First lessons in scientific agriculture for schools and private instruction

TTfc- q { ?(o

LOVELL'8 SERIES OF SCHOOL BOOKS.

FIRST LESSONS

w

SCIENTIFIC AGRICULTURE.

FOR SCHOOLS

PRIVATE INSTRUCTION

BY J. W. DAWSON, LL.D., F.R.S.,

PBINCIPAL OF M'GILL UNIVBRSITY.

PRINTED AND PUBLISHED BY JOHN LOVELL,
AND SOLD BY ROBERT MILLER.

^axonio :

ADAM MILLER, 62 KING STREET EAST..
1864-

Entered according to the Act of the Provincial Parliament, in
the year one thousand eight hundred and sixty-four, by .
John Lovbll, in the Office of the Registrar of the Province
of Canada.

PEEFACE.

The writer of this little book had, in his youth,
some opportunities of becoming familiar with agricul-
tural operations ; and read with eagerness and enthu-
siasm those remarkable works of Liebig and Johnston,
which in 1840 and the following years revived through-
out Britain and America the interest in the apphca-
tions of chemistry to agriculture which had been
awakened by Sir Humphrey Davy. It was subsequent-
ly his duty, as Superintendent of Education in Nova
Scotia, to make an eflFort to introduce the teaching of
agricultural chemistry into the schools of that Pro-
vince ; and more recently it has fallen to him to com-
municate 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 study of Scientific Agriculture into their
schools, and also as a manual for young men who may
be pursuing the subject as a branch of private study.
It is designed to place before such persons the facts
and principles which the experience of the writer hag

IV PBBPACB.

shown to be most important in relation to the existing
state of agriculture in British America.

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 olass. 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 receive 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 elemen-
tary. It makes np pretension to c6|npletene3s, 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 profitable ;
and the writer would advise both the teacher and the
practical farmer desirous of obtaining a more full
acquaintance witli the subject, to add to their libraries
as many as possible of the larger agricultural bopksp,
of which so many are now accessible.

Tlie writer ackjiowledgcs with thanks his gbligatiojas
to Br. T. Sterjiy Hunt, Professor of Applied Ch(fmis-
Htry in lyfcOIll tJnivcreity, and to pROF. Robins of the
McGill Normal School, for rnnny valnablo siiL't^'stifJiis

and correciions.

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CHAPTER I.

■-' '"J'AGE

T/te Science of Agriculture and its uses 9

Nature of the subject .i.>.^ 44 w/«;i.i 9

What may be taught iQ,89h^o|„,^^f,„,^^.,^,,,^,,^^„,f,.,j^,,,U
Uses of such teaching............. .gj.^,.,^„^^,^^j^^,^, 13

CHAPTER II. /, <,Wij,3,Y

ifow may Scientific Agriculture be best taught in skhoUtWiiiJiy^ 15

General Views ....w.. ...; . ....;..;. .. ;...'.".';'' 15

Order to be pursued 17

III / 31,1 ru, II >
CHAPTER III.
Chemical Combination and DecompositibH h ."nk jg ...... .^ . . 20

CHAPTER IV.

Simple aubstances of which pUnis consii^W 24

Organic and Inorganic substances. ,. W<?' a^V

Organic part of the plant. . ►.8lJt>il.)o j;ifiji0.bo(t.wU*V! 25

vi CONTENTS.

CHAPTEB V.

TX0M

Soureet of the Organic food of Plantt 30

Air and water 30

Compounds of Carbon 35

Compounds of Nitrogen 36

Organic compounds .'. 40

Recapitulation 45

CHAPTEB VI.

Structure of Plantt 46

General Structure 46

The Root 47

The ascending Sap, the Stem 50

The Leaves 51

The Bark 54

CHAPTER VII.

Organic compoundt produced by Plantt 56

General Statements 66

Neutral non>nitrogenized substances* . •• 66

Vegetable Acids 61

Nitrogenized substances 63

Conclusions as to the food of plants 65

CHAPTER VIII.

TTu atket of Plantt 6t

Composition of the Aihes 61

Utet of the Asbei 70

CBAPTEB IX.

TktSoU '*

Nature and Origin of 8oill '^<

CONTENTS. tU

Fasb

Arrangement of soils according to mechanical textare. 15

Arrangement of soils according to general chemical

characters 76

Arrangement of soils according to degrees of fsrtilitj. 77

Causes of fertility and barrenness 78

Rotation of Crops 80

Absorbent power of the soil 85

CHAPTER X.

Exhaustion of the Soil 85

Causes of Exhaustion 85

Exhausted soils of Canada 89

CHAPTER XI.

Improvement of the Soil 96

Tillage, &c 96

Draining 98

CHAPTER XII.

Manures 103

General nature of Manures 103

Organic Manures 104

Mineral Manures 117

CHAPTER XIII.

C'ops ^ 130

Wheat 130

The Oat 142

Rye 149

Barley 145

Tin CONTENTS.

Indian Corn 145

Buckwheat 147

Beans and Peas 148

Turnips, Carrots, Mangel Wurtzel, &c 150

The Potato 158

Clover and Grasses 168

Flax, Hemp, Broom Corn, &c 1*72

Orchard culture 175

CHAPTER XIV.
Suggestions as to Practical Applications. .' 182

Appindix 188

1. Application of Meteorology to Agriculture 188

Average number of rainy days, 188

Means and extremes of temperature 190

Periods of Vegetation 191

2. Directions for performing experiments 192

Elements and food of Plants 192

Composition of soils 197

3. Rotation of Crops for Canada 201

FIRST LESSONS

IN

SCIENTIFIC AGRICULTURE.

CHAPTER I.

THE SCIENCE OP AGRICULTURE AND ITS USES.
§1. Nature of the subject.

In our time all useful arts are more or less'closely con-
nected 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 may 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 process, the conditions, in
short, of existence and of action which the Creator has
imposed on the things which He has made. Such know-
ledge must be eminently practical : it is truly power, inas-
much 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 scientifio investigation, and broken in and

9

10 SCIENTIFIC AGRICULTURE.

harnessed for the use of the practical man ; and every day
new uses of substances, improvements ai' processes, adapt-
ations of machines, are being carried out ; while every
new fact or principle utilised brings in its train the uses
of others.

All this appUes eminently to Agriculture. The fanner
is not a mere manual laborer. He has to do with soils of
complex composition, liable to ruinous deterioration and
susceptible of great improvement. 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 uf things cast aside as worth-
less by other artists, that most valuable of all products —
human food. His skill and knowledge make of the desert
a fruitful field ; his ignorance and carelessness may reduce
the most fertile fields to desolation. Above all, the farmer
is an independent workman. Isolated on his farm, he has
to judge for himself in many cases of doubt, — has to plan
his own processes, and to adapt them to his own circum-
stances. In older countries, farming, like great manufac
tures, 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 iudepondeut small
farmers of a country like this must have the intelligence
to manage as well as the skill to work.

None of the arts have derived greater benefits from
Bcienoe, and especially from chemistry, than agriculture.
Soils, manures, and plants have been analyzed ; the causes
of fertility and barrenness, of running out and impoverish-
ment, the means of supply of Uic most valuable consti-
tuents of crops, the enemies and diseases of cultivated
plants, and many similar subjects, have been thoroughly
investigated ; and the result has been that agriculture has
be(X)mc a scientific jirt, and has been brought to a pitch ol"
profitable i)crrectiou that our grandfathers would have
deemed chimerical. But knowledge uf this kind is yet
^oly partially diffused. While In some countrios, by the

INl'RODUCTION. 11

application of scientific knowledge, land that has been cul-
tivated for ages is being brought back to its original fer-
tility, and its produce vastly increased ; in others, through
neglect or ignorance, the most fertile regions are gradually
becoming unproductive.

In our own country there can be no question that m\ich
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 change in this, the mind of the farmer must be
reached in order that his practice may be improved. But
that this may be effectually done, the rudiments of agri-
cultural science must be taught to youth j and the ques-
tion for the educator is — How, and to what extent, can this
be done ?

We must in this carefully avoid encouraging delusive
hopes, or professing to do that which we cannot satisfac-
torily accomplish. We cannot, in the ordinary schools,
train practical chemists or practical fai-mers. Practical
chemistry is a profession to be studied by itself, and re-
quires a long and careful apprenticeship for its successful
pursuit. The practical labor of the farmer can be learned
only on a farm. The teacher must propose to himself the
more humble task of instilling into the minds of the young
the rudiments of the science of farming, and thereby pre-
paring them better to understand its practical processes. —
Let us inquire what he may do in this way :

§2. What unay he taught hy the school teacher.

1. He may teach of the Soil ; of its derivation from
the rocks of the earth ; of its wonderful and complex
composition ; of its action on manures, in retaining them
within it, and parting with them to the roots of plants j of
the causes of its fertility and barrenness ; of its impover-
ishment by cropping; of its improvement by tillage, by

lt~ SCIENTIFIC AGRICULTURE.

draining, and by the application of vaiious substances to
it. He may enter into the reasons of all these, and their
bearing on the practical work of the farmer, on his suc-
cesses, and on his failures ; £>nd may show how the latter
might often be avoided by a proper understanding of the
causes which lead to them.

2. He may teach of the Plant; of the elements of
which it is composed ; of the sources, in the earth, the air,
and manures, 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 materials on which it subsists, the various pro-
ducts which it affords. On these subjects the discoveries
of chemistry and physiology enable us to speak with much
contidence as to the requirements of each crop, and its
relations to the soil, to the air, and to manures, as to
the uses of rotation of crops, and of special manures, and
as to the causes of deficient produce , with many other
important points, which, but for such knowledge, would be
involved in doubt and darkness.

•^6. He may teach of Manures; — a subject hardly less
interesting than the previous topics, and (juitc as useful.
Here we have to consider the decay of dead vegetable and
animal matter, and its resolution into food for plants ; the
losses to which the richer organic manures are liable ; 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. No subject lias in our day more engaged the atten-
tion of chemists, and in none have more important discov-
eries been made.

^ . 4. He may teach of the several Cultivated Crops in
detail, noticing their history, their modes of culture, their
preferences in relation to soil, treatment, and manure; their
produce — it* uses to man and animals — and their enemies
and diseaBCB. Ho may, in like manner, proceed to apply
the principles learned under these heads to the various
modes of tillage, manuring and rotation, and to the treat

INTRODUCTION. 13

nieufc and feeding of domestic animals. In this more
practical department, the amount of instruction need be
limited only by the knowledge of the teacher and the time
at his command.

All these topics lie at the very threshold of agricultural
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 build the highest and most successful
prosecution of the most useful of all arts.

§3. Uses of such teaching.

The advantages of such a course to the young mind arc
many and great. It leads to the consideration of all these
processes by which the great Husbandman above produces
out of the earth food for every living thing, as well as to
those humble imitations of them by which man seeks to
eifect similar results on a smaller scale. In this point of
view, as a means of enlarging the mind, and enabling
it to reason 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 young farmer ta
read with advantage the best works on his art, and to
judge for himself as to the application of their statements
to any particular case. Book farming is little respected by
many good farmers, and, to some extent, deservedly so.
Few agricultural books, and still fewer articles in agricul-
tural periodicals, are really reliable. They too often state
facts or experiments without appreciation of the conditions
on which success or'failure depended. 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. Eveft good agricultural works require a
certain amount of knowledge in those who read them. The

t4 SCIENTIFIC AGRICULTURE.

plainest statements may be misapprehended by a reader not
acquainted with the precise meaning of the terms in which
they are expressed. The most carefully guarded explana-
tions 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 disgrace 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 it. The intelligent young farmer
should have enough of scientific culture to enable him on
the one hand to distinguish the half truths so often pre-
sented from a complete statement of the facts and prin-
ciples 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 also be suflGicient to enable the farmer to
decide as to the application of artificial manures, and
to avoid the losses caused by error and fraud in the
use or manufacture of such materials. It will enable him
to know 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 preservation and improve-
ment. It will teach him to appreciate the requirements of
the different crops and domesticated animals, the special
'uses of their varieties, and the diseases to which they are
liable. It will give him enlarged views on iigriculturo as
practised in various countries and under different circum-
stanoes, as susceptible of a vjist 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.

CHAPTER II.

HOW MAY SCIENTIFIC AGRICULTURE BE BEST TAUGHT
IN THE SCHOOLS?

§1. General vleios.

That agriculture is the most important of the arts; that
in this country it is the occupation of the majority of the
people ; that all are largely interested in its success, and
that this success is connected with the diffusion of intelli-
gence and scientific knowledge, every one will admit ; but
on the questions whether it can be usefully taught in our
schools, and in what way, and to what extent, there may
be some diversity of opinion.

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 i's a legitimate part of the
business of the teacher, to connect, as far as may be, the
subjects of his instruction with the practical work of life,
and especially with those portions of it which are very
generally pursued. He cannot teach the practice of agri-
culture,— that must be done in the field, — but he can
explain its theory, or, to speak more strictly, the natural
laws on which its operations depend.

Much popular misconception exists as to the relation of
theory to practice in the industrial arts. There is a ten-
dency 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 des-

H SCIENTIFIC AGRICULTURE.

titute of any sound reason. The truth lies between these
extremes, and may be illustrated by a familiar example
from another art. A practical seaman must be able
to perform 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 as to the theory of navigation. 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 ship is equally
helpless without practical skill and without science. Both
must be present. It is just so with farming. The farmer
must know the practical operations of his art — how to
plough, to harrow, to sow, to reap ; but he may know
and industriously practise all these, and yet may be run-
ning his farm to ruin as surely as the seaman would his
ship, if he knew not his course and distance. Here sci-
ence 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 requirements of
different cultivated plants; the nature and uses of ma-
' nures ; the causes of sterility and impoveri.-^liment, and the
cheapest and best modes for remedying the one and avoid-
ing the other ; and the materials necessary to renovate
lands that have been already exhausted.

These teachings of science are, further, not merely clever
goeeses and conjectures, but the results of long and patient
inquiry into facts, made by the practical chemist or phy-
siologist, wlio, cacli in his several way, is just as m\ich a
practical man as the farmer.

It is this Hcicntitio aspect of farming which oau be
taught in the schools. Wo can teach the Jbearing of
modern soieutitic discoveries on the improvement of the art,
and we can thereby elevate the profession itwolf, make it
looro attractive to yoting perstnH, and (jontributc not t\

MODE OP TEACHING. 17

little to the industrial wealth of the country. And let it
be observed, that while on the one hand agricultural edu-
cation tends to the improvement 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 business of life, and improving and rendering
more productive an art on which education mainly depends
for its pecuniary support.

For such reasons as these, while in all the more en-
lightened countries there are special agricultural schools
and colleges, and model farms, where the science of agri-
culture may be prosecuted in all its details, efforts are also
made to introduce the elements of the subject into the
Common 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.
The amount of agricultural knowledge communicated in
this way is confessedly slender. Only the merest rudi-
ments can be taught ; yet the wide diffusion of even a
small amount of knowledge of principles, and the thought
and inquiry which this engenders, may be of incalculable
value to the country. Admitting, then, that the elements
of this great subject may thus be taught, our next inquiry
is — How may this be best done ?

§2. 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 disadvantages. It is some-
times best to begin with general principles and rules, and
illustrate them by examples ; sometimes best to begin
with known facts, and follow these up to general prin-
ciples. Further, in any complex subject it may often
be difficult to explain one part of the subject without
reference to others with which the learner may not be
acquainted, Now, that we may ascertain the best order

18 SCIENTIFIC AGRICULTURE.

for proceeding with our present subject, let us consider
the things with which we have to do. The objects of agri-
culture are to obtain from the soil the largest possible
amount of valuable food for men and animals, and, in
connection with this, to preserve the soil in such a con-
dition that it will produce other crops in future years, and
to apply the food produced in the most economical and
useful manner. In attaining 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 subjects the farmer naturally regards in the
light of experience, and with reference to practical opera-
tions. What we have to do, is to bring to bear on their
explanation and improvement, the facts and principles
ascertained by chemistry, physiology, and natural history,
and more especially by the first of these sciences. Agri-
cultural chemistry, in short, is of more importance than
agricultural physiology, botany, zoology, or geology, though
all of these are useful. We shall, therefore, make this
our basis, and bring in the other subjeotfl as we proceed.
Having laid for the learner a foundation of such chemical
knowledge as may appear indispensable, we shall consider
the Plant, the Soil, and Manures ; and having discussed
these, shall proceed to apply the knowledge thus acquired,
to the crops cultivated by the farmer, and to other points
of agricultural practice not previously noticed.

Our arrangement may thus be as follows : —

I. We shall notice the general principles of Chemistry,
in 80 far as absolutely necessary for our purpose.

II. We shall consider the Plant, in the following ai-
ipects: —

1. The composition of its organic part, and the

souroes of it* food.

2. rts structures and functions. ,
15. Itii organic products.

4. Its inorganic part or asbch.

MODE OF TEACHING. 19

III. We shall consider the Soil in the following par-
ticulars :

1. Its origin, and the classification of soils.

2. Its composition, and deductions therefrom.

3. Its exhaustion by cropping.

4. Its improvement by tillage, draining, &c.

IV. We shall treat of Manures, as

1. Vegetable and Animal.

2. Mineral.

V, We shall consider Cultivated Crops, with their
various habitudes and diseases. »

VI, We shall give some practical examples of the uses
of the subject.

According to this arrangement the more theoretical part
of the subject will come first ; but the reader interested in
the practice of agriculture should bear in mind that the
earlier parts, though apparently less practical, nevertheless
contain the principles necessary to the understanding of
the rest.

CHAPTER III.

CHEMICAL COMBINATION AND DECOMPOSITION.

. Instead of explaining the general principles of chemistry
in a formal manner, we shall take a familiar example and
deduce certain conclusions from it. If we take 100 pounds
of pure limestone, and expose it for some time to a red
heat, an invisible air or gas escapes from it, and at length
we have only 56 pounds of quick 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, and it will also be found to consist of a peculiar
substance known to chemists as Carbonic Acid. Limestone
therefore is a compound substance, and can be decomposed
or separated into two other substances. But this process
may be carried still farther. We can obtain from the
44 pounds of Carbonic Acid, 12 pounds of Carbon or
charcoal, and 32 pounds of a gas named Oxygen, and from
the 56 pounds of quick lime 16 pounds of oxygen and 40
of a metal named Calcium. Here then we nave)

12 Carbon and 32 Oxygen, forming 44 Carbonic Acid.
40 Calcium " 16 Oxygen " 66 Lime.

Forming, when united 100 Limestone or Car-
bonate of lime.

First, it is evident that such a union is not a more
mixture of carbon, calcium, and oxygen ; it is that more
intimate union termed Comhination, and wo see that when
two }>odiea tlins romiinr, the result is a. third si(hsta7icn
very different from eilhttr.

COMBINATION AND DECOMPOSITION. 21

Secondly. If we take a number of specimens of pure
limestone from all part's of the world, we shall find them all
to consist of the same substances, and in the same propor-
tion ; or if we form carbonic acid or lime by causing their
ingredients to unite, it will be found that weights of these
corresponding to those which are found in limestone, are
alone capable of combining to form these substances.
These ingredients therefore, combine in uniform and defi-
nite proportions.

Thirdly. If we put some pounded limestone into a glass,
and pour upon it a little sulphuric acid or oil of vitriol, an
effervescence or boiling up will take place, in consequence
of the carbonic acid of the limestone escaping, and after
this has subsided, we shall find that the sulphuric acid has
combined with the lime, forming sulphate of lime or gyp-
sum. In this case, then, the sulphuric acid has expelled
the carbonic, in order that it might itself combine with
lime. The tendencies of bodies to combine with each other,
are then not equally powerf id, so that previously existing
combinations may be decomposed by the addition of new
substances.

Fourthly. After having decomposed limestone* and
obtained carbon, calcium, and oxygen separately, we cannot
decompose these three substances, or separate anything
farther from them ; they are therefore termed simple or
elementary bodies.

Fifthly. It is found that these principles apply to nearly
all the objects known to us : that these arc, like limestone,
compound bodies, and that they arc all composed of a limited
number of simple substances, or Elements, which may be
arranged as follows :

5 Gases— Oxygen, Hydrogen, Nitrogen, Chlorine, Fluorine.

10 Liquids or Solids at common temperatures, — non-metallic,
Sulphur, Selenium, Phosphorus, Bromine, Iodine, Carbon,
Boron, Silicon, Arsenic, Tellurium.

46 or more Metals. — Potassium, Sodium, Magnesium, Alum-
inum, Calcium, Manganese, Lead, Iron, Copper, &c.

Some of these simple substances are familiarly known in
an uncombined state, for example sulphur and copper; but

2» ^lENflFIC AGRICULTURE.

the greater number arc found in nature only in different
forms of combination.

Let us now sum up what we have learned from our piece
of limestone. It has taught us that all substances may-
be resolved into elements which can no longer be
decomposed, that these elements tend in different degrees
to combine with each other ; that these combinations take
place in certain definite proportions ; that the compounds
produced differ materially in their properties from the
elements of which they consist ; and lastly, that these com-
binations may be decomposed or again broken up into their
constituent elements.

We may state these truths as follows :

(1) There are about sixty different kinds of matter
known to chemists,and named simple substances or elonents,
because none of them can be further decomposed or sub-
divided.

(2) These elements have a tendency to combine with
each other and to form compounds; this tendency is
termed the force of chemical ajfinifi/.

(3) When elements combine with each other they unite
in definite proportions ; and in this re^pqct combination
differs essentially from mere mixture.

(4) When clcmeuta combine, the jwopcHics of the res-
ulting compounds are ({uite different from tJwsc of the
constituent elements. In this also coimbination differs from
mixture.

(5) Tvfo or more compound substances may combine
with each other, forming uioro complex couijtouuds. Tiui>
also takes place in definite proportion.^, and produces sub-
Htances having properties different from those of their
conatitueut.«.

(0) Compounds may bo decojupoml into their consti-
tuent elements, and these may bo caused to recvmbine ae
before, or to tmter into new coinhinalions,

(7) As the affinities of substances for each other' art
pot all equally strong, the intruducliou oi'u now substance
may cuutio u compound to be broken up, and the new sub-
Htanco may take i)<)HHes.sion of one or moro of the elcmonts
present and combine with thoui.

COMBINATION AND DECOMPOSITION. 23

(8) It is the business of chemistry to analyze com-
pounds, or separate their constituent elements, and ascertain
the proportions and properties of these,and on the other
hand by synthesis to form combinations from their elements.
It further applies the knowledge thus obtained to the
explanation of all chemical prooesses in the arts and in
nature.

We have in these statements arrived merely at the thi'esh-
old of modern chemistry ; but if these few facts and prin-
ciples are fixed in the mind -they will enable us to proceed.

In accordance then with these preliminary statements,
plants must either be simple or compound. If compound,
which it can easily be shown that they are, they may con-
sist of two or any additional number of elements, and
farther, they may all consist of the same elements, or some
may consist of one set of elements and others of another.
Farther, if they consist of the same assemblage of elements,
these may be in the same proportion or in diiferent pro-
portions ; and lastly, they may be combined into certain
compounds, which again may be united to constitute the
plants. "We shall in the next chapter proceed to give
answers to these questions.

CHAPTER IV.

SIMPLE SUBSTANCES OP WHICH PLANTS CONSIST.
§1. Organic and Inorganic Substances.

