

163. How many, if the first drain be 10 feet from
the side, and the others be 40 feet apart ?

164. What will it cost to drain each Held as de-
scribed in the three preceding examples, both with
and without collars and at each of the depths, 4 feet,
3 feet 6 inches, 3 feet and 2 feet 6 inches ?

165. How much will it cost to lay parallel drains
without collars, four feet deep and one rod apart in a
square 40 acre Held, the first drain being parallel
to one side and eight feet distant from it ?

166. What will it cost to drain a rectangular field
of 16 acres, one side to which the drains are parallel
being 50 rods long ; the drains are to be three feet
deep and 30 feet apart, the first one being 12 feet
from the side of the field ; the pipes are to have
collars ?

167. If the total cost of draining one acre be $85,
if the net annual return from the land be $10 more
after draining, and if the deterioration of the drain
be 2^/o of its cost annually, what per cent, does the
farmer get on the cost of draining ?

168. Suppose that on undrained land a farmer can
raise per acre in successive years 22 bushels of wheat,

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one ton and a half of hay, pasturage for one year at
the rate of two cows on three acres, 35 bushels of oats
and 175 bushels of potatoes ; while on drained land
he can raise 27 bushels of wheat, two tons of hay,
pasturage for one year at the rate of eight cows on
nine acres, 50 bushels of oats and 200 bushels of
potatoes ; if wheat be 80 cents a bushel, oats 33 cents,
potatoes 35 cents ; if hay be $10 a ton and the
pasturage of a cow for one season be worth $6; if
the deterioration of the value of a drain be 2i'7o
annually ; and if, finally, it be held that the greater
ease of working will compensate the cost of harvesting
and manuring for greater crops ; will it pay a farmer
to borrow money at Q^/^ to drain his land 3 feet
deep, drains being on the average 40 feet apart and
being without collars ? What per cent, on the bor-
rowed capital would he have each year for himself,and
what additional annual income would he have from a
farm of 100 acres so treated ?

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CHAPTER XIV.

IMPROVEMENT OF THE SOIL BY MANURES.

§ 1. Gener(d_Natiire _o£ MorWiwes.

Any substance added to the soil by the farmer
for its improvement, or the sustaining of its fertility,
may be considered as a manure. Such substances
may be regarded from different points of view, ac-
cording to their origin, nature and uses.

Some manures are supplied by animal and vegetable
substances, others by mineral substances ; hence the
distinction arises of organic manures and inorganic
manures.

Some are produced on the farm, from the crops it
has yielded, and their application only restores what
has been taken away; others are obtained /ro77i abroad,
and so are actual additions to the soil.

Some act directly as food to plants, others also
indirectly, by making other substances useful ; and
they may do this either by rendering insoluble matters
soluble or, on the other hand, by fixing in the soil
substances which might escape from it in a volatile
state. For instance, gypsum may act directly by
affording sulphuric acid and indirectly by fixing
ammonia.

Some are general manures, that is, they are more
or less beneficial on all soils and to all plants. Of this
kind are the ordinary stable manures and composts.
Others are special, with reference to particular soils
needing them, or with reference to particular kinds

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of plants. Of this kind are such substances as nitrate
of soda, gypsum and superphosphate of lime.

Some afford nourishment principally to the orga^iic
part of plants ; and of this kind the most important
are those which can supply ammonia and carbonic
acid. Others afford the materials of the inorganic
part of the plant ; and of this kind are the various
mineral manures, ashes and some kinds of guano.

In considering any manure, it is necessary to have
regard to all these various uses, if we would wish to
estimate its value or understand its action. For the
present purpose we shall class manures as organic and
inorganic, and shall notice under each its relations to
various soils and plants.

Under the head of organic manures I group all
those fertilizing substances which have formed parts of
animals or plants, and are restored to the soil, whence,
or by the aid of which, they were obtained ; though
some of them cannot, in strict chemical language, be
termed organic.

§ 2. Stable Manure

Eighty years ago one of the ablest of British
American agriculturists said, " More than one-half of
the manure made in the provinces is absolutely wasted
from ignorance and inattention ; and the other half
is much less productive than \ it would have been
under more skilful direction. We have almost no
pits dug upon a regular plan, for the collection and
preservation of the dung which, from time to time, is
wheeled out of the barn. Sometimes it is spread out
on the green sward ; sometimes cast carelessly in a
court or adjoining yard ; but seldom is an excavation
made purposely for retaining the juices which run

215

from it. These are suffered cither to stream along the
surface or sink into the earth ; and in either case,
their utility is sacrificed to inattention or ignorance.
This is no more, however, than half the evil. The
exhalations which arise from the ardent influence of
the summer's sun or from the natural activity of
fermentation, are permitted to escape freely and to
carry with them all the strength and substance of
the putrescible matter."*

There is, no doubt, much more attention given to
this important subject now ; but still, the waste of
barn-yard manure, both solid and liquid, is a great
evil and a fruitful cause of agricultural poverty and
failures of crops. Some years ago, I had referred to
this subject in a public lecture, and happened, imme-
diately afterward, to drive ten or twelve miles into the
country, with an intelligent friend, who doubted the
extent of the loss. We were driving through an old
agricultural district, and, by way of settling the
question, determined to observe the capability of each
barn-yard that we passed, for the preservation of
manure. It w^as early in the spring, and we found
scarcely one barn that had not its large manure heap
perfectly exposed to the weather, and with a dark
stream oozing from its base into the road-side ditch,
or down the nearest slope ; while there was evidently
no contrivance whatever for saving the liquid manure
of cattle. Here was direct evidence, that a large
proportion, probably not less than one-third, of the
soluble part of the solid manure, and the whole of the
liquid manure, which all agricultural chemists think
to be at least equal in value to the solid part, was
being lost. In other words, each farmer was deliber-

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ately losing between one-half and two-thirds of the
means of raising crops, contained in his own barn -yard.
What should we think of a tradesman or manufacturer,
who would carelessly suffer one-halt of his stock of
raw material to go to waste ? And the case of such
farmers is precisely similar. The results of chemical
analysis will enable us to form more precise ideas
of the nature and amount of this waste.

In a prize essay on manures, by Prof. Way, published
by the Royal Agricultural Society of England, the
following analysis is given of the drainings of a dung-
heap, composed of the mixed manures of horses, cattle
and sheep, and in a well rotted condition. The fluid
examined was that washed out by rain water, and
was of a deep brown color. It contained in each
imperial gallon 76464 grains of solid matter, of which
395.66 were volatile and combustible, and 368.98
incombustible or aslics. Its composition was as

follows : —

I. Combustible Part.

Ammonia in a soluble state 36.25

Ammonia in fixed salts 3.11

Ulmic and humic acids 125.50

Carbon dioxide 88.20

Other organic matters (containing 3.59

of Nitrogen) , 142.60

395.66

II. Incombustible Part.

Soluble silica 1.50

Calcium phosphate with a little iron

phosphate 15.81

Calcium carbonate 34.91

Magnesium carbonate 25.66

Calcium sulphate , 4.36

Sodium chloride 45.70

Potassium chloride 70.50

Potassium carbonate 170.54

368.88

Total per gallon 764.64

217

An examination of this analysis shows that eacli
ton of this liquid contained a little less than 1 lb. of
nitrogen, something more than 4 lbs. of potash and
about a quarter of a pound of phosphoric acid ; the
value of the liquid was about 38c. a ton.

An analysis by Dr. Voelcker of stable manure, con-
sisting of a mixture of horse, cow and pig manure,
may be taken as representing the average composi-
tion of manure fourteen days old. It shows that one
ton of stable manure, such as he analysed, consists of

Water 1323 lbs.

Soluble Organic M\ttkr.

Nitrogen 3 lbs.

Other matters 4G-G "

49-(}

iNsoLUBf.K Organic Matter.

Nitrogen ,„ 0-0 lbs.

Other matters 505-3 "

515-2 "

IxoRGANu; Matter.

Soluble. Insoluble.

11-5 lbs. 2 lbs.
-4

Potasb

Soda 1-3

Lime 3-7

Magnesia -2

Silica 24-1

Chlorine -4

Sulphuric acid.. 1 -1

Phosphoric acid 3-6

Oxide of iron, alumina, car])on

dioxide and loss

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22-4

2-y

11-2

1-2
3.6

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Total.

13-5 lbs.

1-7
26-1

3-1

35-3

-4

2-3

7-2

22-6

112-2 ♦*

2000-0

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If, as is customary, we value this manure l)y its
content of nitrogen, potash and phosphoric acid alone

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it is worth for its soluble nitrogen at 15c. a pound,
45c. ; for its insoluble nitrogen, at 5c. a pound, 49^c. ;
for its potash, at 5c. a poun<l, 67 ic. ; and for its phos-
phoric acid at 10c. for soluble and 5c. for insoluble,
54c. ; $2.16 a ton. The value of its remaining inorganic
ingredients is insignificant. Silica is so abundant in
all soils as to be practically worthless, and all other
of the remaui. ig ingredients could be furnished for
less than 10c. It is impossible to valuate the 550 lbs.
of organic matter which is not nitrogen, for want of
a definite standard. This organic matter not only
ministers direoMy t*^ the growth of plants as plant
food, but it um^'H ^\mpii('rates the physical condition
of the soil, and pla^s an important, though as yet ill-
understoc'], part in ma^i^aining the bacterial life of
the soil, on whicn irauy 5f>ortant processes of nitri-
fication and fermental/ion aie dependent. But no
money value can as yet be assigned to these services
Liquid stable manure is a fei'tilizer of great value
as will appear from the following table : —

Compoi^ition of Lnjnul SlnUe Manure (Boiissaingault).

Horse. Cow.

Urea 31-00 18-48

Potassium hipjmrate 4-74 1(5-51

Potassium lactate 20-09 17-16

Magnesium carbonate 4-l(> 4-74

Calcium carbonate 10-82 0-55

Potassium sulpbate 1-18 3-60

Sodium chloride 0-74 1-52

Silica 1-{»1

Water, &c 926-26 937*44

1000-00 1000-00

Urea, as appears from its formula, C H^ N2 O, is
very rich in nitrogen. In decomposing, it changes
into carbonate of ammonia, which, being volatile,

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rapidly escapes, unless prevented by some absorbent
material, as charcoal, or by the chemical action of
sulphuric acid or gypsum.

A similar statement may be made respecting
hippuric acid of which the formula is C^ Hg NO3 ;
tl»e results of its decomposition are, however, more
complex than those of urea.

In the above table, we see that the liquid manure
contains large quantities of potash and soda ; and
that a large portion of it is urea, a substance which
from its abundant nitrogen is, in fact, quite similar to
the richest ingredients of guano. Johnston estimates
the value of 1,000 gallons of the urine of the cow to
be equal to that of a hundredweight of guano. The
farmers of Flanders, — who save all this manure in
tanks, — consider the annual value of the urine of a
cow to be $10.

One ton of licpiid horse manure contains 298 lbs.
of nitrogen, and 15 lbs. of potash; that of the cow
19.4 lbs. of nitrogen, and 19*7 lbs. of potash. On the
presence of these substances their manurial value
largely depends, for phosphoric acid is but an in-
siornificant constituent of the urine of horses and
cattle. One ton of liquid horse manure is worth
$5.22, and of liquid cow manure $3.90.

In the solid manure there is little nitrogen. This
element, so valuable for producing the richer nutri-
tious parts of grain and root crops, is principally
found in the liquid manure. The little that is present,
however, in the solid manure, is soon lost in the form
of ammoniacal vapours, if the dung be allowed to
ferment uncovered. The other oi^ganic matters are
less easily destroyed, unless the dung be allowed to
become " fire-fanged," in which case the greater part

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of it is lost. In the ashes, or inorganic part, we find
all the substances ah'eady referred to as constituents
of fertile soils ; and many of the most valuable of
them are, as the manure decomposes, washed away,
and, along with a variety of organic matters, appear
in the darlc-colored water which flows from exposed
dung-hills. It is not too much to say that the loss of
the volatile and soluble parts of manures, on ordinary
upland soils, cannot be repaid by any amount of out-
lay in the purchase of other manures, that our
farmers can afford ; and we can plainly perceive, that
the prevailing neglect in this one particular, is suf-
ficient to account for the deterioration of once fertile
farms. How, then, is this waste to be prevented ?
In answer to this, I shall merely indicate the prin-
ciples on which the means adopted for saving manures
are founded, with a few general hints on the best
modes of carrying them into effect.

1. The solid manure should be covered with a shed
or ropf, sufficient to protect it from rain and snow.
Its own natural moisture is sufficient to promote,
during winter, a slow and beneficial fermentation.
Snow only*prevents this from going on ; rain washes
away the substance of the fermented manure.

2. The ground on which the manure heap rests
should be hollowed, and made tight below with clay
or planks ; and in autumn, a thick layer of bog mud,
or loam, should be placed on it, to absorb the drainings
of the manure.

3. When the manure is drawn out to the field, it
should be covered as soon as possible, either in the
soil, or, if it must stand for a time, with a thick
coating of peat or loam, — a pile of which should be
prepared in autumn for this purpose. All unneces-
sary exposure should be avoided.

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221

4 Where gypsum can be procured cheaply, it
should be strewed about the stables, and on the
manure heap, for the purpose of convertiuj-^ volatile
ammoniacal vapours iniojixed sulphate of ammonia.
This will also render the air of the stables more pure
and wholesome.

5. It must be borne in mind that the richest
manures are the most easily injured. For example,
many farmers think horse manure to be of little value.
The reason is, that when exposed it rapidly enter.-i
into a violent fermentation and decay, and its more
valuable parts are lost. Such iranures need more
care than others, in protection and coverinjy, so as to
moderate the chemical changes to which they are so
liable, and to save the volatile and soluble products
which result from them.

6. The liquid manure should be collected, either in
the pit or hollow intended for the other manure, or
in a separate pit prepared for the purpose. The latter
is the better method. If a tight floor can be made
in the stable, it should be sloped from the heads of
the cattle, and a channel made, along which the urine
can flow into the pit. If the floor is open, the pit
should be directly beneath it, or the ground below
should be sloped to conduct the liquid into the pit.
In whatever way arranged, the pit should be tight in
the bottom and sides, and should be filled with soil,
or peaty swamp mud, to absorb the liquid. Gypsum
may also be added with great benefit ; and the urine
pit may very well form a receptacle for door-cleanings,
litter which may accumulate about the barn, and
every other kind of vegetable or animal refuse.
These additional matters may occasionally be pro-
tected, by adding a new layer of peat or soil to the top.

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Tlie pit for liquid manure .should be roofed over.
A method much followed in Britain and the continent
of Europe, is to collect the urine in a tank, and add
sulphuric acid to prevent waste of ammonia. When
used, the licjuid is diluted with water, and distributed
to the crop by a watering cart. This is too expensive
for most of our farmers ; but when it can be followed,
it will be found to give an astonishing stimulus to
the crops, especially in the dry weather of spring.
Gypsum may be put into the tank, instead of sul-
phuric acid.

An examination of the table on page 216 will show
that the combustible part contains a large amount of
ammoniacal matter, and the rest is principally the
richest humus or vegetable mould ; while the incom-
bustible part contains all the ingredients in the ashes
of cultivated plants, and these in a soluble state,
ready to be absorbed by the soil and taken up by the
roots. This table, in short, affords the most conclu-
sive evidence of the immense loss sustained by the
farmer who allows his stable manures to be weathered,
and their soluble part washed away by the rains.
No economy in other respects, and scarcely even the
most costly additions of artificial manures, can com-
pensate this waste.

This subject is, in all its details, deserving of the
careful study of every practical farmer.

When the circumstances of the farmer are such
that he cannot provide shelter for his manure heap
and tankage for his liquid manure, he may minimize
the waste by thoroughly underdraining his barn yard.
The leachings of his manure heap will then filter
through the earth instead of flowing away in open
drains, and will leave behind, absorbed by the earth,

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223

such
heap
limize
yard,
filter
open
jarth,

the chief part of their valuable materials, water,
nearly pure, alone escaping hy the drains. The top
layer of the barn-yard soil then becomes very rich,
and should be carted out with the manure and sprea<l
upon the land, its place being supplied by a new
layer of loam, or of mixed loam and peat annually
supplied.

§ 8. (i rre n Mo n urhuj

A large amount of organic matter, in a state rea<ly
to undergo rapid decomposition, may be furnished to
the soil by ploughing in a crop of succulent herbage,
such as buckwheat or rye or clover, grown upon the
land itself. This mode of treatment can, of course,
add nothing to the inorganic wealth of the soil, but it
does greatly increase its organic richness by the ad<li-
tion of a large amount of carbonaceous and some
nitrogenous matter derived from the air, and it
renders available much inert nitrogenous material,
and much inorganic material locked up in insoluble
forms. While the buried vegetation is undergoing
decomposition it affords the most favourable condi-
tions for the development of those lower forms of life
on which nitrification depends ; by which nitrogen in
an assimilable form is abundantly provided for the
vegetation that is to follow. Besides decomposition
immediately generates various powerful acids, as the
acetic, followed as the decomposition advances by
such as the humic and the ulmic, and ending as the
decomposition is completed in the production of large
quantities of carbonic acid, all being in direct contact
with the inorganic particles of the soil, acting power-
fully upon them, and provoking in various ways
many complex chemical changes which issue in

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ministorin^ abundant soluble inorganic food to the
rootlets of the following crop. Hesides the rotting vege-
tation ameliorates the physical as well as the chemical
condition of the soil. It renders loose sands more
coherent and more retentive of moisture and manures,
and it helps to disintegrate cold and lumpy c^*^vs.
Accordingly, green nianuring has been resorted .n
the reclamation both of hungry sands and of soggy
clays. When green manuring is so practised as to
involve the loss of the crop of one year, it is and must
always be an exceptional method of treatment. Then
in order that the farmer may lose nothing, the crop of
the succeeding year nmst be so much more abundant
than it would otherwise have been, as to pay by its
excess the cost of working and seeding the land for
the green crop, together with interest on that cost
and on the value of the land for one year. Onlv in
rare cases can the increase of crops do this.

£!.trveise8.

1()9. The pasture on a certain field is worth $1.00
per acre per month. The owner can pasture it six
months, then plough it up in the fall, put in oats in the
spring and harvest 40 bushels per acre, at a total cost
for labour and seed of $8.55 per acre. Or he can
pasture it three months, put in a crop of buckwheat,
plough it under and put in and harvest a crop of oats
of 55 bushels per acre, at a cost of $10.75 per acre.
Which had he better do, if oats will bring J^5c. a bushel,
and which if he cannot get more than 34c. a bushel ?

§ 4. Other Organic Manures.

The remaining organic manures may be arranged
under the following heads :

225

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$1.00
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lushel,

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1. Tliose which, hke peat, li()<^ mud, leaves, spent
hark, saw-(hist, straw, etc., consist principally or ex-
clusively of woody tihre. 'J'hes(^ suhstances «lecay hut
slowly in the soil, an<l do not yield lar<]fe cjUantities of
the more rari^ and valuable of the substances recjuired
by cultivated ])lants. They art; useful, however, in
two points of view\ They renew the supply of
vegetable matter in the soil, and thereby ameliorate
its texture ; and they atibrd, by their decay, substances
useful in enabling plants to build up tbt^ tissues of
tlieir stems and leaves. They are also admirable
absorbents for the richer parts of putrescent manures;
and by mixture with these substances, they are them-
selves more rapidly decomjioseil. Their use, therefore,
is, as already indicated, to till the urine i)it, to form
the basis of the dung-hill and the covei* of composts
and to serve as litter in the stable and cattle yard.
They may also be used in top-dressing grass, — which
they nt)t only nourish, but protect from the frosts of
winter.

2. A second class ccjnsists of the rapidly decom-
posing remains of aninuils and plants, — as dead
animals, blood, night-soil, tish-ott'al, parings of hides,
green succulent wx'eds, sea weeds, etc. The anin»al
manures of this class, are of great value, being almost
entirely composed of the materials which are most
wanted for the production of the most nutritious parts
of vefjetables. The ve^jetable manures of this class,
though less valuable, afford, in addition to tlieir woody
fibre, much alkaline matter and some nitrogen ; an<l
some of them contain animal substances which ad<l
greatly to their value. Such manures should not be
left exposed, nor should they, except in case of neces-
sity, be applied in a fresh state to the land ; as in

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their raw state, a slight excess of them often exerts a
poisonous influence, and much of their richness is also
apt to be wasted. They should be mixed with earth
or peat, in the proportion, in the case of the rich (a*
kinds, of three to one, and well covered with a coatin^x
of earth. The whole mass will thus become a rich
and valuable manure. In many places, there is
sufficient fish -offal, if treated in this way, to fertilize
large tracts of barren land ; whereas it is now totally
wasted, or spread on grass land, to taint the air with
odours which, if retained under ground, w^ould furnish
the elements of life and vigour to the crops. The
same remark applies to dead animals, and all the
putrescent refuse which is apt to accumulate about
yards and outhouses. Exposed on the surface,
these things are pestilential nuisances ; buried in the
compost heap, they are the materials of sul>sistence
and w^ealth.

As Sea tveed is a very important manure, and is
extensively applied in many parts of the sea coast, a
few additional remarks may be made, respecting its
composition and uses. The ashes of sea weed have
been found to contain :

Soda and potash 15 to 40 i)er cent.