All the fonns of matter which we observe on the globe,
may be divided into two great classes, Organised and
Unorganised matter. To the latter belong all those rocks,
waters, metals, and other substances, which neither are nor
liave 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, &c. These compouds,
being produced by organised bodies or 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 gradually disappear.
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 struc-
tures. It consists however of substances which the plants
have taken from the soil unchanged, and which are therefore
inorganic. By the mere application of heat in presence of
air, or by burning, wo can thus separate the mass of any
organized body, a plant for instance, into two groups of sub-
Btanccs, — the organic, which usually constitutes the greater
part of tho mass, and which burns entirely away, and the
inorganic, or earthy part, which remains as the ashes. Tho
inorganic matter oontainod in tho ashes of plants, though
bj no mwDi of SMondury importance in agriculture, may

SIMPLE SUBSTANCES. 25

be left for the present unnoticed, while we attend more par-
ticularly 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 but of 60 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
(with the exception of their inorganic matter) of but four of
these elements. Carbon, Oxygen, Hydrogen, and Nitrogen.
The same remarks apply, with equal truth, to animal
substances. The following table shows the proportions of
these elements contained in some of the most common ob-
jects of cultivation :

Carbon. Oxygen. Hydrogen. Nitrogen. Ash.

Wheat 455 430 5"? 35 23

Oats 507 3G7 64 22 40

Hay 458 387 50 15 90

Turnips 429 422 56 17 76

Potatoes 441 439 58 12 50

The numbers above refer to 1000 pounds of each seed or
plant, thoroughly dried.

" To the agriculturist, therefore, an acquaintance with
these four constituent parts of all that lives and grows on
the face of the globe, is indispensable. It is impossible ibr
him to comprehend the laws by which Ihe operations of
nature in the vegetable kingdom are conducted, or the reason
of the processes he himself adopts in order to facilitate or
modify these operations, without this previous knov/'e,dge
of the nature of the elements— of the raw material.^ as it
were — out of which all the products of vegetable j>Towih
are elaborated."* First then we shall notice the pronertias
of these four elements of organic matter, and shall then pi o-
ceed to enquire whence they can be obtained by plants.

1. Oxygen — In its pure state, is a gaseous or aeriform
substance, void of co^or, taste and smell. It may be dis-

* Johnsto»'s Lectures.
3

26 gCIENTiriC AGRICULTURE.

tinguished 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,
and enters into many mixtures and combinations. It
constitutes 23 per cent, of the weight of the atmosphere,
where its presence is necessary to the breathing of animals,
and the support of combustion. It exists iu 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 of the ores
of other metals, and the majority of rocks and earths com-
prising the surface of our globe, 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, and of the bodies of its animal
and vegetable inhabitants. It will be seen from the table
above, that it constitutes more than one-third of the weight
of most vegetable substances.

2. Carbon — 14 most familiarly known as common wood
charcoal, which consists of carbon with a small mixture of
potash and earthy and other matters ; it also exists in large
quantity in mineral coal ; black-lead is almost pure carbon ;
and the diamond exhibits it in its purest form. The
diamond differs from wood charcoal only in being more pure,
tnd in a crystalline''^ state. I'orous charcoal, or that of

* If we throw common salt into water, it is dissolvod, that 19
it becomes dividud into minute particles, whioli nro dilT'iiRod
ttirougb tbo wutor. It 11 drop of this solution of utilt bo phictMl on
a piece of glaus, lu it dricH tliu particles of salt unite, and hii-
comt regularly arranged, forming little tronaparent cubes. Thin
if a cnritallitatton, and it may take place either in bodies v liidi
hare been dUioIred in water, or which liave been multfl i"
dlMipat«d bj heat.

SIMPLE SUBSTANCES. 27

wood or bones, possesses the remarkable property of absorb-
in"- from the air large quantities of gases and other exhala-
tions, hence its use in depriving putrid meat and other
decaying substances of their oflFensive smell ; it also absorbs
from water any organic substances which it may contain,
and even some of the inorganic saline substances. Many
of these matters afford valuable nourishment to plants ; and
as charcoal retains them mechanically, and is always ready
to give them to the roots of vegetables, it is a valuable in-
gredient in soils, preventing the volatile parts of manures
from being dissipated in the air. If in clearing forest land,
the wood or any considerable part of it, instead of being
wholly consumed, were burned into charcoal, and this
mixed with the soil, a permanent source of fertility woirid
be secured. Black vegetable mould and peaty matter,
which consist in great part of porous carbon, also possess
this property in an eminent degree.

When charcoal is burned it combines with oxygen, form-
ing carbonic acid gas, which disappears in the atmosphere ;
and when animals breathe, the oxygen of the air which
enters their lungs, combines with carbon derived from the
blood, and is returned to the atmosphere in this same form
of carbonic acid. This gas thus exists in the air ; and as it
13 soluble in water, it is found in rain and springs, hence it
affords to plants a supply both of carbon and oxygen : and
since carbon, in its pure state, is insoluble both in air and
water, this source of obtaining it is of the utmost import-
ance to vegetation, and will afterwards be particularly con-
sidered. Carbon constitutes from 40 to 50 per cent, of
the weight of dried plants.

3. Hi/drogen — Is, like oxygen, a colorless gas, without
taste or smell ; it is however 14 times lighter than air,*
and will not support life or combustion, but on the other
hand is itself very combustible. Combined with oxygen, it
forms water ; with carbon, it forms common coal gas ; and
with carbon it also exists as marsh gas where vegetables are
decaying in swamps. It also combines with sulphur and

• For this reason Hydrogen is used for inflating balloons.

28^ SCIENTIFIC AGRICULTURE.

phosphorus, and i^ these states is often disengaged from
bogs and marshes. The latter compound (Phosphuretted
Hydrogen) undergoes, when exposed to the air, a sponta-
neous combustion, and is the cause of the well-known " Will-
o'-the-wisp " or Ignis Fatuus. As hydrogen is not found
in nature in the state of purity, plants must derive that
which they contain from its compounds, and principally
from water.

4. Nitrogen — sometimes also named Azote, is a gas with-
out color, taste, or smell ; it does not itself burn, neither
will it support the combustion of other bodies ; and animals
and plants die when confined in it. It is less abundant in
nature than any of the other organic elements, yet it is
f«und in the bodies of all animals and plants, and is abso-
lutely necessary to their growth. It forms 77 per cent, of
the atmosphere, and serves to dilute the oxygen of the air,
and to prevent it from acting on both living beings and
dead matter, with too great violence and rapidity. Com-
bined with a large proportion of oxygon, it forms Nitric
Acid ; and in combination with hydrogen, it forms Am-
monia; both of which substances, as we shidl hereafter
see, perform important functions in reference to the growth
of plants.

It thus appears that three of the four elements which
constitute the solid structures of animals and plants, are, in
their pure state, invisible gases, and the remaining one is
identical with ordinary charcoal ; yet into how great a vari-
ety of beautiful forms and valuable products are thoy trans-
muted 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 j)art of tlu^ mass of
vegetables consists ol" substan(^eH composed of three; of tlie^e
elemonU) only — Carbon, Oxygen, and ]{ydrogen. Of tliis
nature are wood, starch, sugar, &c. The substances con
taining Nitrogen, or the nitrogenised substaDoes, are in
comparatively small quantity in plants, though of vast im
jK)rtancc, since they arc those on which the subsistence of
•nimals chiefly dopcnds ; pDr while tho organic part of iht'

SIMPLE SUBSTANCES. 20

plant consists chiefly of non-nitrogenised matter, that of the
animal consists principally of the nitrogen ised.

When we view this subject in relation to tlie food of
plants, it is apparent that while plants may possibly obtain
some supply of the organic elements in their simple state,
they must take them principally from those compounds in
which they exist in nature. It becomes therefore an object of
importance to ascertain the properties of these combinations,
the quantity and condition in which they are found, and
the degree of their utility to vegetation. The substances
most worthy of tonsideration in this point of view are, 1,
Atmospheric Air ; 2, Water ; 3, Carbonic Acid ; 4, Carbu-
retted Hydrogen; 5, Ammonia; (3, Nitric Acid; and
lastly, the vegetable and animal substances existing in
the soil.

CHAPTER V.

SOORCES OP THE ORGANIC POOD OP PLANTS.

In our last chapter, we noticed the four simple substances
which constitute the organic part of plants, and con-
cluded with naming several compounds or mixtures of
these which are found in nature, and may furnish food
to vegetation. These may now be considered in detail.

§1. Air and Water.

1. Atmospheric Air. — The air which we breathe, and
which everywhere invests the surftice of our earth, consists
of an intimate mixture of two of the simple bodies before
described, oxygen and nitrogen, in the proportion of 23 parts
by weight of the former to 77 of the latter. From the
account before given of oxygen, it is evident that its effects
on the blood of animals and on decay and combustion, are
too stimulating and active to permit the continuance of the
present order of nature, if it alone constituted the atmos-
phere ; while on the other hand no animal could breathe,
or organic substance decay in unmixed nitrogen. Our
atmosphere has therefore been wisely composed of a mix-
ture of these two substances, in such proportion that all
necessary processes, whether chemical or vital, may derive
from 4t neither more nor less support and stimulus than
they really require.

As the air consists of oxygen and nitrogen, two of the
constituents of planta, and as it surrounds on every side
their stems and leaves, and even penetrates deeply into the
earth aronnd their roots, wo might naturally suppose that
it aflFords part of tlieir nourishinent. Experiment, however,
appears fo show that plants derive neitlicr oxygon nor

ORGANIC FOOD OF PLANTS. 31

nitrogen directly from the air, though it certainly acts an
important part in producing and carrying to them other
nutritious substances. It is the vehicle in which several
of the substances next to be noticed are conveyed to the
leaves and roots, and its oxygen is the cause of all those
processes of decay by which the food of plants is prepared
in the air itself and in the soil.

2. Water — Is a substance indispensable to vegetation,
and which ministers to it in various ways: —

1st, Water serves as food to plants. In all growing
plants water is contained in an unaltered state, and its pre-
sence in this state is absolutely necessary to their growth.
But water is a compound of oxygen and hydrogen, so that
if vegetables are able to decompose it, they will thereby
obtain two of their constituent elements. That they can
do so, has been shown by cultivating plants in close vessels,
with their roots immersed in water, when it has been found
that the pknts so treated acquired* an increase of weight
which could only be accounted for by supposing that they
had employed part of the water in the formation of wood,
and other parts of their own structures.* It is even pos-
sible that water may thus be rendered solid in the interior
of plants, without any actual separation of its elements,
for wood, starch, sugar and gum, substances which enter
largely into the structures of plants, contain oxygen and
hydrogen exactly in the proportion in which they exist in
water, so that we ay consider wood, starch, and sugar as
consisting of wate. and carbon alone ; a view which will
cease to appear extra rdinary, when we think of the great
changes of appearance ;ind properties which always accom-
pany chemical combina:j(ii. From these and other con-
siderations, which will ap jcar as we proceed, it seems pro-
bable that water aifords to jlunts the greater part of the
hydrogen which they posset; s, and probably also a portion
of their oxygen.

2nd. Water acts as the vehicle by which other nutri-
tious substances are conveyed to plants. It is well known

* T. De Sausiure.

$2 SCIENTIFIC AGRICULTURE.

that a vast number of aubstauces may be dissolved lu
water ; the water therefore which is constantly entering
the roots of plants, brings with it a portion of every solu-
ble ingredient of the soil. When exposed to the air.
water absorbs from it carbonic acid, ammonia and other
gases, beneficial to vegetation, hence the rains and surface
waters always contain these substances, and carry them
along with them when they enter into the roots. Even
snow brings down from the atmosphere these nutritious
substances, and from its porous character absorbs them
from the air, so that the common opinion that it assists
in fertilizing the land on which it falls and is melted,
is not unfounded.

3rd. Certain substances, often present in soils, have
strong affinities for water, or tend powerfully to unite with
it. Thus, if upon quicklime a proper proportion of water
be poured, the lime still remains dry, but expands and
becomes warm, while, at the same time, it increases iu
weight to the amount of one third. The reason of this is
that the water has combined with the lime, and has
become solid. In like manner, common gypsum contains
20 per cent, of water in a solid state, though these
substances do not, in ordinary circumstances, yield up this
water for the use of plants. Common clay also holds
water iu its pores, and even in the driest weather, may
retain enough to keep plants green and flourishing, wlion
soils deficient in clay are completely jiarched.

Although water is thus essential to the growth of plants, ,
its presence in too great quantity, is in various ways in-
jurious to those which are usually cultivated. One of
these ways is that whou the soil is soaked witli water,
air is prevented from entering it, and we shall soon see
that this is of some consequence. Another is that too
much moisture imparts what is very properly named cold-
ness to a soil. If a dish of water be exposed to the air,
it gradaallv evaporates or dries up, and that it may tlius
pass into the state of invisible vapor, the water must obtain
ft large supply of heat, hence arises the chilling influence
of wet olothes, when applied to the body. The same etfcct

ORGANIC FOOD OF PLANTS. 33

is produced by the superfluous} water of a wet suil ; nearly
all the heat which such a soil receives from the sun, is
spent in evaporating the water, and if this be not removed
by draining, or enabled to soak downward, by the addition
of some less retentive substance to the soil, the crops on
such a field will always be liable to be chilled and stunted
in spring, to a degree which even the heat of summer may
be insufficient to repair.

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 cover-
ing of snow which protects our fields from the intensity of
the frosts in winter. Its relations to plants are so im-
portant and so beautifully adapted to the purposes which
they serve, that no apology will be necessary for devoting
a little time to their consideration.

It was befoi'e stated that heat is necessary for the
evaporation of water, — and when this heat is removed
from the invisible vapor 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 that this vapour, when it
touches a cold body, is reduced to the fluid state. These
simple facts will enable us to understand the general causes
of Dew and Rain.

In clear weather, the earth's surface and the air in con-
tact with 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 surrounding ob-
jects. After sunset therefore, the earth's surface rapidly
cools, until, at length, it becomes so cold that the vapour
of the air in contact with it, becomes condensed in the
form of deio, or if the cold be more intense, in that of
hoar frost. But different substances, when allowed to cool,
lose their heat with dilFerent degrees of rapidity ; and of
course, those which cool most quickly and thoroughly,
must collect the greatest quantity of water from the air.

81 SCIENTIFIC AGRICULTURE.

This property also forms the basis of an arrangement bene-
ficial to vegetation ; for grass and other herbage radiate
their heat more rapidly than most other bodies; and hence,
" in the cool of a summer'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 uncon-
scious of its fall."

When the sky is covered with clouds, these return to
the ground the heat which it loses by radiation ; and when
the air is agitated by the wind, its vapour is usually pre-
vented from being sufficiently 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 tempera-
ture 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 ascending from the earth's
surface, and entering cooler regions, will begin to relinquish
the moisture which it contains ; and a cloud will be formed
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
equal portions of air differently heated, and both contain-
ing 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 temperature
will not be sufficient to maintain, in the state of vapour,
all the water of both portions, and consequently water
must bo deposited. When therefore, in our atmosphere, a
current of warm air becomes intermixed with one that is
colder, a quantity of log, mist, or cloud is produced, pro-
portioned to the excess of the watery vapour contiiiuod in
both currentu, nl>ove tli« ((uantity which th«y can retain

ORGANIC FOOD OF PLANTS. 35

when mixed. Lastly, electricity, whose agency is so mani-
fest in thunder storms, acts, in ways not yet well under-
stood, in accumulating clouds, and precipitating their con-
tents to the earth in the form of rain, or, more rarely, as
destructive showers of hail.

§2, Compounds of Carbon.

3. Carbonic Acid — Is a compound of carbon and oxygen,
in the proportion of 6 of carbon to 16 of oxygen. Carbonic
acid is a gas, a little more than one-half heavier than
common air ; it speedily suffocates animals, when obliged
to inhale it, and it extinguishes flame. Like the other
substances known to Chemists as Acids, it reddens vege-
table blue colors, has a sour taste, and is capable of com-
bining with earths such as lime, and with alkalies such as
potash and soda.

Two of the modes in which carbonic acid is produced in
nature, namely, combustion and animal respiration, were
mentioned under the head carbon • but it may be formed
in many other ways. It exists in large quantity in lime-
stone and other rocks, and is given out by volcanoes, and
brought to the surface by springs ; it is also sometimes
disengaged from fissures, &c., in mines, and accumulates
in deep cellars, wells, &c., forming the " choke damp "
which occasionally proves fatal to persons incautiously
entering such places. When wood, straw, or similar sub-
stances, are exposed to air and moisture, a kind of slow
combustion, which we call decay, commences, part of their
carbon and hydrogen combine with the oxygen of the air,
and form carbonic acid and water, until at length nothing
remains but a coaly mass capable of little further change.

In consequence of these processes, it is evident that
carbonic acid must be constantly produced and added to
the atmosphere ; and, if this proceeded unchecked, it
would at length accumulate in so great quantity, that ani-
mal life would be destroyed. But it is found that the
quantity of carbonic acid in the air does not exceed the
one-thousandth part of its weight, and is not increasing.

36 SCIENTIFIC AGRICULTURE.

It is also known that water is capable of dissolving more
than its own bulk of carbonic acid, and consequently that
rain and surface water are always impregnated with it ;
and it is found by experiment, that plants supplied with
the air and water containing this gas, apply its carbon to
the formation of wood and other vegetable products. It
thus appears that the carbonic acid produced by burning;,
breathing, decay, and other processes, and which wouKl
otherwise contaminate the atmosphere, is employed as tlic
food of plants, and is thus, by the wise arrangement of ;i
beneficent Providence, made a source of supplying tlic
most valuable substances which the earth affords to man.

4. Light Carhuretted Hydrogen, — As its name imports,
is a compound of carbon and hydrogen, and is one of
several compounds formed by these substances. It is a
colorless gas, less than one-half as heavy as common air ;
it is incapable of supporting respiration or combustion, but,
when flame is applied to it, burns with a yellowish light, or
if mixed with air or oxygen, violently explodes. It is
abundantly disengaged from beds of bituminous coal, and
is the cause of the frequftut destructive explosions in coal
mines. It is given off from swamps and stagnant pud-
dles, and generally from all places where vegetable matter
is putrefying in fresh water. When organic matters be-
come putrid in sea water, they decompose the sulphates of
soda and magnesia (Glauber and Epsom salts), always
present in such water, and SnJphuretted Ilydroyeti is pro-
duced ; this gas is the cause of the offensive smoU of the
mud of creeks and estuaries.

Both these substances may assist in nourishing the rank
vegetation of swamps, but in the small (quantity in M'hich
they exist in the air, or in the soil of cultivated fields, their
influence on crops can be but trifling.

§3. Compound* of Nitrogen.

R. Ammonia. — The flubstancos which we have hitherto
noticed oaa farnish no nitrogen to plants ; this they in great
part derire from the compound now to be considered. Am-

ORGANIC FOOD OF PLANTS. 37

monia is a compound of nitrogen and hydrogen (N H.*).
Though composed of two gases destitute of taste and smell,
and itself a gaseous substance, it has a burning taste and
pungent smell. Ammonia is absorbed by water to the amount
of 670 times its own bulk ; when thus dissolved in water it
constitutes the common spirit of hartshorn, whose taste and
smell are those of the ammonia which it contains. It
also combines with acids, forming salts ; the most common
of which are, sal-ammoniac — which is a combination of
ammonia with hydrochloric acid;^- and smelling salts — in
which it is combined with carbonic acid. The properties
of ammonia which are of most consequence to vegetation
are the following :

It is produced in the decay of animal and of many vege-
table substances. The strong smell of stables and of urine,
and other animal matters in a putrid state, is principally
owing to the escape of carbonate of ammonia ; hence the
wastefulness of allowing rich manures to remain exposed
to the air until this valuable ingredient becomes almost
entirely dissipated. It has also been ascertained that in
some cases where organic substances are combining with
oxygen in presence of moisture, ammonia is produced from
the nitrogen of the air and the hydrogen of the water.
These facts, with the gaseous nature of ammonia, show
that it must always be present in the air, as, indeed, experi-
ment actually proves.

It is very soluble in water. The ammonia which the
careless farmer allows to escape from his stable and dung
heap is not lost, but only added to the general stock of
nutriment for vegetation. Every shower washes from the
air a quantity of ammonia; and to this the rain water
owes both its softness and its superior power of nourishing-
plants, compared with pure water. It has been proved
by experiment that the average quantity of ammonia de-
posited by the rain on an acre of ground in one year
amounts to about 23| lbs. The moisture of the soil also

• A compound of Hydrogen with the element Chlorine,, to be

iioliccd fiirthor on.

38 SCIENTIFIC AGRICULTURE. ,

serves to retain, and convey to the roots of plants, the
ammonia produced by the decay of manures which may be
buried in it.

It can easily be decomposed, and also separated from
other substances, when combined with them. From the first
property it cannot be doubted that it may, if necessary, when
introduced into the cells of plants, be divided into
its constituent elements, and those applied to purposes
of nourishment. And of the latter, the readiness with
which its compounds undergo changes when exposed to
the action of other bodies, furnishes conclusive evidence.
When, for instance, lime is added to animal manures, a
strong smell of ammonia is instantly exhaled, and hence the
injurious effect of lime when applied to such substances.
When lime is buried in the soil, however, this decom-
posing power may serve to set free ammonia, in circum-
stances favorable to its being absorbed by plants.

When common gypsum (sulphate of lime) comes into

contact with carbonate of ammonia, a double decomposition

takes place; or the carbonic acid and sulphuric acid

change places, and sulphate of ammonia and carbonate

of lime are produced, so that

Carbonate of Ammonia ) ( Sulphate of Ammonia

and s aro changed into { and

Sulphate of Limo. ) ( Carbonate of Limo.

Now carbonate of ammonia, as before stated, evaporates
rapidly when exposed to the air ; whereas the sulphate of
ammonia is not thus volatile ; and the circumstance of a
volatile salt of ammonia being thus changed by the agency
of gypsum into one that is fixed, is of great assistance to
the farmer. Thus when gypsum is strewed on the floor
of a stable, the carbonate of ammonia — which is formed
in Buch places — instead of being permitted to escape into
the air, becomes converted into the sulphate, and remains
united with tho gypsum ; every pound of gypsum thus
saturated with ammonia is able to supply all the nitrogen
required by twelve pounds of wheat. Of all tho manuros
produced on a farm, urine is undoubtedly the most valu-
able ; but a great part of its utility depends upon the
qnantity of nitrogen which it contains ; ana if it bo allowed

ORGANIC FOOD OF PLANTS. 89

to dry up alone, much of this escapes as carbonate of am-
monia : this loss also may be prevented by gypsum. A
part of the influence of gypsum, when strewed upon fields,
may also be explained by this property; for the gypsum
lying on the soil, not only fixes and prevents from escaping
the ammonia which may rise from the ground, but attracts
it from the air ; and thus, from the very winds that blow
over the soil, it gathers valuable nourishment for the grow-
ing crops.

Ammonia is largely absorbed by various substances.
Powdered charcoal absorbs ninety times its bulk of
ammonia, and decayed wood seventy-two times its bulk ;
hence these substances, when plentifully contained in a soil,
are capable of collecting and retaining, for the use of
plants, an abundant store of nitrogen. In a manner
somewhat similar, burned clay, coal ashes, and the red
oxide of iron (red ochre) absorb ammonia from the air.
The effects of burned clay as a manure, and the fertility
of those bright red soils which are colored by oxide of
iron, are partly to be ascribed to this cause.

By referring to the little table of the composition of
wheat, oats, &c., formerly given, it will be seen that nitro-
gen constitutes but a small portion of these and other
vegetable substances, From this, however, we must not
conclude that nitrogen is of little importance. All those
parts of plants which afford the most valuable articles of
food to animals contain nitrogen ; and the production of
such nutritious substances is the principal object of agri-
culture. Wheat contains more nitrogen than oats, and these
more than potatoes; and the nutritive powers of these
three crops are nearly in proportion to the quantity of
nitrogen which they contain ; so also, in some degree, are
their values in the market. It must always be an object
with the farmer to produce the most nutritive and valuable
crops ; and since these are the crops which contain the
most nitrogen, it must be of importance that he should
supply as much as possible of this element to his fields.
Hence one part at least of the great value which experience
attaches to guano and the richer animal manures, which

4^ SCIENTIFIC AGRICULTURE.

either contain ammonia, or are capable of yielding it in
the soil.