Lime 3 " 21

Magnesia 7 '* 15 "

Common salt 3 " 35

Calcium phosphate 3 " 10 "

Sulphuric acid 14 " 31

Silica 1 " 11

These are all important substances, and, in addition
to the nitrogen contained in the organic part of the
weed, nmst exercise an important influence. Seaweed,
however, is but a temporary manrrc, as it decays
very rapidly ; and it is extremely unwise to place the

007

t.

tlition
If the
Iwecd,
[ecays
je the

whole dependence on it, to the exclusion of other
manures, especially of the stable manure. The farmer
should save his stable manure, and consider the sea
weed an additional, or supplementary aid. In this
way, there will be no danger of his having to complain
that, notwithstanding constant applications of sea
manure, his land is becoming poor. He nuist also
remember, that sea weed does not contain all the
materials of land plants, in due propoi'tion ; and that,
therefore, it cannot supersede the necessity of other
fertilizers. With respect to composting sea weeds,
some good farmers on the sea coast compost carefully
all the weed obtained in autumn, and apply, in the
recent state, that procured in spring. It has also
been successfully applied as an autumn dressing to
grass. This is certainly better than the practice,
which I have observed in some places, of top-dressing
grass with the stable manure, and applying nothing
in the drills with green crops but sea weed.

Land weeds form a somewhat useful kind of man-
ure, as they are often rich in alkalies, and other
constituents of crops. Rank road-side weeds are
especially valuable ; and their removal prevents the
dissemination of their seed, and improves the appear-
ance of the country.

3. A third class is formed of those manures of
animal and vegetable origin which, though highly
fertilizing,- are not liable to rapid decay ; and are,
therefore, permanent in their effects, and may be kept
for application in a dry state. Such are bcnies, hair,
hoofs, hen manure, guano, wood ashes, and soot.

Banes are of great value, as they afford that rare
and important substance, phosphate of lime, along
with a rich animal matter ; ground bones, " b<me dust,"

m

I i

I i

i !

228

arc now an important article of traffic as manure, and
are of great value, — as five bushels are considered to
be sufficient manure for an acre of turnips, especially
if mixed with a little wood ashes. Every farmer
should collect and apply Ixmes. They are very
valuable, even after being burned or boiled with
potash for soap, because, they still contain their
phosphate of lime, though deprived of their animal
matter. Where means for grinding bones cannot be
obtained, they may be broken into small pieces by
the hammer ; they may then be mixed with an equal
quantity of earth or ashes, moistened, and left to heat
before being put into the drills. For practical illustra-
tions of the value of bones, I may refer to Jackson's
Agriculture. Among other instances, he mentions,
that a dressing of 000 bushels on 24 acres of poor
pasture had so improved the grass, as to double the
yield of butter ; and this effect endured I'or many
years. In this case the pasture had been laid down
for ten years, and, no doubt, much of its natural phos-
phate of lime had been exhausted, to form a constitu-
ent in the milk and bones of the cattle that had fed
on it.

Hair and Hoofs are rich manures, though they
decay slowly. Such substances, from tanneries, etc.,
should be saved, and applied to the land. At the rate
of twenty or thirty bushels per acre, they produce
marked effects.

Giiano is a manure produced by the slow decay of
the droppings of sea birds, in dry climates, and is
chiefly obtained from islands on the coast of Peru.
Peruvian guano formerly containe<l from fifty-six to
sixty-six per cent, of ammoniacal salts and organic
matter, and from 16 to 28 per cent, of phosphates.

1 1

229

they

rate
)duce

Ind IS
IPeru.
lix to
[ganic
lates.

Now, however, the rich deposits formerly worked beiii<i:
exhausted, inferior grades containing only about 8 per
cent, nitrogen, 1215 per cent, phosphoric acid, and
2'8 per cent, potash are alone attainable : even these
are probably sophisticated. Very excellent artificial
guano is now made in Newfoundland and in Maine
from iish refuse, by boiling, pressing, and drying, and
then coarsely grinding or crushing. When pure and
genuine, these artificial guanos are among the richest
of portable manures.

Wood ashes may be applied with any crop ; but not
in very large quantity, as they not only act powerfully
as a manure, but exert a caustic or decomposing in-
fluence on organic manures, and on the roots of plants.
Fifty bushels per acre, is the largest quantity that
can be safely applied to heavy soils, rich in vegetable
matter. Lighter soils should have a much smaller
quantity ; and on light soils even a few bushels will
produce marked benefits. Kelp — or the ashes of sea
weed — and peat ashes, are similar in their effects to
wood ashes, but less powerful.

The great value of wood ashes may be estimate 1
from the remarkable effects produced by them in new
land, where the ashes of forests, the growth of cen-
turies, are at once applied to the surface. The sub-
stances which they afford, may be learned from th(i
following analysis of the ashes of beech wood :

I'otash 15.83 per cent.

Soda y.79

Common Salt 0.23 "

Lime 02.37

Gypsum 2.31 "

Mairnesia 11.29

Oxide of Iron 0.79 "

Phosphoric Acid 3.07 "

Silica 1.32

I

I

If
I*

r

m

230

These are the principal substances on which new
land depends for its fertility ; and the loss of which,
either by wasteful cultivation or by repeated burn-
ings followed by rain, causes its exhaustion. These
ashes produce the best effects when a considerable
proportion of the vegetable matter of the soil remains
unconsumed ; both because this vegetable matter
serves to retain the ashes, and because it prevents
their caustic effects from being too sti-ongly felt. On
the other hand, when the vegetable matter is entirely
consumed, the ashes are rapidly wasted, and the crops
suffer from deficiency of organic manure. Leached
ashes, having lost their potash and soda, are of less
value than recent ashes, but are still of great utility.

Peat ashes, though less valuable than those of wood,
have been extensively used as manure, especially in
Holland, and in applying peaty matter as manure, the
value of its inorganic part should be taken into
account. Hunt gives the following analysis of the
ashes of peat from St. Dominique, Quebec :

"A watery solution of the ash contained chlorine
and sulphuric acid combined with potash and soda,
and a large amount of sulphate of lime. The whole
of the alkaline salts were dissolved by the water.
The ash was strongly alkaline in its reactions, and
contained, as might be expected, the magnesia and
some of the lime in a free state." 100 parts of it
gave me :

Lime 47.040

Magnesia 8.150

Ferric Oxide..... 4.380

Alumina 2.440

Oxide of Manganese 040

Potash 330

Soda 254

231

^rine
ioda,
[hole
iter,
and
and
►f it

lo

lo
lo
lo
U

Chlorine 241

Sulphuric Acid \hl7'.\

Phosphoric Acid 932

Carbon dioxide 23.060

Silica 4.920

Sand (mechanically i)re.sent) 4.040

100.000

Such a substance must act powerfully on any soil
in want of sulphates, phosphates, lime, or silica, and
it is probable that the ashes of peat from most of our
bo<^s would be found to possess similar properties.

Soot contains ammonia, and sulphates, carbonates,
hydrochlorates and phosphates of lime, potash, soda,
magnesia, etc. It is, therefore, a very powerful
manure, and, like guano, need be applied but in small
(juantity.

To this class of manures, I may add the offal of
codfish, which may be obtained in large quantity in
some of the fishing districts. If dried, and packed in
old barrels or crates, it might be preserved and con-
veyed into the interior districts. As it consists
largely of phosphate of lime and rich animal matter,
it is nearly as valuable as guano, and would be well
worth 5s. or 6s. per cwt. It should be cut up, or
crushed, and mixed with soil to ferment before being
applied. It should be used in drills with potatoes or
turnips.

It may also be of service to add here, that night-
soil, urine, and other offensive animal substances, may
be converted into a manure of great power, and quite
inoffensive, by mixing them with powdered charcoal,
or charcoal and gypsum, or even with dry earth.
They may then be sown like guano, and will produce
similar effects. Artificial manures, called jKnuirdtcs^

^iii

!l,

i :

if : !

V I !

232

are often prepared in this way. Farmers would find
it profitable to have constantly at hand a (juantity of
charcoal and powdered gypsum for such purposes.

The value of the manures above enumerated
depends almost wholly on the nitrogen, phosphoric
acid and potash which they contain, the availability
of these substances being considered. For immediate
effect nitrogen in bone meal is worth four times as
much as the same amount of nitrogen in ground
leather scrap. In guano, bone meal and the more
readily T)utrescible animal matters, nitrogen may be
estim ,«ecl as worth 15c. a pound. Phosphoric acid
occaYS in manures combined with lime in the three
forms mentioned on page 101. The ter-phosphate
i i the form in which it occurs in bones, and in apatite ;
i he diphosphate, or, as it is often called in connection
vvith manures, reverted liosphate, is slowly produced
when calcium monophosphate and calcium ter-phos-
phate are mixed. Monophosphate or superphos-
phate is the form in which it should be found in
artificial manures.

Pure calcium ter-phosphate is soluble only to a
very small extent in water — about one part in 90,000
— but to twice as larcje an amount in water saturated
with carbon dioxide. The diphosphate is more soluble,
one part dissolving in about 18,000 parts of pure
water, and being four times as soluble in water
saturated with carl)on dioxide. The monophosphate,
or superphosphate, is readily soluble in water. Phos-
phoric acid in the state of ter-phosphate may be
valued in manure at 5c. a pound, in the state of
diphosphate at 6c. a pound, and in the state of super-
phosphate at 10c. a pound. In insoluble phosphates
generally phosphoric acid may be valued as in the

233

iind
y of

>.

■ated

boric

)ility
diate
es as
L-ound
more

^y

be

c acid
three
sphate
patite ;
aection
oduced
phos-
n-phos-
und in

[y to a
90,000
Iturated
IsoluUe,
)f pure
water
)spbate,
Phos-

bay

be

^tate oi
\i super-
)Spbates
in the

ter-phosphate of lime. Potasli may be valued at 5c.
a pound.

A useful mode of estimating the value of ferti-
lizers is to reduce the above prices to a price for each
one per cent, in a ton of manure. One per cent, of a
ton is of course 20 lbs. Therefore twenty times the
value of a pound of any fertilizer is the value of (me
per cent, of it in a ton of manure. Estimated thus
one per cent, of nitrogen per ton is worth about
$3.00, of phosphoric acid in superphosphate $2.00, in
reverted phosphate $1.20, of ter-phosphate and insol-
uble phosphates in general $1.00, and of potash $1.00.

Exami)les\

170. What, by the above scale of values, is the
worth of one ton of barn-yard manure, which con-
tains '76% of nitrogen, '14 of soluble and "18 of in-
soluble phosphoric acid and "96% of potash ?

171. What is the worth of 100 gallons of liquid
stable manure weighing 11 lbs. per gallon and con-
taining '8% of nitrogen, '3% potash and an inappre-
ciable amount of phosphoric acid ?

172. What is the worth of bone dust per ton, the
guaranteed analysis of w^hich give }1'5% of nitrogen
and 20% of insoluble phosphoric acid ?

173. What is the worth per ton of a sample of bone
dust containing 27% of insoluble phosphoric acid and
5% of nitrofjen ?

174. Calculate the value per ton of an artificial
manure containing 3 per cent, nitrogen, 5% soluble
phosphoric acid, 5% reverted phosphoric acid and
2J% potash ?

175. If all the phosphoric acid in the foregoing

n

m

111:

m

2:]4

sample had been soluble, what would the value have
been per ton ?

176. Another brand of artificial manure contains
2°/ nitrogen, 4% soluble and 2 J% reverted phosphoric,
acid, and 2J% potash, what is it worth per ton?

177. What is the worth per ton of a fertilizer con-
taining 8% nitrogen, 8^ soluble phosphoric acid, 2%
reverted phosphoric acid, 2% insoluble phosphoric
acid and 2°/^ potash ?

178. A sample of Saldanha Bay guano contained
9% nitrogen, 0*2% insoluble phosphoric acid and 1«^%
potash ; what was it worth per ton ?

179. Formerly Chincha Island guano gave 13%
nitrogen, 12% phosphoric acid (insoluble) and 2%
potash. What would its worth be per ton if it could
be now procured ?

180. A sample of Peruvian guano sold at S70.00
per ton, showing 81% nitrogen, 14% phosphoric acid
and 2% potash. Was this price excessive ? What
should it have sold for ?

181. When the above guano was sold chemists
valued its nitrogen at 30c a pound, its phosphoric
acid at 6c a pound, and its potash at 4Jc a pound.
What was the ton of guano worth at these prices ?

182. What is the value of 1 ton of wood ashes as
described on page 229 ?

183. What is the value of 1 ton of peat ashes as
lescribed on page 230, if its potash and phosphoric
acid alone be considered ?

184. What is the value of 1 ton of the ashes of
sea- weed containing 15% of potash and 5% insoluble
phosphoric acid ?

185. What is the value as manure of one bushel of
wheat ? of barley ? of oats ? of rye ? of maize ? of

h

have

tains
loric,

• con-

J, 2%
)hovic

,aine(l

i 1-3%

: i3y„

id 2/
i cou

&

$70.00
c aciil
What

leniists
jphoric
[pound.

les?

iVies as

ihes as
iphoric

ihes of
isoluble

shel of
lize ? of

235

peas ? of potatoes ? of carrots ? of mangolds ? of
rutabagas ?

N.B. — Consult tables on page 141, and reckon the
phosphoric acid as soluble.

18(3. What is the value for manure of one ton of
wheat straw ? barley straw ? oat straw ^ rye straw ?
corn stalks ? pea straw ? timothy hay ? red clover
hay ? green maize ? green rye ? green oats :*

§ 5. Mineral or Intyrganic Manures.

After what has been already said, it is scarcely
necessary to mention here that manures of this kind
may be as truly the food of plants as substances that
have already actually formed parts of vegetable sub-
stances. Any of the substances mentioned above as
necessary ingredients in fertile soils, or in the ashes
of crops, may produce valuables effects, if they can be
procured from the rocks of the earth, or any other
source, and applied to the land. The beneficial
influence of these substances may be summed up
under the following heads : —

1. They may supply original chemical or mechanical
wants in the soil. They may furnish substances
required by some or all crops, and previously defici-
ent ; and thus not only directly promote the growth
of crops, but enable them to avail themselves of other
materials which, though abundant, they could not
use, from want of that which was deficient. For
instance, if clover contains in its ashes 28 per cent, of
lime, and if the soil contains so little that, in the
course of the season, the plants can get only half the
(juantity they require, they will take just so much
less of everything else, and produce little more than
half a crop. Hence the addition of lime to such a

236

soil will enable clover to take a great deal more of
other kinds of food, and the effect on tlie crop will
be very marked. On the other hand, if the soil con-
tains a sufficiency of lime, its addition as a manure
may produce no appreciable effect. We learn from
this, the nature, in part at least, of what is called the
stimulating and exhausting effect of mineral manures;
and also the reason of their frequent failure. A
farmer who finds by experience that some mineral
ingredient, as lime, gypsum, etc., produces marked
benefit, continues to apply it, and neglects other
manures, until at last it produces no effect, and he
finds that his land is completely run out. He now
says that, after all, his supposed fertilizer was only a
" stimulant," and condenms it ; whereas the error is in
his own ignorance of the fact that, though necessary
to fertility, it only rendered more necessary a suffi-
cient quantity of the other kinds of food required. It
is just as if a farmer were to find the appetite and
flesh of his cattle falling off* and were to add some
salt to their food ; and finding this to remedy the
evil, were to withhold all other nourishment and
attempt to feed them on salt alone. Again, a farmer,
anxious to improve, learns that great benefits have
resulted from some mineral manure. He at once
applies it on a large scale, and is surprised to find
that it does no good whatever. The reason probably
is, that his land has already enough of it, while that
to which it has been successfully applied had not.
He should have ascertained by experiment on a small
scale, or by an analysis made by a competent person,
the actual state of his land in reference to this
particular substance ; and then he might have pro-
ceeded with certainty. These errors, arising from

237

^viU

;on-

lurc

rom
the

ires;
A

icral

rked

3th er

(1 he
now

nly a

' is in

jssary
suffi-

h\. It

e ami
some
y the

it and
armer,
have
once
,0 tind
obably
le that
id not.
small
person,
o this
e pro-
from

imperfect knowledge, work incalculable mischief to
the cause of agricultural improvement. The true
course with respect to mineral manures, is to test the
land as to its wants ; and then to supply what it
needs, without neglecting other ordinary manures.

2. Mineral manures may produce chemical changes
in the soil, which may preserve or render useful other
substances previously present, or may decompose
poisonous ingredients. I have already had occasion
to notice the effect of gypsum in saving ammonia, and
that of lime in decomposing sulphate of iron, an<l
neutralizing vegetable acids. Lime also exerts a
powerful influence in decomposing inert vegetable
matter, and even small stones and gravel wluch may
contain matter useful to the soil. This is what we
may call, if such a term can be properly used, the
true stimulating effect of mineral manures.

After these general remarks, it will not be neces-
sary to dwell at any great length on the separate
mineral manures. I shall therefore briefly indicate
their uses, sources, and the modes in which they may
be best applied.

Lime is an important ingredient in the ashes of
most plants. It exists most abundantly in the state
of carbonate, either in the form of limestone or in the
substances called marls, and which consist of mix-
tures of carbonate of lime with sand and various
earthy matters. Lime, in both of these states, is
abundant in most parts of this country ; though it
may be observed, that those tracts whose soils are
most deficient in lime, are precisely those in which
beds of limestone and marl are most rare

Marl is found in large beds, especially in the
gypsiferous districts of New Brunswick and Nova

If.

.--.«»J*i

\t

L'38

Scotia. Tlicsi' lars^c marl Itcds arc usually of ^rcy or
la'own colors, and often contain small irrc«(ular veins
of j^ypsum. The decaying surface of many heds oi
limestoiK' also affords a substance which may ho
classed with the marls. In some low <^rounds whicli
have formerly been ponds or lakcN thei'e are beds of
clay mixed with fi'esh-water shells: and in creeks
and harbors there are mussel and oyster beds wliich
afford a similar substance, containin;^ also nnich valu-
able animal matter; these are known as shell marls.
They exist in very many parts of Canada, numerous
localities bein<]^ noticed in the Reports of the (Geo-
logical Survey. On some parts of the coast also largo
quantities of sea-sh(;lls, mixed with sand, may be col-
lecte<l on the beach, an<l may be called shell-marl, as
they are (piite analogous in composition and ettects.
All these substances may ])e applied in large (piantity
with benefit to most soils; more especially as in this
mild state the lime exercises no destructive influence
on the organic matter of the soil. The earthy marls
may be used for mixing with composts, or laid on as
a top-dressing. The shell marls, which contain much
animal matter, should be covered and composted with
earth, and applied with root or grain crops. Marls
may be distinguished from common clays and sands
by a very simple test. Put a little of the sul»stance
into a wine glass or tumbler, and add a little water,
sufficient to make it into a thin paste. Then pour in
a few drops of hydrochloric acid, and obso'-' if ny
eftervescence or boiling up occurs. If a I, it

will boil up with considerable foi po* one,

with less force; and if not a marl a dl, tl re ^\ ill be
no efiervescence or scarcely any. Limest »ne may be
distinguished from other rocks in the same way.

289

or
inH

oi

\>o
licU
s of
jeks
Incli

larls.
jroiis
Ooo-
largo

e col-
Lvl, as
ttects.
intity
I this
uonce
marls
on as
much
1 with
Marls
sands
stance
water,
our in
•»' iiy

1, it
me,

V ill be
inay he

y-

Limestone ordinarily requires to be burned in
order to be rendered tit for application to land.
Burning deprives it of its carbon dioxi<le, and brings it
into the state of (juick or caustic lime, calcium oxide,
or after it is slaked with water, into that of calcium
hydroxide, or lime combined with water. In these
forms, it is most suitable for mixing with crude vege-
table matters, as peat, which it is desirable speedily
to decompose, and also for application to some bogs ;
but in these forms its application in large (juantity to
very light soils is most dangerous. It remains, how-
ever, but a short time in the state of caustic lime, for
whether in the soil or on the surface, it gradually
absorbs carbon dioxide from the air and from the
organic matters with which it comes into contact, and
passes back into the state of carlx)nate, the same state
in which it was before being burned ; so that ulti-
mately the principal result of the burning is that of
reducing the lime to fine powder, which can be uni-
formly diffused throughout the soil. This change
does not, liowever, fully take place for a very l6ng
time. It is principally this strong affinity for carbon
dioxide whicn causes lime to hasten the decomposition
of organic matters, by creating a powerful demand for
the carbon dioxide which is one of the principal pro-
ducts of their decay; and as this carbon dioxide is a
useful part of the food of plants, in poor soils an
excess of caustic lime not only wastes the organic
matter, but takes away the little vegetable food which
it is producing. In like manner, caustic lime is alto-
gether unsuitable for mixing with rich animal
manures, as the rapid decay which it induces sets free
and wastes all the ammonia which they contain. This
is well shown by mixing a little quick lime with

17

fir''

240

III

1

J 'I

IMIHH

if

guano. The intense odor of ammonia given off indi-
cates at once the destructive action of the lime, and
the large quantity of ammonia in the manure. If a
rod dipped in hydrochloric acid be held over the
mixture, the ammonia becomes visible as a white
cloud of hydrochlorate of ammonia.*

As a decomposing agent, then, quick lime is most
rapid and efficient, but mild lime acts in the same
way, though more slowly. To the action of both
kinds, however, the presence of air is necessary. The
oxygen of the air is required in the decay of all kinds
of organic matter, and since lime acts in promoting
decay, its influence will in a great measure depend
on the greater or less readiness with which air can
penetrate to the vegetable matter of the soil. For
this reason, when lime is mixed with organic matter
in close vessels or in very stiff impermeable clays, it
tends to harden and preserve, rather than to decom-
pose it ; in such soils therefore, draining and loosen-
ing the ground are necessary in order that lime may
exert its proper influence.