6. Nitric Acid — Is a compound of nitrogen and oxygen
(NO'), and, when dissolved in water, is the substance
commonly known as aquafortis. It combines with a great
number of substances, and it is in these states of com-
bination that it is usually found in nature. Common salt-
petre is composed of nitric acid and potash. When
applied to plants, nitric acid and its compounds act by
supplying nitrogen, and perhaps also oxygen. In some
plants, such as tobacco and the beet, which contain much
nitrate of potash, it remains in an unaltered form.

In warm climates, decaying animal matters often pro-
duce nitric acid instead of ammonia : this, however, does
not so often occur in temperate regions. If heaps of
earth, mixed with decaying matters, be left for some time
exposed to the air, and if the earth be afterwards washed
with water, a quantity of nitrates of lime, potash, &c.,
will be obtained from it. In France and Sweden, saltpetre
for the manufacture of gunpowder is obtained in this way.
The sides of limestone caverns, the mortar of cellar walls,
the earth of mud dykes, and compost heaps, become impreg-
nated with nitrates in a siinilar manner. In the district of
Axica in Peru, deposits of nitrate of soda are found beneath
the soil, and the mineral dug thence is exported to Britain,
where it is advantageously employed as a manure. In
France it has been found that the rain annually deposits
about thirty pounds of nitric acid on each acre.

In this climate nitric acid and its compounds cannot be
go abundantly obtained as ammonia, and arc not so mucli
under the control of the husbandman : but whenever they
can be procured, in any of the ways noticed above, thcv
will be found very beneficial.

§4. (Jrgnnir f'omjiouvr/s.

7. The Organic Matters contained in the Soil. — Every
fertile Boil containH a portion of vegetable or animal matter
produced from pIuntH which have grown upon it, or urti-

ORGANIC! FOOD OF PLANTS. 41

ficiaUy added in the form of manure. Such matters have
always been considered very eflEicacious in increasing the
productiveness of a soil ; we must therefore now enquire
how, and to what extent, they can afford nourishment to
crops. This enquiry becomes more important, when we
consider that all the substances hitherto noticed are fur-
nished to vegetation by the atmosphere, and consequently,
that if plants really derive any organic matter from the
ground on which they grow, it must be furnished by the
substances now to be considered.

In the very outset of this investigation, we find some
facts which limit the amount of influence attributable to
organic manures.

1. Their very nature shows that they themselves are
products of vegetation, so that a time must have been
when there was no vegetable mould. The first plants that
grew in any place must have been nourished solely by dead
inorganic matter.

2. In accordance with this, it is found that plants
supplied with air, water, carbonic acid, and ammonia, (or
watered with rain water, which contains the other sub-
stances), will grow in sand or clay altogether destitute of
animal or vegetable manure.

3. Plants growing in a wild state add to, rather than
diminish, the quantity of vegetable soil. Land left long in
grass, or covered with forest trees, becomes richer in v^e-
table mould ; green crops, such as clover, when ploughed
in, act as manure to soil, which would be impossible if
their own substance had been derived from it; and in
moist places, vegetables often add to the soil so much
organic matter that thick beds of peat become accumulated.

It is evident, therefore, that plants can obtain from the
air and water substances such as the first six compounds
which have been described, can convert them into vegetable
matter, and when they die, leave this to forpi vegetable
mould. But it is equally evident, from the experience of
all farmers, that organic manures greatly increase the lui-
urianse of crops. This may be accounted for in the folloW'
ing ways :

42 SCIENTIFIC AGRICULTURE.

1. Some organic substances, such as gum and sugar,
are soluble in water, and when plants are watered with
solutions such as these, their vigour is increased. It is,
however, plain, that no manure applied by the farmer can
contain much matter of this kind, and very little of it can
be left in the soil by plants which decay where they grew.

2. Vegetable matters placed in the soil soon begin to
decay or ferment ; and in the earlier stages of these pro-
cesses several substances are produced different from any
which existed in the living plant, but perhaps capable
of being taken into the sap of other vegetables, and
aiding their growth. Most of these substances pro-
duced in decay are, like woody fibre,* compounds of
oxygen, hydrogen, and carbon, but in different pro-
jwrtion; and many of them are acids, so that they are
capable of combining with lime, potash, and similar sub-
stances, and of carrying them with them into the roots of
plants. Two of the best known of this class of substances
have received the names of hum^ts and humic acid. Tlio
former is merely woody fibre in a particular stage of decay,
and the latter is produced from humus, when potash or
other alkalies are brought into contact with it.

3. The final result of the decay of animal and vegetable
matters in the soil is, that they become resolved into am
monia, carbonic acid, and the other substances which mo
have already considered ; and their slowly producing thosi'
around the roots of plants, probably explains a large por
tion of their efficacy as manures. It also partially explains
the utility of loosening and pulverizing the soil ; for decay
being a slow process of combustion, air is necessary in order
that the manures may be rendered available, and this is
more readily admitted into the loosetiod soil.

4. We must not forget that all vegetables yield a
quantity of ashes, or inorganic matter, and thi.s also is set
^ee whou .they dooay in tho soil. Thoir effoots in tl

lis

• Woody ftbw it belt known hi tlie form of wood of Im h
but the Btems, roots, and leavea of nenrly nil ])lant8, in g
part coniUt of it.

Vilt

OfeGANtC fOOD OF PLANTS. 43

Way cannot at present be considered, but wc shall hereafter
see that they form a most important part of the action of
organic manures.

5. Organic substances improve the color of the soil,
darkening it to such a degree that it becomes more absorb-
ent of solar heat. They also improve its mechanical tex-
ture, and render it more absorbent and retentive of soluble
and volatile manures.

While, therefore, plants can obtain the greater part of
their organic constituents from the winds and rains of
heaven, they are also greatly assisted by the presence, near
their roots, of matters which have, already formed part of
organised structures. These are particularly important in
the earlier stages of growth, as a plant which is enabled by
their means to attain a state of vigorous health, will possess
a greater power of attracting and assimilating substances
not yet organized, than its more weakly neighbors, which
have been forced from their very infancy to depend upon
the kindness of nature for a subsistence ; hence the
improvement which careful cultivation can effect in vege-
tables of every kind; and hence the luxuriant herbage which
springs from the well-manured fields of the careful and indus-
trious farmer, is able, by means of its well-developed roots
and abundant foliage, to use, in its own increase, all the
matter brought by air or water within its reacli, while these
bounties of Providence are in a great measure lost to the
starveling crops of an impoverished farm.

§5. Recapitulation.

Before leaving this part of the subject, it will be useful
to repeat the most important of the conclusions deducible
from what has been already stated.

We have seen that plants consist of organic sub-
stances, differing from any forms of dead matter, and
of inorganic matters derived from the mineral matter of
the soil.

The organic part of plants we have found to consist of
three gases, oxygen, hydrogen, and nitrogen, and one solid

44 SCiENTIFiC AGRICULTURE.

substance, carbon ; and these are obtained irt the following
ways: — 1st, The Oxygen of plants is obtained principally
from water and carbonic acid. 2ndly, Their Carbon is
nearly all derived from carbonic acid. 3rdly, Their Hy-
drogen is obtained principally from water, but probably in
part from ammonia. 4thly, Their Nitrogen is principally
derived from ammonia, and partly from nitric acid. 5thly,
A portion of all these substances is obtained by plants
from the remains of other vegetables which have existed
before them. In general, plants derive the materials of
their organic part from water, carbonic acid, and ammonia
or nitric acid, floating in the atmosphere, or brought down
in rain and dew, or aisengaged in the soil; and in so
far as this part of the food of plants is concerned, it chiefly
belongs to the farmer to supply to the soil substances capable ;
of affording ammonia, or nitric acid, and carbonic acid.
Some of the reasons why these views of the supply of food
to vegetation should be adopted, as well as some of their
practical applications, have already been mentioned. The y
will, however, more fully appear, after we have examined
the structttre of plants, and the moans J>y which tlnv
convert their food into the various substances for whirli
they are cultivated.

CHAPTER VI.

THE STRUCTURE OF PLANTS.

§1, General Structwe.

The substances which we have viewed as constituting
the food of plants, when taken into the system of a vege-
table, have entered into a chemical and vital laboratory,
where they are destined to undergo a series of changes,
ending in their assuming forms and properties very differ-
ent 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 general structure of all plants is nearly the same.
The wood of the hardest tree, Jis 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 trans-
mitting 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 extend-
ing 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 wood of different 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 % pursuit full of interest anjj

46 SCIENTIFIC AGRICULTURE.

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.

The trunk and branches of a tree may be viewed as
consisting of three parts — Bark, Wood, and Pith. The
true Bark consists of a tissue of cells, closely em-
bracing the tree, of a white or brownish color on the older
parts of the trunk, and green on the young extremities of
the twigs. This inner or true bark is covered and pro-
tected from the air by an outer skin or covering, which in
some trees, as the white birch, 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 inor-
ganic matter, constituting 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, ami
extending from the centre of the wood to the bark, so as Id
form thin plates stretching across the wood, and called tin-
siloer grain, or medallarij rays. The office of tlusc
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 steins, consists of large ei'lls
placed horizontally, and it probably serves to store up
superabundant sap till it is recjuired by the plant. Tlu.-c
structures, though most obvious in the trunk, are con
tinned into the branches, and, in some degree, into tin
leaves. Though the structure which we have noticed pre-
vails in trees, and in a great nutnbcr of herbaceous plants.
there is a large proportion of the vegetable kingdom wlii( h
showK no regular arrangement of bark, wood and pith ; and
the whole of the grains and grasses are of this last kiml.
In these plants however, the parts discharging the di tier
ont functions of wood and bark are not wanting, but
rather intiniuttilj uiiitxid inst-ead of being separated iiiti>
different jxirtions. We may now consider the lunetjons iif
thoM) organs wliich belong to nearly all plnnts.

STBUCTUBB OF PLANTS, 47

§2. The Root,

The larger branches of the root, like those of the trunk,
consist of bark and wood ; but in their smaller ramifica-
tions both bark and wood become soft, porous, and easily
penetrated by water ; and these minute and greatly divided
extremities of the roots, penetrating to every part of the
soil around a plant, are its true mouths or feeders.* The
spongy rootlets are capable of taking only fliiid food ; no
particle of clay or other undissolved matter can enter them;
they absorb water, and this in so large a quantity that a
sunflower three feet high has been stated to draw from the
soil thirty ounces of water in twelve hours of a sunny day.
But the water of the soil is not pure ; it contains a great
variety of mineral and other substances in solution, and
these it must carry to the roots of every plant which grows
upon it. Do all plants then, which can grow on the same
soil, require from it the same kinds of food ? Experiment
shows that ^.-is c;innot be the case. If « pea and a plant
of wheat giow 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 strength-
en its straw, while those of the pea will be found to afford
scarcely any of tliis earth. The water of the soil must
have brought i* 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 abso-
lutely necessary. It becomes therefore an interesting ques-
tion whether the roots themselves have the power of select-
ing 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 pro-
per kinds of food.

This point has been much disputed, it may however be

• Hence, in transplanting, great care should be taken to pre-
serve uninjured the small fibres of the roots. Plants should not
))e carelessly " torn out of one place and thrust into another."

is SCIENTIFIC AGRICULTURE.

rendered more simple by a reference to animals. Of these
we know that every species is endowed with the skill ne-
cessary for choosing the most suitable nourishment, and
yet that the ordinary food of each includes much that must
be afterwards rejected ; while all are liable occasionally to
mistake what is poisonous for what is nutritive. In the
same manner it can be shown that plants altogether refuse
to receive some substances even when placed in contact
with their roots in a soluble state ; and yet that they do
absorb much which they afterwards reject, and in some
instances that they admit matter which proves highly inju-
rious or poisonous to them. In plants also, as in animals,
there are always matters of various kinds, which have served
some purpose in their economy, but have finally become
useless ; and the roots of plants are the organs by which
the excretion of these matters is effected.

The substances thus excreted by plants, are either or-
ganic or inorganic. With respect to the former, Macaire
found that vegetables carefully taken from the ground, and
placed in water, gave forth from their roots substances
having the properties of gum, extractive matter, opium,
and other organic compounds ; more recent observations,
however, have shown that at least a part of these effects is
due to the escape of the juices from wounded parts of the
roots. A better instance of the excretion of organic matter
is furnished by the fact, that when grain is made to sprout
in powdered chalk, after germination has taken place, a
part of the chalk (carbonate of lime) is found to be convert
cd into acetate of lime ; acetic acid (vinegar) having been
produced in the young plants and given out by their roots
to combine with the lime.

The quantity of inorganic matter voided by plants i.s
well shown by some experiments of De Saussurc. First :
he found that after vegetablt's have attained nearly to
their full growth, tlioy yield much more ashcH, in propor-
tion to their own weight, than jifterwards, when the seed is
ripened ; thus a plant of wheat, when ripe, contained les«
than one half the proportionat(> (|uankity of ashes contained
in a piftnt before flowering. Sei-ondly: thai this wa»

STRUCTURE OF PLANTS. 49

caused by an actual, return of inorganic matter to the soil,
and not by an excess in the growth of the organic parts,
was shown by the circumstance, that while the whole quan-
tity of ash diminished, some of its ingredients greatly
increased in quantity. Thus wheat contains a large propor-
tion of silica, and it was found that the quantity of this
earth in the ripe plant was to that in the green in the pro-
portion of four to one, so that the other ingredients must
have been lost to a much greater extent than the propor-
tion before stated. Thirdly : the quantity of silica con-
tained in the ashes of wheat affords in another way a proof
of the excretion of inorganic matters. Silica alone cannot
be dissolved in water, but when it combines with potash,
soda, or other alkaline substances, in certain proportions,
it becomes soluble, and in this state it enters into the ves-
sels of plants. Silica however requires nearly half its
weight of potash or soda to render it soluble, and on exam-
ining the ashes of ripe wheat, it was found that the quan-
tity of silica which they contain is four times that of their
alkaline matter; or that there is present in the ripe plant
only half the quantity of alkali required for the solution of
the silica which it contains. It is evident therefore that a
portion of potash or soda has been separated from the
silica with which it was 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. Plants have there-
fore the power of sending back to the soil useless or inju-
rious substances, whether obtained unaltered from the
ground or formed in their own system; and it is even pos-
sible that some of the matters thus ejected may, as in the
case of the alkali just noticed, combine with substances in
the soil, and thus become fitted to be again absorbed with
beneficial results.

The well known benefits of a rotation of crops have been
attempted to be explained by supposing that the excre-
ments disengaged from the roots of a plant, must be hurt-
ful t« others of the same kind if planted in the same soil,
lyliile on tjie other hand they might be nutritive to plants

50 SCIENTIFIC AGRICULTURE.

of other kinds. Thus if the roots of a pea be placed in
water, they communicate to it in time a brown color, in
consequence of gummy secretions being thrown off from
the plant ; and if, after the water has thus been filled with
excrements, another plant of the same kind be placed in it,
it will not flourish ; but if, instead of a second pea, we
' place in it a plant of wheat, this will grow luxuriantly and
take from the water a part of the matter previously de-
posited in it. In the same manner, the soil in which any
species of vegetable has long been cultivated may become
surcharged with its excrements, and the substitution of
some other crop, which can free the soil from these, may
be rendered necessary. It is evident that the inorganic
matters rejected by plants cannot have much influence in
this way, since these previously existed in the soil; and
we shall afterwards see that the quantity of these mineral
matters taJcen from the ground and not returned to it, is
one very powerful cause of the rapid deterioration of plants
when long cultivated on the same soil. The organic excre-
tions derived from that food which is obtained from the
elements afforded by air and water, are alone capable of
rendering the soil poisonous to the plants from which tliey
proceeded. We must not, however, forget that these secre-
tions may, like other organic matter, be decomposed ; so
that, after a sufficient interval, their injurious etlect must
entirely cesise ; hence it is found that fallowing, which gives
time for the excrements in the soil to decompose, may on
this account be substituted for a rotation of crops.

The ktest experiments and observations on this subject
seem to show that the organic excretions of plants hav«,
practically little effect on their culture, and that the extoni
to which they remove mineral in.ittcr from the soil is really
the ])rincipal cause which renders the soil unsuitable to
them. Tliis wo must consider under another division of
our subject.

§3. The Ascending Saj). — Tlis Stem.

Tlic water absorbed by the roots Is carried upward into
the stem, becoming, in its progress, more or loss mixc(|

STRUCTURE OV PLAJNTS. 51

with the fluids existing in the plant. In consequence of
this intermixture, 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 several causes — 1st, the water and carbonic
acid drawn up from the soil contain the elements of sugar,
and may possibly be converted into it by the action of the
wood, or of the young buds ; to what extent such transfor-
mations can be effected by the wood, is not however very
certain. 2nd, many trees store up in autumn a quantity
of starch, and possibly other substances, in the cells of their
stems and roots ; and that the stai'ch 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. 3rd, in spring, before the leaves are developed,
growth is going on vury slowly, and the sap not being used
in the formation of wood and leaves, is allowed to accumu-
late 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 ta furnish materials for their growth, and for
the formation of wood ; and for this reason it cannot then
be obtained in the same quantity or of the same quality as
in early spring.

§4. 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 the microscope, other struc-
tures appear. The surfaces of the leaf, especially the lower
one, are found to be perforated with numerous minute

62 SCIENTIFIC AGRICULTURE.

openings, communicating with small cavities in its interior ;
the green matter is found to consist of cells filled with a
soft green substance; and the fibres are found to be
formed of vessels similar to those of the wood. Into the
leaves thus constructed, the sap is conveyed from the stem
by means of the stalk and fibres ; from these it passes into
the cells of thie green matter, where it is exposed to the
action of the external air, and of the light and heat passing
through the outer membranes. Under the influence of
these powerful causes of chemical change, thf leaf becomes
the seat of important processes.

1 . A large portion of the water of the sap escapes from
the leaves by evaporation and perspiration. Water con-
tained in a vessel in which the roots of a growing plant are
placed, is gradually drawn up and given out by tlie leaves,
until at length, if not renewed, it becomes altogether ex-
hausted ; and then the plant droops and withers, because
the leaves are rapidly exhaling its fluids, while the roots
are receiving no new supplies. This emission of water
proceeds with the greatest rapidity when the plant is ex-
posed to the direct rays of tlie sun, and iVi darkness it
becomes very slow or ceases altogether. Thus the .sun-
flower, which, in a sunny day, can give ofi* 30 ounces of
water, emits only 3 in a dry night, and none in a dewy
one. In consequence of this rapid escape of water, the
substances which it held in solution are lei't in a more con-
centrated state, and ready to bo deposited wherever they
arc required. The large quantity of water v I ich thus passes
througli their system, also enables plants id obtain from
the soil abundance of many substances wliidi are contained
in it in very small quantity, or are with difliculty soluble
in water.

The powers of the leaves, with reference to water, are
not limited to exhalation ; tlicy also in some cases can
absorb it from i\w atmofipluTe, or from the rain and dew
which falls upon tlicin. It is thus that drooping plants
may l>e revived by watering their leaves, and thus that the
air plants of China and Buenos Ayres flourish when sus-
pended from the walls and balconies of liouses, without
|iny connection with the ground.

STRUCTURE OF PLANTS. 5S

2. The leaves absorb and decompose carbonic acid, a
gaseous substance, 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
carbonic acid, or having a little more artificially added,
and then placed in the sun, after some time it will be found
tliat a part of the carbonic acid has disappeared, and that
a quantity of oxygen corresponding to that which it con-
tained, occupies its place. This change is effected by the
leaves, which therefore have the power of absorbing car-
bonic acid and retaining the carbon, at the same time
expelling its oxygen.

But while this process proceeds with rapidity in sun-
shine, it goes on much more slowly in the shade, and in
darkness gives place to one of a contrary nature. The
leaves, which by day receive and decompose carbonic acid,
by night emit carbonic acid and absorb oxygen. In
plants growing in ordinary circumstances, the former pro-
cess is carried on to a much greater extent than the latter,
which appears in some respects to serve for resting and
renewing the exhausted powers of the leaves.

The decomposition of carbonic acid 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 decompo-
sition can only proceed in the presence 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 sub-
stances contained in their roots, are unable to obtain the
necessary 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

54 SCIENTIFIC AGRICULTURE.

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

3. The leaves absorb and emit other gaseous bodies
beside carbonic acid. 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 required
by the sap. The various odours and perfumes exhaled by
many leaves and flowers are all volatile matters, formed in
their cells and vessels, and which would probably be inju-
rious 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.

§5. The Bark.

The principal 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 downward, adding new matter
to the outer surface of the wood, and the inner surl'aeo of
the bark, and penetrating by the medullary rays to nourish
the interior 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, beconi
ing mixed with the ascending sap, is again carried upward
to the leaves. In some plants, such as the grasses, which
have no true bark, the descending sap probably passes
through a particular sel of vessels, which are mingled among
those which carry the ascending sap.

From the very short and general view wliich we liave
taken of the nutrition of vegetables, it appears that their
food is obtained from the water contained in the soil, and
by the leaves from the atmo.spheric air ; that the substances
obtained from both these sources are united in the leaves;
and that they there umk^rgo clianges fitting them for being
OOnTerted into tlie various matters which are Jound in
the rodte, stems, and fruits of plants. The nature of these
ohangea, and of tliu Hubstunccs which result from them,
•re neit to be considorod.

CHAPTER VII.

ORGANIC COMPOUNDS PRODUCED BY PLANTS.

§1; General Statements.

We have seen that carbonic acid, water, ammonia, and
other substances which form the food of plants, are taken
into their cells and vessels, and constitute the raw material
which affords the carbon, oxygen, hydrogen, and 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 all that almost endless variety of
woods, resins, oils, gums, acids, sugars, and other matters
which are contained in plants, and wliich can, for the
most part, be prepared in no other way than by the agency
of vegetable life.

It is to the presence of different compounds of these
descriptions that vegetables owe the diversity of tastes,
odours, colors, and of nutritious, poisonous, or medicinal
properties, which we find in different plants, and in diffe-
rent 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 contained in its food.

To examine in detail all this vast variety of vegetable
products, and endeavour 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 tlie most
difficult questions in the science ; questions many of which
are yet unanswered, or but very imperfectly understood.
There are however, some of these substances so generally

56 SCIENTIFIC AGRICULTURE.

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-nitrogenised and the Nitrogenised.

§2. Neutral Non-nitrogenised Substances.

The greater part of the substance of v^etables consists of
compounds destitute of nitrogen, containing 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 vary
somewhat in its composition, probably because the cells
and vessels of wood become incrusted or partially filled
with another matter named Lignin, which cannot be sepa-
rated from the true woody fibre. It is perhaps for the
same reason that the composition of cotton, pith, and the
cellular matter of soft vegetables, is found to differ from
that of the wood of trees. This difference appears in the
following table :

Oak Wood. Cellular matter.

Carbon 50.00 44.80

Hydrogen.. 6.20 6.20

Oxygen 43.80 49.00

100 100

The most remarkable fact shown by these analyses is,
that the quantity of oxygen is ncarlv 8 times tliat of the
hydrogen ; or, in other words, that these two elements are
in the proportions required to fornx water ; so that woody
and cellular matter may bo viewed as composed of char-

PRODUCTS OF PLANTS. 57

coal and water ; though it is evident that the water or its
elements, 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.

According to the rule of definite proportions formerly
stated, considering the equivalent of carbon to be 6, that
of oxygen 8, and that of hydrogen 1, and dividing th«
quantities given above by these numbers, we find the
shorter and more accurate expression for the composi-
tion of the cellulose or cellular matter to be : *

QU glO QIO

2. Starch. — This substance is, like wood, contained in
nearly all plants, but in a different form and for different
uses. While wood is the material 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 large roots or
underground 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 little 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 quantities
of starch, destined to furnish the first food to the seedling
plant. Thus wheat contains from 39 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 what plants
have prepared for theirs.