The decomposing power of lime, explains its bene-
ficial influence on peat-bogs, and other soils sur-
charged with moisture and undecayed woody matter.
In such places the vegetable matter, long soaked in
stagnant water, produces in the slow cl anges which
it undergoes, the humic, ulmic and otber organic
acids, which communicate what is very properly
named sourness to the soli, and render it fit only for
the growth of coarse grasses, ferns, moss and similar
plants. But when lime is applied it enters into com-
bination with these acids, and at the same time causes

* The same test indicates the escape of ammonia from rich manures
when decaying too rapidly.

r

li-

Qd

: a
lite

lOSt

ime

)oth

The

inds

.ting

pend

• can

For

tatter

yrs, it

;com-

osen-

niay

Ibene-
sur-

atter.

,ed in
hich

•ganic

>perly
y ^or

limilar

com-
lauses

Imanures

241

the inert woody matter to decay and fill the soil with
products valuable as food for plants. It is to this
cause that we must also in great part ascribe the
beneficial change which lime effects in pasture lands
overgi'own with coarse grasses, or more useless
herbage, causing this rank vegetation to give place to
tender grasses and clover. In all these cases the lime
is merely the means of bringing into a useful form a
quantity of matter previously existing in the soil in
an inactive or positively injurious state. In the case
of swampy land, however, we must not forget that
lime will prove only a partial and temporary remedy,
unless it be assisted by draining.

The facts already stated will enable us to under-
stand the utility of composting peat, black swamp
mud, and similar substances, with lime. By the
decomposition which they are thus caused to undergo,
they are converted into valuable manures.

Since the benefit of lime arises in great part from its
power of bringing into use the stores of food already
present in the soil, it is plain that its eftects must be
greatest in soils which ctmtain abundance of vegetable
matter, and also that its tendency is to exhaust this
matter more rapidly than if lime were not used.
Heavy liming, therefore, when not accompanied with
other manures, must, at each successive application,
produce less effect, and end in causing comparative
barrenness. From observing this injurious effect of
the misapplication of lime has arisen the English
proverb that, " Lime makes rich fathers, but poor
sons." The Germans have a better proverb, to the
effect that heavy liming and heavy manuring must go
together.

These considerations also show how lime may

242

iu

" burn up " and impoverish some light soils, by wast-
ing with unnecessary rapidity their already small
stock of vegetable mould. When applied to such
soils, lime should be either in the form of clay marl,
or of composts made of peat, sods, ditch cleanings or
similar matters, which will furnish it with materials
to act upon, without exhausting the soil.

Lime also exerts an important influence on the
inorganic materials of soils. It has been already
mentioned that the soluble salts of iron present in
some boggy lands, and injurious to vegetation, are
decomposed by lime, owing to its superior affinity for
the acids which they contain. Another change of
the mineral matter of the soil, effected by lime,
depends on its affinity for silica, which is sufficiently
powerful to enable it gradually to decompose frag-
ments of granite, trap, and other rocks consisting of
silicates, combining with their silica and setting free
their potash, soda, etc., in forms very useful to crops.
Beside these, there can be little doubt that lime aids
in effecting many other changes among the mineral
ingredients of soils, tending in many cases to make
their constituent parts more available for the nourish-
ment of vegetation.

Duration of the effects of Lime. — When lime, in
the quick state, is placed in the soil, it acts energetic-
ally from the moment of its application until it is
reduced to a state of partial mildness, when its
influence is exerted more slowly. This slower action,
however, continues with unabated, or even increasing
vigor, for two or three years ; and although it may
then diminish, the influence of a heavy liming may be
felt even thirty years after its application. The
decrease of the influence of lime may be accounted

r

243

m
jetic-
lit is
its
ttion,
ising
may
Ly be
The
inted

for in ilifierent ways. It is usually applied only to
the soil near the surface, and has a tendency to sink
downwards into the subsoil. In light soils, this may
be caused by the fineness of its particles, which causes
them to be washed down between the coarser grains
of the soil. In rich and close soils, however, it is very
probably due to the earth-worms, those industrious
agriculturists which are constantly employed in carry-
ing to the surface tl e finer parts of the soil, on which
they feed, a process which must result in the Inirying
of every substance which they are not inclined to
devour. Lime is also dissolved by water impregnated
with carbon dioxide, and is rendered soluble by com-
bining with various acids present in the soil, and in
these states much of it is absorbed by the roots of
crops, and much washed away from the ground by
rains. Anoth'?r mode in which the influence of lime
may gradually become insensible, is by its combining
with silica, and forming an insoluble compound,
possessing none of the active properties of lime.

Qiuiiitity of Lime tvhich should be applied. — When
land is originally destitute of lime, a large quantity
may be mixed with the soil, with beneficial results.
This will be evident when we consider that in order
to give one per cent, of lime to a soil six inches deep,
we nmst apply above thrt^e hundred bushels of lime
to an acre. If, therefore, the lime be well mixed with
the soil, a large (|uantity may be used without pre-
ducing any very grf;at change. The quantity of lime
whicli should be applied, depends, however, in a very
great degree, on the nature of the soil. Clay groun<l
and swampy land are often benefited by very largo
doses; as much as seven hundred bushels on the acre
have been added to land of this description, without

n !

214

producing any bad ettects. Light and sandy soils, on
the other Jiand, may bo injured by a dose which would
be much too small for clay land. To these circum-
stances, therefore, attention must be paid, as well as
to the proportion of lime naturally present.

Since lime gradually disappears from the soil, it is
necessary that the supply should be renewed at
intervals ; and it is plain that a more uniform effect
will l)e secured by adding small quantities frequently,
than by using large doses at long intervals. The
practice of farmers has, however, varied very much
in this respect, according to their various circum-
stances. In some parts of Scotland, forty-six bushels
of vjctick lime per acre, are applied every live years ;
in others, tv.^o hundred to three hundred bushels are
used once in nineteen or twenty years. In Flanders,
ten to twelve bushels are applied once in three years,
or forty to fifty bushels once in twelve years. In
many parts of England, lime is applied once in every
rotation of three or four years. The different length
of the intervals in these cases does not appear to be
of very great importance, and may be varied by every
farmer to suit his own convenience. Small applica-
tions at short intervals are, however, evidently safer
and more efficacious than large doses seldom repeated.

Enough has now been stated to show the uses of
lime and their reasons, and to prevent us from being
deceived by the hasty assertions, respecting its utility
and inutility, frecjuently made by persons whose
views on the subject are only partial. The results of
an enlightened view of \, hat is known with respect
to this valu'able manure, may be summed up as
follows : —

1st. Lime has ult'iimddy the same effects whether

In

be

es

of

being
ItiUty

^hosc
llts oi

^spect
as

ictbcr

i

245

it be applied in the quick, air-slacked, or mild state ;
it should be well mixed with the soil, but kept as
near the surface as possible ; and it should be renewed
at intervals of a few years.

2dly. The mechanical effects of lime in opening and
loosening the soil, are always beneficial on heavy
soils, except where' these are very wot and undrained ;
and, on the other hand, they are sometimes injurious
to very light and dry ground.

3dly. The chemical effects of lime, when properly
applied, are — affording a necessary part of the food
of crops ; bringing into activity tlie inert vegetable
matter of the soil, and decomposing some mineral
compounds which are injurious to vegetation, and
others whose constituents are of great utility when
set free by its action. By these means it tends to
discourage the growth of moss and many other useless
plants in pastures and hay fields, and encourage that
of valuable grasses and clover ; to increase the quan-
tity and improve the quality of grain and green crops ;
and to augment the benefit of vegetable manures.

4thly. When applied to land already abounding in
lime, or very deficient in vegetable mould, it may
produce no benefit ; and applied in too large quantity,
or when not accompanied with sufficient supplies of
vegetable manures, it may be highly injurious l)y
exhausting and impoverishing the soil.

5thly. Just as some cultivated plants cannot thrive
without a good proportion of lime, there are some
wild plants native to poor non-calcareous soils which
are destroyed by liming. Hence liming and sowing
with grass are sometimes sufficient to replace the most
useless plants with nutritious grasses.

Some varieties of limestone contain a large

»«ii

M i

II

\m

246

proportion of luajijnesia, which, when added to the soil
in quantity, produces an injurious eiiect. These lime-
stones are generally known as niagnesian limestones
or dolomites.

2. Gypsum. — The uses of this substance liave
already been often I'eferred to. 1. Gypsum supplies
sulphate of lime to crops, and, in general, is the
cheapest form in which the sulphuric acid — shown by
analysis to be present in the ashes of cultivated
plants — may be obtained by the farmer. For in-
stance, 1000 lbs. of dry clover and timothy hay are
said by some analysts to contain from 3 J to 4^ lbs. of
sulphuric acid ; or we may estimate the quantity of
sulphate of lime, or gypsum, required by a moderate
hay crop, at 20 to 30 lbs. per acre. When gypsum is
naturally deficient in the soil, great results may be
expected from its application, especially in the growth
of those crops which contain lai'ge quantities of this
substance. 2. Gypsum possesses great value from its
property of converting ammonium carbonate — one of
the most volatile products of the decay of animal sub-
stances— into the ammonium sulphate, according to
the equation CaSO^ + 2 (NHJ CO3 = 2 (NH4)
SO 4 4- CaC03. The great advantage is that the
ammonium sulphate, not being volatile, is not lost in
the air.

The influence of gypsum is thus very different
from that of lime or marl. It does not tend either to
waste or render available the vegetable matter of the
soil ; nor does it remove the sourness and coldness of
heavy soils. On the contrary, it rather tends to give
body to light soils. As already stated there is reason
to believe that on many exhausted soils in the in-
terior of Canada gypsum will be found to be of great

247

in

irent

jr to

the

iss of

give

lason

in-

:reat

value, the soils heing deficient in sulphates. In the
vicinity of the sea, experience has sliown that gypsum
is less useful than farther inland; apparently because
the sea spray carried hy the wind supplies to the soil
a small (juantity of sulphate of soda, which serves
instead of gypsum. Again, some soils, es])ecially
those in the vicinity of the gypsum beds, are already
well supplied with this substance ; and some soils in
slaty districts, though deHcient in gypsum, receive
supplies of sulphuric acid from the sulphuret of iron
contained in the slate. C-oal ashes, peat ashes and sea
weeds where applied, also furnish small (juantities of
gypsum. The second use of gypsum, however, to
which I have referred, is one that applies to all soils
and situations. In the stable, the urine-pit, the dung-
hill, and the compost-heap, gypsum is always useful;
and when scatteVed on the potato or turnip drills, or
the hills of corn, it will always stand sentinel over the
rich manures beneath, and preserve their ammonia in
the soil. This is especially true in the case of light
sandy soils. For such uses every good farmer should
always have at hand a supply of powdere<l gypsum.
The cheapest way of rendering gypsum fit for use
is to break it into pieces, and burn it after the man-
ner of lime — though it does not recjuire so great heat
as limestone. Burnine: onlv drives off its water,
without producing any other chemical change. After
burning, it may V)e easily crushed into powder; but
nuist be kept dry, otherwise it will set into a solid
mass. The fine rubbish of gypsum quarries, and also
the marly beds in their vicinity, may often afford a
very cheap supply of gypsum. Crushed gypsum is
offeree! for sale under the name of land plaster.
Gypsum constitutes a necessary part of couunereial

II

li

I

i

I.

V.

I

248

superphosphates; each one per cent, of soluble or
reverted phosphoric acid is accompanied by two per
cent, of gypsum.

It may seem contrary to the above remarks in
reference to gypsum, that in the United States, where
plaster has been largely applied, it has been accused
of running out, or impoverishing the land. This is
well explained by Norton on a principle already
referred to : " In many cases a few bushels per acre
bring up land from poverty to a very good bearing
condition ; complaints are, however, made that after a
time it injures the land, in place of benefiting it.
This, in almost all instances, results from using it
alone, without applying other manures at the same
time. The explanation is of the same general nature
as tliat given under lime. The farmer has taken
away a variety of substances, and * has only added
gypsum. If the lan<l is entirely exhausted at last
under such treatment, it is obviously not the fault of
the gypsum. Theie are many large districts where
it produces no effect ; but it may always be considered
certain that where gypsum or lime does no good,
there is already, in one form or another, a supply
naturally in the soil ; or, as has been previously
explained under lime, there is some physical or
chemical defect which prevents its action."

3. Potash and Soda. — The sources of these in the
ashes of plants have been already referred to. Sea
salt contains soda in combination with chlorine ; and
it may be made more useful to plants by mixing it
with (juick lime. It will generally be found very
useful to slack lime intended for land with sea water;
and no better use can be made of refuse salt or brine,
than to pour it upon quicklime or mix it with a

249

the
Sea
and
ig it
I very
later;
)rine,
ith a

9

lime compost. Granite contains a large proportion of
potash ; and though a granite compost may soem a
strange thing, crushed granite has actually in Eng-
land been mixed in heaps with ([uick lime, for the
purpose of setting free its potash. This is the only
recipe that I know, for meeting the wishes of a
gentleman in one of our moi'e rocky districts, who
once said to me, " There would be some use in your
agricultural chemistry, if you could dissolve these
granite rocks for us." Farmers who can obtain the
smaller dust and fragments of granite (juarries an<l
masons' sheds, where granite is worked, and who arc;
not located on granitic soils, will find it pay to cart
such material and mix it with the hme they intend
to apply to their land, covering the whole with a
thick coating of clay and letting it stand for a few
months. The effect will be greater if the granite be
previously burned like the liiiie. The softer varieties
of trap rock, which also contain much alkaline
matter, may be treated in the same way ; or may be
usefully applied to poor soils without any preparation.

The great source of potash at present is the
Stassfurt mine in Germany, which yields, besides
rock salt, ahnost inexhaustible ((uantities of a double
chloride of potassium and magnesium, with potassium,
sodium and magnesium sulphates. From these min-
erals potassium chloride, i^called in the trade muriate
of potash), and potassium sulphate, both mixed with
various impurities, are prepared and largely used in
agriculture, more paiticularly as intermixtures with
other substances in the manufacture of artificial
manures. These preparations are sold at prices such
that their potash may be valued at 5c. a pound.

4. Phot^yhate of Lime. — Small quantities of this

250

lii<,f]ily valual)le substance arc contained in most lime-
stones, and conduce greatly to the benefits resulting
fi'om liming. Those varieties of lime which contain
large numbers of impressions of shells and scales of
fishes, are usually most valuable in this way. Some
thin and impure limestones of little use for ordinary
purposes, are rich in phosphates. This is especially
the case with beds containing many of the fossil
shells called Liin/uhv, and with some beds of the coal
districts containing scales of fishes. In many parts
of Canada there are extensive beds of apatite, a
crystalline phosphate of lime, which are quarried for
exportation. This mineral is crushed and prepared
with sulphuric acid, which renders it soluble as super-
phosphate of lime. When manufactured in this way,
it is invaluable on the worn out farms of the older
districts of this country. Superphosphate of lime
may be purchased at from $14 to J$24 a ton, according
to the percentage of solul)le phosphate it contains.

Bone-dust, guano, and the liquid manures of stables,
are important sources of this substance to the farmer,
and have been noticed under the head of organic
manures.

Coal AsJics. — The ashes of coal consist principally
of silica and alumina, which constitute over 86 per
cent, of their weight. These substances are in a fine
state of division, and give the ashes a great power of
absorbing liquids and gases. Coal ashes also usually
contain oxide of iron, carbonate of lime, sulphate of
lime, magnesia, and minute quantities of silicates of
potash and lime, and of phosphate of lime.

Though the ashes of diffei'ent kinds of coal differ
somewhat in composition and absorl)ent power, and
are much inferior as manure to wood ashes, yet they

261

oie al^vaJ^s of some service, more especially when
employe,! ,, a ,sorl. an,l retain lic)„i,I ..uJnuros mul l"
soiul,!,. an.l volatil.. parts of orfranic suhstancos

, and
they

I' !

CHAPTER XV.

CHOI'S.

(

UncliT this liead wc shall consider the bearing of
the principles pn^viously stated, on the plants
ordinarily cultivated in British America, and shall
notice the peculiar habitudes of these plants and
their diseases and enemies.

§ 1. W/mU.

^ All the kinds cultivated in this country belong to
one species, but ot* this there are two leading varieties,
— the spring and winter wheat, — and under each,
many subordinate varieties, produced by culture and
selection.

Wheat, when permitted, sends its roots deeply into
the ground, an<l therefore prefers a deep soil, or one
that has been deepened by subsoiling and under-
draining. It reijuires to have in the soil a supply of
both mineral and organic food in a well elal>orated
state. Hence it will neither thrive in a poor soil, nor
in one the riches of which consist of vegetable matter
in a crude or undecomposed state. It also very
readily permits weeds or grasses to grow beneath its
shelter. P'or these reasons, newly burned land, land
that has been fallowed and manured with composted
manure, or land clean and well manured, that has just
carried a soiling crop, or clover or peas, is most suit-
able for winter wheat. Spring wheat should follow
a hoed crop. On lea land it is very subject to rust,
and also to the attacks of the Hessian fly, whose

253

of
•ated
nor

very
Ih its
land
)sted
just
suit-
)llow

'USt,

rhose

:

larvre are generally present in the grass, and destroy
the wheat which takes its place. Tht» place of wheat
in the rotation of a scientific farmer nuist, therefore,
be like that assigned to it in the ordinary Scottish
four-course rotation, viz., after a green crop and
before grass, which is sowed with the wheat.

The organic part of the grain of wheat consists
principally of gluten, albumen, starch, gum, sugar,
oily matter, and the woody matter of the husk. Of
these ingredients the most important in reference to
human food are the gluten and albumen, which are
also the substances whose elements are least easily
obtained from poor soils. They are obtained from the
richer kinds of manures ; and their nitrogen, — the
most difficult of their elements to procure, chiefly
from the auunonia and nitric acid afforded by these
manures aided by the atmospheric supply. It is also
worthy of remark, that the percentage of gluten
varies according to the amount of such rich materials
in the soil. Hence the wheat of well manured land
is not only more abundant, but yields bushel for
bushel more flour — and more nutritious flour than
that of poor land. The rich and well tilled soils of
this country produce wheat equal to that of any
country in the world. The poor and worn out lands
furnish inferior grain, milling badly, and yielding an
inferior flour deficient in gluten.

The ash or earthy part of wheat is also of some
importance, especially as for this the plant is entirely
dependent on the soil ; and though this part of the
plant is comparatively small in quantity, yet its due
supply is absolutely necessary to healthy growth.

More than one-half of the ash of the straw of
wheat consists of silica, an element sufficiently abund-

^j

254

:iH

ant in most soils ; but it is to bo observed that this
element can be obtained only by the aid of potash or
soda, which i uist therefore be present in the soil.
Potash and soda are also required independently of
the conveyance of nUica. The ashes of 1000 lbs. of
tl^e grain of wheat contain 6 or 7 lbs. of potash and
soda ; the straw contains a much smaller proportion.
Wheat also contains in its asli, lime, ffVDSum
magnesia and conunon salt, but in small (juantity.
The ingredient of the ash of wheat, which of all
others is the nicst important, is bone earth or phos-
phate of lime, ot* which about 100 lbs. are taken by a
good crop of wheat from an acre of ground. This
may appear to be a small quantity, but it must be
borne in mind that this substance is scarce even in
fertile soils. It is chietiy the presence of alkalies
and phosphates derived from the ashes of the woods
that causes wheat to produce so r.bundantly in new
land.

The facts respecting the composition of wheat
stated abov^e, indicate that manures containing nitro-
gen, phosphates and alkalies, are especially suitable
to it. Such manures, in addition to the richer farm
yard manures, are nitrate of soda, muriate of potash
and superphosphate. Of these the first is always
valuable, and the last is more important to spring than
to winter wheat.

After peas, when tlie ground is clean, or after a
hoed crop, th-; ground is sufficiently prepared for
sowing wlieat by the use of the cultivator, but after
a soding crop or clover, or if the ground be weedy, it
will be necessary to plough the land. For winter
wheat the ground should be ready for the seed dui-ing
the first part of September ; not much earlier lest the

255

)le

^ays
jhaii

;r a
for

ifter
it

Inter

jiing
the

too abundant leafai^e be smotliered under the snow,
nor much later lest the growth l>efore aiTestod by
winter be insufficient to shelter the roots. From one
bushel to two busliels of well ripened seed is suffi-
cient for each acre, the larger amount is required in
poor soils with spring wheat sown broadcast, the
smaller in rich soils with winter wheat drilled in.
With winter wheat timothy is sown and clover on
the same crop in spring. With spring wheat both
timothy and clover are sown. These grasses flourish
under the shade of the wheat.

If w inter wheat be partially thrown out by frosts,
it is well to roll it in the spring ; and, where labor is
available, it is well to hoe and weed it at the same
time. Generally, however, the crop grows without
further care after the seeding until harvest.

Wheat should be harvested for the miller when the
straw immediately beneath the ear begins to turn
yellow ; for the straw of wheat, if cut sufficiently
early, and chopped with a straw cutter, is highly
nutritive food for cattle and horses, and is nmch
relished by them. In this country wheat is generally
cut too late, and the grain is thick in the husk and
inferior in flouring qualities, and thr straw is com-
paratively worthless. By cutting i in mediately after
the grain is tilled, and before the straw is wholly
dead, both would be much more valuable and
nutritious.

Wheat, though the most important of grain crops,
has, of late, acquired the character of being a precarious
crop, especially in the older districts. It becomes
therefore necessary to enquire into the diseases and
l)lights to which it is liable. We may consider these
n some detail, remarking in the first place that none

18

250

n

of them arc peculiar to British America, all of them
being more or less experienced in most or all the
countries in which wheat is cultivated.

1. Mud. — A reddish or rusty substance attached to
the straw and leaves of wheat in the end of summer
or in autunm. When examined by the microscope,
it is found to be a parasitic fungus or mould whose
minute and invisible seeds or spores arc wafted by
the winds, or Ijorne to the plar.t with the water it
absorbs from the soil, and taking root in the cells and
vessels of the stem and leaf, weaken or kill it by
feeding on its juices.

Its attacks are favored by the following causes :
Fird, damp and cold weather succeeding warmth, at
the time when the straw is still soft and juicy ; hence
late grain is very liable to rust. Secondly, a deticiency
of the outer silicious coat, which in the healthy state
protects the surface of the straw, or an unnaturally
soft and watery state of the plant. These unhealthy
conditions may proceed either from poverty and
want of alkalies in the soil, from the presence of too
much crude vegetable matter, as sed or raw manure,
or from a wet and un<lrained state of the land, which
both causes the crop to be late and fills it with
watery juices. Thirdly, it is highly probable that
one inducing cause is the accumulation of sugar and
albuminous matter in the stra^v , and the inability of
the plant, owing to the ./ant of phosphates, to turn
this sugar and albumen i^ito the starch and gluten of
the seed. Foitrfhly, it is proltable that when the
grain of rusty wiieat is sown, or when sound wheat
is sown in ground in which wheat has rusted in
previous years, the crop may be more easily affected
by the disease, because the sporcM of the rust fungus
may be attached to the seed or may be in the soil.

too
mre,
rhich
[with

that

and
jy of

turn
len oi:
the

'heat

id in
lected

mgus

257

The best preventives of rust tlicreforc ai-e : First,
healthy seed; Secondly, early sowinf^; Tliinlhi,
draining; i^oi!?'////^, abstaining from sowing wheat in
lea land: Fift/ihj, preparing the soil in such a manner
that it shall be sufficiently rich, yet not tilled with
crude vegetabhi matter, paying attention to the
supply of alkalies and phosphates.

2. Mildew. — This term is often used in this country
as synonymous with i-ust ; but properly speaking,
mildew is the effect of the gj-owth of other fungi,
which are however not dissimilar in their habits from
the rust fungi ; though in this climate less destructive.

3. Smut or Bunt. — This also is a parasitic fun<>us,
whicir gTOVVt!i ivdliin the gi-ain, and converts its
substance into a dark colored fetid mass of spores or
mould balls, which under the microscope look like
rough berries, and are filled with the nninite dust-
like spores of the smut. Its mode of propagation is
pretty well understood and easily guarded against.
When smutty grain is threshed, the infected seeds
are broken, and the smut being of an adhesive nature
attaches itself to the sound grain, and when this is
sown, the tiln-ils of the smut pass u])ward through
the sf.em, and infect the crop. In like manner, if
sound grain be put into bags or boxes which have
contained snmtty grain, or if it be threslied on a floor
on which suuitty grain has l)een latcdy threshed, it
will be infected. These causes of the disease shoidd
therefore be avoided by all prudent farmers.

If clean seed be sown in land that is not itself
infected the crop will be free from smut ; but it is
difficult to secure clean seed as one kernel of smutty
wiieat ccmtains as many as forty million spores of
smut. Seed must be cleaned, which is done either by

I' i.

25S

washing off' tlie adliercnt spores by alkaline waslies,
or l)y destroying the vitality of these spores ]>y
steeping the seed in poisonous licpiids, or by plunging
it into hot water. Of course in the latter cases the
steeping must not be continued long enough to kill
the seed itself. Thus the seed may be allowed to
soak for a day in a solution of 1 lb. of caustic potash
or 24 lbs. of hardwood aslies in () gallons of water,
then washed, drained and dried by stirring slaked
lime, gypsum or wood ashes with it. Or four bushels
of seed may be stirred up with a solution consisting
of one pound of copper sulphate, blue vitriol, to 4
(juorts of water, and dried as before. Or the seed
may be dipped for five minutes into a bath of scald-
ing water at a temperature of 185" F.

4. Ergot. — This is an unnatural enlargement of the
grains of wheat, by which they are converted into a
black spongy substance about twice the length of the
ordinary kernel, and of a very poisonous nature.
This disease, like rust and smut, results from the
growth of a parasitic fungus in the wheat plant.

Ergot does not usually destroy any large propor-
tion of a crop, but when not attended to, may make
it useless or deleterious by its poisonous properties.
When observed, the grain should be sifted through
sieves oufBciently small to retain the enlarged ergot
grains. This should be attended to whether the
grain be intended for the mill or for seed.

It is said that low moist lands are more subject to
ergot, and that in such lands the disease may be
removed by thorough draining. This view, which
seems to be confirmed by experience in this country,
deserves the attention of farmers whose fields are
infested by this nuisance.

259

the

)ugh

U'got

the

;t to
be
[hich

ptry,

are

5. TJie Wheal Midge or Weevil 1ms in recent tiinog
been the niost destructive of all wheat hliofhts. It is
improperly called weevil ; the weevils, properly so
called, being a tribe of beetles, the young of which
destroy corn in gi'anaries. It is only by a careful
study of the habits of a creature of this kind, that we
can hope to counteract its ravages.

The observations of naturalists in England, where
the creature has been much longer known than in
America, have proved tliat the destroyer is the larva
or grub of a miiuite midge, which deposits its eggs in
calm sununer evenings, on the chaff' scales, whence the
little grub when hatche<l creeps inward to the young
grain, on whose juices it feeds. When full grown it
descends to the soil and passes the winter in the
ground. The following experiments and observations
made many years ago, an<l I believe the first which
clearly established the facts of the case, will suffice to
give a view of the habits of these creatures.

A (quantity of the larvjx) were procured, full grown
and in that motionless and torpid state in wdiich they
usually appear when the grain is ripe. A portion of
these larv{\3 were placed on the surface of moist soil in
a flower pot. In the course of two days the greater
number of them had d<^scended into the ground, pre-
viously casting their skins, which remained at the
surface.* I afterwards^ascertained that they had pene-
trated to the depth of more than an inch, an<l were of
a whitish color, softer and more active than they had
previously been. The fact is thus established, that
these apparently torpi<l larva), when they fall from
the ripe wheat in autunu), or are carelessly swept out

*Someobservntions of Dr. Fitch, and Mr. I). J. Browne, render it proba-
ble that the skin is souietinies cast in the car before descending to the
Kround.

260

from tlie tlircsliin^^ floor into th'3 ])arn yard, at once
rosumo tlioir activity, and bury themselves in tlie
ground.

The larva} thus Imried in the ground were allowed
to renjain undisturbed during winter and spring, the
flowerpot being occasicmally watered. About the en<l
of June they began to reappear above the suii'ace, in
the winged form; the little grubs ci'eeping t(^ the sur-
face an<l projecting about half their bodies above it,
when tlu! skin of the upper part burst and the full
grown winged mi<lge came forth and flew off! This
completes the round of changes which each genera-
tion of these little creatures undei'goes, and we have
thus actual evidence of each stage of its pre egress from
the Q^^g to the perfect insect.

The perfect midge is a pretty little creature, its
body l)eing of a bright yellow color like that of the
larva, its two large wings perfectly transparent with
iridescent reflections, its eyes black, and its antennae
or feelers long and jointed ; the male is smaller than
the female, and has its ant(Mina) ornamented with
hairs. The flies are most active in calm and warm
evenings, when they may sometimes be seen in clouds
."'Ver the wheat fields. British observers say that the
female deposits her eggs within the chaff; but here,
they generally appear to be deposited without.

However we may dread the destructive pow
the midjie, we cannot withhold our admiration

ers

of
from

the singular instincts with which it has been endowed.
I'he female insect de])()sitini'" her eiriifs where food and
shelter are provided foi* the young brood; the larvae
when shaken from their summer abode by the storms
of autunui, at once entering on a ncnv and untried life
in the soil; and the chrysalids working their way to

2C1

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with

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and
kxrvj\3
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I life
ky to

the surface in the ensuint^ smnmer, to assume their
winged state in time for the new crop of wheat, dis-
play a series of adaptations wliich may convince us,
that, however annoying in the meantime to us, a
creature so gifted cannot be without important uses
in the economy of nature.

It is evident that if no check were opposed to the
increase of these creatures, they must ultimately, in
every country where they occur, consume the whole
or nearly the whole of the wheat crop. There are
however such checks, some in natural causes, and
others in expedients which may be adopted by man.

In Europe the larvjD of several small parasitic insects
prey on those of the midge, and no doubt greatly limit
their increase.* Dr Fitch has observed one such enemy
of the midge in the United States. In this country, in
cold and Imre winters, it is probable that many perish;
though it is quite an error t(3 suppose that wet weather
can kill the larvae wheti in the ground. Moisture in
the ground, indeed, seems to be essential to their life.
Windy or stormy weather at the season when they
are on the wing, nuist also greatly interrupt them in
depositing their e^^^^. Accordingly they are observed
to be most abundant in sheltered situations, and
elevated and airy places are less liable to suffer from
their attacks.

It appears from what has b(;en sai«l above respect-
ing the habits of the midufe, that durinfj the orreater
part of its existence it is bey()n<l the control of the
farmer. He camiot prevent it from depositing its
eggs, nor can he extract the larv{\3 fn^m the growing
crop ; and in the ground in autumn and w^inter they
are almost eiiuallv brvond liis reach. He can

*i^OQ a paper by Mr. Billiugs in the Canailian Naturalist, vol, 1, p. 450.

u. &

III

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262

however destroy (ts many of them as he can house
with his grain. In this country, as in l^>ntain, the
full grown larvjD remain in tlio cliafi' until the grain
is ripe, or until they are shaken to the ground by the
first violent storms of autumn. When grain is
observed to be infected, it sho ild be attentively
watched and cut so soon as this can be done without
serious loss. In this country wheat is often left till it
is too ripe ; over ripe grain being much inferior to
that which is earlier cut in the quantity and quality
of its flour ; and when the weevil is pi'esent there is
a double gain in early cutting. It would also be
advisable whenever it is possible, to reap, rather than
cradle, the grain, in order to avoid shaking out the
insects. The wheat should be threshed on a close
barn floor which will not allow the larv{\3 to fall
through, and when the grain is cleaned, all the cltaff
and dust separated from it sJtotdd he hiirned, or if
the chaff be saved for fodder, it should be kept dry,
and none of it allowed to be mixed with the litter or
thrown on the manure heap.

This method costs little trouble, causes no loss, and
if faithfully followed out, would grer.tly diminish if
not altogether prevent the losses occasioned by the
w'eevil. It is worthy of attention,even in cases where
the crop is only affected to a small extent. The midge
often destroys a fifth, fourth, or even a third of a crop,
without exciting much attention, and it is only when
almost total loss ensues that great alarm is excited ;
but even these partial losses are not of small impor-
tance, and by destroying the larv^aB in a season in
which only a fourth of the crop is lost, we may
perhaps prevent a total loss in the next season. I
is true that wheu this precaution is neglected, Provi

2Hn

prop,
rhen
|ted ;
)or-
in
[nay
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>vi

(lenco, kinder to tlu^ fanner tlian lie is to liinisolf, may
by some of the natural causi's already mentioned,
check the increase of the <lestroyers ; hiit this will
not always occur, and certainly furnishes no excuse
for ne<ijlecting the means of safety which are placed
within our reach.

As an illustration of the savin*;- which can be
effected by destroyin*^ the larvae which are housed
with the <{rain, I mav mention that tlu» friend who
furnished me with specimens for experiment, informed
me that from the wheat of ei^ht acres he hadoljtained
about fo(ir htis/ids of larvje of the weevil. Aft(ir
making a large deduction for dust mixed with them,
this (juantity nnist have contained about 150 millions
of the insects. If thesi; insects, instead of being
Inirned, had been scattered over the gnaind, they
miglit, if the ensuing season had prove<l favorable to
them, have destroyed the greater part of tiie wheat
crop (m the farm.

Various other expedients for the destruction of the
midge have been propose<l or adopted. When the
Hies are observed to be on the wing they might be
prevented from depositing their eggs by kindling
tires on the windward side of the field, or by agitating
the grain by stretched lines carried by men or boys, in
the calm evenings when the midges are most active.
These however are clumsy and troul)lesome expedients,
though, when they can be attended to, they may do
much good. It is also probable that if the ground
were deeply ploughed, after the larvje had fallen uptni
it in autunni, they might be too det^ply covered to
permit of their escape in the spring. In the ordinary
system of rotation, howx'ver, this could not be done
without losing succeeding hay crops ; an<l it is doubtful

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if it would 1x3 vciy cfiectual. Perliaps tlio most
ctfL'ctual rciiHMly ever |)ropf)s<Ml, is that of discon-
tiiiuin<^ tlio culture oF wheat for a y(3ar, and tlius
dcpriviu^^ the midges of the necessary food for their
larva). This is however an expensive expedient, and
it re((uires the consent of all the farmers in t\u) district
affected. In the ^reat majority v)f cases, it mi^ht be
rendered altogetlier unnec(^ssary, if the method of
destroying the larva) already described were generally
adopted.

The most popular remedy liitherto tried has been
late sowing in the case of spring wheat, and early
sowing in that of winter wheat, so as to have the
wheat in blossom too late or too early for the insect.
This, liowever, in the case of spring wheat, subjects
the grain to rust, and necessitates the use of early
varieties of grain, which are not usually so heavy or
productive as others. In the case of winter wheat, it
renders it more liable to the attacks of the Hessian
Hy. It is also probable that in a few years the habits
of the creature and the date of its appearance will
chan(/e to sttit tJie liUenesH or edd'tness of the grain
which forms its foo(b and then the late sowing: will
prove quite inett'ectual. It is also deserving of notice,
that bearded varieties suffer less than the bald, as the
awns obstruct the insects in depositing their eggs.

The facts above stated may be summed up as
follows :

(1.) The insect deposits its eggs on the grain about
the time when it is in flower, and usually in the

evennio-.

(2.) The larva when hatched attaches itself to the
young grain and prevents its growth.

(.'I) When full grown it becomes stiff and torpid,
and if left lon^- enouj^h falls to the o-round.

or,r>

as

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irpi<l,

(4.) It l)\irk's itsL'lt' in tlic^ f^nmiid ami tlnis prtfssos
the winter.

(5.) In spring, it (Mnori^es from tlic f^n'ouinl as a
perfect insect, in wliicli state, if tlie weather l>e favor-
able, it seeks the o-rowinn^ wheat for the i)Urposc of
clepositin<j^ the ^a^rnis of a new hrood.

Lastly, thouo'li tliere are many partial remeilics, the
only sure one is to cut ('(Wh/ <f nd desfroi/ all (he </r(ths
found after flrrcshivi/ tie fjra'ni. To ensnre safety,
this should be kept up as regularly as the washing of
seed wheat to avoid smut.

5. Tlie Hessian fly is a relative of the wheat

midg'e, and at one time threatened, like it, to destroy

the culturii of wheat. Its rava^t's have, however, in

late years materially diminishcMl. It attacks the

stems of the y(nui<jf or half oi-own plants, establish in<.(

itself at the base of the shoot oi" in the joints, and

when abundant wholly destroys tin* cr(jp. The e<^<^s,

accoi'ding to the best observations, are deposited on

the leaves, whence the little larvae or maixuots when

hatched make their way downward between the; leaf

and the stem. There are two broods, one produce<l

from eggs deposited in winter wheat in autunni, the

other produced from eggs deposited in spring, and

attacking both spring and winter wheat. The best

remedies are careful tillage and preparation of the

ground, and abstaining from sowing on lea land, wheat

grown on which is especially liable to be injui-ed.

Burning the stub])le an<l ploughing it inider, rolling

the young wheat, mowing it in autumn or cutting it

in spring, an<l late sowing, are all remedies that have

been reconun(;nded, especially in tlu^ case of winter

wheat. There can be no do\ibt however that the

principal cause of the excessive nniltiplication of this

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266

insect is the want of any rational system of rotation
of crops ; an«l the introduction of tliis usually arrests
its ravages.

Several parasitic insects prey on the larvji) of the
Hessian fly and greatly diminish its numbers.

^i- ^/Ytf? ^imy W\fVli\ ^^ ^ naked catei'pillar of the
cut-worm trihe, of a gray color, with black and brown
bands. Their native haunts appear to be meadows
ami similar phices, when^ they devour the leaves of
grass, Imt in some seasons they migrate in innnense
numbers to tiie grain fields and strip the grain of its
leaves. When full grown they pass into the pupa
state, under clods and in the L''roun<l, and emerge as
plain gray moths. The injuries inflicted by these
cre*itures are usually quite local. The only way of
arresting their progress seems to l>e l)y digging
narrow and deep ditches across their path, and killing
them as they accumulate in these ditches.

7. Wheat is attacked by the larvtw of many other
in.sects. Those of certain little flies of the genus
(JIdorops establish themselves in the stem. Other
flies of the genus Oscinix, in their larv%'X state, eat the
young grain. Several beetles, moths and neuropterous
insects also prey on it. None of these have however
been so destructive as the midges, and the habits of
many of them are very imperfectly known.

8. The Oat Aphis is a little plant louse which appears
in vast num])ers on wheat, oats and other grains, and
often causes much alarm and inflicts some injury on
the crop, though not usually to a great extent. It
appeared in great abundance in Canada in 1801.

Wheat, long the staple crop of Canada, has ceased
to be profitable in the older provinces, partly through
exhaustion of the soil, partly through the increased

207

and
on
It

Lsed

kigh

sed

ravages of enemios, especially the midge, but chiefly
through the fall of price in the markets of the world,
due to the large amounts annually produced in coun-
tries newly accessible to the commerce in bread-
stuffs. How much does it cost to produce a bushel of
winter wheat in Canada? Let us investigate two
cases. First, let the crop be fall wheat preceded by
summer fallow. Then there may be one deep plough-
ing, followed by fiarrowing and rolling, one gang
ploughing with harrowing and rolling, one going
over with the cultivator, one harrowing, one drilling
in of seed wheat and timothy togetlier, followed in
the spring by broad-casting clover, then harvesting
and housing the crop, threshing and preparing for
market. Of these operations it would be fair to
charge the crop of hay that will succeed with one-
half of cost of cultivating, of harrowing once, of
rolling once, and of drilling in seed. It WM)uld also
be fair to charge one-half year's interest of the value
of land occupied, and one-fourth of wear and tear of
implements to the hay crop. There remains as the
cost of raising and housing the crop of one acre of
fall wheat, 1st ploughing, $ti ; 2nd ploughing, SI ;
two harrowings and one rolling, SI. 20 ; one-half cost
of cultivating, of harrowing once, of rolling once, and
of drilling in seed, SI ; co.st of harvesting, S2.25 ; cost
of seed, SI. 20; three-fourths of wear and tear of
implements, say Si. 50 ; 6% of value of land, woith
say S50 per acre, for one year and a half, S4.50 ;
total cost in the barn, SI 5.65. The cost of preparing
for market and marketing may be set <lown at 5c. a
bushel. The average yield of one acre of fall wheat
in Ontario is 22 bushels grain and a ton and a half of
straw. If the straw be valued at S4 a ton the net

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268

cost of raising a Imsliel of wheat will bo between 48c.
and 40c., say 48jc. plus the value of the nitrogen,
phosplioric acid and potash removed in the grain.
At the values state<l above this will be in each bushel,
for nitrogen 1*2 lbs. at 15c., ItSc. ; for phosphoric
acid '55 lbs. at lOc, 5Jc. ; for potash '37 Ib.s. at 5c.,
2c. ; a total value of 25ic. for these materials. The
cost then of a bushel of wheat to the farmer is 744c.,
and if he can succeed no better than this he cannot
attbid to raise wheat for less than this price per bushel.
If, however, he can raise as good an average crop as is
done at the Agricultural College in Cuelph, namely
27 bushels per acre, with 2 t(ms of straw, the cost per
acre for laboi", for wear and tear of tools and for rent
of land remaining the same, the cost per bushel of
wheat under these heads will be reduced to 2cSjc.
To this add cost of threshing, cleaning and marketing,
5c. a bushel, and value of material deported from the
land, 2oic., and the farmer will be able to sell wheat
without loss at 59c. a bushel.

Suppose, however, that the land is kept clean and
that a crop of wheat is to succeed a crop of peas, '^riie
cost of preparing the land will be greatly reduced,
the wear and tear of implements will be correspond-
ingly re<luce<l, and the crop of wheat will be charge-
able only with one year's rent of the land. Suppose
further, for simplicity's sake, that none of the cost of
preparing the land is charged against the hay crop,
and that the wear and tear of implements is charged
as before. Then the cost of putting in the crop will
be, one gang ploughing, Si per acre ; one harrowing,
40c. ; one rolling, 40c. ; drilling in seed, 40c. ; wear
and tear of implements, $1.50; 6% of value of land
for one yeai', $3 ; harvesting, $2.25 ; cost of seed,

and
The
acc«l,
)ond-
rge-
pose
st of
I crop,
Li'ged
will
ving,
wear
land
seed,

269

Sl.20 ; total cost per acre of crop delivered in barn,
S10.15. If the returns be estimated as before, the
cost of raising a bushel of wheat will be for labor,
rent and wear and tear of implements, etc., until the
wheat is stacked in the barn, 19c. with the smaller
crop, and with the larger crop 8c. a l)Uslu'l. Adding
the cost of threshini»;, cleanin<r and marketiuijf at oc.
a bushel as before, and of material deported from the
farm at 25Jc., the farmer can sell wheat without loss
at 50c. a bushel in the first case, and JJDc. a bu.shel in
the second case. Indeed, if the land be clean, a crop
after peas of 13 bushels of wheat with straw in pro-
portion per acre is, in the long run, more proii table
than ^2 bushels aft«'r a bare fallow ; an«l 17 bushels
after peas is as profitable as 27 bushels after the bare
fallow.

N.B. — Let the pupil verify the foregoing state-
ments. Let him also calculate the cost per bushel of
wheat-growing in the actual circumstances of the
farmers in his neighborhood, where, in all probability,
a different mode of preparing the land would be
adopted, where the cost of each operation would be
differently estimated, and where also land has a
value differing from that a.ssumed above.