• • In any chemical text-book the learner will find the table of
chemical equivalents or combining values of substances, accord-
ing to which these formulas are framed.

58 SCIENTIFIC AGRICULTURE.

Starch when pure is colorless and tasteless ; it is not
dissolved by cold water, but in boiling water it is readily
soluble. It consists of carbon 44, hydrogen 6.2, oxygen
49.8, in 100 parts, so that its composition is the same
with that given for cellular matter, and may, like it, be
represented by C^ W 0''.

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 those roots and
seeds used for human food. Gum dissolves in water,
forming mucilaginous solutions ; that obtained from dif-
ferent plants differs in solubility, some 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, C' W 0'\

4. Sugar. — The most familiar example of this sub-
stance is common cane sugar, which is found abundantly
in the sugar cane, maple, Indian corn, beet, and various
other plants. The composition of cane sugar differs little
from that of starch and gum. It is C" H" 0".

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 gra2)e sugar,
which contains more of the elements of water than any
of the substances before noticed, its composition being
C" H" 0'^. This sugar is less soluble in wat<»r and
less sweet than the coimnon variety. It is ibund in
honey, in germinating seeds, in fermented liquors, in the
grape, gooseberry, apple, plum, and most other fruitw. Jt
Ui therefore especially the sugar of fruits and growing
seeds, aa cane sugar is especially that of the general nap.

Before proceeding farther, we may pause for a little to
oonsidor some of the mutwil rcUt turns of the four sub- ■
stances which have just been described. They are pro-
duced by vegetables in greater abundance than uny other
subetanceH, and arc concerned in most of ihv. chungos
which take place by the agency ol' vegetation. 'I'hat (hoy
inuy'bi! more readily obtained by all plants, they are coni-
poHed^of cttrbuti, oxygon, and hydrogen alone, ho that

PBODUCTS OF PLANTS. 59

whenever carbonic acid and water are present, the materials
for their formation can be obtained ; and these, as we have
already seen, may be found in every place where vegetation
can subsist.

While they all consist of the same elements, they contain
them in the same or nearly the same proportions. In this
respect we may indeed regard them as only one substance,
capable of assuming several diiFerent forms ; in its soluble
states of gum and sugar circulating in the sap, and supply-
ing nourishment to every organ, and in its more insoluble
forms stored up as starch for future nourishment, or fash-
ioned into tough woody 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 stai'ch, and gum into sugar, and
vice versa, we have abundant proof in many common pro-
cesses. 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 converted into sugar ; the
sugar of the beet or of maple sap, when these plants begin
to grow in spring, soon disappears and becomes converted
into woody stems and leaves ; and when a potato is planted
and begins to grow, its starch furnishes the material for its
stems and foliage, after having first been taken up in the
sap in the form of gum and sugar.

Such changes as these 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 . Bi/ 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, and when fermented and
baked, gives a light and not unpalatable bread. 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

60 SCIENTIFIC AGRICULTURE.

British gum, and forms a good substitute for gum Arabic.
Lastly, in the manufacture of British gum, a portion of
the starch is sometimes changed into sugar. Heat, there-
fore alone is capable of transforming starch into gum, and
gum into sugar.

2. By Acid^ and 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 quantity 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 sugar ; and in France potato starch thus
transformed is employed to some extent in the manufacture
of brandy and fermented liquors. 100 lbs of starch
mixed with 600 of water, and 10 of sulphuric acid, by
boiling for seven or eight hours, produce about 112
lbs. of grape sugar.*

Cane sugar may also by the action of acids be readily
changed into grape 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, crystallizes
in little lumps.

Alkaline substances are also capable of effecting some
of these transformations. If sawdust be boiled in a strong
solution of pure potash, a portion of the woody fibre will
assume the properties of starch.

Since wo can so easily, by artificial means, produce
these transformations, it cannot be doubted that they can
be still more readily effcctod within living plants. Human
art can, however, iniitatt; 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,

• This i>ro«:cviH miglil probably bo usefully oniploycd iu uiak-
ing sugar for duwoHtic itsu ; grapo sugar of this kind would
for many purposcH furni a substitute for that of tho cane.

}

Ci2jji2Qi2 r i„to 1 4 Car. Acid— C* 0*

PRODUCTS OF PLANTS. 61

and gum into sugar ; but chemistry is altogether unable to
reverse the process, and convert sugar back again into
wood.

The plasticity of these compounds of carbon and the
elements of water, is not however limited to mutual trans-
formations. By various kinds of decomposition they can
be changed into other substances such as alcohol and vine-
gar. One of the most common changes of this kind is/er-
mentation. When to a decoction of malt, or to the juices
of sweet fruit, we add a little of any matter in a ferments
ing state (yeast for instance), carbonic acid begins to
escape, and in time the grape sugar contained in these
liquids is found to be changed into alcohol or spirit. In
this case

Grape sugar, or | is divided J 2 Alcohol — C H^^ 0*

i— C* 0*

Q12 JJU QU

The carbonic acid escapes from the fermenting liquid in
bubbles, and the alcohol remains in the water. By further
exposure to the air the alcohol thus produced absorbs a
portion of oxygen from the atmosphere, and is changed
into vinegar.

These artificial modes of transforming wood, starch and
vinegar, though they may not show us exactly the ways
in which those 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 bodies found in most plants, the acids.

§2. Vegetable Adds,

1. Acetic Add or Viner/ar is one of the most 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 composition of vinegar is carbon
4, hydrogen 4, oxygen 4, so that like grape sugar it contains
equal proportions of carbon and the elements of water.

62 SCIENTIFIC AQRICULttJIlE.

In conformity with this similarity of composition, a solu-
tion of cane sugar with a little vinegar added to it, when
exposed to the air for some time, becomes changed into a
solution of vinegar.

2. Tartaric Acid—\& composed of C* H^ 0'^ con-
taining therefore proportionally more oxygen, and less hy-
drogen, than the acetic. It is contained in sorrel and
in some berries, and, in combination with potash, abounds
in the grape. The bitartarate of potash obtained from
the latter fruit, is the well known cream of tartar.

3. Citric or Lemon Acid — differs little in composition
from the last, (C'f H' 0")- I* gives acidity to the
lemon, orange, cranberry, and strawberry.

4 Idalic Acid — differs slightly in composition from
the tartaric. It is C H** 0^". 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 C* H^ 0\

These and many other acids occur in greater or less
abundance in most plants ; and though they do not consti-
tute an important part of their bulk, they are of sonio
consequence. They communicate to many fruits and
other articles of food an agreeable acidity. Tliey 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 contained in the tissues or sap ; for ex-
ample, in converting starch into sugar. And lastly, thoy
are themsolves capable of being transformed into various
useful products, as we often sec to be the case in the con
version of a H<jur unripe fruit into a sweet ripe one. In
this change the acid jiroscnt in superabundant quantity in
the unripe fruit, and causing it to be unpalatable and
unwholesome, is oonverted into grapo sugar, and the fruit
in thus rendenHl ngn'cal)li' to the tnst«', and nutritive.

PRODUCTS OF PLANTS. 63

§3. Nitrogenised Substances.

These, though present in much smaller quantity than
the non-nitrogenised constituents of the plant, are of vast
importance both to the plants themselves and to the ani-
mals which feed on them. In the plant they appear to
determine all the vital changes by which the other sub-
stances are produced ; and to the animal they are the mate-
rials out of which alone its most important tissues can be
formed.

1st. If we take a small quantity of the dough of wheaten
flour and wash it on a linen or muslin* rag so as to remove
the starch which forms a large constituent of the flour, we
find remaining on the cloth a substance of a remarkably
sticky and tenacious character. It is known as the
gluten of wheat, and it is to this substance that the flour
owes its capacity for constituting a tenacious paste and for
forming raised bread. It is a nitrogenised substance, in-
soluble in water, but soluble in acids and alkalies ; and is
similar in composition with the flesh of animals. It con-
stitutes from ten to twenty per cent, of the grain of
wheat. Other grains contain this substance, but in less
quantity than that of wheat.

2nd. In Indian corn a similar substance, or rather a
modification of the same, occurs, and has Jbeen called Zein.
Another similar substance occurs in considerable quantity
in peas and beans, and is named Lcgmnin.

3rd. If the juices of many succulent plants, as of the
tubers of the potato, are heated to the boiling pojnt, 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 egg. This substance may be re-
garded as chemically identical with gluten, but it differs
in being 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
Blatters seem to be mutually convertible, they may be re-
garded as related to each other in the same manner in
which starch is related to sug-ar or scum.

64

SCIENTIFIC AGRICULTURE.

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

The following table from Norton shows the proportion of
nitrogenised substances contained in several of the most
important ^ains and roots :

Wheat.

Oats.

Rye.

Indian
Corn.

Peas.

14

42
6

24
2
9
3

Potatoes.

Turnips.

Water

Starch

Gum & sugar
Nitrogenised

subtances. .
Oil

15

42

9

15
2

15
2

16
•38

7

16
6

15
2

100

12
40
14

13
3

16
2

12

40

6

17
9

14
2

75

15

2

2
i
4

1

86

7»
2

i
2
1

Woody fibre .
Ashes

100

100

100

100

100

100

In this table the quantity of nitrogenised matter ex-
presses very nearly the flesh-producing value of the several
substances when used as articles of food ; and in this respect
such facts are not only important in relation to the nature
of plants, but in relation also to their use as food for meij,
and animals. All the edible substances afforded by the
vegetable kingdom may be grouped under two heads — the
heat-producing and the flesh-producing. Under the former
come starch, sugar, gum, and oil. These substances,
by their combustion in the body, keep up animal heat, and
prevent waste and thinness. Animals fed on such sub-
stances and not exposed to cold, tend to accumulate fat ;
on the other Imnd, the consumption of such food ena-
bles them to endure cold. To the second clnss belong
gluten, albumen and Icguniiti, which afford the matoriul

* Pectin, a labfianoe allied to gam, occurs here Instead of
starch.

PRODUCTS OP PtiAUTS. 05

of flesh and sijieW. 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 cream produced by milch cattle may
also be influenced in the same way. But these are sub-
jects too extensive to be considered in this place.

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

§4. Conclusions as to the Food of Plants.

The organic food of plants consists in part of gaseous
or aeriform substances, and in part of substances not aeri-
form, or fixed. The gaseous part of the food may be ab-
sorbed 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 dis-
solved. 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 combustible
part may be obtained either in a gaseous or fixed state,
either from the air or from the soil ; those that constitute
its ashes or incombustible part, as we shall find, only from
the soil.

In respect to both of these classes of substances, the root
and the soil are the most important practical subjects of
consideration ; since the air is alike or nearly so at all
times in its composition, and cannot in this respect be re-
gulated by the farmer. Still, as, the leaves absorb food
from the air, whatever gives it the largest amount of healthy
leaf will enable the plant to do this most effectually, and
sufficient exposure to air and light are also absolutely ne-
cessary. The farmer, by taking proper care of the root
and the soil, thus provides also for the proper action of the
leaf and the air.

In respect to the particular elenjents of the organic part

66 SCIENTIFIC AGRICULTURE.

of the food of plants, while it is useful itb have in the soil
organic matters yielding carbonic acid, 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 form large and healthy leaves and roots, and may
thus be able to avail themselves of the stores of carbonic
acid and ammonia aflForded by nature. It is thus to be
observed thafwhile the organic part of the food of ordi-
nary plants may be furnished by the air and rain, yet the
more important cultivated plants require more than this
in order that tliey may yield large crops ; and further, that
the small and starveling plants of a poor soil have not suf-
ficient 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
the material of the inorganic part, they are still of great
value.

CHAPTER VIII.

THE ASHES OP PLANTS.

^1. Convposition of the Ashes.

We have already seen that the combustible or organic
part of the plant, at least in the kinds cultivated by the
farmer, largely preponderates over the ashes. We are not
on that account, however, to suppose 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 fol-
lowing table, from Norton, representing tlie results of chem-
ical analyses of the ashes of plants, will enable us to
illustrate these points.

Table of the composition of the ashes of several cultivated
plants.*

Potash

Soda

Lime

Magnesia

Uxides of Iron and

Mangane8e

SHica

(Miloriiip

Sulphuric Acid

Phosphoric Acid.. .

Carbonic Acid

Charcoal in Asli, 1

and loss I

23.2

a. 8

0.1
17.5

I 0.1

0.8

0.3

(K5

49.2

trace

4.5

WhMt.

29.5

tracp

2.9

15.9

trace

1.3

trace

1.0

47.0

2.4

100.0 100.0 100.0

7.2
0.3

8.5
5.0

1.0

67.6
0,6
1.0
8.1

5.7

R;«.

32.8
4.4
2.9

10.1

0.8
0.2

1.5
47.3

100.0

Oabt Potilou. TuraiiM.

1^27.2

4

9.9

0.4

2.7

0.3

10.6

43.8

0.3

51.5

trace

1.8

5.4

0.5

8.6

2.7

7.1

11.3

10.4

42.0
5.2

13.6
6.3

1.3

3.5

13.«

7.6

100.0 100.0 100.0 100.0

H.,.

18.2
2.3

22.9
6.7
1.7

2.6
2.7
6.0

• The teacher should copy this table on a large scale, and
attach it to the wall of the school-room. T&e pupils may copy
it on their slates, and should be prepared to answer questions as to
the properties and sources of the substances, and the proportions
in which they occur in different plants. Much time may be pro-
fitably spent in this exercise.

68 SCIENTIFIC AGRICULTURE. "

The substances in this table may be shortly described
as follows :

1. Two of them, Potash and Soda, are alkalies, that is
they are highly soluble in water, have a caustic and alkaline
taste, combine with acids to form salts, and with oils to
form soaps ; change vegetable blue to green, and yellow
to brown ; and tend, when strong and pure, to corrode
animal and vegetable substances. Potash is a compound
of the metal potassium with oxygen ; soda is a compound
of the metal sodium with oxygen. For uses in the arts,
potash is obtained principally from the ashes of wood,
but the ashes of all land plants contain it. The common
potash of commerce, as obtained from wood ashes, is not
pure, but a compound of the substance with carbonic
acid. Common nitre or saltpetre is a compound of pot-
ash with nitric acid. It is named the nitrate of pot-
a.sh, and may serve as an example of the salts of potash.
Soda is commonly obtained from sea salt, which is a chhv
ride of sodium, or from the ashes of sea weeds and
sea-side plants. The common washing ?oda is a compound
with carbonic acid ; and with an additional dose of that
substance, soda fonns the bi-carbonate of soda used
for effervescing draughts. The nitrate of soda is a salt
similar in some respects to saltpetre, and exten^vely used
in agriculture. The sulphate of soda is common Glauber's
salt. Sea salt, a compound of the metal sodium with
chlorine, is the most abundant of all the natural sources
of this substance.

2. Two other substances in the table arc alkaline
earths, — Livic and Magnemi. Tlieir chemical properties
are somewhat similar to those of the alkalies, but they arc
less soluble in water, both in their pure state and when
in combination with carbonic acid. Hence they are less
active in the manifestation of their alkaline powers. Linic
exists very abundantly in nature as carbonate of lime, whicli
forms marble, limestone and chalk, and occurs in mail,
in soils, in the shells of aquatic animals, and in the ashes
of plunt«. Wlien carbonate of lime is expo.sed to a red
heat, it loses it«i carbonic acid, and quick or caustic linit

ASHES OF PLANTS. 69

remains. Gypsum or Plaster of Paris is the sulphate of
lime. Lime is a compound of the metal calcium with
oxygen. Magnesia is less abundant than lime, but occurs
with it in dolomites or magnesian limestones, and in soils.
The medicine ]^psom salt is sulphate of magnesia. The
calcined magnesia of the shops is this earth uncombined.
Magnesia is a compound of the metal magnesium with
oxygen.

3. Two other substances in our table are ordinary metallic
oxides, the oxide of iron and the oxide of manganese. The
<jommoa metal iron every one knows; and when on expo-
sure to air and moisture it rusts, it combines with oxygen
and constitutes an oxide known as the peroxide of iron,
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, the protoxide, 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 peroxide. Common green vitriol is the sulphate
of the protoxide of iron. The oxides of iron occur in
very small quantity in the ashes of plants.

Oxide of manganese occurs in still smaller quantity,
and is sometimes absent. It is hence not supposed to be
essential to their healthy growth.

4. The next substance in our list is Silica, an oxide of
the element silicon. Silica is one of the most abundant
substances in nature — common flint, sand, and rock crystal
are examples of it. It generally constitutes the far greater
part of the bulk of the soil. Though silica in itself is
quite insoluble and infusible, yet in combination with alka-
lies and alkaline earths, it forms silicates which are fusible
in the heat, and some of them quite soluble in water.
In this form it enters into the roots of plants, and
in some of them, especially in the grains and grasses,
appears in large quantity. The silicates of potash and
soda are specially important to plants in this respect.

5. Chlorine, the next substance in the table, is very
diflferent from the last substance. It is an element, and

7^ SCIENTIFIC AGRICULTURE.

when pure is an air or gas heavier than common air, of a
greenish color, and is suffocating and irritating when
inhaled. It rapidly decomposes certain organic com-
pounds, combining with the hydrogen of them to form an
acid known as hydrochloric acid. Hence it is used to
decompose offensive odours in the air, or as a disinfectant,
and to decompose coloring matters in fabrics, or as a bleach-
ing material. In the ashes of plants it does not occur
pure, but in combination with soda or its metallic base
sodium, constituting chloride of sodium or common salt, a
substance of vast importance to the health both of plants
and animals.

6. The two next substances in our table. Sulphuric
Acid and Flwsphoric Acid, are called acids as having a
sour taste, the property of reddening vegetable blues, and of
combining with alkalies and similar substances to form salts.
Sulphuric acid or oil of vitriol, is a compound of sulphur
and oxygen. In the ashes of plants it occurs in combina-
tion with lime and pota.sh. Phosphoric acid is a com-
pound of phosphorus and oxygen. In connection with
lime it forms phosphate of lime or bone earth, one of
the most important substances in nature, since of It the
bones of animals are composed ; and the plants on which
these animals feed must contain it in order to afford nou-
rishment to their bones. It is also a substance present in
comparatively small proportion in soils, and hence one that
deserves the most careful study of the agriculturist in regard
to its preservation and supply.

The last linos of the table represent carbonic acid, which
wc have already considered, unoonsumcd charcoal and loss
in the processes of analyses ; so that we have in all nine, or,
including the oxide of manganese, ten distinct substances
which require attention in considering the ashes and the
inorganic food of plantfl.

{^2. Usfit of the Afih'n.

There are certain general Htatcmcnta in relation to these
substanccfl, which lie at the very basis of scientific iigricul
turo, and should bo iirmly fixed in the mind of the farmer.

ASHES OF PLANTS. 71

1. The substances found in the ashes of plants are not
present accidentally, but are absolutely essential to the life
and health of the plant. In every soil, and in every cli-
mate, a plant of wheat will be found to contain in its ashes
all the substances mentioned in the table, and if deprived
of any one of them it cannot thrive.

2. Different plants and diflferent parts of the same
plant contain the materials of the ashes in different propor-
tions. For example, in the ashes of the potato, potash
largely predominates ; in those of wheat, silica and phospho-
ric acid ; and in the wheat plant, while silica is the leading
ingredient in the ashes of the straw, phosphoric acid pre-
vails in the ashes of the grain.

It is to be observed here that substances very similar to
each other in properties may sometimes to a certain ex-
tent be substituted the one for the other. Thus, in default
of potash, soda may be used to some extent instead. Dif-
ferent varieties of the same species of plant also differ
somewhat in their proportions of ash. But with these limi-
tations, the law is invariable that every plant must have its
own special proportions of these materials.

3. The absolute quantity of ashes is different in diffe-
rent plants, and in different parts of the same plant, and
also in different stages of growth of the same part. Thus
wood rarely contains more than from 1 to 2 per cent, of
ashes, while hay may give 6 to 14 per cent. The straw of
wheat contains 6 per cent, or more, the grain only 1 to 2 per
cent. The young leaves of trees have little ashes, the old
leaves a very large quantity.

4. The substances contained in the ashes can be ob-
tained by the plant only from the soil, or from the manure
which the farmer places therein. They cannot 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 be found, when we come to consider its
composition, to contain these in unlimited quantity, it
follows that cropping must •exhaust the soil of the inorganic
food of plants.

"T2 SCIENTIFIC AGRICULTURE.

These truths in relation to the inorganic constituents of
the plant, are among the most valuable results of modern
chemistry in its application to agriculture, and must be
borne in mind in all our subsequent studies of the subject.

If we ask why these ash ingredients are so important, it
is probable that a full and complete answer cannot yet be
given. It may be stated however, that they are useful me-
chanically 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. This last is by far the
more important use, and deserves some detailed considera-
tion before we advance further.

The absorption by plants into their system of earthy
matters constituting their ashes, appears to bear a direct
relation to the power of forming those non-nitrogenised
substances of which the greater part of the fabric of plants
consists. This might be inferred from the intimate union of
the ashes with the woody matter, and also from the denser
and harder woods yielding much ash ; but it is also confirm-
ed by experiments, especially by those of Boussaingault. It
would seem that when plants are deprived of supplies of
earthy matter the leaves do not possess the power of decom-
posing carbonic acid, and forming woody and similar sub-
stances.

It would also seem that certain earthy matters are
specially related to certain kinds of non-nitrogenised
matter — for example, that all plants which produce much
starch, sugar, or gum, refjuire much potash. It is also to bo
observed that in some specicSs of plants a much loss propor-
tion 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
itB fitness for the growth of other kinds of plants. A
fir tree may thrive on soil quite too poor in alkalies and
otlior earthy matters for tlio healthy growth of a mapl •
tree.

With regard to the nitrogcnisod constituents of the
plant, as gluten and albumen, it would seem that the

ASHES OF PLANTS. 73

presence of sulphates and phosphates is of especial impor-
tance 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
ricli in nitrogen.

The proportions of the several kinds of earthy matter
required by plants are also sensibly different, as well as the
gross quantities. This is readily seen by a glance at the
table, which shows that the ashes of one plant may
contain as much potash as all or nearly all the other sub-
stances ; another as much lime, another as much silica. The
power of selecting these substances appears, in the healthy
state of the plant, to reside mainly in the root, but the ac-
tion of the root in this respect is determined by the require-
ments of the plant and the changes going on in all its
parts. Hence the requirements of the same plant may not
be the same in different stages of growth.

CHAPTER IX.

THK SOIL.
§1. Nature anH Origin of the Soil.

The soil is derived from the waste of the rocks of tin:
earth's crust ; but it is not a mere mass of rubbish ; on the
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 pi-operties
in reference to the nutrition of the plants that grow on it.

With regard to the origin 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 distinet
minerals : 1st, quartz or flint, which is nearly pure silica ;
2nd, feldspar, with flat and shining surfaces of a white or
reddish colour, and usually the largest ingredient in tlu'
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 dl
iron, oxide of manganese, potash, and sometimes magnesia.'

Now a mass of such granite is slowly acted un by th
weather; that is, by the rain-water charged with carboni.
acid. The latter substance gradually decomposes the feh!
spar, removing its potasli and soda, and leaving tip
silica and alumina, which then become soft and crumbliiiL
and iiltimately fall into fine clay. The feldspar being thus

*If the tcaclior can obtain a piuco' of gruuitc, thcso mincrnl
may be eaailr ihown tu the pupils. The nlliod rocic Bycnile \m^
the mineral hornblende instead of niicii. iluriibieiidc \^ usually
of a blackiib colour, and consists principally of silicH, mugnosin,
lime, and oxido'of iron.