The organic part of the kernel of the oat very
much resembles that of wheat. Oatmeal contains 10
to 12 per cent, of gluten or an analogous substance,
and is scarcely inferior to wlu'aten Hour as an article
of nutriment. In its inorganic ingredients or ash, it
differs from wheat in proportion though not in kind;
and, if grain alone be considered, a crop of oats re-
quires from the soil nearly twice the amount of

i

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It ':

I. I

\

270

inorj^oinic matter rcqiiirtMl ]>y wlieat. It is tluTcfore a
great mistake to sup|K)se that the oat is so much less
exhausting than wheat, that the farmers ran aficml to
overlook this effect. The oat, however, can take
nourishment from raw and uiidecomposed vegetalile
matter, such as sod, peat, etc., from wliich wheat can
obtain little nutriment.

As in the case of wheat, silica, alkalies and phos-
phoric acid are the principal ingredients of the ash.
Silica and potasli are, how^ever, removed in larger
(juantity than by wfieat. The oat also carries off
from the soil a larger proportion of g3^psum ; hence
it thrives in gypseous soils, or in sour soils which
contain sulphuric acid, after they liave been limed.
The (juantity of bone-earth re(|uired by the oat is,
however, less than that retjuired by wheat.

The above remarks show the proper place of the
oat in the rotation to be that which it usually bears
in the ordinary Scottish rotation, viz: the first grain
crop after ploughing up the sward. It is w^ell fitted
for this, not oidy by its power of extracting nutri-
ment from the decaying sod, but also by its dense
shade, which prevents to a great extent the growth of
weeds and grasses. This last character, as well as its
great demands on the soil for inorganic food, unfit it
for sowing with grass seeds, or occupying the place of
wheat in the rotation.

It is barbarous farming to extract two successive
crops of an exhausting grain like the oat from any
ordinary soil, or to take a crop of oats and then let
the land run out into ijrass. Nothing but dire neces-
sity can excuse these practices, which are unhappily
too prevalent. The manure produced from the oat
straw, or its equivalent, should in all cases be restored

27i

its
It it
of

tny

let
jes-

I oat
red

to the soil in the succeedinpf year, for a jifreen crop.
If this be done, the soil is improved, rather thaii
deteriorated.

Our country is well adapted to the growth of oats,
and this applies even to those parts of it in which
wheat is uncertain. Oats must therefore always form
a prominent object of attention to our farmers; more
especially in the colder and less productive districts.

Few crops re(]uire more frequent changes of seed
than the oat. When cultivated for a number of years
in the same soil in our climate, it aci^uires a thick
outer husk at the expense of the kernel, and becomfes
more liable to dust-brand. Experience has proved
that the best change of seed is that imported from
Scotland; and no oats are superior for this climate to
the early varieties of that country. They are thin-
skinned and heavy, and bear cultivation here for five
or six years before they acquire the appearance and
defects of run-out oats. Indeed, for two or three
years after importation, they greatly improve in size
and appearance, though probably not in actual value,

Oats should be sown as early in the spring as the
ground will admit, and be cut when the straw of the
head turns yellow while the stalk below is green.
From 2 to 2 1 bushels per acre will be enough of seed.

The Black or Tartarian oat is chiefly recommended
by its earliness. It is inferior as a mealing oat both in
quantity and quality, and though in some quarters a
preference is given to it as food for horses, there can
be no doubt that the white is more nutritious. Much
loss is also sustained in this country by the cultiva-
tion of those lean, chaflfy and bearded oats, that have
been run out by long cultivation, and mixed by care-
lessness with better varieties.

19

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272

The dust brand and the grubs of the Harry-long-
legs often injure the oat crop, but I am not aware
that they have ever become so destructive as to call
for any special attention on the part of the cultivator.

The cost of raising a crop of oats may be estimated
as follows: One ploughing of greensward, in autumn
if possible, S2 pe^ acre ; one gang ploughing in spring,
$1 ; one harrowing, 40c.; one rolling, 40c.; one drill-
ing in of seed, 40c.; cost of seed, 70c.; wear and tear
of implements, $1 ; interest on land, S3; cost of har-
vesting, S2.25; total cost per acre, S11.15. The aver-
age crop in Ontario is 85 bushels per acre; the average
of 11 years on a good farm was 50 bushels and the
maximum on the same farm was 70 bushels. The
price per bushel for threshing an<l marketing may be
stated at 5c. per bushel, and the value of manure is
12c. (see example 185). The straw may be estimated
at 1 J tons in the first case, 2 tons in the second and
2J tons in the third, and may be valued at S5 a ton.
This makes the total cost of raising a bushel of oats
in each case to be 28c., 20c. and 15c.

Rye, like wheat, is of two kinds, winter and spring;
but the latter is but seldom grown in this country.

The grain of rye does not differ very materially in
its composition from that of wheat. It contains,
however, more sugar and less gluten ; and the gluten
is of a somewhat different nature, at least in its
mechanical properties, and is less fitted for the produc-
tion of a well-raised bread. Rye takes less from the
soil than wheat. The difference is principally in the
straw, which contains less lime, silica, and bone-earth
than that of wheat. The ash of the grain differs
very slightly from that of wheat.

273

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Rye prefers light soils, and may be mllde very use-
ful in l)ringinf( in light ground unfit for the growth
of wheat. It also forms a suhstitutc for wheat when
the latter grain appears to ho in danger of heing
destroyed hy weevil ; hut in ordinary circumstances it
should not he sown on ground capahle of producing
wheat, heing much inferior to tliat grain as an article
of food, live straw is of little or no value as fodder;
hut is excellent for thatching, collar-making, and
basket-making, and makes tolerable hats.

Rye may be sown later than wheat because of its
greater hardiness, and should be harvested when the
straw is yellow, except at the green knots.

It is said that rye has occasionally suffered from the
wheat fly, but sliglitly. Its worst enemy is the ergot,
a fungus-like eniargement of the grain, which, like
the ergot of wheat, renders it black and poisonous.
When the ergot is observed, it should be carefully
sifted from the grain before grinding. TIk; principal
inducing cause of ergot appears to be too great mois-
ture in the soil; and where this is the casi', the cul-
ture of rye should not 1)0 persisted in, when the ergot
is found to appear constantly or often in it.

The cost of preparing an aero of land for rye is
less than for wheat, both because it may be grown on
lighter and more easily worked lan<l, and because
the tilth need not be so tine as for wheat. But as an
offset to this the straw is less valuable to the farmer.
The cost of preparing an acre for a crop of rye, of
seeding it, and of harvesting it, is about $9.50, against
which must be set the value of 2 terns of straw at $8
a ton, leaving a net cost for erne acre of grain $.*i..50.
A crop of l\0 bushels per acre will cost the farmer
12c. per bushel in the barn. To this must be added

274

tho cost of threshing an<1 marketing, 5c., and of
material deportetl from the farm, 21c., a total net cost
of 38c. per bushel.

§ 4. Baijjiy.

Barley is either two-rowed, four-rowed, or six-
rowed, according to the number of vertical rows of
grain in the head. The two-rowed is the favorite
English bai'ley, the four-rowed called here ;s culti-
tivated to some extent in Ireland and the North of
Scotland, but the six-rowed is that which is best
adapted to our Canadian agriculture and is that which
is all but universally cultivated.

The grain of barley nmch resembles in its compo-
sition that of wheat, but it contains less gluten and
more starcli and sugar. It is therefore less nutritious,
though in wholesomeness it yields to no other grain.
In many parts of the country, barley is little known
except for its use as pot-barley, and its value as a
material for the manufacture of alcoholic liquors. Its
culture as a bread corn should perhaps be more widely
extended. To most persons the flavor of barley
bread is very agreeable, and barley-meal pottage is
certainly superior to that of Indian meal or rye flour.
Barley is also an excellent substitute for wheat, when
the latter is in danger from weevil. It is a very sure
crop, and very early; and suits admirably for sowing
with grass seeds. Its true place in the rotation is the
same with that of wheat. It may, however, be sown
in lea land, though it is not so suitable for this as
the oat.

Because of its larger yield barley takes rather more
from the soil than wheat, and the excess is principally
in silica, bone earth, lime, alkalies and gypsum. It is

8l

275

lore

[ally

it is

tluircfoiv a niistako to suppose that a <^<mh1 crop of
Iwirley <loos not re(|uiri' a soil in ^oo«l condition, \mt
as barley sends its roots niueh aloni^ the snrt'ace and
not to a ^n*eat depth, it is h'ss dependent on deep
tiUaye than wheat. Alkalies and es[)ecially soda are
liighly favomhle to its <^rowth, and it prefers light
and loamy soils.

Barley may be sown as soon as tlie ground is ready
in spring, and shouhl be harvested as .soon as the
straw is white an<l the ears are curved downwards.

The cost of raising a ci'op of barley after a clean
hoed crop may be thus estimated : One gang plough-
ing, one harrowing, one rolling, drilling in .see<l, wear
and tear of implements and interest on value of land,
^0.20; the cost of seed may l)e 9()c. and of harvesting
S2.25 per acre, $9.85 per acre in all. A crop of 80
bushels per acre, with two tons of straw worth $4>
a ton, will therefore cost the farmi^r 4ic., .say 5c. a
bushel, stacked in the barn. To this add cost of
threshing and marketing, say 5c. a bushel, and value
of deported nitrogen, potash and phosphoric acid, 17c.
a bushel. The net value of a bushel of barley to the
farmer is thus brought up to 27c. a bushel.

§ 5. Indian Corn.

An inspection of the table, page 141, will show that
maize, being very rich in oily and fatty matters, has
a very high value as an article of food, especially for
fattening stock. In this climate, Indian corn requires
a light,jdeep_spil, and a good supply of rich manure.
Gypsum should be strewed on the top of the hills or
drills, both as a direct manure, and to prevent the
escape of the ammonia from the manure beneath.
The most convenient place of corn in the rotation is

270

as a liVLHrn crop, since the tr«uitineiit vvliich it rc(|uiro3
ami its ertects on the soil are not very <litterent from
those; of the turnip ami carrot, (lood corn may, how-
ever, V)e raised in lea land, and also after ^^reen crops
in place of wheat, hut in hoth cases manure is rtMjuircMl
in addition to that alrea<ly in the soil. It is ln^tter to
plant corn in drills, like turnips hut farther apart,
than in hills. Nothing is gained hy havin<^ the; plants
crowded ; they reijuire much ail* and light. . n stiff'
soils they should he well earthed up, or the see<ls may
he planted in the tops of the drills, hut in light land
they should he planted on the level. Frecjuent hoeing is
very heneficial, as also cleaning and earthing >vith a
light plough or cultivator. Pumpkins are often planted
with corn ; many good farmers, however, l)elieve that
the gain in pumi)kins scarcely repays the loss in corn.
This must depend <m the degree to whicli the leaves
of the pumpkins deprive the corn of air and light,
and on the impediments wliich the vines offer to the
proper culture of the corn.

It is useful to cut off' the feather or hloom, the male
flower of the corn, after it has served its purpose in
fertilizing the ear. This should he done when the
heird or tassel of the ear hegins to wither, hut not
hefore ; and as few large leaves as possihle should he
cut off' with the top, as all the leaves are useful in
aiding the growth (jf the ear. The tops make good
fodder, and when deprived of them the corn is less
likely to he hroken down hy autumnal storms.

Corn is liahle to injury by smut, allied to that which
infests wheat. The smutty ears, which are (juite con-
spicuous by their deformity, should be broken off*,
carried away and burnt, as, if thrown upon the
ground, the spores will continue to develop. Smutty

1

e in
the
not

\1)C

I in

rood

less

lliich
con-
off,
the
lutty

277

corn shouM not he fed to animals, as it is unwhole-
some, and evon j)oisonous.

Corn is suhject to the attacks of ^'nil)s winch hur-
row in the stalks, after the manner of the larvae of
the Hessian tiy in wheat. The easii'st remedy appears
to he sowin<r sutficieiitly thick to allow spare plants
for the grnhs. When, however, time can he spared
to pull up and destroy every plant that shows hy the
fading of the leaf the presence of the j^rub, the lal)or
will he repaid hy the diminished number of grubs in
the ensuing season. The seed is also sometimes de-
stroyed by s(|uirrels, birds, etc. This may be pre-
vented by steeping the seed in anything tliat makes
it distasteful to these depredators. Steeping in urine,
soft soap or nitre, and drying with lime or gypsum,
are said to be serviceable; but suiearing with tar has
also been practised, and is stated to be more certain.

The meal from corn raised in this country is finer
and more delicate in flavor than that from Southern
and Western corn. This should cause it to bring a
higher price; and should in connection with the pro-
ductiveness of the crop, conunend its culture to all
farmers who have the sandy or loamy soils which it
prefers. Even if too late to ripen, it is valuable for
fodder, if cut innnediately after the frost strikes it.

Corn is now largely employed as a green crop or for
ensilage purposes. More detailed reference to corn in
this relation will be found in Chapter XVI.

§ 6. Buckwheat.

The extended culture of this plant cannot be con-
sidered as an indication of improved or prosperous
agriculture ; since this grain is generally a substitute
for others, or a refuge from the want caused by

pi

m

^ll^

278

impoverishment of the ground. Buckwheat, however,
is a grain of some value, and, if properly used, need
have no connection with bad farming.

The kernel of buckwheat contains from 6 to 10 per
cent, of gluten, and 50 of starcli, with 5 to 8 per cent,
sugar and gum. (Norton). It is, therefore, inferior in
nutritive power to all the grains previously noticed ;
though still a very valuable article of food. A portion
of the inner husk is usually ground with the flour ;
giving a dark color, and bitter taste. When this husk
is entirely removed, the Hour is pure white, and so
dense as to resemble rice flour, or potato farina ; and,
either in bread or cakes, is a light and agreeable article
of food. Of course the quantity of this fine flour is
much less than that of the coarse kind; but the refuse
is useful for fattening hogs ; and if good flour were
more generally made, its use would be extended and
its price enhanced.

Buckwheat does not make great demands on the
soil. Its large leaves obtain a great part of its nutri-
ment from the air; and it requires but a small pro-
portion of mineral matter. Hence it can be success-
fully cultivated on very poor soils, though it certainly
thrives better on those that are rich. From the dense
shade which it produces, it is an admirable extermi-
nator of weeds ; and hence, makes a good preparatory
crop for weedy soils or poor grass land. The scattered
seeds of the buckwheat itself are, however, apt to be
troublesome in the succeeding crop. In England and
the continent of Europe, buckwheat is often usefully
employed in reclaiming poor soils, by ploughing it in
when green. A large amount of vegetable matter is
thus given to the soil ; and I have no doubt this would
be found useful in bringing in light and worn-out

oils in this country.

279

the
utri-
Ipro-

;ess-

[ense
Irini-
itory
lered
,0 be

and
fully
lit in

jr is
jould
li-out

The stems and leaves of huekwheat, cut i];iven, make
good summer food for cattle ; hut are less nutritious
than clover. Large heaps of huekwheat husks are
sometimes seen near mills. They should he composted
and applied to the land ; and would he found to he
excellent manure.

S 7. Beans iind Pens.

9J I - —

These plants are remarkahlc foithf large amount of
nutriment which their seeds contain, and which is
greater even than that of the hcst wheat or oats.
Hence, though the}^ cannot in ordinary circumstances
form so large a part of the crop as thf cereal gi-asses,
they are important ohjects of the farmer's attention.

The French or ihvarf klduet/ heans arc very
valualde as a green crop. Their produce is not very
large, but is highly nutritive ; and they have the merit
of being the best table substitute foi-the potato. They
require compost manure, and to be kept clean froui
weeds. They may very well occupy a portion of the
drills prepared for turnips, as the sanje manures and
mode of culture suit them, and the time for sowini; is
also the same. French beans should not he in the
ground till the buds of fruit trees are bursting, as
they are very liable to be nipped by late frosts, or
rotted by cold damp weather. The China, white
Canterbury, or small white calavanca, are the best for
this climate. The imported calavancas are rather late ;
but by picking the earliest ripe pods for seed, they
soon l)ecome sufficiently eai'ly. Kidney beans contain
28 per cent, of legumin, a substaiice analogous to
gluten, and 43 per cent, of starch. {Jo/nisfon.)

The horse bean may be cultivated in the same
manner as the French dwarf, but nmst be sown early.

i

1^^

l''i

I i

I

280

It is used exclusively, at least in the dry state, for the
food of animals, especially horses and hogs. It is
more nutritious than the oat, and better for working
horses ; though at first it is often difficult to induce
them to eat it. The small horse or tick bean of
England thrives well in this country ; though some
farmers here prefer the early cluster, or some other
variety of the broad horse bean, as being more
productive, and ripening equally well in this climate.
The straw of these beans, if chopped or broken up, is
excellent fodder, little inferior in nutritive properties
to ordinary hay.

Beans of all kinds require from the soil a large
quantity of potash and lime, principally for their stems.
Manures and composts, containing much of these
substances, are, therefore, especially adapted to them.

The Pea approaches very nearly to the bean, in
point of nutrition, and perhaps excels it in fattening
power, and its straw, or haulm, if saved in good
condition, is stated to be little inferior to meadow
hay. The straw of the pea contains a large proportion
of lime ; and hence, this substance, or composts
containing it, form very proper top-dressings for a pea
crop. The pea occupies a difterent place in the
rotation from the bean ; for, though the dwarf varieties
may be cultivated in drills as a green crop, it ordin-
arily thrives very well if sown broad-cast, in any
tolerably rich land that is not overrun with weeds.
Peas have, indeed, no regular place in a rotation, and
are somewhat uncertain. They are therefore rathei
giving way, in the best farming districts, to the
culture of beans and turnips. The pea often suffers
much from the pea-worm, which is the larva of a
small species of u^oth, or in other cases of a little

the
'.t is
cing
luce
1 of
iome
►ther
more
aate.
ip, is
ii'ties

large
items,
these
them,
m, in
,ening
(Tood
'adow
jrtion
posts
a pea
the
ieties
rdin-
any
B^^eeds.
, and
athei
o the
utf'ers
of a
little

1

3

281

beetle. No treatment applied to the seed can avert
the attacks of these creature?, since the eggs from
which the larvje are produced are deposited by the
parent insects in the blossom, or young pod. Where,
indeed, farms have become infested with this pest, it is
best to cease for a few years the attempt to grow peas.
The best palliative is to sow very early ; and it seems
worthy of enquiry, whether early peas, sown in early
spring, might not be gathered in sufficient time to
permit a crop of buckwheat to be taken from the
same ground. At all events, l)uckwheat might be
sown and ploughed in to enrich the soil.

§8. Turnips, Carrots, Mangel Wwrzel^ etc.

These, in most of the countries of the northern
teuiperate zone, form staple green crops, and probably
contribute as much to the money returns of the
farmer as any other crops. In this country, as yet,
their capabilities have been very imperfectly tested ;
though there can be no doubt that their culture is on
the increase. They demand, however, more humidity
in the air than is found far inland, and they are
conse(|uently better adapted to sea-board districts, or
to well watered soils. In reference to these crops,
Johnston remarks, with nmch truth: " To raise them
the farmer must prepare, must save, and must husband
his manures ; he must feed his cattle better, and will
thus be led to improve his breeds of stock ; while the
better harvests of grain he obtains after the
green crops, will make these green crops themselves
more profitable, and therefore olijects of more useful
attention. The spread of green crops in England an<l
Scotland has been invariably the prelude to agricul-
tural improvement, and to an amelioration, not only

if'

282

in the practice, l)ut in tlie circunistanct^s also of tlie
fanners."

All these roots contain a hirge proportion of water;
an<l tlieir nutritive portion is made up of albumen,
su<^ar, gum (pectin), and starch. These substances
are present in various proportions, according to the
kinds of roots cultivated, and the nature of the soil
and manures. All of these root crops re(|uire from
the soil much potash, soda, lime, bone-earth, and
gypsum, as well as some vegetable matter ; and the
manuj'es intended to afford these substances should,
when practicable, be in the form of well rotted
composts. Long manure will rarely afford a heavy
crop. Artificial manures, especially salt, gypsum and
superphosphate, are very valuable in the culture of
green crops. About 200 ll)s. of each oi the n)anures
mentioned above may be sown broadcast on each acre
shoi'tly before the sowing of the seed. Root crops
require, for perfection, a deep and fine tilth, and a
soil ke])t free from weeds. They are therefore more
dependent on continuous labor than any other
agricultural crop, and are the most costly crops that
the farmer raises. Carrots and long-shaped mangels
require a deeper soil than turnips and globe-shaped
mangels. ^

The proper place of green crops in a rotation is
between two crops of grain ; as, after oats and before
wheat or barley. The oats will have greatly smothered
and starved out weeds by their dense shade, and the
manure abundantly furnished with the root crop,
^vell assimilated to the soil, will aid the development
of the wheat or barley. The preparation of the soil
for a green crop in a good clay loam will consist of
^ang ploughing the stubble as soon as possible after

283

f the

k'ater;

mien,

ances

o the

e soil
from

, and

1(1 the

houkl,

rotted

lieavy

in and

bure of

iinures

ih acre

crops

and a

|e more

other

s that

angels

haped

Ition is
before
)thered
bnd the
crop,
)pment
he soil
isist of
after

rowings

the preceding crop is taken off, repeated h
to destroy sprouting weeds, spreading a heavy
dressing of barn yard manure well rotted, ridge
ploughing in the fall — at the same time subsoil plough-
ing if the ground be in suitable condition, harrowing
as soon as possible in the spring, cross ploughing
with the gang plough, sowing artificial manure, ancl
drilling in the seed. Then for the destruction 'of weeds
the horse-hoe must be kept going between the drills
from the time the seed appears until the development
of foliage renders this impracticable. When the
young plants are firmly established, hoe by hand and
thin out the rows, leaving the finest plants and
destroying all weeds. The mode of harvesting will
depend on the character of the crop.

The Turnip. — The following quotations are from
Judge Peters' " Hints to the Farmers of Prince
^^ yard Island": "The Swedish turnip, rutabaga,
.appears to be best suited to this climate, especially on
account of its property of keeping well in winter.

" As to the best time for sowing Swedes, there is
much difierence of opinion ; they may be sown from
the 20th of May to the end of June ; they continue
to increase in weight until the frost compels us to
pull them, and therefore, the earlier they are sown,
the heavier will be the crop. When sown in May, I
have ahvays found them escape the fly ; but the best
protection against this insect is thick sowing — never
sow less than three lbs. of seed to the acre, and you
will seldom be without sufficient plants after the fly
has done its work. Aberdeen Yellows may be sown
from the first to the end of July.

" The turnip has two very troublesome enemies, —
the turnip flies (two species of Altica), and the cater-

1 ■,

k 1

i

: !

i!

ib.

IL

L..

pillar of a moth which attacks the leaves in autumn.
Against the ravages of the fly, the following expedi-
ents may be adopted : First, — late sowing, the fly
being most destructive in May, and the early part of
June. Secondly, — abundant seeding, which enables
the plants to start more vigorously, gives a better
chance of selecting strong plants when thinning, and
affords food to the fly without losing the crop. The
farmer should remember that the fly makes a point
of taking its share first, and consequently he must
provide for it if he wishes to have any left for him-
self. Thirdly, — sowing while the ground is moist,
immediately after the drills are made, and selecting,
if possible, the commencement of moist weather.
Fourthly, — watering the ground when the seed is
sprouting, with diluted urine, soap suds, or guano
and water, or the drainings of a manure pile.
Fifthly, — sprinkling lime, wood ashes, soot, or guano
over the young plants, or on the drills when the
plants are appearing.

" By adopting these methods, or such of them as
may be practicable, a crop may always be secured ;
and if any vacancies occur, they can be sown with
white turnips until the beginning of August, or they
can be supplied with plants of mangel wurzel, a bed
of which is very useful for this purpose, as they will
stand transplanting in any weather. Various dress-
ings for the seed have been recommended, but these
do little to protect the leaves ; and I have known
some of the most oflfensive of them — as for instance,
codfish oil and sulphur — to fail entirely in driving
oflf the insects. It may also be observed, for the
encouragement of those who wish to extend their
turnip culture, that large fields usually suffer less
than small patches, for a very obvious reason.

imn.
ledi-

5 fly

rto£
ibles
etter
, and
The
point
must
him-
noist,
cting,
ather.
sed is
guano
pile,
guano
n the

lem as
mred ;
with
they
bed
will
dress-
these
mown
stance,
[riving
lor the
their
>r less

285

" The worm, or caterpillar, has been found a diffi-
cult enemy to deal with, as it sometimes attacks the
turnip (chiefly the white and Aberdeen varieties) in
immense numbers, and devours them very rapidly.
In England, flocks of young ducks turned into the
fields have been found to destroy the grubs ; and it is
likely that watering with soap-suds, lye, lime water,
etc., would do something toward diminishing their
numbers.

" Some complain of turnips being difficult to keep;
those who find them so keep them too close ; with
proper management there is no difficulty in keeping
any quantity. They should be put in piles in the
field when first pulled, and covered with tops or straw,
and a little earth. Here they will sweat a little. A
dry day should be chosen to cart them to the root-
house. My root-house is dug four feet deep, and
then the roof pitched from the earth, and covered
with seaweed and earth, well sodded over ; the floor
formed of slabs and longers, raised six inches from
the bottom, and divided into three divisions. It will
contain about two thousand five hundred bushels of
roots, and I generally fill it full, and have never lost
any turnips. In the top there is a chimney, which is
never shut, night or day, during the winter ; the
vacancy below, and the partitions, allow all the
confined air to ascend, and as it is constantly escaping
through the chimney, no frost comes down. Any one
who will ventilate his root-house in this way, will
find the turnips as sound in June as when first put
in. The situation of the root-house is a matter of
importance ; it should be attached to the barn, and
entered from the barn ; this will save a deal of labor in
carrying the roots to the cattle during winter. Some

286

store them in their cellars, which are the worst places
that can be selected, as they are generally too hot and
close to preserve the turnips, too far from the barns
for convenience, and the gas which escapes from
them renders the air of the houses unwholesome.

" The Mangel Wurzel (niayigold), is, of all green
crops, the best for milch cows. It produces a large quan-
tity of milk without communicating to it any disagree-
able flavor, and it keeps remarkably well in winter.
The mangel wurzel transplants well ; and its thinnings
may be very properly used to fill up any gaps that
may occur in turnip drills. It r^ciuires a somewhat
stronger and deepei* soil than the turnip, and in light
soils the yellow globe variety will be found moro
profitable than the common long red.

"The Carrot is also a most profitable and sure
green crop, especially in the lighter kinds of soils, and
is admirably adapted for the winter feeding of work-
ing cattle and horses.

" The Parsnip is well deserving of culture as a
field crop. It thrives in the heavier kinds of soil, and
yields a large quantity of very nutritious roots, which
should be left in the ground during winter, and may
be dug in early spring, at a season when little succu-
lent food can be procured for stock. It would
form an admirable resource in case of deficiency or
loss of other roots stored in autumn. The carrot,
parsnip, and mangel wurzel should be sowed as early
as possible. I have even sowed them on a small scale
in autumn, with success. "

As has been remarked, green crops are the most
costly crops that the farmer raises. Indeed, it has
been asserted that they do not pay for themselves
directly, that they are profitable to the farmer only

r\

287

places
ot and

barns

from

e.
orreen

o

3 quan-
sagree-
winter.
innings
ps that
newhat
in light
d moro

nd sure
oils, and
)f work-
re as a
[soil, and
,s, which
,nd may
e succu-
would
iency or
carrot,
as early
lall scale

tihe most

it has

jmselves

ler only

through the manure which, when fed to live stock,
they supply for other crops, and through the extirpa-
tion of weeds which results from frequent tillage.

The cost of raising an acre of any green crop may
be stated approximately thus : One ridge and subsoil
ploughing, ^3 ; two gang ploughings, $2 ; three har-
rowings, S1.20 ; seed and drilling seed, $1.20 ; horse-
hoeing twice, $1.60; hand-hoeing twice, $4.50; cost
of hauling and spreading 15 tons of barn -yard
manure, $3.75 ; cost of distributing mineral manures,
50c. ; cost of harvesting roots, $8.00 ; rent of land
and wear and tear of implements, $4.00 ; total cost
exclusive of value of manures, $30.25. Value of man-
ures, 15 tons of barn-yard manure, containing 200
lbs. of available nitrogen, 200 lbs. of potash
and 100 lbs. of phosphoric acid, of which one-half
is soluble, $47.50 ; 200 lbs. of 80% muriate of pot-
ash yielding 100 lbs. of potash, would cost $5 ;
200 lbs. of superphosphate yielding 20 lbs.
soluble phosphoric acid $3.20 ; and 200 lbs, gyp-
sum, 50c.; total value of manures, $56.20. The total
cost of raising a bushel of turnips, of carrots, or of
mangolds will be found by adding the cost per bushel
for labor, for interest on land and for wear and tear
of implements, to the cost per bushel of manures.
The former cost is easily ascertained beyond the possi-
bility of dispute ; but the latter cost is calculated in
two ways, namely, either by charging the green crop
with a certain estimated share of the total value of
manures supplied, or by charging the value of the
manures carried off' in the green crop. The first way
is open to serious objection in that the proportion of
manure left over for succeeding crops is less, the larger
the green crop. It has been assumed that one-half

so

t I

288

the manure supplied is left behind by the green crop,
and this is a just estimate when the manuring is lib-
eral and the crop only average. But for large crops
it is an erroneous estimate. The largest crop of tur-
nips reported from the Agricultural College, Guelph,
is 900 bushels per acre. Such a crop (see table,p. 141)
will remove from the soil 162 pounds of nitrogen,
276 pounds of potash, and HI] pounds of phosphoric
acid, while the amount supplied in manure as given
above is 200 lbs. of nitrogen, 300 lbs. of potash
and 120 lbs. of phosphoric acid, of which 50
lbs. is in the insoluble state. The requirements
of the crop for other substances will be rather more
than sufficiently met. It is evident that very little
of the manure furnished is left by such a crop for the
crop that is to follow.

The fairest way of estimating the cost in manure
of the crop is to value the ash ingredients removed
by it as has been done in arithmetical exercise 185.
The cost then of raising a maximum crop of turnips,
900 bushels per acre, is for labor, rent and wear and
tear $30.25, divided by 900, 3'4c.,and for manure 5'2c.
(see rutabagas in example 185); total cost per bushel,
8-8c.

Examples.

187. The maximum crop of carrots reported from
the Agricultural College, Guelph, is 900 bushels, and
of mangolds is 1 ,020 bushels ; what is the cost of
raising them per bushel ?

188. What would be the cost per bushel of raising
the average crop in Guelph College if the ground were
worked as stated in the text above, the average being
635 bushels turnips, 595 bushels carrots and 797
bushels mangolds ?

289

. crop,
is Ub-

cvops
)f tur-
luelph,
p. Ul)
trogcn,
spboric
Ls given

potash

lich 50
trements
ler more
[jry little
p for the

I manure
removed

rcise 1^5.

I turnips,

wear and
Liire 5'2c.
ir bushel,

Irted from
isbels, and
^e cost of

I of raising
ound were
Irage being
and 797

189. What is the cost per bushel of raising the
average crop of Ontario, 420 busliels of turnips, »SH5
bushels of carrots, an<l 402 bushels of mangolds ?
The ground being less thoroughly worked, omit from
your calculation one gang ploughing, one subsoil
ploughing, one harrowing and one horse-hoeing ; as
mineral manures are not generally employed omit the
cost of distributing them.

§ 9. Pota(oe.9.

The potato contains in its tuber a larger proportion
of nutriment than the turnip or carrot, chietly in the
form of starch with a little albumen. It requires the
presence in the soil of potash and lime in considerable
quantity. Much more than one-half of the ash of
the stem of the potato consists of these substances,
and potash forms nearly one-half of the ashes of the
root or tuber. Potash is contained in the stable man-
ure usually applied to the potato, and in soils contain-
ing lime it thrives well, and is less liable to disease
than in others. Some persons suppose that the appli-
cation of lime and wood ashes causes the potato to be
scabbed. This, I believe, is a mistake, but salt and
door manure seem to produce this effect. Though the
potato will thrive, wheil otherwise in a healthy state,
with raw stable manure in contact with its roots, yet
there can be no question that it grows better with
rotted manure well mixed through the soil. It is
probable that much of the efficacy of sea- weed, which
is much used as a manure for potatoes on the sea
coast, depends on the soda which it contains supplying
the place of potash. The sea manure is thus very
useful on the slaty soils; and on the granite soils,
which contain mucli potash, the lime afforded by the

290

sea-weed is probably of moro importance than tlie
soda. Animal manures affording nitrogen are also
very important to the vigorous growth of the potato,
as to most other cultivated plants.

The potato of late years has had to contend with
two most destructive enemies, — the fungus of the
potato disease, and the potato bug.

The potato disea«-e or rot is produced by the growth
throughout the tissues of the potato plant of the
mycelium of a fungus. The disease commences with
the development of a very minute rough brown ball,
the resting spore of the fungus, which, having been
produced at the close of the previous season by the
fungus, has lain dormant through the winter either
in the groun i, in crude farm-yard manure, or attached
to the potatoes planted as seed. The mycelium pro-
duced by the development of the resting spore pene-
trates the sprouting potato, grows upward through the
young plant, ramifies into every part, and soon through
the stomata of the leaves protrudes, to the open air,
branches bearing minute capsules that contain innu-
merable spores. These soon ripen, the capsules burst
and countless millions of spores arc drifted by the air
to neighboring plants. Whenever they reach the
leaves or green stems of potato plants, they begin to
develop, and their mycelium penetrating by the sto-
mata grows throughout the substance of the newly
infected plant.

A little consideration will show how to explain the
leading facts as to its mode of occurrence.

1. The general diffusion and simultaneous occur-
rence of the disease over extensive regions, is a remark-
able fact.

2. The disease has usually attacked the crop at that

291

n the
3 alHO
)oiaio,

[\ with
of the

growth
"of the
es with
(vn haU»
ig been
1 by the
jr either
attached
ium pro-
ire pene-
ough the
through
)pcn air,
ai\ innu-
[les hurst
^y the air
[each the
begin to
. the sto-
he newly

[plain

the

lus occur-
la remark-

rop at that

staffe of the growtli when the tops are fully formed,
and the formation aiK I filling up of the umlergroumi
tubers are most rapidly proceeding.

I}. The disease has usually first made its appearance
in the leaves, and descended from these to the stems
or roots. In the leaves and stems it appears in the
form of death and decay of the tissues, very similar
to that which results from frost, or the application of
any poisonous substance. In the tuber, its progress
can be distinctly observed, and is somewhat curious.
The tuber consists of a vast number of little cells, or
bags, tilled with a fluid containing vegetable albumen
and other substances in solution, and having small
grains of starch floating in it. There are usually
several of these starch grains in each cell. Through
this cellular tissue pass bundles of vessels or tubes
communicating with the eyes or bud on the surface of
the potato. The disease usually commences at the
surface, immediately under the skin, and usually near
the eyes, and penetrates inwards along the bundles of
vessels. Under the microscope it is seen to be accom-
panied by the growth of this minute parasitic fungus,
analogous to that which causes inildew in wheat.
From the vessels it spreads to the walls of the cells,
and the fluid they contain becomes decomposed and
blackened ; and after all the rest has been reduced to
a brown putrescent mass, the starch grains still remain
entire. It has been observed in some instances, that
in proceeding from the stem to the roots, the disease
appeared first in the tubers nearest to the stem.

The ravages of all destructive fungi are much
aggravated by any circumstances which diminish the
vitality of the plants or animals on which they prey;
and, on the other hand, whatever gives constitutional

292

strength to the plants or animals attacked tends to
diminish the virulence of the disease produced by
parasitic fungi. Hence, as tending to the general
well-being of the potato plant, the following are very
important temporary remedies or palliatives.

1. Early j)lantiv (J, Viwdi planting early sorts; because
this gives greater probability of avoiding the effects
of autumnal chills and rains. This remedy has been
found very effectual in Nova Scotia.

2. Change of seed, especially from poor and cold
localities to richer and mild'er situations. The Scottish
low country farmers have obtained excellent results
by importing seed potatoes from the bleak and poor
highland districts.

8. Selecting those varieties which have proved least
liable to the disease ; and these will generally be found
to be such as have been recently introduced, or lately
procured from the seed.

4. Planting in dry soils, and underdraining more
moist soils, if necessary to plant in them. The dry,
sandy uplands of some districts have almost entirely
escaped the disease, when the crop has been put in
early.

5. Applying well-rotted niannre, and ploughing it
in, instead of putting it with the seed in the drills.
Guano and composts made with liquid manure, have
proved themselves better than stable manure. This
and the two last remedial agents act by giving the
plants a ijreater degree of healthy, general vigor, than
they could derive from run-out seed, in wet soil, or in
contact with rank manure.

6. Planting in new soil and the use of mineral
manures. It is generally observed that the potato
has been most healthy when planted in new, virgin

293

nds to
led by
reneral
ce very

because
3 effects
Las been

md cold
Scottish
it results
and poor

)ved least
r be found
. or lately

ning more
The dry,
t entirely
en put in

oughing it

the drills.

nitre, have

ure. This

oiving the

vigor;

than

t soil, or m

)f mineral
the potato
lew, virgin

soil, before the unskilful agriculturist has extracted
from it the stores of alkaline and other mineral man-
ures remaining in it from the ashes of the forest.
The composition of the ash of the potato at once ex-
plains the reason of this, as the table on page 141
shows.

Potash forms more than 50^ of the ashes of the
roots, and an examination of any table of analysis of
the tops would show in addition to nuich potash a
very large amount of lime.

Now these substances, potash especially, arc plenti-
fully supplied to the soil by the ashes of the woods,
and are usually deficient in exhausted lands. Hence,
if we apply to run-out or long cultivated soil, lime,
wood-ashes, cfypsum (sulphate of lime), common salt
(chloride of sodium), bone dust (phosphate of lime),
we supply it with some or all of the more important
substances in the above table, and thus assimilate it
to the virgin soil in which experience proves the potato
to thrive best. I have found, by experience, that
healthy potatoes (though not a large crop) could b*»
obtained by planting with no other manure than &,
pint of unleached wood-ashes in each hill, in seasons
when potatoes planted with ordinary manure were
blighted.

For the same reasons it is, of course, unwise to raise
successive crops of potatoes on the same soil. When-
ever, on old land, a proper rotation of crops is not
attended to, there is much greater likelihood of failure.
7. Storing in dry cellars is of the first importance,
when the crop is infected. I have found that potatoes
in which brown spots of disease were already formed,
had the progress of the change arrested l)y being
kept dry ; and that the diseased spots dried up and
lost their putrescent character.

294

8. Where there is no hope of otherwise saving a
crop, the rotting potatoes may be grated or ground
up, and the farina and starch saved. With a little
extra washing, it will be nearly as good in quality,
though usually less in quantity, than that from sound
potatoes. Every farmer should have a grater or
grating machine for potatoes, and in autumn should
prepare a quantity of farina. It is excellent for
children's food, puddings, to mix with flour for bread,
etc., and it will keep for several years.
. All the above, and probably other expedients, have
been approved by experience as useful palliatives.
In short, anything that tends to place the plant in a
natural and healthy condition appears to give it a
much greater power of resisting the cause of disease,
whatever that may be.*

Can any reason be assigned for that apparently
universal weakness of constitution which more than
forty years ago threatened to deprive us entirely of
this much prized esculent ? Is there anything in the
past history or present condition of the plant, likely
to produce such an effect ? I have long thought that
there is such a cause, and shall now proceed to
explain it, in connection with the only means of
counteraction which have suggested themselves.

Of all our crops, the potato alone has been contin-
uously propagated by natural or artificial division of
the plant. The tuber of the potato is a sort of under-
ground stem, with eyes or buds intended to produce
young shoots in the year following the formation of
the tuber and with a store of starch, albumen, &c. to
nourish these young shoots in the early stages of their

• To this I may add thit when the disease is observed in the stalks, the
potatoes should be du? at once. If they must bo left in the ground, the
stalks should be pulled out.

295

^g a
3una
little

ality,
iound
gr or
hould
it tor
bread,

,, have
atives.
at in a
e it a
Usease,

rently

e than

rely of
in the
likely

Iht that
eed to
ans of

Is.
Icontin-

ision of

under-

)roduce

ttion of

&c. to

)f their

[stalks, the
Iroundi the

growth. These tubers, then, in the natural state of
the plant, must serve to continue its existence from
year to year, and to extend the individual plant into
a group or bed of greater or less extent. But this
process is not intended to be perpetual. The longest-
lived forest tree must eventually die, and so must the
group or stool of the potato, which, originally
founded by a single seed from a ball, is only one
plant increased in extent by a spontaneous division
of its roots into detached tubers. It gradually
exhausts the neighboring soil, until its own vital
energy diminishes, and at length it will die out ; and
if a new plant occupies its place, it must be a seedling
produced from the balls which have fallen on the
spot.

Have we a right to expect that plants propagated,
not by natural generation through the seed, but by
perpetual division of the plant, should continue to be
healthy for an indefinite period ? We may not know
the minute changes which bring about the debility of
age, but we know that such debility does overtake
plants as well as animals. Fine varieties of carnation,
propagated by cuttings or layers, in a few years
degenerate, and must be abandoned by the florist.
The same happens to other florists' flowers, though in
some more slowly. Grafting and budding fruit trees
is but continuing the lives of individuals, and despite
the vigor of the new stock, grafts from very aged
trees of old varieties, show the debility of the parent.
Hence, most of the finest fruits of a century or two
ago have degenerated and become less worthy of
cultivation, and have been replaced by new varieties
from the seed. This seems to be one of the great
laws of vegetable life ; and accordingly, even those

296

ui

plants which, like the potato, have been furnished
with tubers to provide for the continuance of indivi-
dual life,have also been provided with seeds to produce
new individuals, and thus permanently continue the
species.

Taking this view of the matter, we should rather
wonder that the potato has lasted so long, than that
it now fails. We can, in truth, account for its long
duration only by taking into consideration the variety
of soils and climates in which it has been cultivated,
the frequent changes of seed, and the occasional
raising of new varieties from the ball.

If, however, this cause has had any real influence
on the plant, why has it not merely run out or died
of old age, instead of contracting a malignant and
fatal disease ? The analogy of other vegetables leads
us to believe that plants do not always simply die out
under the influence of degeneracy or old age. The
worn-out carnation loses the size and brilliancy of
its flowers ; the old varieties of fruit trees lose their
vigor of growth, degenerate in their fruit, and become
very liable to the attacks of parasitic fungi and
animals ; the ancient forest, its trees decaying at the
heart, and overgrown externally with lichens, mosses,
fungi, and excrescences, usually perishes by tempests
or fires, before it undergoes the slow process of natural
death. So with the potato. Under high cultivation,
its starchy and albuminous parts, those which are
valuable for human food, have been increased, while,
by constant reproduction from the roots, the vitality
of the living buds has been diminishing. The potato,
at one time the most certain and hardy of crops, has
gradually become tender. The "curl" and "dry rot"
began many years ago to cut off the young shoots and

29;

ishecl
icUvi-
oduce
le the

rather
,n that
,s long
variety
Avated,
jasional

liluence
or died
ant and
les leads
J die out
re. The
^ancy ot
se their
become
ngi and
g at the
mosses,
tempests
f natural
Itivation,
hich are
ed, while,
le vitality
e potato,
rops, has
dry rot"
Ihoots and

the planted tubers, apparently because tl 'ire was not
sufficient vegetative life to enable the living bud to
control and use the abundant nutriment for it in the
cells of the tuber. This difficulty was overcome in
part, by changes of seed, planting the whole tubers,
and other expedients ; and the life of the plant was
protracted a little longer, as might have been expected,
to be attacked only by a worse disease.