THE SOIL. 75

broken up, the quartz and mica fall asunder into sand and
flat scales, and a soil results, which in its texture will be
partly of a sandy and partly of a clayey nature, and as to com-
position 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 be 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 gran-
itic 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 follows that
in the main the soils of all parts of the world are alike, diffier-
ing principally in the proportions of the not very numerous
substances of which they are composed.

Such being the origin of the soil, it is evident that, regard-
ing it from different points of view, we may for practical
purposes form different classifications or arrangements of
soils. Let us next consider these.

§2. Arrangement of Soils according to Mechanical Texture.

We may regard soils as more or less coarse or fine, and
thus obtain a classification depending on the mechanical

76 SCIENTIFIC AGRICULTURE.

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 finest and most tena-
cious clay ; and in general, those soils are best adapted for
agriculture which consist of mixtures of sand with a mode-
rate quantity of clay and a little vegetable matter. "When
sand or other coarse matter predominates, the soil is deli-
cient 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 consequently 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 is proposed by Professor Johnston :

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

2. iStrovg Clay, or brick clay, contains from 5 to 20
per cent. sand.

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

4. Loam has from 40 to 70 per cent. sand.

5. Sandy Loam has from 70 to 90 per cent. sand.
fi. Light Sand has loss than 10 per cent. clay.

§3. Arrangement of soils according to their gt^cral
chemical characters.

We may cla.s8ify soils according to their predominant m
loading ingredients. Here wc may divide soils int
organic and inorganic partes, the former consisting of tli-
roinains ol" plants and animals mi.xcd with the soil, the int
ter of the mineral substances originally proseni in it. The-
last again may consist of silica, alumina, or lime in pi'
dominant ([uantity. llonco wo obtain such a classification
as tho following : —

1. Organic noils, or those of bogs, and tho vegetable
mould of the woods, consisting in great part of partially
duuuuiposed vog;otublu matter,

THE SOIL. 77

2. Silicious soib, or those in which silicious sand is the
prevailing ingredient, and which are often formed from the
waste of sandstone rocks.

3. Argillaceous soils, or those which consist principally of
clay, and are often formed from the waste of slates and
shalcB.

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. Arrangement of soils according to details of compo-
sition and relative fertility.

We may classify soils of any or all tlie kinds separated
in the above heads, according to their fertility 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, is absolutely bai-ren ; but we cull a soil barren
which will not produce such plants as t^e farmer cultivates.
Such a soil may be made fertile by adding to it tlie sub-
stances in which it is deficient ; but if this cannot be done
except at a cost as great or greater than that for which fer-
tile soil can be procured, the soil may be regarded as prac-
tically barren and worthless.

The mechanical texture and predominant ingredients of
soils, though important to their fertility, do not absolutely
determine it. A sandy, loamy or clay soil, or a silicious or
calcareous soil may or may not contain all the materials of
the ashes of oiir crops ; and if it does not it will be bar-
ren. This obliges us to consider the composition of soils
in detail. Bearing in mind then the three classifications of
soils above explained, let us next proceed to consider
their composition.

This will be seen at a glance in the following table, from
Johnston, representing the ingredients of three different
wils, with their relative properties.

78

SCIENTIFIC AGRICULTURE.

Composition of soils of different degrees of fertility.

Fertile

Fertile

without

with

Barren.

Manure.'

Manure.

40

97

50

648

833

778

57

51

91

59

18

4

8i

8

1

61

30

81

1

3

i

2

trace

trace

w

2

i

\

4i

n

40

4J

14

41

1000

1000

1000

Organic matter,

Silica (in the sand and clay,) . . . .

Alumina (in the clay,)

Lime,

Magnesia,

Oxide of iron,

Oxide of manganese,"

Potash,

^, , '. > chiefly as common salt
Chlorine, S

Sulphuric acid,

Phosphoric acid,

Carbonic acid, (combined with the

lime and magnesia,)

Loss,

§5. Causes of Fertility and Barrenness.

Jn considcrinf^ this table, it is appai-ent that the fertile
soil contains all the substances present in the ashes of plants,
while the soil fertile with manure is deiicient in some of
them, which can however be supplied in the ordinary course
of agriculture. The barren soil on the other hand is desti-
tute of so many of the most important of these substances,
^h&t it can scarcely be rendered I'ertile.

Wo also find that, even in tlie fertile soil, tlic constituents
pf the ashes of plants are present in very difl'erent propor-
tions from those in which they occur in the plant; some of
those most abundant in the plant being the rarest in tlu; 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 con-
tiiining this food, and giving suj)p()rt and proU'ction to the
plant aud its roots. The substance alumina, which wc find |

THE SOIL. 79

in the soil and not in the plant, is especially important in
these Avays.

We thus learn that it is possible to reduce a fertile soil
to barrenness without materially altering its weight, bulk,
or mechanical texture. More precisely, we find that the
substances necessary to the plant, and present in smallest
quantity in the fertile soil, and absent from the more barren
ones, are potash and soda, chlorine, sulphuric acid, and
phosphoric acid. Of these, potash and phosphoric acid are
both the most important to the more valuable crops, and
the most difiicult and costly to procure.

It results that in so far as inorganic matters are con-
cerned, the alkalies and bone earth stand first as of prac-
tical importance in the theory of agriculture. We could,
by adding to the soil in the second table suflScient quanti-
ties of bone earth, potash, soda, gypsum, and common salt,
remedy most of its deficiencies. Further, since a small
percentage in the table amounts to a large quantity in the
soil of an acre of land, the quantity of these substances
present in the fertile soil may be sufficient for many crops,
and that required by the more barren soil for even one crop
may be very considerable.

We must also consider here the difi'erences of the soil
and mh-soil. The upper soil may be fertile and the sub-
soil barren, 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 sub-soil 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 sub-soil with
the soil may be injurious, in the latter it may be beneficial.

Again our table shows that the fertility or barrenness of
soils does not altogether 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, curbonic acid and ammonia to nourish
the organic part of the plant. It is setting free, little
by little, the earthy matters of its own ashes. It is also by
ite decay inducing chemical changes, which tend to set free

80 SCIENTIFIC AGRICULTURE.

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 colour of the soil, and thus enables the sola;-
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. Important though the organic matter of
the soil is, the mineral matter is more so.

The table of the composition of soils, when compai-ed
with that of the ashes of cultivated plants, throws light on
the causes of exhaustion of soils, and on the advantages of
rotation of crops. Soils manifestly become exhausted
when, by a succession of crops requiring much of sonic
particular substance, that substance is removed from the
soil to such an extent that the crop can no longer obtain
a sufl&cient quantity ; and the number of crops which :i
soil will give, depends on the amount of such matter whicli
it originally contained. The particular substance fir^^t
exhausted will be that which was originally most <lt
ficient in the soil, and on which the ci'op in question
makes the greatest demands. Further, the exhaustion
of one substance is fatal to the fertility of the soil, csji
cially for such crops as require much of that eabstanc
since the plant cannot, except within very narrow limit
substitute one element for another. Again, in referein
to rotation, it is plain that a soil may be exhausted for v\
plant, when it still retains food for another. A pl:n
requiring mucli ashes may thus alternate with one rcquirii
little; a plant requiring mudi silica and j)hosphoric acid,
with one requiring much alkali or lime; u plant feodin;;
mainly on the surface with one feeding mainly on the subsoi I .
Of course, that rotation may be of permanent service, ii
is neccHBory that advantage bo taken of the change of ci(i|i
to restore the subntjinces exliaustcd in Ibrmer years.

Our table also enables us to understand tlio uses < l
$peciul manuren and viinernl mannres. If n soil is d'li
cient in iiulphuric acid, and cuntnins all the otlier requisii

THE SOIL. 81

of fertility, then gypsum (sulphate of lime) will be the
special manure that it requires ; but if it has enough of
sulphuric acid and is deficient in phosphoric acid, then
gypsum will do no good, but bone earth will produce or
restore fertility. Again, after a heavy dressing of one
of these substances, it may not be required for several
years, but some other substances may be needed ; and this
all the more because the larger crops will exhaust such
other substances more rapidly than the spialler crops did
previously. It is evident that to apply such special and
mineral manures with economy and success, requireff much
knowledge, and that the application useful on one soil may
be quite useless on another, and the application useful on a
tioil in one season useless in another. In no point do
practical men, who make experiments with mineral manures,
orr more widely than in this. Such errors can be best
avoided either by having an accurate analysis of the soil,
by making small experiments with special manures, or by
comparing the composition of the plants which fail or suc-
ceed on the land in question, and inferring from this the
.substances deficient.

Lastly, this subject connects itself with the diflferences
>r good and bad seasons, and with many diseases of culti-
vated crops, which at first sight do not appear to depend
on the soil. The farmer whose land is becoming exhausted,
•often deceives himself by supposing that there has been a
succession of unfavorable seasons, or that the seasons are
becoming worse. His land may be in such a state that in an
unusually favorable season it will produce a good crop, but
not in an ordinary season, and since the large crop exhausts
it more than the small one, it yiay be even worse 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 unhealthy condition of a plant, depend-
ing on deficient nutriment from the soil, is the predisposing
cause of diseases and failures. If the soil has the materials
il' the straw and leaves of wheat, and has not the phos-

82 SCIENTIFIC AGRICULTURE.

phates I'equired for the grain, the latter cannot be pro-
duced ; 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
accumulated to this use, these become a prey to the fungi,
which cause rust, mildew, 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.

These considerations embrace all the essential points
relating to the soil, which can be deduced from its com-
position ; but one most important question remains, which
cannot be answered by chemical analysis alone. This is,
to what extent are the substances present in the soil j)rac-
tically availahle for the use of plants ? On the one hand
the nutritive substances contained in the soil might be in a
state so soluble that they might bo exhausted in a single
season. On the other hand, chemical analysis may, and,
no doubt, often does, shew the .presence in the soil of
nutritive substances which are in a state so insoluble that
they cannot be obtained by the roots of plants witliin the
time to which they are restricted for their growth.
Theory and experience concur in proving that soils differ
very much in these respects, and that while all soils have
considerable power of retaining in their pores even thr
most soluble substances, some part with them too readily,
and others retain them too firmly, or only part with them
when exposed to various preparatory processes. Tlio
management of the soil with refbrcn(je to the use and
retention of nutritive substances is one of the nio.st
difficult problems, both for the clicmist and the practical
liinnor.

i?n. Atiaiirlii III III' rr.tm'ii iiiif /nnnr uf llw anil.

The al).s<irh('iit nn<l rcliiiniiig jiowor ol sciil is (iiic of its
nioHt romiirkable prnpt'rties ; and much additional pro-
tniiiuiice Iium boun given to it by recent exjterimentfl ^

THE SOIL. 83

detailed by Baron Liebig in his late work on "The Natural
]jaws of Husbandry." The arable soil is not a mere
sieve through which any matter in solution can pass freely ;
but, on the contrary, it has a greatr 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 different substances. In passing through any ordinary
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 substances is less; in heavier soils,
greater ; in soils having 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 soils. 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 substances
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 are found to part with these bases to the
soil : the acids present entering into other combinations,

It would seem from various experiments that the matters
thus absorbed by the soil are more readily available to plants
than those in chemical combination with its ingredients.
The latter are only little by little set free by decom-
position ; and this is believed to explain the fact that
chemical analysis often shews a lai'ger amount of nutritive
substances than experiment proves to be practically avail-
able, and also the effect of tillage in improving soils.
Thus, if an analysis shows a large quantity of phosphate
of lime in a soil, it may yet happen that plants like wheat,
which re({uire much of this substan<fe, may not be able to
f)l)tain it in time, in consequence of its occurrence in the

154 SCIENTIFIC AGRICULTURE.

form of solid paiiicles or sand. Tillage, by stirring the
soil and promoting the solution of these particles and
their mechanical absorption by the ground, may make
them readily 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 absorb-
ing power, it retains the substances dissolved till required
by the roots of the crop.

Certain chemical manures also, as common sjilt and
lime, are highly' important in the solution of inert sub-
stances; and the matters thus dissolved, being absorbed
by the soil, ai'e 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 fertilisers.

The absorbent power of soils also serves to illustrate the
advantages of subsoil ploughing and draining, as it is of
the highest importance to bring pll parts of the soil within
reach of the air and water permeating it, and that it may
absorb nutritive matters instead of rejecting them froBi its
Hurface. 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 impover
ish the land by allowing its soluble constituents to bi
carried off by water.

It follows, from these considerations, tliii! our estimad
of the value of arable land must depend iiiuinly on it-
richness in the ingredients of cultivated crops, on i]\<
availability of these ingredients, and on its power of al -
soi;bing and retaining the manures placed in it by tin
larnier, or produced by the decomposition of its own mu-
terials. .1

I

CHAPTER X.

EXHAUSTION OP THE SOIL.

§ 1. Causes of Exhaustion.

Johnston gives the following estimate of the quantity of
matter taken from an acre by an ordinary English four
course rotation. lie 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.

Turnip

roots

Barley,
grain straw

Potash 145.5

Soda 64.3

Lime 45.8

Magnesia 15.5

Alumina 2.2

Silica 23.6

Sulphuric Acid. . 49.0

Phosphoric Acid. 22.4

Chlorine ' 14.0

5.6
5.8
2.1
3.6
0.5
23.0
1.2
4.2
0.4

4,5
l.l

12.9
1.8
3.4

90.0
2.8
3.7
1.5

Clover

Rye

Wheat.

Total.

grass
28.5

graiuistraw

45.0

3.3

0.6

239.0

12.0

9.0

3.5

0.9

96.6

63.0

16.5

1.5

7.2

149.0

7.5

2.0

1.6

1.0

32.9

0.3

0.8

0.4

2.7

10.3

8.0

62.0

6.0

86.0

299.2

10.0

8.0

0.8

1.0

72.8

15.0

0.6

0.6

5.0

51.5

8.0

0.1

0.2

0.9

25.6

Total, pounds 970.9

If we were to suppose the common four years' rotation
j 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 ;
[I And if we inquire as to the nature of this loss, we find that

^6 Scientific agriculture.

it might be repaired, if we except the silica, which, Ijeing
abundant in nearly all soils, may be left out of the account,
by the following quantities of mineral manures :

325 lbs dry Pearl Ash. 150 " Quick Lime.

333 " Carbonate of Soda. • 200 " Epsom Salts.

43 " Common Salt. 83 " Alum.

30 " Gypsum, 210 " Bone dust.

These substances would be ' required to replace those
taken away, provided that no part of the crops or th;-
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 the most exhaust-
ing to the soil. Practically however, the difference between
a rotation such as this, and no rotation, includes the suppos-
ition that manures are introduced with the green crops,
whereas where there is no rotation, grain crops arc often cul-
tivated for a successibn of years without manure.

Whatever the crops cultivated, it is apparent that crop-
ping for successive years without manuring, must ultimately
exhaust the soil or render it barren . A very rich soil may lon;^
endure such cropping, owing to the great quantity of these
substances contained in it ; a poor soil will be reduced !>
sterility sooner; a shallow soil will fail sooner than a deep
one, a light soil sooner than a stiff one.

Further, the more available substances in the 5oil will he
exhausted first. The less soluble will remain, and thus ■
soil may become barren while it still retains much of ll
food of plants: in this state its productiveness may partiality
and temporarily be restored by leaving it at rest, and
especially by fallowing and tillage, or by ploughing in of
^een crops, all of which processes tend to set free some <ii'
the previously insoluble substances.

If wo coujpare the table of the substances removed 1
crops with tliat 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. Wo cannot exhan
any ordinary soil of silica, alumina, or oxido of iron ; iv
can A soil naturally calcareous bo exhausted of its lini<

EXHAUSTION OF SOILS. 87

but there are few soils which can bear several crops without
manure and not suffer an appreciable exhaustion of their
available phosphates and alkalies. This gives to these
•ubstances a very great importance as mineral manures.

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 some-
times regarded as tlie 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 vegetable matters which have grown upon
the soil, and these are exhausted with tlie 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 subsoil, 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 destruct-
ive cropping, the land will ^ill yield, something after repose
or fallowing, or subsoil or trench ploughing.

As the soil becomes gradually poorer under exhaustive

'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, &o.,
attack the crop and diminish still farther the yield. All
these evils are aggravated if the same variety of grain is
cultivated without change of seed. In these circumstances

I 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 farther cotjfirmed in
it when he finds that ploughing in a green crop or adding

88 SCIENTIFIC AGRICULTURE.

stable manure, though it increases the straw, does not mucli
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 be fertilized except
by restoring them to it.

This sad picture of exhaustion applies to large portions
of eastern America, and is the principal reason why tin-
wheat culture continually recedes to the west, leaving the
exhausted fields to be occupied with buckwheat or otlu i'
inferior grains.

Some curious cases of special exhaustion of single sul -
stances have been observed by 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 removed in the bones and milk of cattle,
gradually tell on the quantity of these substances in tlio
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, iu
this case, beginning to be deficient.

It follows from the above statements, that to know ll
nature, causes and remedies of exhaustion in any particular
case, we must study the originiJ composition of the soil, tlio
substances which have been removed from it by croppin
and the best and cheapest way of supplying those whi'
liave become deficient.

It also follows that the fertility of the land can bo main-
tained only by restoring to it an adccjuate amount of the
substances of which our crops deprive it, or by rendering
frewh quantities of these still in the soil available to plants
by tillage, fallowing, &c. This la.Ht mode however loads ;>t
length to a total exhaustion of the soil, if pursued with<
recourse to thi; other. Fortunately for the farmer, li
produce which Ik; must sell ott" the larui docs not takouv
80 much inorganic matter iis that which he nniy keep ;
for instance, he disposes only of grain and aninml produ>
he can keop for the sustcnauce of tlic Innd nil the stra^

EXHAUSTION OF SOILS. 89

hay, roots, &c., oi* 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 indefinite period, though the introduction
of additional manures will even in this case be more or
less requisite. In China and Japan a scrupulpus and
painstaking economy of every kind of animal and vegetable
manure has maintained the fertility of the soil from the
most remote ages, and will continue to do so, and to support
a dense population for an indefinite period, and this without
any knowledge of scientific principles. On the other hand
the neglect of manures in some districts of North America
establishes a drain upon the land, which no amount of
scientific knowledge can remedy except at very great cost.

§ 2. — Exhatisted Soils of Canada.

Many verv instructive facts in relation to the exhaustion
of soils in Canada, are disclosed by the analyses of Cana-
dian 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 analysed was a vegetable mould from
the alluvial flats of the valley of the Thames in Western
Canada, and is said to have yielded 40 or even 42 bushels of
wheat to the acre, and in some instances, to have been suc-
cessfully cropped for thirty or forty years without manuring.
Dr. Hunt describes this soil as fillows : —

" 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 begiin to adopt it, and have
commenced the cultivation of clover, which grows finely,
especially with a dressing of plaster, which is used to some
extent.

'' The natural growth of these lands is oak, and elm, with
black walnut and whitewood trees of enormous size ; the
black walnut timber is already becoming a considerable

7

90 SCIENTIFIC AGRICULTURE.

I

article of export. Fine groves of 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 $-om the seventh lot of the first range of Kalcigh.
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 con-
tained but a trace of white silicious sand.

" No. 1 consisted of —

Clay 83.4

Vegetable matter 12.0

Water.. 4.6

100.0

100 parts of it gave to heated Hydrochloric Acid —

Alumina 2.620

Oxyd of Iron and a little Oxyd of Manganese 5.660

Lime '. 1.500

Magnesia 1.060

PoUsh and Soda 825

Phosphoric Acid 400

Sulphuric Acid 108

Soluble Silica 290

I)

This, it will be observed, is a soil rich in alkali< -,
phosphoric acid, and soluble silica; and on these accoun
eminently adapted for the growth of wheat as well a.s
nearly all other ordinary crops.

With this may be compared a soil from Chambly, in
Lower Canada, respectihg which the following remarks
arc made :

*' The soils of this Seigniory are principally of a rcddi !i
clay, which, when exposed to the air, readily fulls down into
a mellow granular soil. In the places where I Imd an
opportunity of observing, it is underlaid at tho. dej)tli of
three or four l'tt«'t by an exceedingly tenacious bhio clny.
which breaks into angular fragments, and resist^s the acti
of the weather. The upper olaya constitute the win
bearing soils, and v/vrv. originally eov(!red with n growtli
maple, elm, und birch; distinguished from tin m }>\

EXHAUSTIO>;r OP SOILS. 91

covering of soft woods, principally pine and tamarack, is a
gi-avelly 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 indicated 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 man-
ured ; 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 improve-
ment of their lands have been very small ; so that the
Richelieu valley, once the granary of the Lower Province,
has for many years scarcely furnished any wheat for expor-
tation. 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, only 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 *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
successive years without receiving any munure. No. 3 ; the
latter supported a scanty growth of a short thin wiry grass,
which is regarded as indicative of an impoverished 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
Ifarm of Mr. Yule."

No. 2 contained a small amount of silicious sand and
jtraces of organic matter, and gave 5.5 per cent, of water.

100 parts of it yielded to heated Uydrochloric Acid :

■100.0

92 SCIENTIFIC AGRICULTURE.

Alumina 3.300

Oxyd of Iron 8.G80

Manganese 160

Lime.... 711

Magnesia 2.310

Potash 536

Soda 340

Phosphoric Acid 418

Sulphuric Acid '. 020

Soluble Silica 180

No. 8 consisted of —

Silicious sand with a little feldspar 9.0

Clay 79-2

Vegetable matter 0.8

Water 50

100 parts of it gave —

Alumina not determined

Oxyd of Iron 4.560

Lime 347

Magnesia 888

Potash) 380

Soda \

Phosphoric Acid 120

Sulphuric Acid 031

Soluble Silica 080

By the action of wat«r, a solution containing minmo
traces of chloHdo 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 pebM
and 12 of coarse gravel ; that, portion which passed thron
the flicvc consisted of —

Gravel 7B.0

Clay 1.3.7

Vegi-table matter C.l

Water B.2

100.0 )

The Boil was vcsry red, and the sand siliciotis and quite \
ferruginous, couHisting of the disintegrated syenitic rocks *
which make up tho courser i>ortionB.

EXHAUSTION OF SOILS. 93

100 parts gave —

Alumina 2.935

Oxjd of Iron 5.505

Lime '. 150

Magnesia 409

Potash 109 •

Soda 144

Phosphoric Acid 220

Sulphuric Acid 018

Soluble Silica 080

The first of these soils, (No. 2) that which liad not been
hausted, 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
exhausted soil, No. 3, we see at once that the latter has
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, soda, and phos-
phates, is, in truth, the cause of its present sterility ; and
when we consider that the straw and grain of thirty crops
of wlieat have been taken from it without return, we have
sufficient reason for the change.

The third soil. No. 4, characterised 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 phos-
phoric acid as the worn out soil. No. 4, and is not behind
it in soluble silica. An equal quantity of ordinary manure
would probably produce more effect on it than on the
exhausted soil. No. 4.

Another term of comparison is afforded by a soil from

I the farm of Major Campbell, at St. Hilaire, which is said

i to have been reclaimed from comparative exhaustion, by

manuring and draining. It is a heavy clay, and afforded,

on analysis, in 100 parts :

94 SCIENTIFIC AQMCULTtmE.

Alumina 12.420

Oxyd of Iron 7.320

Lime 697

Magnesia 1.490

Potash' 591

Soda , 231

Phosphoric Acid 390

'Sulphuric Acid 022

Soluble Silica 105

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 proprietor, and
to the admixture of unexhausted subsoil by draining and
deeper ploughing.