I come now to the method which the above views
would lead us to consider the only certain one, with
a view, if not to the final extirpation of the disease,
at any rate to its reduction to harmless dimensions.

It is to cultivate the potato from the ball, for several
generations continuously, until the hereditary taint
is removed, and then to distribute the healthy tubers
to such agriculturists as will pledge themselves to
abandon entirely the culture of the present exhausted
and diseased varieties.

These views of the author, first published by him
in the Report of the Agricultural Societies of
Massachusetts for 1851, have since been often repro-
duced by various writers, and reduced to practice in
the production of new varieties of the potato by
cultivation from the seed — varieties which, possessing
the vigor of youth, have successfully resisted the
attacks of the potato disease, and have wholly super-
seded the worn-out varieties which preceded them.

At pres'^nt the potato-bug is the greatest enemy of
the potato crop ; but it is successfully combated by
Paris Green, a compound of copper and arsenic,
and a most virulent poison. It is applied either
by sprinkling a weak solution in water over the
plants as soon as the bugs make their appearance, or
by powdering the plants, preferably while wet with

298

! Ul

mAli '

dew or rain, with a mixture of flour or plaster of
Paris with a small quantity of Paris Green.

The cost of raising a crop of potatoes may be
reckoned, exclusive of manures, at a little more than
that of a crop of turnips ; — say $34 an acre. The
average potato crop in Ontario is 175 bushels per
acre. This makes the cost per bushel irrespective of
manures 19'4c a bushel, to which must be added for
material removed from the soil 5'.3c, making a total
of 24*7c a bushel. If, however, a maximum crop
of 250 bushels, be raised, the cost per bushel is reduced
to 18'9c. Usually, every bushel of potatoes sold at
less than 25c., is sold at a loss to the farmer.

§ 10. Clover and Grasses.

In a country where the winter is long and severe,
these must always be important crops; though, as
already hinted, when treating cf the climate, it is
certain that the extended culture of root crops, to be
fed to cattle and horses in winter, would very much
lessen the present difficulties in this respect. I have
already quoted the opinion of Professor Johnston on
this subject, and now give an additional extract, on
the former and present state of Scotland :

"The same state of things as now exists in New
Brunswick, existed in Scotland, in connection with
this branch of husbandry, a >out a hundred years ago.
Cattle were killed at the end of summer, and salted
for winter use, because the stock of hay at the farmer's
command was not sufficient to keep them through the
winter months. The beef these cattle gave was so
poor that it took the salt badly, was hard and indi-
gestible, and kept badly in the brine. Now, the cattle
are not killed in the autumn more than at other

299

r of

than
The
s per
ive of
id for
, total
I crop
iduced
sold at

severe,
ugh, as
t

)S,

e, it IS
to be
much
I have
ston on
ract, on

in New
3X1 with
iars ago.
>d salted
farmer's
>ugh the
i was so
^nd indi-
e cattle
,t other

seasons. The present modes of husbandry provide
winter food for all the stock the farmer finds it conven-
ient to keep. When killed, the beef or mutton is now of
excellent quality ; lar^e quantities of both are for-
warded, all the year through, to the southern markets ;
and it can be cured for the naval service, or for any
other use."

It appears to me that, in the present state of our
husbandry, the most important points to be considered
in reference to hay crops, are, in the first place, the
injurious practice of cutting hay from the same ground
for a great number of years in succession ; and
secondly, the best modes of promoting and ensuring
the growth of clover. To these subjects, therefore,
I shall devote the remainder of my remarks under
this head.

The skilful farmer should never forget that run-out
hay land is in every respect unprofitable. It costs
almost as much per acre for fencing, mowing, and
raking as better ground, and yields little, and this of
very inferior quality, possessing little nutritive power.
In dry seasons, also, it cannot be depended on. Hence,
one acre capable in a good season of yielding three
tons, or two tons in a poor season, is far more valuable
than six or seven that in a good season may yield,
perhaps, one ton per acre, and in a poor season may
fail altogether. Hay land should be sown out in good
heart, and then not more than two crops should be
taken, at least without some fertilizing top-dressing ;
and even with top-dressing, not more than three or
four. After this, if it cannot be broken up, it should
be left for pasture. Circumstances may render neces-
sary partial deviations from this rule ; but the prin-
ciple should be considered as settled, that every

300

deviation will entail loss in the end. Every farmer,
on ploughed land, can at least apply this principle to
a part of his land — and the larger that part the better.
In connection with this it must be remembered that
good summer pasturage, independent of more direct
benefits, does much to aid good winter keeping. Hay
culture, without impoverishing the land, is, after all,
not so difficult as may be imagined, if the produce be
fed out upon the farm ; for the liquid and solid manure
of the animals that consume the hay, contains nearly
all that the hay took from the soil; and if saved and
restored, no impoverishment results. On the other
hand, the grand secret of hopelessly and rapidly
impoverishing the farm and the farmer is to crop the
land in hay till it will bear no more, and then let the
manure go to waste, or sell off the hay. Johnston, in
his Report on New Brunswick, gives the following
example of a prevalent error in this respect : " I
visited the farm of a most intelligent gentleman, one
of the best farmers in his neighborhood, and I believe
most desirous to improve; who informed me that after
one dressing with mussel mud, from the sea bank not
far from his farm, he had taken one crop of potatoes
or turnips, one of wheat, and eight successive crops
of hay; and he seemed to think that the land had
used him ill in not having given him more. For the
first four crops, from such an application, a British
rent-paying farmer would have been thankful and
content; and in taking these, he would have been
thought rather hard upon his land."

The timothy grass (herd's grass) usually cultivated
in this country, is one of the best of grasses, in every
respect. It is, however, often treated with injustice,
by being allowed to remain too long before cutting.

301

xmer,
pie to
letter,
d that
direct
Hay
ier all,
Luce be
nanure
nearly
^ed and
e other
rapidly
crop the
1 let the
[iston, in
ollowing

pect: "I
man, one
I believe
[hat atter
)ank not
potatoes
ve crops
Land had
For the
British
[k£ul and
^ave been

jultivated

\ in every

injustice,

:e cutting.

Wliere there is a hxrge crop to be cut, and few hands,
mowing should, if possible, be conniienced befoir,
rather than after the flowering of the head, — which
is the time when the grass contains the largest (juantity
of nutritive matter. It is true, however, that few
grasses will bear late cutting better than lierd's grass.
Even when left to ripen its seeds, it is worth more as
food than many of the light grasses of worn-out lands.
The substances which this grass re(|uircs to be present
in the soil are very much the same with those needed
for grain crops. Its favorite ground is a moist and
deep soil.

Clover is a most valuable adjunct to herd's grass,
especially in the lighter soils ; but the conditions
necessary for its successful culture are as yet vt?ry
imperfectly known in this country. The ashes of
clover contain large quantities of potash, lime and
gypsum. These substances must therefore be present
in the soil. Clover loves a calcareous soil, and hence
it is observable that in those soils which, from the
vicinity of beds of lime and gypsum, are naturally
rich in calcareous matter, clover thrives without any
trouble. I place first, therefore, among the requisites
for the successful culture of this crop, the presence of
lime and gypsum in the soil. If not naturally present,
they must be supplied artificially. The next requisite
is a deep and dry soil. Clover sends its roots deeply
into the ground, and will not thrive in shallow, wet
soil. To fit it for clover, such soil should be drained
and subsoiled. Thirdly, the leaves of the clover must
not be destroyed by the scythe or by cattle in the
autumn of the year in which it is sown. These leaves
ought to be employed till the frost kills them, in pre-
paring nourishment for the growth and strengthening

r J

302

of the root ; and if cut early witli the grain, the plant
is so enfeebled that it has little chance of standing in
winter. In reaping, the wheat straw should be cut
so high that the scythe or sickle shall not touch the
clover leaves. This high stubble will also shelter the
clover in winter. Of course no cattle or sheep should
be allowed to enter the stubble fields in autumn.
Fourthly, the ground should be rolled in spring, to
press in the clover roots. Fifthly, after clover has been
sown several times, in the ordinary course of succes-
sive rotations, the land becomes "clover-sick," as it is
termed, and the crops fall off. Clover-sickness is due
to the attacks of a minute eel-worm, which destroys
the vitality of the root and stem. Whatever adds to
the vigor of the plant enables it more successfully to
contend with the foe, so that manuring with wood
ashes, lime composts, and urine, have been found
beneficial.

But, when ground has become thoroughly infected
by the presence of this pest, no course seems to be
open to the farmer except to abandon for some years,
eight or ten, the cultivation of red clover on that spot.

Neglect of these facts is the principal cause of the ,
two great evils complained of in this country in
respect to clover, viz : the winter-killing of the roots,
and the too early ripening and death of the top in
summer. These losses are otten attributed to particular
varieties of seed ; but they depend far more on the
nature of the soil and treatment, — though of course,
some unfavorable seasons occur, in which no manage-
ment is altogether eflfectual ; and as the natural life of
red clover does not extend beyond two or three years,
it cannot be expected to remain permanently in the
land. Shallow, undrained, poor soils, which do not

303

plant
ng in
)e cut
ch the
,er the
should
itumu.
•ing, to
as been
succes-
as it i«
s is due
lestroys
adds to
dully to
th wood
n found

infected
IS to be
lie years,
[hat spot.
56 of the ,
intry in
; roots,

le top in
[articular
on the
ff course,
manage-
:al life of
:ee years,
bly in the
do not

allow the roots to become large and strong in the first
year; destruction of the leaves of the first year in
autumn; deficiency of lime and alkalies; and neglect
of rolling, — are the principal causes of winter-killing;
and the same causes, with the addition, in old farms,
of clover-sickness, cause the crop to ripen prematurely.
Clover, like peas and beans, is a leguminous plant,
that is, it produces its seed in pods, and like all
leguminous plants it appears to nourish in small
callosities on its roots a form of bacterial life
that in ways ill understood as yet, has the power
of assimilating nitrogen from the air, rendering such
plants independent of the nitrogen of the soil, and,
indeed, enabling them by their growth to enrich the
soil in nitrogen, rather than, as all other plants appear
to do, to impoverish it. The whole subject is one
that is as yet under observation and discussion, and
it is impossible to speak with the definiteness that all
practical men must desire ; but, perhaps, it is not
premature to say, 1st, that a leguminous crop usually
shows an amount of nitrogen in its nitrogenous material
greater than it has taken from the soil and from the
manures supplied to it ; 2ndly, that this assimilation
of nitrogen is due to the growth of microdemes which
feed upon the carbonaceous matters accumulated in
the soil, and the growth of which is speciall / favored
by leguminous plants ; 3rdly, that this is the most
plausible explanation yet offered of the value
of clovftr as a fertilizer for grain crops ; and,
4thly, that as a practical lesson derived from these
considerations, every farmer should arrange that in
turn every part of his land should be made to carry
at frequent intervals, a crop of peas, of beans, of
vetches, or of clover in one of its forms, red clover,
white clover, alsike, etc.

81

804

V' ?

The place of a crop of clover and timothy, in a
rotation, is after wheat, rye, or barley, the seed, in
the case of spring grains, being sown with the grain,
or in the case of fall grains, the timothy may be sown
with them, and the clover broadcast and lightly
harrowed in on the green grain in the spring. For
one or two years after the grain with which it is
sown has been cut, hay may be cut, and the land
pastured for a year or even longer afterward,
before breaking up for oats.

It is difficult to estimate the cost of a crop of hay,
for two or three reasons ; first, the labour of preparing
the ground must be done for the grain, even if the
hay crop were not to follow ; secondly, no further
labour is expended on the ground for the second crop
of hay and for the pasture that may follow ; thirdly,
it is not possible to state quantitatively the relation
of the clover to nitrogen, as it is not believed that all
the nitrogen of the clover crop is abstracted from the
soil. However the hay must be charged at least
with the cost of seed, and, when clover is sown in the
spring upon fall grain, the cost of sowing and harrow-
ing must be charged against it, then the cost of
saving the hay, the rent of the land, the wear and tear
of implements, and the value of the ash ingredients
and nitrogen of the crop must also be charged
against it.

The account of the hay crop will stand something
like this : seed and seeding, $5.00 ; harrowing, 40c ;
mowing, making, and hauling hay, two years, $4.00 ;
rent of land, two years, $6.00 ; wear and tear of
implements, $2.00 ; total $17.40. The average hay
crop of Ontario is Ij tons of mixed timothy and
clover, three tons for two years, costing $5.80 for

iiy, in a

seed, in
he grain,

be sown
I lightly
ng. For
ich it is
the land
Iter ward,

►p of hay,
preparing
^en if the
10 further
scond crop
7 ; thirdly,
le relation
3d that all
1 from the
d at least
►wn in the
id harrow-
he cost of
ir and tear
ingredients
)e charged

something
)wing, 40c;
ears, $4.00 ;
ad tear of
verage hay
mothy and
r $5.80 for

SOS

that $13.94 a t n L hTc^'^ "? ''"^-^ "'°^'""- *«14; •«>
and clover If two L *'""°'''"« ""'■^•-''l ""'"thy

year, the ^Ji^ .SueltV^'Li^T' ^''^

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1

CHAPTER XVI.

Soiling and Silos.
§ 1. Green Fodder.

Pasturing stock is not profitable employment of
arable land. The amount of food which stock can
find on three acres of grazing land is not equal to
that which can be grown as a crop en one acre.
Temporary pastures that follow hay as usually grown
from timothy, and clover seed only, contain but few
and haphazard species of grass, and these do not
afford sufficient variety to enable the pasture to meet
vicissitudes of season, especially the drouths to which
in Canada we are somewhat liable. Ccmsequently
such pastures cannot be depended on ; if they are
made to carry as much stock as they can in rainy
weather, the stock will^be apt to suflfer from insuflfi-
cient food in dry weather. Besides much more
of the manure of grazing animals is wasted than of
stall fed animals. On the other hand, pastures and
grazing animals require but little labour, while the
process of growing a crop and of cutting it and dis-
tributing it to animals involves much labour.

Accordingly, agriculturalists have sometimes re-
sorted to soiling, that is to the growing of such
crops as peas and oats, oats and vetches, rye, maize,
clover, lucerne, or millet, which are cut green and
fed to stock in stables or in paddocks too small to
provide sufficient pasture. In this way abundant
food is supplied to animals at all times, their strength

307

nt of
k can
lal to
5 acre,
crrown
it few
lo not
o meet

which
^uently

y are
rainy

nsuffi-
more
Ihan o£

es and

ile the
d dis-

les re-

ii such

inaize,

m and
Imall to

mndant

ltren<j;th

is not wasted in searching for it, and, consequently,
working cattle and horses, milch cattle and fattening
cattle, are kept in better condition. But the confine-
ment and want of exercise eventually tell against the
health of young cattle and cattle used for breeding.

Not only is the process of growing soiling crops, of
cutting them and distributing them laborious, but
the labour of cutting and distributing can neither
be intermitted nor postponed, no matter how urgent
the occasion. Consequently the system of complete
soiling has never obtained in Canada, except in
the treatment of city horses and cows. But in all
well conducted farms, on which a sufficient amount
of live stock is carried, partial soiling is necessary and
should become universal. Soiling crops, with the
exception of rape, are usually either gramineous or
leguminous. Of the former, in addition to the grasses
commonly cultivated for hay, may be mentioned
w^inter rye, oats, millet and maize ; of the latter, red
clover, lucerne, alsike, vetches and peas are employed.
Mixtures of gramineous and leguminous plants are
frequent for soiling purposes ; as, orchard grass and
red clover, timothy and red clover as for hay, timothy
and alsike, oats and peas, oats and vetches.

Winter rye is especially valuable because it may bo
used in the spring, and the ground that has borne it
may carry a crop of millet, Hungarian grass, corn or
rape, immediately following it. Red clover and
orchard grass yield two, and lucerne three or four
cuttings in one season. Rape is valuable as a late
soiling crop, eaten off by sheep or cattle where it
grows. The special advantage of corn is that it
yields more food per acre than any other soiling crop,
except, possibly, lucerne.

308

m

i!i

§ 2. Ensilage.

In a climate so rigorous as ours, where for half the
year all kinds of stock must be stabled and fed, it is a
matter of no sn)all importance to the health and good
condition of live stock to furnish them with a suffi-
cient amount of succulent food for use with the hay
and grain, that must be their principal dependence.
Where roots can be profitably grown, they may be
fed to stock, but in many parts of Canada soil and
climate are uncongenial to roots, so that the root crop
is held to be uncertain and unprofitable. Casting
about for means to remedy this deficiency, farmers,
within the past fifteen or twenty years, have begun to
imitate, on the large scale, with green fodder, the pro-
cess which is exemplified on the smaller scale, by
the housewife who preserves fruit and vegetables by
sealing them in air-tight cans.

It has become abundantly clear of late years that
all those changes taking place in dead organic sub-
stances, which are called decay, fermentation, or
putrefaction, are dependent on the development,
growth and multiplication of minute forms of life, both
animal and vegetable, but especially vegetable. If these
living forms can get no access to the dead organic
matter, it will not undergo putrefactive change. These
living forms never spring up of themselves ; they are
not generated by decay ; they are produced by the
development of germs which are the offspring of
parents like themselves. These germs abound in the
air, in the water and in the soil, wherever life is or

has recently been. But they are
They are not found, for instance, at
the air, as on the sumniits of lofty m

not everywhere,
great heights in
ountains. They

309

f the
b is a
good
suffi-
5 hay
lence.
Ly be
I and
t crop
asting
rmers,
DTun to
le pro-
de, by
Dies by

k that
c sub-
on, or
pment,
'e, both
i these
organic

These
hey are
by the
ring of

in the

e is or

^ where.

ligrhts in

They

may be killed by high temperatures or by poisonous
gases, and they may be excluded from confined
spaces by sealing, or even strained out by layers of
fibrous material, as cotton wool. All these facts are
exemplified in many ways. The housewife boils
the fruit which she intends to can, that she may
destroy the germs which, if sealed in with the fruit,
would inevitably cause moulding, fermentation and
decay. She seals the cans while hot, that she may
exclude all such germs for the future. The surgeon
washes his hands and his instruments in a solution of
corrosive sublimate in order that he may kill all
adherent germs and avoid their introduction into a
wound ; and he covers the wound itself with lint that
has been sterilized, that is that has had adherent
germs killed, in order to strain all such germs out of
the air that finds its way to the injured part.

When a very large mass of dead stalks and leaves
is thrown into a heap in the moist state, its surface is
exposed to all the influences of the atmosphere ; but
its inner part is acted on in a way quite different. At
first the oxygen included in the mass acts upon the
carbonaceous matters present, and carbon dioxide is
formed, while at the same time the temperature rises
and the living germs begin their work. But in the
dense interior of the mass the heat generated, and the
carbon dioxide produced are imprisoned. The temper-
ature rises until the oxygen is all consumed, by which
time it has risen high enough to destroy many of the
living germs ; and the rest deprived of the oxygen on
which their active life depends, and surrounded with
an atmosphere of poisonous carbonic gas, are either
killed or rendered inert. In the interior of the mass,
then, crushed down by its own weight, the generation

if -.

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V

310

of heait and all fermentations (juickly cease, and change
being arrested in the interior, it may be months or
even years before decomposition, slowly creeping
inward from the exterior, can reach the centre ; more
especially because the living germs are largely filtered
out of the air by the strawy mass of dried-up leaves
and stems that form the outside covering. The
core of such a mass of fodder would be so little
changed after many months as to be much relished
by stock as an accompaniment to hay. It is evident
that the process of thus preserving fodder in a
succulent state would be much more economical if
outside waste were diminished by piling the mass in
a receptacle air-tight below and at the sides. This is
now usually done, and much fodder is annually pre-
served in the green state.

Material so preserved is called silage, the air-tight
receptacle is called a silo, the verb to ensile is used to
assert the act of packing away silage, and the word
ensilage is used as the name of that act.

The silo should have its sides so constructed as to
exclude air and frost. This is secured by constructing
its walls of two thicknesses of boards with tar paper
between. The structure must be strong and firmly
braced to resist the very considerable inside pressure
due to the weight of the material. The inside walls
should be smooth, so that the silage may sink easily
and compactly downward as it yields to the weight
above. The roof of the silo must be weather-proof.
Doors should be made in the roof or in the gables for
the introduction of the material to be ensiled and for
ventilation, while other doors ranging at intervals
from top to bottom of one side will afford facility for
removing the silage for use. The earthen floor of the

311

lange
hs or
eping
more
Itered
leaves
The

little
slished
vident

in a
lical if
nass in
This is
ly pre-

ir-tight
used to
e word

r

d as to
acting
I- paper
tirmly
ressure
e walls
: easily
weight
-proof,
les for
.nd for
tervals
lity for
r of the

silo must be so far raised above the general surface
that water will not stand upon it.

Any green fodder may be used for filling the silo.
Clover, quite green, even dripping with rain, may be
put into the silo, as also green oats or any of the
grasses. But experience shows that corn sown in
rows three feet apart and cut when the ears are
beginning to glaze, gives the richest and most abun-
dant silage from a restricted area.

The corn, if corn be ensiled, is cut, brought to the
silo, run through a cutter which cuts it into lengths
of about half an inch and is piled into the silo so as
to keep it well tilled up at the sides. As the silage
will begin to mould at the surface in three or four
days, the work of tilling must go on with only an
occasional interruption of a day or two until it is
complete. Sometimes a covering of straw or of
marsh grass is spread upon the surface when the silo
is full, and well trampled down to exclude air as
much as possible. But it is not necessary to take
this trouble. If the upper surface is left exposed a
few bushels of silage will spoil at the top, Imt will
preserve the rest from injury. Of course in that case
the farmer will remove the ears of corn from the last
load ensiled. If clover be ensiled there is danger that
it may be too dry when put away!

The silage soon heats, sometimes reaching a tem-
perature of 140 F. in the middle, and, softened by
the heat, subsides under its own pressure into a com-
pact mass, shrinking about 30^ of its height and
weighing after shrinkage between 50 and CO lbs. to the
cubic foot. The silo may be left undisturbed for a
month to ripen its contents; but may then be opened,
and will furnish nutritious and palatable food for
many months to come.

312

Many modifications of the mode of ensilage are in
use. Sometimes the silage is made of uncut green
fodder, piled in a huge stack, firmly compacted, and
finished off with a haystack on the top. Sometimes
it is piled in underground pits, trodden and rolled
firir^ -md covered with earth. Each modification has
its cpecial advantages which will appear in practice,
but the principle is the same in every case, viz : by
the size of the mass and its close compression to
exclude air from the interior.

1 ?ije u-jrt of corn skilfully trertted will produce 20
tons (t ^ \.\g{i equal in feeding value to about 6J tons
o^ hay. 0 «ie ^jost of production will be about as
^ollov'^ : For vl'^'Ughing sod in the fall, $2 ; gang
ploughing ii. {^pji* ;»•, 75c.; harrowing, 25c.; seed and
seeding, $2; horse-hoeing twice, $1.25 ; cutting, haul-
ing, running through cutter, and piling in the silo, S5;
rent of land $S ; wear and tear of implements and
rent of silo, $4.50, a total cost of $18.75, say $1 a
ton. The value of the substances removed from the
land is not reckoned, as theso will be returned to
it in manure. If the silage were sold, which is never
the case, the value of the substances removed from
the ground, $14, would be added, and would make the
net cost approach $1.75 per ton.

tre in
rreen
I, and
times
rolled
m has
ictice,
z: by
on to

ice 20
J tons
out as
; gang
id and
•, haul-
;ilo, ^5 ;
ts and
$1 a

.m the
Ined to
never
ll from

,ke the

A ppendix.—Synonyms.

Scientific chemical nomenclature has been much
modified of late years, but the older names still
survive in conmierce and occur in works on agricul-
ture, works many of which are of great value. In
the preceding chapters the aim has been to use an
approved modern terminology, although, especially
in quotaticms from other works, there are a few devia-
tions. To diminish the risk of confusion in the mind
of the student who consults other works or who
examines trade circulars and catalogues, meeting
diverse names for the same substance, a little table of
synonyms is here appended, in which are placed first
names as used by Koscoe, which are the names chiefly
used in this little work, followed by other names,
placing last any that now occur in commerce only.
The last names have not always the definiteness of
the first names in the lists ; thus carbonic acid scmie-
times means CO2 called preferably carbon dioxide,
and sometimes H2 CO3 to which (page 90) the term
properly belongs ; the term potash sometimes means
potassium monoxide, K2 O, sometimes it means potas-
sium hydroxide or caustic potash, HKO. Names
thus misplaced are enclosed in parenthesis below.

The student should, however, observe that many of
the names are fundamentally identical. Sometimes
elements of the names are merely inverted in order,
as chlorhydric for hydrochloric, or chloride of sodium
for sodium chloride. Sometimes an adjective form is
preferred to the noun form of a word, as sodic sul-
phate for sodium sulphate.

f I '■ M^

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314

The table is restricted to the elements and their
compounds discussed in chapter V.

ELEMENTS.

Oxygen, vital air.
Nitrogen, azote.
Carbon, charcoal, diamond.
Iron, ferrum.
Sodium, natrium.
Potassium, kalium.
Aluminum, aluminium.

BASES.

Sodium monoxide, sodic monoxirle, soda.

Sodium hydroxide, sodic hydroxide, caustic soda,
(soda).

Potassium monoxide, potassic monoxide, potassa,
potash.

Potassium hydroxide, potassic hydroxide, caustic
potash, (potash).

Calcium oxide, calcic oxide, quick lime.

Calcium hydroxide, calcic hydroxide, slaked lime.

Magnesium oxide, magnesic oxide, magnesia.

Ferrous oxide, protoxide of iron.

Ferric oxide, sesquioxide of iron.

ACIDS.

Nitric acid, hydrogen nitrate, aquafortis.

Hydrochloric acid, chlorhydric acid, muriatic acid,
spirit of salt.

Carbonic acid, hydrogen carbonate.

Sulphuric acid, hydrogen sulphate, oil of vitriol.

Phosphoric acid, trihydrogen phosphate, tribasic
phosphoric acid.

their

ic soda,
potassa,
caustic

1 lime.

tic acid,

itriol.
tribasic

815

SALTS.

Sodium nitrate, nitrate of sodium, nitrate of soda,
Chili saltpetre.

Sodium chloride, chloride of sodium, sea-salt, rock-
salt, common salt.

Sodium carbonate, carbonate of sodium, carbonate
of soda, (soda), washing soda.

Hydrogen sodium carbonate, bicarbonate of soda,
(soda), baking soda, (saleratus).

Sodium sulphate, sulphate of soda, salt cake,
Glauber's salts.

Monosodium phosphate, dihydrogen sodium phos-
phate, superphosphate of soda.

Bi-sodium phosphate, hydrogen bi-sodium phos-
phate, neutral phosphate of soda.

Ter-sodium phosphate, trisodium phosphate, sub-
phosphate of soda.

(There are the same variants of the scientific
names of the potassium salts as of the soda salts.
Trivial names of two of these salts follow.)

Potassium nitrate, saltpetre.

Hydrogen potassium carbonate, (saleratus).

Calcium carbonate, calcic carbonate, carbonate of
lime, chalk, marble, limestone.

Calcium sulphate, calcic sulphate, sulphate of lime
and when combined with water, gypsum, alabaster.

Monocalcium phosphate, monocalcic phosphate,
superphosphate of lime.

Bicalcium phosphate, bicalcic phosphate, dicalcic
phosphate, reverted phosphate of lime.

Tercalcium phosphate, tricalcic phosphate, bone
ash, apatite.

Magnesium sulphate, sulphate of magnesia ; com-
bined with water, Epsom salts.

Ammonium chloride, sal ammoniac.

I

816

Note. — As the sole aim of the reviser of this book
is the direction of pupils in our schools to the sys-
tematic study of agriculture, the most important and
the most interesting of all our arts, he will gladly
receive from practical men and from teachers hints to
its improvement ; and, as far as the time at his dis-
posal admits, he will clear up difficulties in the minds
of teachers, and suggest ways of solving problems
and conducting illustrative experiments by communi-
cations to the Educational Record.

s ■

I'

I
-. I.

Ill

\\i\\

} book
e sys-
nt and
gladly
ints to
lis dis-
minds
oblems
iimuni-

Answers to the Arithmetical

Examples.

N.B. — When answers are not exact, the figure given in the
last decimal place is the nearest to the exact answer, whether
greater or less than it.

1—1 *» I *» i *» 4 ; 20; 40 cubic inches.

2—60; 240; 259-2; 518-4; 2160 pounds.

3—500; 400; 200; 100; 22-2222; 4-6296; 3-4722; 23148;
1-1574; -5787; -3858 pounds.

4—14-43 times.

5— 535 -68 grains.

6—13-07 cubic feet.

7-593-96; 37-1; 51972; 816-7; 131777 grains.

8—1-1088; -1380; 2-9106; 9-84; 7-623 ounces.

9—3-2258; 2-9093; 465484; 33249; 1-3113; 2-1158 cubic
inches.
10— -902; 14-43; 1-0307; -6559; -4066 volumes.
11—2; 1-129; 1493; 1-879; -6907; 1-191; 1-8668.
12—3-2258; 1-6129; 1; 1-1088; 2-46; -0693.
13— -0693.
14—1-5246; -0693.
15— -58905 ; 1-0256.
16 --4158; 1-0395; -9979; -9997.
17—49-4577 cubic inches ; 6-4516 cubic inches ; -1304.
18— -1584; 1-0015; 1.933.

19 — -99996 ; oxygen is required in very small amount.
20 — If a column of mercury 30 inches high, resting on a base
of one square inch, weighs 14-715 lbs., a column one inch high,
on the same base, weighs one-thirtieth of 14-715 lbs., tiiat is,
•4905 lbs.
21-15-205; 14-96; 14-519; 13-9302 lbs.
22—14-372; 14-136; 14-396 lbs.
23-1913-012 lbs.
24—8-45 lbs.
25-282-19 lbs.
26 — '4785 grains ; 1 -544 cubic inches.

318

27— 474 -8 lbs.

28— ()0 11)8. per square inch.

29— ir)()4 grains.

JiO — Nitrogen exerts a pressure of 28 lbs. on the square inch,
and oxygen 7 lbs. There are in each cubic footo*'*'«e mixture
988-93 grains of nitrogen and 282-55 grains of ox

31-277-23 (Uibiciniaies.

32—14-284 lbs.

33— -433; 58-8G; 58427 lbs.

34—52-8 lbs.

35— 0-91 7 lbs.

36—3-74 lbs. pressing the paper downward; therefore tlie
water would run out.

37-14-284 lbs.; 2912 inches; 4180-9 lbs.

38— 110-45 feet; 115-83 feet.

39—81-5 feet.

40— -08; -164; 7-2; 4198-4 quarts.

41— 34-5(); 70-85; 3110-4 cubic inches.

42—1-49; -64; 899 grains.

80-9; 1-54;
.1 dioxide ;

43— -745; -32; 44-95; 2-98; 128; 1798; 1-44; -0
•GO ; 92-9 grains.

44 — 1555-2 cubic inches or 770 75 grains of cui.
and 17-28 cubic inches or 5*49 grains of nitrogen.

45 — -82 cubic inches or 298 grains of oxygen, and 1*0 cubic
inches or -509 grains of nitrogen.

40 --8; 1-8; 1-25; 13-55.

47— -81; 1-79; 1-24.

48—1 cubic inch; 2-6.

49— -01 cubic inch ; 2-7.

50—4-1; 6-43; 0-85; 891; 24-19 cubic inches.

51—523°; 1014°; 1505°.

52 147 0°.

53-412-7°.

54—34-15 inches.

55-32-77; 32-24; 31-01; 3041; 29-85; 2878; 23-98 grains.

50 — 225 heat units.

57—1800 heat units.

58-92° ; 1200 heat units.

59— 7| ounces ; 50 heat units.

00—17 minutes 12 seconds.

61 — 1 hour 13 minutes 80 seconds.

62—17 minutes 55 seconds.

63— 212A.

64 — 40 15 degrees.

j

319

e inch,
lixture

fore the

)-9; 1-54;
dioxide ;
1-C cubic

Igrains.

66 — 6 heat units.

60—72"; 140 heath nits.

67— 10175 ; 70-25"; 6643".

68— 1746 lbs.

69-136-2".

70— It will begin to freeze in 3 niinutea 1(> seconds, and wil
be completely frozen in 11 minutes 50 seconds more.

71 — 2 hours 31 minutes.

72-^r lb.

73—46-27".

74-75-5".

75—87267 tons.

76—18925 tons.

77—82009 tons.

78—24183 tons.

79— 3-9 grains; 25%; -76%.

80 — At a quarter past two dew begins to form, there will
be no hoar frost, ♦' ^r the temperature tails no lower than to 33".

81—83-84%; 43 37%.

82-C,i3, lb.; O, i^lb.

83— Ca, 1600 lbs. ; O, 040 lbs.

84— Ca, 10 lbs. ; C, 3 lbs. ; 0, 12 lbs.
* 85— C, 24 '1»8.; O, n4 lbs.

86—4; 5-5ibrt.

87— With 8 lbs. of oxygen, forming 9 lbs. of water.

88— Ca, 30 lbs. ; C, 9 lbs. ; O, 'Mi l])s.

89— CO,, 132 lbs. ; Ca, 120 lbs.

90— C, 48 lbs. ; O, 64 lbs.

91 — 14 lbs. of carbon monoxide unite with S lbs. of oxygen
to form 22 lbs. carbon dioxide.

92 — Iyj oz. of O will be needed ; ^ oz. of H.^O and I/5 oz. of
CO2 will be formed.

93—37-1 grains.

94— I60Z.; 14 oz.; 22 oz.

95—6-17; 98-71 ; 8637; 135-73 grains.

96—145-59 lbs.

97—819-6 lbs.

98—16; 1-1088.

99—14; -9702.

100 — (a) That two volumes of hydrogen and one of oxygen
make two volumes of vapour of water; {b) that oxygen is
bivalent ; (c) that the specific gravity of vapour of water is nine
times that of hydrogen, and compared with air is -6237 ; {d)
that water consists of two parts by weight of hydrogen united

m

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320

with sixteen parts by weight of oxygen, or, more simply, one-
ninth of the weight of water is hydrogen iftid eight-ninths is
oxygen; {e) that three volumes of hydrogen and one of nitro-
gen make two volumes of ammonia gas; (/") that nitrogen is
trivalent; (g) that the specific gravity of ammonia is eight
and a half times that of hydrogen, or, compared witli air, it is
•589; that ammonia consists of three-seventeenths hydrogen
and fourteen-seventeeiiths nitrogen. See pages 57, 58, 77, 80,
81 and 83.

101— U'^joz.

102—0; 8 ; 8»j ; 55'4 ; 1777^ lbs. H, 1 ; 1^ ; 6-9 ; 222| lbs.

103 — 1 volume H, 1 volume N, 3 volumes O; by weight 1
part H, 14 parts N and 48 parts O.

104—384 lbs. O; 112 lbs. N; 8 lbs. H.

105—35-5 and 2-46.

106—16.

107-4-176 oz. and -882 oz.

108—1 volume each of H and CI make one volume HCl ;
2 parts in 73 by weight are H, the rest being chlorine; 1265.

lU9-36if lbs.

110—22; 1-5246.

Ill— About six ten-tliousandths.

112— 27 -m; tons.

113—7-54 tons.

114—80 lbs.

115-l.»lbs. S; 32« lbs. O; U lbs. H.

116—32; 2-218.

117—2 lbs. 8 oz. ; 4 lbs. 7 oz.

118—1 lb. 11 oz.; 6 lbs. 2 oz.

119—23 oz. Na ; 8 oz. O ; 8^* grains II.

120— 4() lbs. Na ; 71 lbs. (1 ; 7 ft. 8 in. high.

121— (a) 2.,".j oz. ; (/>) 3.'.5 oz. ; {c) 3,,^., oz. ; (c/)5.,^- oz. ; {e) S\^
oz; (/)5J\, 6z.; (f/)3/, oz.; (//)2;?|oz.; {i) 2|;j oz.

122— ;«) 2K + 0=K,0; (/>) K + H,0 = H + KHO; (c)K + Cl =
KCl,orK,0 + 2HCl = U,0 + 2KCl, orKHO + HCl = H20 + KCl;
(d) K2O + 2HNO3- H,0 + 2KNO3 orKHO + HN03= H2O +
KXO3 ; ('') K20 + H2CO3 = H20 + K2^'^3= water and potassium
carbonate,or K HO + H 2CO3 = H20 + KHCO3 = water and hydro-
gen potassium carbonate; (/) 1^2^ + ^2804 = 1120 -}-K2S04 =
water and potassium sulphate, or KHO + H2SO4 = H20-f-
KHS04 = water and hydrogen P=t issium sulphate ; {g) either
K 2O + 2H 3 P04 = H20 + 2KH 2^04 = water and two molecules of
mono-potassium phosphate, or KIIO + H,l*04 = H2O +
KH2PO4; either K2O+ H.,P04 = H20 + K2HP04 = water and

821

iths is
" nitro-
(gen is
J eight

ir, it is
drogen

,77,80,

39.

eight 1

ne HCl ;
. 1-265.

I ; {e) ^\t

i)K + Cl =
^,0 + KCl;
1= H2O +
jotassium
fndhydro-

Ug) either
klecules of
1= H,0 +
vater and

bi-potassium phosphate, or 2KH0 +H.PO4 = 2H20 n-KaHPO^
either 3K2O+2H3PO4=3HaO+2K8P04= three molecules o
water and two molecules of ter-potassium .phosphate, or
3KHO+H3P04 = 3H20+K3P04.

123 — S^ oz. ; 9 frrains ; 56 grains.

124— 14 lbs. N; 39 lbs. K.

125— $87-92.

126 -$4-98: $4-18; $3-14; $3-:^9 ; $269.

127 $63*27.

128~(a) 829|l grs. K, 170}2 grs. O; {h) m^ jjrs. K, 285i grs.
O, 17^ grs. H ; (c) 523^/, grs. K, 47(Ji^7, ^r^- <'l ; ('0 386rVj grs.
K, 475AV grs. O ; ISS^^^, grs. N; (0 448^^ grs. K, mu grs. O;
183|2 grs. S; (/) 286IJ grs. K, 470fU grs. O ; 235 jV grs. S ; 7^
grs. k ; (g) 565^\ grs. K, 347 .If grs. (), SiV^ grs C ; {h) 390 grs.
K, 480 grs. 0, 120 grs. C, 10 g"rs. H ; 0) 286[^ grs. K, 470} I! grs.
O, 227if grs. P, 14rf grs. H ; ( j) 448,«, grs. K, 36711

grs. K, 301

) J

grs. O,
grs. O, imj

178Ji grs. P,5|-5 grs. H; (k) 5511,
grs. P.

129-71f lbs. Ca; 28| lbs. O.

130—71 lbs.

131—44 lbs. CO, will be absorbed; 18 lbs. H.O will be set
free and evaporated ; 100 lbs. Ca(X)., will remain.

J 32 1 ^-'^ lbs.

133— 60 'lbs. Mg ; 40 lbs. O.

134—10661 lb. O; 933', lb. Hi.

135—529-4 grains.

136— All tlie differences cannot be given liere; but, from the
proximate analysis of wheat grain tlie ultimate analyses
deduced would be (', 389-4 ; O, 370-3; 11, 546 ; N, 208 ; and of
wheat straw C, 3632 ; O, 383-7 ; H, 51 4 ; iN, 3-4.

137— (a) 34795 tons; (b) 10534-8 tons; (r) 485-9 tons; (rf) 27-5
tons ; {e) 7-5 tons ; (f) 91-7 lbs. ; {g) 54 tons.

i:~8 — 1-07 inches.

139 24'24 lbs.

140-7700 lbs.' of CO, ; 68 lbs. of NH3 ; 2232 lbs of H2O;
6416^ tons.

141— A little more than 187,.

142-92* lbs.

143-121 a lbs.

144— Loam.

145 — Sandy loam.

146— Loani.

147-Sand.

148 — Strong clay.

1^,

M: U

h

1

1

\

1

i

i

m

322

149—911 lbs. per cubic foot; 3996630 lbs. per acre, one foot
deep.

150—80 lbs ; 3484800 lbs.

151— 277500 lbs

152 — Orjranic matter, 194 tons; silica, 1296 tons; alumina,
114 tons ; lime, 118 tons ; magnesia, 17 tons ; oxide of iron, 122
tons ; oxide of manganese, 2 tons; potash, 4 tons ; soda, 8 tons;
chlorine, 4 tons; Kulphuric acid, 4 tons; phosphoric acid, 9 tons;
rarbonic acid, 80 tons.

153-102^ loads.

154— $550.

155— $456.

156— -14.

157— -16.

i:)8— -473;

159— -605 ;

160 --35.

161 -800 rods.

1()2— 880 rods.

I(i3~^)80 rods,

164—

As in 161

426 ; -4 ;
57 : '55 :

•453.
•59.

((

162

((

163

Depth,
with collars
without "
with
without
with
without

(<

4 ft.
$640
$600
$704
$660
$544
$510

'A ft. 6 in.
$61600
$576-00
$677-60
$633-60
$523-60
$489-60

3 ft.
$584-00
$544-00
$642-40
$598-40
$496-40
$462-40

2 ft. 6 in.
$544-00
$504-00
$598-40
$554-40
$462-40
$428.40

165— $4800.
1(>6— $1022.
167- 9}2 7„.
168—2-21 7„; $99-20.

169 — In the former case he will gain 5c per acre, in the latter
he will lose 10c per acre by ploughing in buckwheat.
170 -$3-70.
171— $1-48.
172— $24-50.
173— $42.
174 -$33-50.
175— $37-50.
176— $23-00.
] 77— $31-40.
178— $37-50.
179— $79-00.
180— It was worth onlv $42-25 a ton.

3ne foot

iluinina,
ron, 122
,, 8 tons ;
il,9tons;

323

181 -$7110.
182--$i8-90.
183-$i.2«.

184— $20.
-'.'■'; nfa^ef'^SS,"' "l„?Toc' ""t^.'^f '"^v''- = ""t". '2<-- ; rye

oat 'traw^^S3r'r;e''Xf \T'-f •'"' ''"^'^y «"•»»•, $2M6-
straw, $4-79 ;timotiryi,ay**i'7f'.l^,i T" '■"'"'«• «'''-*2; pea
.nai.e, 7ne.; g,«en r^el-5* grien .'a^al!!. r"' ' *»52; sr^n

H , ^i. , (arrets, ll/c; mangolds, 9 7c.

2 ft. 6 in.
$544-00
$504-00
$598-40
1554-40
$462-40
$428.40

the latter