That this last cause had some share in the result, is indi-
cated 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 givgs the natural quality of the soil. It
shows in 100 parts:

Alumina 4.;}80

Oxj'd of Iron 6.245

I.ime 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 solublo
silica. The subsoil is a vast store of mineral manure,
ready to he applied to use by under-draining and subsoil
ploughing. It would seem that this applies very gonorally
to the exhausted clay soils of (^anada, whicli, having Ihmh
undrained, ploughed in a shallow manner, and cropped 1 \
plants which iVcA in these circumstances only on the su
face soil, might be renovated by tile draining and the u-
of the 8ubik)il plough more easily than by the apjilicatiou of
manuriul HubiituncuH. Thi.s is a fact which holds foiili u

EXHAUSTION OF SOILS. 95

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 soil. It would also
require the addition of some organic matter, as, for instance,
peat or bog mud.

In leaving these Canadian soils, it is deserving of
remark, that even the richest of them are rather poor in
sulphuric acid, and would, therefore, probably be benefited
by the use of gypsum.

CHAPTER XI.

IMPROVEMENT OF THE SOIL.

This may be either mechanical, by acting on the texture
of the 8oil and its relations to water and the air, or chemical,
by adding to it nutritive substances. The former only will
be considered in this place. The latter will come more
naturally under the head of manures.

§ 1. Tillage dx.

Several methods of improving the mechanical condition
of the soil are within the reach of the farmer.

One of these is the ancient and most important ex-
pedient of tillage. The stirring and loosening of the soil by
the plough, the spade, the harrow, the subsoil plough, and
other implements, are not merely necessary preparations iur
the seed, but important means of ameliorating the soil.
The chemical changes proceeding 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 fillefl with
air, the smaller with water. This is the condition of a mcl
low, well prepared soil. It is the condition most favourablo
to the germination of seeds and the penetration of roots, a>
well as to the complex chemistry of the soil itsell'. The roots
of a crop exhaust the soil in their vicinity, while other por-
tions remain unUmched ; but tillage mixes the whole again,
and gives the roots of the succeeding crop a better oppor-
tunity of extracting nutriment.

Again, there are in most soils small fragments of vege-
table and mineral matter, which, if exposed to the action of
the air and moisture, would yield up their constituents as
iuod for plants. Tillage «nnblt!s thorn to do so. Henow

IMPROVEMENT OF SOILS.- 97

the maxim of some farmers that much and careful tillage
is equivalent to manure. Hence also the benefit of fallow-
ing, 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 of 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 ex-
hausted 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, pro-
long for some time, though not for ever, the fruitfulness of
the soil.

Subsoiling may be done either by the subsoil plough,
contrived for the purpose, or by running a second plough
in the furrow caused by another. In the former case the
subsoil is merely stirred and broken ; in the latter it is mixed
with the soil, which may in some cases have a temporarily
injurious effect. In either way, a few inches are added to
the available depth of the soil, and this may be increased
by a second or third subsoiling. Subsoil ploughing is of
immeuse benefit when the surface has been run out by bad
farming, and also in soils having a hard '*pan " beneath the
plough. I have known cases in which the subsoil plough has
been the means of producing good crops from cold white
sand and clay, previously very unproductive. In very wet
and flat land, however, draining should go before or accom-
pany subsoiling, otherwise an injurious wetness may result.
Another mode of improving the soil, is the addition of
substances capable of changing its texture. Thus shore
sand is sometimes carted upon stiff" clays with benefit. In
like manner coal-ashes, lime rubbish, sandy marl, peat com-
posts, and many other substances ordinarily employed as
manures, tend to lighten and pulverize the ground. On
the other hand, marsh and creek mud, and similar sub-

9B SCIENTIITC AGRICULTURE.

stances, much improve the texture of light and gravelly
soils, by making them more retentive. In applying manures
containing much sandy and earthy matter, it is always to
the interest of the farmer to consider the effects which they
may have on the mechanical qualities of the soil, and to use
them on those portions of ground where their effects in this
respect will be most beneficial.

§ 2. Draining.

Another and most important mode of ameliorating the
soil is under-draining, or draining Tjy tiles and similar con
trivances. No expedient has proved so serviceable in im-
proving the mechanical qualities of the soil ; and even in warm
and dry climates like that of Canada, it has been found
most profitable by all who have skilfully employed it. —
Its various beneficial effects may be shortly summed up as
follows : —

It makes the soil warmer, by draining off the water which
otherwise would keep the ground cold by its evajx)ratiou.
For this reason, it enables the gi-ound to be worked earlier
in spring and later in autumn, 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 already described, saves the riches of
the soil from waste.

It allows the roots of plants to penetrate deeply into th.
soil, instead of being stopped, as they oft<>.n arc,'at the dcpt I,
of a few inclies, by a hard subsoil, or by ground saturated
with water, or loaded with substances injurious to vegetation.
For tills reafion, drained lands stand drought better than
undrainedi and tlieir crops are also larger and more healthy.
Ilenco also it ol'ten liappens that draining benefits oven
light landH, if they happen to liave an impcrnioable. subsoil.

It [)ermit« froo access of uir, thus preventing the " sour
injj" of the soil, and bringing ninnurefi of nil kinds into a fit
Btato for absorption by llic roots.

1

IMPROVEMENT OP SOILS. 99

It prevents injury to the soil from the water of springs
and other waters coming from beneath by capillary attrac-
tion. 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 throwing oxit
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 alike injuries
from drought and excessive moisture ; economizes manures ;
and is equivalent to the deepening of the soil, and length-
ening of the summer.

The following short summary of the methods of under-
draining is taken from " Norton's Elements of Scientific
Agriculture. " It is to be hoped that its practice will soon
be familiar to every farmer in our country.

" 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, on even a
foot of surface. Manures, also, cannot easily sink down
beyond the reach of plants. On such a soil, too, deep plough-
ing could be practised, without fear of disturbing the
top of the drains. The farmer should not, by making his
drains shallow, deprive himself of the power to use the sub-
soil 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 tJiey should be made, and
the materials to be used."

'* The ditch should, of course, be wedge-shaped, for con-
venience of digging, and should be smooth on the bottom."

l^DO SCIENTIFIC AGRICULTURE.

" Where stones are used, the proper width is about six
inches at the bottom. Small stones should be selected, or
large ones broken to about the size of a hen's egg, and the
ditch filled in with these to a depth of nine or ten inches.
The earth is apt to fall into the cavities among larger stones,
and mice or rats makes their burrows there; in either case
water finds its way from above, and washes in dirt and mud,
soon causing the drain to choke. With small stones, chok-
ing from either of these causes cannot take place, if a good
turf be laid, grass side down, above the stones, and the earth
then trampled in hard. Cypress or cedar shavings are some-
times used, but are not quite so sale as a good sound turf.
The water should find its way into the drain from the sides,
and not from the top."

" Stones broken to the size above mentioned are expen-
sive in this country, and in many places they cannot be pro-
cured; in England, it is now found that tiles, made of clay
and burned, are cheapest. These have been made of vari-
ous shapes.

"The first used was the horse-shoe tile. This was so
named from its shape ; it had a sole inade 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 Iwre 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 pitice ; 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,
having been previously made <juite smooth and struighjl
They are simply placed end to end, then wedged a litt
with small stones, if necessary, and the earth packed lia
over them. Water will always find its way through tl
jolntH. Such pipiis, laid at a depth of from 2^ to 3 feol
and at proper distances between tlic drains, will, in timfl
dry the Htiffcflt clays. Many farmers have thought that wat
would not find its way in, but expurienoe will soon shotj

IMPROVEMENT OF SOILS. 101

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 penetrated through the whole mass
of soil that is within the influence of the drain, making it
all, after a season or two, light, mellow, and wholesome for
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 discharge 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 cen-
tury. The pipe tiles are used of from 1 to li^ inches dia-
meter 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 dis-
charge an immense quantity of water, and is quite sufficient
for most situations. These small drains should not ordin-
arily be carried more than 400 to 500 feet before they pass
into a large one, running across their ends. Where a very
great quantity of water is to be discharged, two large-sized
. horse-shoe 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 ait off the springs ; but it is now found most effica-
cious to run them strmght down, at regular distances apart,
according to the abundance of water and the nature of the
soil. From 20 to 50 feet between them, would 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 drains running
straight down, and discharging into a main cross-drain at
the foot, are amply sufficient. "

" Tile machines are now introduced into this country, and
tiles will soon come into extensive use. Their easy porta-
bility, their permanency when laid down, and the perfection

102 SCIENTIFIC AGRICULTURE.

of theii- work, will recommend them for general adoption.
It is also to be noticed, that it takes less time to lay thcni
than stones, and that the ditch required for their reception
is smaller and narrower. The bottom of it need only be
wide enough to receive the tiles. The upper part oi" the
earth is taken out with a common spade, and the lower pair
with one made quite narrow for the purpose, being on 1\
about four inches wide at the point. The bottom is finishcu
clean and smooth, with a peculiar hoe or scoop. This is
necessary, because the tiles must be laid on an even smootli
foundation, "

With regard to these mechanical modes of improviuu
the soil, it may be stated with truth —

1. That except in some cases of naturally deep and well-
drained soils, no soil has a fair chance of showing its capa-
bilities without deep ploughing and draining.

2. That many partially exhausted 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 improvements
liave proved themselves to be among the cheapest and most
profitable that can be attempted.

CHAPTER XII.

IMPROVEMENT OF THE SOIL BY MANURES.

§ 1. General Nature of Manures.

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, according to their origin,
nature, and uses.

• Some manures are supplied by animal and vegetable
substances, others by mineral substances ; hence the distinc-
tion arises o^ organic manures , and inorganic manures.

Some ai'e produced on the fann, from the crops it has
yielded, and their application only restores what has been
taken away ; others are obtained from abroad, and so are
actual additions to the soil.

Some act directly as food to plants, others a^o 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 indirect-
ly 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 of plants. Of this kind
are such substances as nitrate of soda, gypsum, and super-
phosphate of lime.

Some afford nourishment principally to the organic part
of plants ; and of this kind the most important are those

104 SCIENTIFIC AGRICULTURE.

which can supply ammonia and carbonic acid. Others
aflFord 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 inoi-
ganic, and shall notice under each its relations to various
soils and plants.

§ 2. Organic Manures.

Under this head, I group all those fertilizing substanotn
which have formed parts of animals or plants, and arc
restored to the soil, whence, or by the aid of which, they
were obtained ; though some of them cannot, in sti'ict clu-
mical language, be termed organic.

Stnhle Manures. — One of the ablest of British American
agriculturists has said, " More than one-half of the
manure made in the provinces is absolutely vested from
ignorancti and inattention ; and the other hali" is much
more unproductive 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 dimu,
which, frouFtime to time, is wheeled out of the barn.
Sometimes it is spread out on the green sward ; sonictinu s
cast carelessly in a court, or adjoining yard; but selchnu is
an excavation madfe, purjMisely for retairung the juiti s
which run from it. These are suft'ered cither to stream
along the surface, or sink into the earth ; and in cithor
ca>KJ, their utility is sacrificed to inattention or ignoran.
This is no more, liowever, than half the evil. The exli
lationb wliicli ariw; from the ardent inliuence ol' the sum
iner's sun, or from the natural activity of fermentation,
are jwnnitted to escaiHJ freely, and to carry with them all
the Btrengih and Hubstanoe uf the putrescible matter."'''

• Youug** "Letters of Agricola," liallfuz, 1822.

MANURES. 105

There is, no doubt, much more attention giTcn to this
important subject noW ; but still, the waste of barn-yard
manure, both solid and liquid, is a great evil, and a fruit-
ful cause of agricultural poverty, and failures of crops.
About two years ago, I had referred to this subject in a
public lecture, and happened, immediately afterward, to
drive ten or twelve miles into the country, with an intelli'
gent 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 thiit we passed, for the pre-
servation of manure. It was in early spring, and we found
scarcely one barn that had not its large manure heap per-
fectly 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
deliberately losing between one-half and two-thirds of the
means of raising crops, contained in his own barn-yard.
What would we think of a tradesman or manufacturer,
who should carelessly suffer one half of his stock of raw
material to go to waste ; ajid 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 thi.s v.'uste.

Compost io.'i 0, Solid Stable Manure (Richardson).

Carbon <■ 37.40

Hydrogen 5.27

Oxygen 25.52

Nitrogen 1.76

Ashes 30.05

100.00
8

106 SCIENTIFIC AGRICULTURE.

Compoiition of the Ashes of Stable Manure (Richard son).

Potash 3.22"

Soda 2. TO

Lime 0.34

Magnesia 0. 26 }■ Z'.

Sulphuric Acid 3.27 1 ^

Chlorine 3.15 ^

aiica 0.04 ^

3 a

Phosphate of Lime 7.11 1

" of Magnesia 2.26 1

" of Oxide of Iron 4.68 1

Carbonate of Lime 9.34 )■ ^^

" of Magrnesiar 1.631 2. -

Silica 27.01 I

Sand, &c 34.96 J

100.00

Composition of Liquid Stable Manure (Boussaisgault).

Horse. Cow.

Urea 31.00 18.48

Hippurate of Potash 4.74 10.51

Lactate of Potash 20.09 17.16

Carbonate of Magnesia 4.16 4.74

•' ofLime 10.82 0.55

Sulphate of Potash 1,18 3.60

Chloride of Sodium 0.74 1.52

Silica 1.01

Water, &c 910.76 921.32

1000.00 1000.00

Urea, the principal organic ingredient of Urine, consists of—

Carbon 20.0

Hjdrogen u 6.6

Oxygen 46. 7

Nitrogen 26. 7

100.0

Urea is very rich in nitrogen. In dftcompoHing, it
•Uangeii into oarbonato of ammonia, which riipidly 08-

MANURES. 107

capes, unless prevented by some absorbent material, as
charcoal, or by the chemical action of sulphuric acid or
gypsum.

In the above table, we see that the liquid manure con-
tains large quantities of potash and soda ; and that a large
portion of it is urea, a substance very rich in nitrogen,
and, in fact, quite similar to the richest ingredients of
guano. Johnston estimates the value of 1000 gallons of
the urine of the cow, to be equal to that of a hundred
weight 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.

In the solid manure, we perceive that there is little nitro-
gen. Thia element, so valuable for producing the richer
nutritious 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 organic matters are less easily destroyed, unless
the dung be allowed to become " fire-fanged," in which
case the greater part of it is lost. In the ashes, or inor-
ganic part, we find all the substances already referred to
as constituents of fertile soils ; and many of the most val-
uable of them are, as the manure decomposes, washed away,
and, along with a variety of organic matters, appear in the
dark-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 outlay in the purchase of other
manures, that our farmers can afford ; and we can plainly
perceive, that the prevailing neglect in this one particular,
18 sufficient 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 principles on
which the means adopted for saving manures should be
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
roof, sufficient to protect it from Vciin and snow. Its own
natural moisture is sufficient to promote, during winter, a

108 BCIENTIFIC AGRICULTURE.

slow and beneficial fermentation. Snow only prevents this
from going on ; rain washes away the substance of the fer-
mented 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 unnecessary exposure should be avoided.

4. Where gypsum can be procured cheaply, it should be
strewed about the stables, and on the manure heap, for tho
purpose of converting volatile ammoniacal vapours into
jixed 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 tlie most easily injured. For example, many farmers
think horse manure to be of little value. The reason is,
that when exposed it rapidly enters into a violent fermen-
tation and decay, and its more valuable parts are lost.
Such manures require more care than others, in protection
and covering, so as to moderate the chemical changes to
which they are so liable, and to save the volatile and sol-
uble 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 sepa-
rate pit prepared for the purpose. The latter is the better
method. If a tight floor can be made in tlio stable, it
should be sloped from the heads of the cattle, and a chan-
nel made, along which the urine can flow ink> the pit. If
the floor is optui, the pit should b<^ directly beneath it, or
tho ground below should be sloped to conduct the Hcjuid
intf) the pit. In what^iver way arranged, the pit should
}m' tight in the botf^mi and sides, and should l»e filltul with
soil, or peaty swanij* mud, to iibsorb the liquid. (Jypsuin
may alRO bo added with groat biiuefit ; and the uiiiie pit
may very well form a receptacle for (loor-clcanings, litter
whieh niny accumulate alxtut the barn, and every other

MANURES. 109

kind of vegetable of animal refuse. These additional mat-
ters may occasionally be protected, by adding a new layer
of peat or soil to the top. The pit for liquid manure
should be roofed over. A method much followed in Bri-
tain and the continent of Europe, is to collect the urine in
a tank, and add sulphuric acid to prevent waste of ammo-
nia. When used, the liquid 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. Gyp-
sum may be put into the tank, instead of sulphuric acid.

In a prize essay on manures, by Prof. Way, published
by the Royal Agricultural Society of England, the follow-
ing analysis is given of the drainings of a dung-heap, com-
posed of the mixed manure of horses, cattle, and sheep, and
in a well rotted condition. The fluid examined was that
washed out with rain water, and was "of a deep browii
color. It contained in each imperial gallon 764.64 grains
of solid matter, of which 395.66 were volatile and combus-
tible, and 368.98 incombustible or ashes. Its composition
was as follows : —

I. COMBDSTIBLB PaRT.

Ammonia, in a soluble state 36. 25

do in fixed salts 3.11

Ulmic and humic acids 125.50

Carbonic acid. 88.20

Other organic matters (containing 3.59

of Nitrogen 142 . 60

395. 6G

II. Incombostiblb Part.

Soluble silica 1 . 50

Phosphate of lime, with a little phos-
phate of iron 15.81

Carbonate of lime 34.91

Carbonate of magnesia 25.66

Sulphate of lime 4.36

Chi oride of sodium 45. 70

Chloride of potassium 70 . 50

Carbonate of potash 170.54

368.98

Total per gallon 764 . 64

110 SCIENTIFIC AGRICULTURE.

It will be observed- that the combustible part contains n
large amount of ammoniacal matter, and the rest is princi-
pally the richest humus or vegetable mould ; while the
incombustible 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, aifords the most conclusive 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 compensate this waste.

This subject is, in all its details, deserving of the careful
study of every practical farmer.

§ 3. Organic Manures (continued).

The remaining organic manures may be arranged under
the following heads :

1. Those which, like peat, bog mud, leaves, spent bark,
saw-dust, straw, &c., consist principally or exclusively of
woody fibre. These substances decay but slowly in tlH>
soil, and do not yield large quantities of the more rare and
valuable of the substances required by cultivated plants.
They are useful, however, in two points of view. Tiny
renew the supply of vegetable matter in the soil, ami
thereby ameliorate its texture; and they afford, by their
decay, substances useful in enabling plants to build up tin-
tissues of their stems and leaves. They are also admirable
absorbents for the richer parts of putrescent manures ; and
by mixture with these substances, they are themselvi
more rapidly decomposed. Their use, therefore, i-
already indicated, to fill the urine pit, to form the !■

the dung-hill and the cover of composts, and to h'v\c iw
litter in the stable and cattle yard. They may also bo
us<;d in top-dressing grass, — which thoy not only nourish,
but protect from the frosts of winter.

2. A second class consists of the rapidly decomposing
remains of uniuials and plants, — as dead animals, blood,

MANURES. Ill

night-soil, fish-offal, parings of hides, green succulent
weeds, sea weeds, &c. The animal 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 vegetables. The vegetable man-
ures of this class, though less valuable, afford, in addition
to their woody fibre, much alkaline matter and some
nitrogen ; and some of them contain animal substances
which add greatly to their value. Such manures should
not be left exposed, nor should they, except in case of
necessity, be applied in a fresh state to the land ; as in 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 richer kinds, of three to
one, and well covered with a coating 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, would
furnish the elements of life and vigour to the crops. The
same remark applies to dead animals, and all the putres-
cent refuse which is apt to accumulate about yards and
outhouses. Exposed on the surface, these things are pes-
tilential nuisances ; buried in the compost heap, they are
the materials of subsistence and wealth.

As Sea weed 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 composi-
tion and uses. The ashes of sea weed have been found
to contain :

Soda and Potash 15 to 40 per cent.

Lime 3 " 21

Magnesia 7 " 15

Common Salt 3 " 35

Phospliate of Lime 3 " 10

Sulphuric Acid U " 31

Silica 1 " 11

112 SCIENTIFIC AaRICULTtJRE.

These are all important substances, and, in addition to
the nitrogen contained in the organic part of the weed,
must exercise an important influence. Sea weed, however,
is but a temporary manure, as it decays very rapidly ; and
it is extremely unwise to place 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
.=ea manure, his land is becoming poor. He must also
remember, that sea weed does not contain all the materials
of land plants, in due proportion ; 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
aytumn, 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 prac-
tice, 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 manure, as
they are often rich in alkalies, and other constituents ol"
crops. Rank road-side weeds are especially valuable ; and
their removal prevents the dissemination of their seed, and
improvert the appearance of the country. The ploughing
in of green vegetables — an buckwheat, clover, or turnip tops,
— may also be considered as the application to tiie soil of
a somewhat rich vegetable manure ol this cluss.

3. A third class is formed of llu>.«o manures of animal
and vegetable origin which, though highly fertilizing, arc
not liable to rapid decay ; and arc, therefore, permanent
in their effects, and may be kept for application in a dry
state. Such are bones, hair, lioof's, lien manure, guano,
wood ashes, and soot.

lionet are of great value, as they afford that rare and
important substance, phosphate of lime, along with a rich
aniBtl aiAlter; ground bones, and " bone dust," are now

MANURES. 113

an importaut article of traffic as manure, and are of
great value, — as five busliels are. considered to be suf-
ficient manure for an acre of turnips, especially if mixed
with a little wood ashes. Every farmer should collect and
apply bones. They are very valuable, oven 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 illustrations of the value
of bones, I may refer to Jackson's Agriculture. Among
other instances, he mentions, that a dressing of 600
bushels on 24 acres of poor pasture, had so improved the
grass, as to double the yield of butter ; and this effect
endured for many years. In this case the pasture had
been laid down for t<)n years, and, no doubt, much of its
natural phosphate of lime had been exhausted, to form a
constituent in the milk and bones of the cattle that had
fed on it. In another case, he mentions a ten-fold yield
of turnips, and a great improvement in succeeding grain
crops, as resulting from its application.

Hair and Hoofs arc rich manures, though they decay
slowly. Such substances, from tanneries, &c., should be
saved, and applied to the land. At the rate of twenty or
thirty bushels per acre, they produce marked effects.

Guano is a manure produced by the slow decay of the
droppings of sea birds, in dry climates, and is chiefly ob-
tained from islands on the coast of Peru. It is very rich
in nitrogen and phosphates, and may hence be regarded
as the most concentrated form in which the most rare and
expensive parts of the food of plants can be supplied.
It contains, in the solid form, all the substances which
are present in liquid manure in a state of solution. From
two to four cwt. of guano per acre on most soils will
raise a good crop of turnips, and a succeeding grain crop ;
^ut as guano does not contain much of the ruder and more
common organic raattern useful in the soil, it is best to use

114 SCIENTIFIC AGRICULTURE.

one or two cwt. of guano, with half the usual quantity of
other manure. To render the guano more easily applied,
it should be mixed with sand or dry soil before sowing it.
Guano is one of the most valuable of manures, and is
especially applicable to soils worn out by the culture of
grain crops. Peruvian guano contains from fifty-six to
sixty-six per cent, of ammoniacal salts and organic matter,
and from 16 to 23 per cent, of phosphates. Very excellent
artificial guano is now made in Newfoundland and in
Maine from fish refuse, by boiling, pressing, and drying,
and then coarsely grinding or crushing. When pure and
genuine, these artificial guanos are among the most rich
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 influence 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 eiFects to wood ashes, but less powerful.

The great value of wood ashes may be estimated from
the remarkable effects produced by them in new land,
where the ashes of forests, the growth of centuries, are :ii
once applied to the surface. The substances which tho\
afford, may be learned from the following analysis of tli
ashes of beech wood :

Potash 16.83 per cent.

Hoda 9.79 "

Common Salt 0.23 "

Lime 62.37 "

Oypsum 2.31 "

Magnesift 11.29 "

Oxideoflron 0.79 "

Phosphoric Acl«l 3.07 "

Hilicft 1.32 " _

These are the principal subtancos on which new land
depends for Its fciUility ; and the loss of whidi, citlu'r by

MANURES. 115

wasteful cultivation or by repeated burnings 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 stshcs, and because it
prevents their caustic effects from being too strongly 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 Hol-
land, 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, C. E, :

" 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 ex-
pected, the magnesia and some of the lime in a free state."
100 parts of it gave me :

Lime 47.040

Magnesia 3.150

Peroxyd of Iron 4.G80

Alumina 2.440

Oxyd of Manganese . 040

Potash 330

Soda 254

Chlorine. 247

Sulphuric Acid 9.175

Phosphoric Acid 932

Carbonic Acid 23.060

Silica 4. 920

Sand (mechanically present) 4.040

These ingredients combined in the usual manner, will
give the following compounds for 100 parts :

116 SCIENTIFIC AGRICULTURE.

Carbonate of Lime 52 . 4l0

Magnesia \ ^^ p*^* *« ^"^°**«« \ '.'. .v.'.:::: ^I'.tll

Peroxyd of Iron 4.680

Alnmina 2 . 440

Oxyd of Manganese . 040

Phosphate of Lime 2.019

Sulphate of Lime (gypsum) 15.085

Sulphate of Potash . 605

Sulphate of Soda 076

Chlorid of Sodium 412

Silica 4.920

Sand 4.040

100.308

Such a substance must act powerfully on any soil in
want of sulphates, phosphates, lime, or silica, and it is pro-
bable that the ashes of peat from most of our bogs would
be found to possess similar properties.

Soot contains ammonia, and sulphates, carbonates, mu-
riates and phosphates of lime, potash, soda, magnesia, (See.
It is, therefore, a very powerful manure, and, like guano.
need be applied but in small quantity.

To this class of manures, I may add the offal of codfish,
which may be obtained in large quantity in some of tlu>
fishing districts. If dried, and packed in old barrels ov
crates, it might be preserved, and conveyed into the
interior districts. As it consists entirely of phosphalr
of lime and rich animal matter, it is nearly as valuable
as guano, and would be well worth .'is. 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 liere, that night-soil.
urine, and other offensive animal substances, may be con
verted into a manure of great power, and quite inoffensive
by mixing them witli powdered charcoal, or charcoal and
gypsum. They nniy then be sown like guano, and will
produce similar effects. Artificial manures, called p)ii
drettcM, are often prepared in this way. Farmers wouM
find it profitable, to have constantly at hand a quantity <>i
charcoal and j)owdereJ gy|»fluu), for such ]»urpoaeH.

MINERAL MANURES. 117

§ 4. Mineral or Inorganic Manures.

After what has been already said, it is scarcely neces-
sary 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 substances. Any of the
substances mentioned above as necessary ingredients in
fertile soils, or in the ashes of crops, may produce valuable
effects, if they can be procured from the rocks of the earth,
or any other source, and applied to the land. The bene-
ficial 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 deficient ; and thus
not only directly promote their growth but enable them to
avail themselves of other materials which, though abun-
dant, 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
quantity they require, they will take just so much less of
3verythiiig else, and produce little more than half a crop.
Hence the addition of lime to such a soil will enable clover
f'^ take a great deal more of other kinds of food, and the
t on the crop will be very marked. On the other
land, if the soil contain a- sufficiency of lime, its addition
lis a manure may produce no appreciable effect. We learn
rom this, the nature, in part at least, of what is called the
stimulating and exhausting effect of mineral manures, and
|.lso the reason of their frequent failure. A farmer who
finds by experience that some mineral ingredient, as lime,
;ypsum, &c., produces marked benefit, coptinues to apply
t, and neglects other manures, until at last it produces no
|ffect, and he finds that his land is completely run out. He
lOW says that, after all, his supposed fertilizer was only a
stimulant," and condemns it ; whereas the error is in
is own ignorance of the fact that, though necessary to
ertility, it only rendered more necessary a sufficient quan-

118 • SCIENTIFIC AGRICULTUKE.

1

tity 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 ofi", and were to add some salt to their food ; and
finding this to remedy the evil, were to withhold all other
nourishment and attemp't to feed them on salt alone. It
is easy to fall into an error of the opposite kind. A
farmer, anxious to improve, learns that great henefits 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 sue-,
oessfully 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 imjici-
fect 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 want
and then to supply what it needs, without neglectin
other ordinary manures.

2. Mineral manures may produce chemical changes in
the soil, which may preserve or render useful other sub-
stances 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, and neutralizing vegetable
acids. Lime also exerts a powerful influence in dccom-
jwsing inert vegetable matter, and even small stones and
gravel which may contsiin matter useful tt) the soil. This
is what we may call, if sucli a term can be properly used,
the true stimuhitinff effect of mineral manures.

After these general remarks, it will not bo necessary id
dwell at any great length on the separate mineral manures.
I shall therefore briefly indicate their u.se.«i, sources, ami
the modes in wliich they may be best applied.

lAme'w an important ingredient in the ashes of iin
plants. It also renders the soil lighter, and promotes tin
decay of vegetable mutter. In conscijucnce of (his 1.

MINERAL MANURES. 119

property, it can be applied in the largest quantities to
heavy lands, rich in vegetable matter ; on light and poor
lands it should be used with caution. I have already
pointed out in treating of soils, many kinds of land to
which it may be advantageously applied ; and where this
is doubtful, an opinion of its necessity may be formed by
observing whether the crops already referred to as con-
taining much lime, such as clover and some of the green
crops, thrive on the land in question ; and by trying ex-
periments on a small scale. When competent chemical
aid can be obtained, an analysis of the soil may be resorted
to in cases of difficulty.

Lime exists most abundantly in the state of carbonate,
either in the form of limestone or in the substances called
marls, and which consist of mixtures 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 Scotia. These large
marl beds are usually of grey or brown colors, and often
contain small irregular veins of gypsum. The decaying
surface of many beds of limestone also affords a substance
which may be classed with tho marls. In some low grounds
which have formerly been ponds or lakes, there are beds of
clay mixed with fresh-water shells ; and in creeks and har-
bors, there are mussel and oyster beds which afford a
similar substance, containing also much valuable animal
matter ; these are known as shell marls. They exist in
' very many parts of Canada, numerous localities being
noticed in the Reports of the Geological Survey. On
.sf)rae parts of the coast also, large quantities of sea-
shells, mixed with sand, may be collected on the beach,
and may be called shell-marl, as they are quite analo-
gous in composition and effects. All these substances
may be applied in large (juantity with benefit to most
'^oils; more especially as in this mild state the lime exer-

120 SCIENTIFIC AGRICULTURE.

cises no destructive influence on the oi'ganic matter of
the soil. The earthy niai'Is 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 ~aiids
by a very simple test. Put a little of the substance into a
wine glass or tumbler, and add a little water, sufficient io
make it into a thin paste. Then pour in a few drops of
muriatic acid, and observe if any efiervescence or boiling
up occurs. If a good marl, it will boil up with consider-
able force ; if a poor one, with less force ; and if not a
marl at all, there will be 'no effervescence or scarcely any.
Limestone may be distinguished from other rocks in the
same way.

Limestone ordinarily requires to be burned in order to
be rendered fit for application to land. Burning deprives
it of its carbonic acid, and brings it into tlie state of quick
or caustic lime, or after it is slaked with water, into
that of hydrate of lime, or lime combined with water.
In these forms, it is most suitable for mixing with crude
vegetable matters, as peat, which it is desirable speedily lo
decompose, and also for application to some bogs ; but in
these forms its application in large quantity to very liglii
.soils is most dangerous. It remains, however, but a shoi ;
time in the state of caustic lime, for whether in the soil i>
on the surface, it gradually absorbs carbonic acid from t!i
uir and from the organic matters with which it comes int
contact, and pas.ses back into the state of carbonate, tli
same state in which it was before being burned; so tli;i
ultimately the principal result of the burning is that oi
reducing the lime to fine powder, which can be uniformly
(liffuHcd throughout the soil. Tliis cliange docs not, how
ever, fully take place for a very long time. It is prineipallj
this strong affinity for carbonic acid, which causes lime to
haHten the d<xjomiK)Hition of organic matters, by creating %
Itowurful demand for the carbonic acid which in one of thf
priucipul pruductH of their decay ; and us this carbonic acm
i.s a UNoful part of tlie food of plants, in poor soils an czoeiM

MINERAL MANmiES. 121

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 altogether unsuitable for mix-
ing 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 guano. The intense odour of ammonia given off, in-
dicates at once the destructive action of the lime, and the
large quantity of ammonia in the manure. If a rod dipped
in muriatic acid be held over the mixture, the ammonia
becomes visible as a white cloud of muriate 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 decompose it ; in such
soils therefore, draining and loosening the ground are ne-
cessary in order that lime may exert its proper influence

The decomposing power of lime, explains its beneficial
influence on peat-bogs, and other ^oils surcharged with
moisture and undecayed woody matter. In such places
the vegetable matter long soaked in stagnant water, pro-
duces in the slow changes which it undergoes, the humic,
ulmic and other organic acids, which communicate what
is very properly named sourness to the soil, and render it
fit only for the growth of coarse grasses, ferns, moss, and
similar plants. But when lime is applied, it enters into
combination with these acids, and at the same time causes
the inert woody matter to decay and fill the soil with pro-
ducts valuable as food for plants. It is to this cause that

* The same test indicates the escape of ammonia from rich
manures, when decaying too rapidly.

9

1S2 SCIBNTiriC AGRICULTUBE.

we must also iu great part ascribe the beneficial change
which lime effects in pasture lands overgrown with coarse
grasses, or more useless herbage, causing this rank vegeta-
tion 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 apartial and temporary remedy, un-
less it be assisted by draining.

The facts already stated will enable us to understand 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 vain
able manures.

Since the benefit of lime arises in great part from its
power of bringing into use the stores of food already pro-
sent in the soU, it is plain that its effects must be greatest
in soils which contain abundance of vegetable matter, and
also that its tendency is to exhaust this matter more ra-
pidly 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 caus
ing comparative barrenness. From observing this inju
rious 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 " burn
up" and impoverish some light soils, by wasting with un
necessary rapidity their already small stock of vegetablf
mould. When applied to such soils, lime should be eithor
in tlie form of clay marl, or of composts made of peat,
sods, ditch cleanings or similar matters, which will furni.^li
it with materials to act upon, without exhausting the soil.

Lime also exerts an important injiuenccon the inorganir
rhateriaU of aoiln. It has been already mentioned that
the soluble salts of iron present in some boggy lands, and
injurious to T«getatioii, are decomposed by lime, uwimr Id

MINERAL MANURES. l2S»

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 suffi-
cieflitly 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, &c., in forms very useful to crops.
Beside these, there can be little doubt that lime aids in
effecting many other changes among the mineral ingre-
dients of soils, tending in many cases to make their con-
stituent parts more available for the nourishment of vege-
tation.

Duration of the effects of Lime. — When lime, in the
quick state, is placed in the soil, it acts energetically, 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 un-
abated, 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 appli-
cation. The decrease of the influence of lime may be
accounted for in different ways. It is usually applied only
to the soil near the surface, and has a tendency to sink
downwards into the sub-soil. 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 agricxilturists, which
are constantly employed in carrying to the surface the finer
parts of the soil, on which, they feed, a process which must
result in the burying of every substance which tliey are
not inclined to devour. Lime is also dissolved by water
impregnated with carbonic acid, and is rendered soluble
by combining with various acids present in the soil, and
in these states much of it is absot'bed by the roots of crops,
and much washed away from the ground by rains. An-
other 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.

l2i SCIENTIFIC AGRICtLTURE.

Quantity of Lime which should he 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 must apply above
three hundred bushels of lime to an acre. If, therefore,
the lime be well mixed with the soil, a large quantity may
be used without producing any very great change. The
quantity of lime which should be applied, depends how-
ever, in a very great degree, on the nature of the soil.
Clay ground and swampy land are often benefitted by very
large doses; as much as seven hundred bushels on the
acre have been added to land of this description, without
producing any bad effects. Light and sandy soils, on
the other hand, may be injured by a dose which would
be much too small for clay land. /To these circumstances,
therefore, attention must be paid, as well as to the propor-
tion of lime naturally present.

Since lime gradually disappears from the soil, it is ne-
cessary that the supply should be renewed at intervals ;
and it is plain that a more uniform effect will bo secured
by adding small quantities frequently, than by using large
doses at long intervals. The practice of farmers has, how-
ever, varied very much in this respect, according to their
various circumstances. In some parts of Scotland, forty
six bushels of quick lime per acre, are applied every fi\ c
years ; in others, two hundred to three hundred bushels
arc used onco in nineteen or twenty years. In Flanders,
ten to twelve bushels are ripplicd once in three years, or
forty to fifty bushels once in twelve years. In many parts
of Kngland, lime is applied once in every rotation of thrct
or four years. The different length of the intervals in
these cases, docs not appear to be of very great importancc
and may bo varied by cv(;ry farmer to suit his own conv(
nicnec. Small api)lications, at short intervals are, however,
evidently safer and more efficacious than large doHcs seldom
repoatod.

Enough hau now been stated to show the usee of linn
and their reasons, and to prevent ua from being deceived

MINERAL MANURES. 125

by the hasty assertions, respecting its utility and inutility ,
frequently made by persons whose views on the subject are
only partial. The results of an enlightened view of what
is known with respect to this valuable manure, may be
summed up as follows : —

1st. Lime has ultimately the same eflfects whether it be
applied in the quick, air-slaked, or mild state ; it should
be well mixed with the soil, but kept as near the surftice
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 wet 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 ap-
plied, are — affording a necessary part of the food of crops ;
bringing into activity the 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 encour-
age that of valuable grasses and clover ; to increase the
quantity 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 by 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 de-
stroyed by liming. Hence, Timing and sowing with grass
are sometimes sufficient to replace the most useless plants
with nutritious grasses.
Some vaiieties of limestone contain a large proportion of

126 SCIENTIFIC AaRICULTURE.

magnesia, which, ^vhon arlded to the soil in large quantity,
produces an injurious effect. These limestones are gen-
(Crally known as magnesian limestones or dolomites.

2. Gypsum. — The uses of this substance have already
been often referred 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 instance, 1000 lbs. of dry clover and timothy hay, con-
tain from 3J to 4^ lbs. of sulphuric acid ; or we may esti-
mate 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 gi-owth
of those crops which contain large quantities of this sub-
stance. 2. Gypsum possesses great value, from its property
of converting the carbonate of ammonia — one of the most
volatile products of the decay of animal substances — into
the sulphate of ammonia. This action has been already
explained in treating of ammonia.

The influence of gypsum is thus very different from that
of lime or marl. It does not tend either to waste or ren-
der 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 interior of Canada gypsum will bo
found to be of great value, the soils being deficient in sul-
phates. In the vicinity of the sea, exporienoc has shown
thai gypsum is less useful than further inland; apparently
heoausc the sea spray carried by the wind supplies to the
Boil a small <juantity of sulphate of soda, which serves
instead of gypsum. Again : some soils, especially those in
the vicinity of tho gypsum beds, are already well suppHod
with this flubstanoo ; and some soils in slaty districts,
though deficient in gypsum, receive supplies of stilphuric
acid from the sulphurut of iron contained in the slate.
Coal ashes, peat aslu^s, and sea weeds, where applicMl, also
famish nniall quantities of gypsum. The ^ond use of

MINERAL MANURES. 127

^psum, however, to which I have referred, is on* 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 scattered 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 powdered gypsum.

The cheapest way of rendering gypsum fit for use, is to
break it into pieces, and burn it after the manner of lime,
— though it does not require so great heat as limestone.
Burning only drives off its water, without producing any
other chemical change. After burning, it may be easily
crushed into powder ; but must 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.

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
benefitting it. This, in almost all instances, results from
using it alone, without applying other nianui cs at the same
time. The explanation is of the same general nature as
that given under lime. The farnier has taken away a
variety of substances, and has only added gypsum. If the
land is entirely exhausted at last under such treatment, it
is obviously not the fault of the gypsum. There 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 of both naturally in the soil ; or, as has been pre-
viously explained under lime, there is some physical or
johemical defect, which prevents their action."

T28 SCIENTIFIC AGRICULTURE.

3. Potaih and Soda. — The sources of these, in the ashes
of plants, have been already referred to ; and there are not
many ways in which- they can be directly obtained from
the mineral kingdom. Sea salt contains soda in combina-
tion with chlorine ; and it may be made more useful to
plants by mixing it with quick lime. It will generally be
found very useful to slake lime intended for land with sea
water ; and no better use can be made of refuse salt or
brine, than to pour it upon quick-lime, or mix it with a
lime compost. Granite contains a large proportion of pot-
ash ; and though a granite compost may seem a strange
thing, crushed granite has actually in England been mixed
in heaps with quick lime, for the purpose of setting free
its potash. This is the only recipe that I know, for meet-
ing the wishes of a gentleman in one of our more rocky
districts, who once said to me, " There would be some U!<e
in your agricultural chemistry, if you could dissolve these
granite rocks for us." Farmers who can obtain the smaller
dust and fragments of granite quarries and masons'
sheds, where granite is worked, and who are not located on
granitic soils, will find it pay to cart such material, and
mix it with the lime 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 lime. The
softer varieties of trap rock, which also contain much alka-
line matter, may be treated in the same way ; or may be
usefully applied to poor soils without any preparation.

4. Phosphate of Lime, — Small quantities of this highly
valuable substance, are contained in most limestones, and
conduce greatly to the benefits resulting from limini'
Those varieties of lime which contain large numbers of iin
pressions of shells and scales of fishes, are usually mci
valuable in this way. Some thin and impure limestom
of little use for ordinary purposes, are rick in phospliatis.
This is especially the case with beds containing many d
the fossil shells called Lingula', and with some bods of tli.
eoal distriotfl containing scales of fishes. At North Elm
l$j and South Burges* in Upper Canada, ther<; arc bcil

MINERAL MANURES. 129

of crystalline phosphate of lime, which are quarried for
exportation. The mineral in this state requires to be
crushed and prepared with sulphuric acid, which renders it
soluble as a Superphosphate of Lime. When manufactured
in this way, it is invaluable on the worn out farms of the
older districts of this country,*

Bone-dust, guano, and the liquid manures of stables, are
at present the chief sources of this substance to the farmer,
and have been noticed under the head of organic manures.

Coal Ashes. — 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 diflferent kinds of coal differ some-
what in composition and absorbent power, and are much
inferior as manure to wood ashes, yet they are always of
some service, m^re especially when employed to absorb and
retain liquid manures and the soluble and volatile parts of
organic substances,

* Superphosphate of Lime is now manufactured in Canada,
and should be used by all farmers on old lands.

CHAPTER XIIL

CROPS.

Under this head we shall consider the bearing of the
principles previously stated, on the plants ordinarily culti-
vate^ in British America, and shall notice the peculiar
habitudes of these plants and their diseases and enemies.

§ 1. Wheat.

This, the first of our farm crops, is the Triticum vulgar e
of botanists. All the kinds cultivated in this country belong
to one species, but of this there are two leading varieties, —
the spring and winter wheat, — and under each, many subor-
dinate varieties, produced by culture and selection.

Wheat requires to have in the soil a supffly of both min-
eral and organic food in a well elaborated 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 undecom-
posed state. It also very readily permits weeds or grasses
to grow beneath its shelter. For these reasons, newly
burned land, land that has been fallowed and manured with
composted manure, or land that has been previously cleaned
and manured with a green crop, is most suitable for wheat.
On lea land it is very subject to rust, and also to the
attacks of the Hessian fly, whose larvae are generally pre-
sent in the grass, and destroy the wheat which takes it
place. The place of wheat 'u\ tlic rotation of a scientific
farmer, must therefore be that assigned to it i^i the ordins
Scottish four-course rotation, viz., after a grcon crop an<
before gross, which is sowed witli the wheat.

The organic part of the grain of wheat consists principallj
of gluten, albumen, ittaroh, gum, sugar, oily mntlcv, and thi
l¥0ody matter of the husk. Of those ingredientn the mc

CROPS. 131

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
I most difficult of their elements to procure, chiefly from the
ammonia 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 deflcient
in gluten.

The ash or earthy part of wheat is also of some impor-
tance, especially as for this the plant is entirely dependent
on the soil ; and though this part of the plant is compara-
tively 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 con-
sists of silica, an element sufficiently abundant in most
soils ; but it is to be observed that this element can be
obtained only by the aid of potash or soda, which must
therefore be present in the soil. Potash and soda are also
required independently of the conveyance of silica. The
lashes of 1000 lbs. of the grain of wheat contain 4J lbs, of
I potash and soda ; the straw contains a much smaller pro-
portion. Wheat also contains in its ash, lime, gypsum,
magnesia and common salt, but in small quantity. The
ingredient of the ash of wheat which of all others is the
I most important, is bone earth or phosphate of lime, of
i which about 70 lbs. are taken by an ordinary crop of wheat
I from an acre of ground. This may appear to be a small
I quantity, but it must be borne in mind, that this substance
! is scarce even in fertile soils. It is chiefly the presence of
j alkalies and phosphates derived from the ashes of the woods,
; that causes wheat to produce so abundantly in new land.

132 SCIENTIFIC AGRICULTURE.

It is also worthy of notice, that wheat, when permitted,
sends its roots deeply into the ground, and therefore pre-
fers a deep soil, or one that has been deepened by subsoil-
ing and under-draining.

The facts respecting the composition of wheat stated
above, indicate that manures containing nitrogen, pli(. -
phates and alkalies, are especially suitable to it. Sucli
manures are guano, urine, animal refuse, ashes, and
crushed bones.

Kespecting the uses of the grain of wheat, it is unnc^
sary to say anything. It is not however very generally
known, that the straw of wheat, if cul bufficiently early,
and chopped with a straw cutter, is highly nutritive food
for cattle and horses, and is much relished by them. In this
Qountry, wheat is generally cut too late, and the grain is
thick in the husk and inferior in flouring qualities, and
the straw is comparatively worthless. By cutting imii;(>-
diately after the grain is filled, and before the straw i.s
wholly dead, both would be much more valuable and nutri-
tious.

Wheat, though the most important of the grain cm] s,
has, of late, acquired the character of being a precai i
crop, especially in the older districts. It becomes tl;>
fore necessary to in(juire into the diseases and blights to
which it is liable. We may consider these in some detail,
remarking in the first place that none of them are peculiar
to British America, all of them being more or less expe-
rienced in most or all the countries in which wheat is
cultivated.

1. Rust. — A reddish or rusty substance ittached to the
straw and leaves of wheat, in the end of Miuuner or in au-
tumn. When examined by the microscojie, it is found to
be u parasitic fungus or mould of the genus Vrcdo, M'hose
minute and invisible seeds or spores are waited by tlic
winds, or borne to the plant witli the water it absorbs
from the soil, and taking root in the cells and vessels of
the stem and leaf, wcokcu or kill it by feeding on iti
juices.

It« attacks arc favored bv the following causes: Firtt, i

•CROPS. ISiJ

damp and cold weather succeeding warmth, at the time
when the straw is still soft and juicy ; hence late grain is
very liahle to rust. Secondly/, a deficiency of the outef
silicious coat, which in the healthy state protects the sui-face
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 pre-
sence of too much crude vegetable matter, as sod or raw
manure, or from a wet and undrained 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 albu-
minous matter in the straw, and the inability of the plant,
owing to 'the want of phosphates, to turn this sugar
and albumen into the starch and gluten of the seed.
Fourthly, it is probable that when the grain of rusty wheat
is sown, or when sound wheat is sown in ground in which
wheat has rusted in previous years, the crop may be more
easily aff"ected by the disease, because the spores of the rust
fungus may be attached to the seed or may be in the soil.
The best preventives of rust therefore are : First,
healthy seed ; Secondly/, early sowing ; Thirdly, draining ;
Fourthly, abstaining from sowing wheat in lea land ;
Fifthly, preparing the £oil in such a manner that it shall
be sufficiently rich, yet not filled with crude vegetable mat-
ter, and paying attention to the supply of alkalies and phos-
phates.

2. Mildew. — This term is often used in this country as
synonymous with rust ; but properly speaking, mildew is
the effect of the growth of other fungi, usually of the
genus Puccinia, 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 fungus, Uredo
foetida, which grows within the grain, and converts its
substance into a dark colored fetid mass of spores or mould
balls, which und^r the microscope look like rough berries,
and are filled with the minute dust-like seeds of the smut.
Its mode of propagation is pretty well understood and

134 SCIENTIFIC AQRigULTURE.

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 fibrils of the smut pass upward
though the stem, and infect the crop. In like manner, if
sound grain be put into bags or boxes which have contained
smutty grain, or if it be threshed on a floor on which
smutty grain has been lately threshed, it will be infected.
These causes of the disease should therefore be avoided by
all prudent farmers.

In addition to this however, the seed wheat should
always be washed before sowing, that any particle of smut
which may happen to be attached to it may be removed.
In this way the increase of the eVil may be effectually
guarded against.

" It is quite certain, that the disease may be at an
time propagated by rubbing sound wheat against tluu
which is infected by the fungus. If then tlhe seed be
sown in this condition, the result may be easily predicted.
The method also of counteracting the evil at once suggests
itself. It is merely to cleanse the wheat which is about to
be sown, from all the smut which may have attached itself
to it, by reason of its adhesive character. The princii)le
of effecting this object clearly must be, to use means to
convert the oily matter which causes it to stick obstinately.
into a soapy matter which will allow it to be readily washed
off. Chemistry here comes to our aid. An alkali will con-
vert oil into soap, and this is the basis of all effectual ih-ess-
ing, as it is called, of seed corn. Almost every district has its
peculiar dressing, but the best are merely modifications oi
this principle. Whatever other ingredients may be used,
the effective constituent is some alkaline matter in the form
of a ley. Lime, which possesses alkaline properties, Iwis
aooordingly not unfrequeutly bean resorted to ; it must not
howeyer DO too much slaked in using, or it loses these
properties and thus often fails. Common potash and sub
HtanccH containing ammonia, for example, the liquid excri
ments of animals, have been adopted for remedies. Soin'
persons employ brine sulphate of copper (blue vitriol)

CROPS. 135

arsenic and other things not possessing alkaline properties.
Whenever these methods succeed, it cannot be for the
reasons advanced, but it may happen that they destroy the
vegetative powers of the seeds of the fungus, though they
still remain fixed to the grain."*

It must be observed, that it is not merely steeping but
washing that is necessary to cleanse the grain, and the
washing process should be aided by some alkaline sub-
stance. Solution of j^otash, ley of wood ashes, and stale
urine, are the best washing fluids ; and the grain should
be stirred in them for some time, and the liquid carefully
drained or poured off, after which the grain may be dried
by stirring slaked lime, gypsum or dry wood ashes with it.
This method is more certain than the common steeping in
brine or blue vitriol.

The same precautions are useful in guarding against the
Dust Brand or dusty smut, Uredo segetum. This how-
ever is less dreaded by farmers, and there is reason to
believe, that its seeds or sporules are more often present in
the soil than those of the true smut, as they are scattered
about by the winds in autumn.

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. It is uncertain
whether it is merely a diseased gi'owth or a parasitic fungus
substance, though the latter seems the more probable view.

Ergot does not usually destroy any large proportion of a
crop, but when not attended to, may make it useless or dele-
terious by its poisonous properties. When observed, the
grain should be sifted through sieves sufficiently small to
retain the enlarged ergot grains. This should be attended
to, whether the grain be intended lor 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 seeiiis to be con-
firmed by experience in this country, deserves the attention
of farmers whose fields are infested by this nuisance.

• " Blights of the Wheat."— London.

136 SCIENTIFIC A(}RICULTmiE. •

•

5. The Wheat Midge or Weevil, Cecidomyia Tritici and
G. cerealis of naturalists, has in recent times been the most
destructive of all wheat blights. It is improperly called
weevil ; the weevils, properly so called, being a tribe of
beetles the young of which destroy corn in granaries. 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 m England, where the
creature has been much longer known than in America,
have proved that the destroyer is the larva or grub of a
minute midge, which deposits its eggs in calm summer
evenings, on the chaff scales, whence the little grub when
hatched 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 experi-
ments and observations made many years ago, and I
believe the first which clearly established the facts of the
case, will suffice to give a view of the habits of these crea-
tures. They refer to the C. Tritici.

A quan'ity of the larvae were procured, full grown and in
that motionless and torpid state in which they usually
appear when the grain is ripe. A portion of these larvae were
placed on the surfiice of moist soil in a flower pot. In
the course of two days, the greater number of them had
descended into the ground, previously casting their skins,
which remained at the surface.* I afterwards ascertained
that they had penetrated to the depth of more than an
inch, and were of a whitish color, softer and more active
than they had previously been. The fact is thus estab
lished, that these apparently torpid larvae, when they fall
from the ripe wheat in autumn, or are carelessly swept out
from the threshing floor into the barn yard, at once resume
their activity, and bury themselves in the ground.

The larvie tlnis buried in the ground, were iillowcd to
remain undisturbed during winter and spring, the flower

• Some obserrftlions of Dr. Fitch, and Mr. D. J. Browne, n i
der it probable tliat the skin is sometimes cast in the car befui
descending to the ground.

CROPS. 137

pot being occasionally watered. About the end of June
they began to re-appear above the surface, in the winged
form ; the little grubs creeping to the surfaee, and pro-
jecting about half their bodies above it, when the skin of
the upper part burst and the full grown winged midge
came forth and flew off. This completes the round of
changes which each generation of these little creatures
undergoes, and we have thus actual evidence of each stage
of its progress from the egg to the perfect insect.

The perfect midge is a pretty little creature, its body
being 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 antennze
ornamented with hairs. The flies are most active in calm
and warm evenings, when they may sometimes be seen in
clouds over the wheat fields. British observei's say, that
the female deposits her eggs within the chaff; but here, they
appear to be generally deposited without.

However we may dread the destructive powers of the
midge, we cannot withhold our admiration from the singular
instincts with which it has been endowed. The female
insect depositing her eggs where food and shelter are provi-
ded for the young brood ; the larvae when shaken from
j their summer abode by the storms of autumn, at once

I entering on a new and untried life in the soil ; and the
', chrysalids working their way to the surface in the ensuing

summer, to assume their winged state in time for the new
J crop of wheat, display a series of adaptations which may

II convince us, that, however annoying in the mean time to
. us, a creature so gifted cannot be without important uses
I in the economy of nature.

It is evident, that if no check were opposed to the
p increase of these creatures, they must ultimately in every
I country where they occur, consume the whole or nearly
I the whole of the wheat crop. There are however such
ji checks, some in natural causes, and others in expedients
; which may be adopted by man.

In Europe the larvae of several small parasitic insects

10

188' SCIENTIFIC AGBICULTUKE.

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 bare winters, it is probable that many perish ;
though it is quite an error to suppose that wet weather can
kill the larvae when in the ground. Moisture in the
ground, indeed, appears to be essential to their life.
Windy or stormy weather at the season when they are on
the wing, must also greatly interrupt them in deposit-
ing their eggs. 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 been said above respecting the
habits of the midge, that during the greater part of its
existence it is beyond the control of the farmer. He can-
not prevent it from depositing its eggs, nor can he extract
the larvse from the growing crop ; and in the ground in
autumn and winter, they are almost equally beyond his
reach. He ran however destroy as many of them as he
can house loith his grain. In this country, as in Britain,
the full grown larvae remain in the chaff until the grain is
ripe, or until they are shaken to the ground by tlie first
violent storms of autumn. When grain is observed to be
infected, it should be attentively watched and cut so soon is
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 present,
there is a double gain in early cutting. It would also be
advisable whenever it is po.ssible, to reap, ratlicr 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 larvaa to fall through, and when the
grain is cleaned, all the chaff and dust scjxirated from it
should be burned, or if the chaff bo saved for ibdder, it
should be krpt dry, and none of it allowed to be mixed
with the litter or thrown on the manure heap.

* Soe A paper by Mr. liilliugi in ths Canadian Natumi
rol. I, p. 460.

CROPS. 13&

This method costs little trouble, it causes no loss, and if
faithfully followed out, would greatly diminish if not alto^
gether prevent the losses occasioned by the weevil. 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 importance, and by destroying the larvae in
a season in which only a fourth of the crop is lost, we may
perhaps prevent a total loss in the next season. It is true,
that when this precaution is neglected, Providence, kinder
to the farmer than he is to himself, may, by some of the
natural causes already mentioned, check the increase of
the destroyers ; but this will not always occur, and certainly
furnishes no excuse for neglecting the means of safety
which are placed within our reach.

As an illustration of the saving which can be effected by

destroying the larvae which are housed with the grain, I

may mention that the friend who furnished me with speci-

i mens for experiment, informed me that from the wheat of

I eight acres he had obtained about /owr bushels of larvse of

i the weevil. After making a large deduction for dust mixed

Iwith them, this quantity must have contained about 150

! millions of the insects. If these insects, instead of being

burned, had been scattered over the ground, they might if

the ensuing season had proved favorable to them, have

destroyed the greater part of the wheat crop on the farm.

Various other expedients for the destruction of the midge

have been proposed or adopted. When the flies are

observed to be on the wing they might be prevented from

depositing their eggs by kindling fires on the windward

V 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 troublesome 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 larvse

,had fallen upon it in autumn, they might be too deeply

140

SCIENTIFIC AGRICULTURE.

covered to permit of their escape in the spring. In th§
ordinary system of rotation however, this could not be
done without losing succeeding hay crops ; and it is doubt-
ful if it would be very effectual. Perhaps the most effec-
tual remedy ever proposed, is that of discontinuing the
culture of wheat for a year, and thus depriving the
midges of the necessary food for their larvae. This is how-
ever an expensive expedient, and it requires the consent of
all the farmers in the district affected. In the great major-
ity of cases, it might be rendered altogether unnecessary,
if the method of destroying the larva; already described
were generally adopted.

The most popular remedy hitherto 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, however, in the
case of spring wheat subjects the grain to rust, and necessi-
tates 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 fly. It is also probable that in a few years the
habits of the creature and the date of its appearance will
change to suit the lateness or earliness of the grain which
forms its food, and then the late sowing will prove quite
ineffectual. It is also deserving of notice, that bearded
varieties suffer less than the bald, as the awns obstruct the
insects in depositing their e^s.

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 evening.

(2.) The larva when liatched attaches itself to the young
grain and prevents its growth.

(8.) When full grown it becomes stiff and torpid, and if
left long enough falls to the ground. j

(4.) It buries itself in the ground and thus passes thfi
winter.

(5.) In spring, it emerges from the ground as a porlcuL
insect, in which state, if the weather be favorable, it soeki i
the growing wheat lor the purpose of depositing the germs t
of u new brood.

CROPS. 141

Lastly, though there are many partial remedies, the only
sure one is to cut early and destroy all the gruhs found after
threshing the grain. To ensure safety, this should be kept
up as regularly as the washing of seed wheat to avoid
smut.

5. The Hessian fly {Cecidomyia destructor) is a relative
of the wheat midge, and at one time threatened, like it, to
destroy the culture pf wheat. Its ravages have however
in late years materially diminished. It attacks the stems
of the young or haM" grown plants, establishing itself at the
base of the shoot or in the joints, and when abundant
wholly destroys the crop. The eggs, according to the best
observations, are deposited on the leaves, whence the little
larvae or maggots when hatched make their way downward
between the leaf and the stem. There are two broods, one
produced from eggs deposited (in winter wheat) in autumn,
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 injured. Burning the stubble and
ploughing it under, rolling the young wheat, mowing it in
autumn, or cutting it in spring, and late sowing, are all
remedies that have been recommended, especially in the
3ase of winter wheat. There can be no doubt however
that the principal cause of the excessive multiplication of
this insect is the want of any rational system of rotation
jf crops; and the introduction of this, usually arrests its
ravages.

Several parasitic insects prey on the larvas of the Hessian
Sy and greatly diminish its numbers,
j, 6. The Army Worm, (Leucania exlranea,) is a naked
caterpillar of the cut-worm tribe, of a gray color, with
)lack and brown bands. Their native haunts appear to be
'neadows and similar places, where they devour the leaves
'f grass, but in some seasons they migrate in immense
'lumbers to the grain fields and strip the grain of its leaves.
W'hen full grown they pass into the pupa state, under
lods and in the ground, and emerge as plain gray moths.

142 SCIENTIFIC AGRICULTUKE.

The injuries inflicted by these creatures are usually quite
local. The only way -of arresting their progress seems to
be by digging nariow und deep ditches across their path,
and killing them as they accumulate in these ditches.

7. Wheat is attacked by the larvae of many other insects.
Those of certain little flies of the genus Chhrops establish
themselves in the stem. Other flies of the genus Osdnis,
in their larva state, eat the young grain. Several beetles,
moths, and neuropterous insects also ^rey 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 numbers 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 1861.*

§2. The Oat. — [Avena sativa.)

The organic part of the kernel of the oat very much
resembles that of wheat. Oatmeal contains 10 to 18 per
cent, of gluten or an analogous substance, and is scarcely
inferior to wheaten flour as an article of nutriment. In its
inorganic ingredients or ash, it diffiers from wheat in pro-
portion though not in kind ; and it requires from the soil
nearly twice the amount of inorganic matter required by
wheat. It is therefore a great mistake to suppose that the
oat is less exhausting than wheat, if both straw and grain
be removed from the soil. The oat however can take
nourishment from raw and undecomposed vegetable matter,
such as sod, peat, &c., from which wheat can obtain little
nutriment.

As in the case of wheat, silica and alkalies are the prin-
cipal ingredients of the ash. Both are however in larger
quantity than in wheat. The oat also carries off" from the
soil a larger proportion of gypsum ; hence it thrivo.s in
gyp6d0U8 soils, or in sour soils whioh contain sulphuric

* ^ a paper b^ Dr. Lawion in Canadian Naturalist^ tol, 7,

CROPS. 143

acid, after th«y have been limed. The quantity of bone-
earth required by the oat is nearly the same in proportion
with that required by wheat.

The above remarks show the proper place of the oat in
the rotation, to be that which it usually bears in the ordi-
nary Scottish rotation ; viz : the first grain crop after
ploughing up the sward. It is well fitted for this, not
anly by its power of extracting nutriment from the decay-
ing 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 inor-
ganic food, unfit it for sowing with grass seeds, or occupy-
ing 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
grass. Nothing but dire necessity can excuse these prac-
tices, which are unhappily too prevalent. The manure
produced from the oat straw, or its equivalent, should
in all cases be restored to the soil in the succeeding year
for a green crop. If this be done, the soil is improved,
rather than 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 require more frequent changes of seed than
the oat. When cultivated for a number of years in the
same soil in our climate, it acquires a thick onter husk at
the expense of the kernel, and becomes more liable to dust-
brand. Experience has proved that the best change of
seed is that imported from Scotland ; and no oats are su-
perior for this climate to the early varieties of that country,
as the early Angus, Hopeton, Dutch, &c. 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 impor-
tation, they greatly improve in size and appearance, though
probably not in actual valut.

144 SCIENTIFIC AGRICULTURE.

The Black or Tartarian oat is much cultivated in this
country, but its only good quality appears to be 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 coun-
try by the cultivation of those lean, chafiFy and bearded oats,
that have been run out by long cultivation, and mixed by
carelessness with better varieties.

The dust brand and the grubs of the Harry-long-legs
{Tlpula) often injure the oat crop, but I am not aware
that they have ever become so destructive as to call for anj
special attention on the part of the cultivator.

§3. Rye. — {Secale cereale.)

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 production 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, but a little more gypsum.
The ash of the grain differs very slightly from that of
wheat.

Rye prefers light soils, and may be made very useful in
bringing in light ground unfit for the growth of wheat. It
also forms a substitute for wheat when the latter grain
appears to be in danger of being destroyed by weevil ; but in
ordinary circumstances, it should not be sown on ground
capable of producing wheat, being much inferior to that
grain as an article of food. Rye straw is of little or no
value as fodder; but is excellent for thatching, collar-mak-
ing, and basket-making, and makes tolerable hats.

It is said that ryo has occasionally suffered from the
wheat fly, but slightly. Its worst enemy is tlie ergot, a
fungus-liko enlargement of the grain, which, like the ergot
of wheat, rondern it black and poisonous. When the ergot is

CROPS. 145

observed, it should be carefully sifted from the grain before
grinding. The principal inducing cause of ergot appears
to be too great moisture in the soil ; and where this is the
case, the culture of rye should not be persisted in, when
the ergot is found to appear constantly or often in it.

§4. Barley. — (^Hordeum vulgare,^

The grain of barley much resembles in its composition
that of wheat, but it contains less gluten and more starch
and sugar. It is therefore less nutritious, though in whole-
someness 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.

Barley takes rather more from the soil than wheat, and
the excess is principally in silica, bone earth, lime, alkalies,
and gypsum. It is therefore a mistake to suppose, that a
good crop of barley does not require a soil in good con-
dition, but as barley sends its roots much along the surface
and not to a great depth, it is less dependent on deep til-
lage than wheat. Alkalies and especially soda are highly
favorable to its growth, and it prefers light and loamy soils.

§5. Indian Corn, — (^Zea mays.)

The composition of the grain of Indian corn is very
variously stated by different chemists. According to Salis-
bury of New York, quoted by Norton, it contains 60 per
cent, starch, 10 per cent, fatty matter, and 12 to 16 per

146 SCIENTIFIC AGRICULTURE.

•cent, gluten and analogous substances. This would give it
a very high value as an article of food, especially for fatten-
ing stock. In this climate, Indian corn requires a light,
deep soil, 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 as a green crop, since the treatment
which it requires and its effects on the soil are not very
different from those of the turnip and carrot. Good corn
may however be raised in lea land, and also after green
crops in place of wheat, but in both cases manure is re-
quired in addition to that already in the soil. It is better
to plant corn in drills, like turnips, but farther apart, than
in hills. Nothing is gained by having the plants crowded ;
they require much air and light. In stiff soils they should
be well earthed up, or the seed may be planted in the tops
of the drills, but in light land it should be planted on the
level. Frequent hoeing is very beneficial, as also cleaning
and earthing with a light plough or cultivator. Pumpkins
are often planted with corn ; many good farmers, however,
believe that the gain in pumpkins scarcely repays the loss
in corn. This must depend on the degree to which the
leaves of the pumpkins deprive the corn of air and light,
and on the impediments which the vines offer to the proper
culture of the corn.

It is useful to cut off the feather or bloom, the maU
flower of the corn, after it has served its purpose in ferti-
lizing the ear. This should be done when the beard or
tassel of the ear begins to wither, but not before ; and as few
lai^e leaves as possible should be cut off with the top, as
all the leaves are useful in aiding the growth of the ear.
The tops make good fodder, and when deprived of them the
corn is less likely to be broken down by autunmnl storms.

Corn is subject to the attacks of grubs which burrow in
ihe stalks, after the manner of the larvae of the Hessian fly
in wheat. The easiest remedy appears to be sowing suflli-
oiently thick to allow spare plants for the grubs. When,
however; time can h% spared to pull up and destroy every

CROPS. 147

plant that shows by the fading of the leaf the presence of
the grub, the labour will be repaid by the diminished
number of grubs in the ensuing season. The seed is also
sometimes destroyed by squirrels, birds, &c. This may be
prevented by steeping the seed in anything that 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 smearing with tar has also been prac-
tised, and is stated to be more certain.

The meal from corn raised in this country is finer and
more delicate in flavour than that from Southern and
Western corn. This should cause it to bring a higher
price ; and should in connection with the productiveness
of the crop, commend 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 out immediately
after the frost strikes it.

§6. Buckwheat. — (^Polygonum fagopyrum and
P. tataricum.^

The extended culture of this plant cannot be considered
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 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 starch, with 5 to 8 per cent, sugar
and gum (Norton). It is, therefore, inferior in nutritiva
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 colour,
and bitter taste. When this husk is entirely removed, the
flour 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 j

148 gClENTIFIO AGRICULTURE.

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 nutriment from
the air ; and it requires but a small proportion of mineral
matter. Hence it can be successfully 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 exterminator 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 soils in this
country.

The stems and leaves of buckwheat, cut green, make
good summer food for cattle ; but are less nutritious than
clover. Large heaps of buckwheat husks are sometimes
seen near mills. They should be composted, and applied
to the land ; and would be found to be excellent manure.

§7. Beans and Peas.

These plants are remarkable for the lai^e amount of nu-
triment which their seeds contain, and wl'lch is greater
even than that of the best wheat or oats. Ilenoe, though
they cannot in ordinary circumstances fon)i so large parts
of the crop as the cereal grasses, they are important objects
of the farmer's attention.

The French, or dwarf Jcidnri/ beans, (J*haseobm vnlga-
ri$, var. nanu$,) are very valuable 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 for
the potato. They reauire compost manure, and to bo kept
clean from weeda. 1 hey may very well occupy a portion

CROPS.

U^

of the drills |)repared for turnips, as the same manures and
mode of culture suit them, and the time of sowing is also
the same, French beans should not be 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 calavan§a,
are the best for this climate. The imported calavangas
are rather late ; but by picking the earliest ripe pods for
seed, they soon become sufficiently early. Kidney beans
contain 23 per cent, of legumin, a substance analogous to
gluten, and 43 per cent, of starch (Jolmstoii) .

The liorse hean (Vida/aha), may be cultivated in the
same manner with the French dwarf, but must be sown
early. 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 proper-
ties 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 Fea 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 different
place in the rotation from the bean ; for, though the dwarf
varieties may be cultivated in drills as a green crop, it
ordinarily thrives very well if sown broad-cast, in any tole-
rably rich land that is not overrun with weeds. Peas

ISO SCIBNTIPIC AORICULTUKB.

have, indeed, no regular place in a rotation, and are some*
what uncertain. They are therefore rather giving way, in
the best farming districts, to the culture of beans and
turnips. The pea often suflFers much from the pea-worm,
which is the larva of a small species of moth, or in other
cases of a little beetle (^Bruchus pisi). No treatment ap-
plied to the seed can avert the attacks of these creatures,
since the eggs from which the larvae are produqed are de-
posited by the parent insects in the blossom, or young pod.
The best remedy 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, buckwheat might be sown and ploughed in,
to enrich the soil.

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

These, in most of the Countries of the northern tempe-
rate zone, form staple green crops ; and probably contri-
bute 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 largely on the increase. In
reference to these crops, Johnston remarks, with much
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 grain crops them-
selves more profitable, and therefore objects of more useful
attention. The spread of green crops in England and
Scotland has been invariably the prelude to agricultural
improvement, and to an amelioration, not only in the prac-
tice, but in the circumstances also of the farmers."

AH these roots contain a large proportion of water; and
their nutritive portion is made up of albumen, sugar, gum
(pectin), and starch. These substances are present in
Various proportions, according to the kinds of roots culti-

CROPi. 151

Vated, and the nature of the soil and manures. All of
these root crops require from the soil much potash, soda,
lime, bone, earth, and gypsum, as well as some vegetable
matter ; and the manures intended to afford these sub-
stances should, when practicable, be in the form of well
rotted composts. Long manure will rarely afford a heavy
crop.

As the turnij) is the most important of these roots, and
it is very desirable that it should take its proper place in
our provincial agriculture, I quote from Judge Peters'
" Hints to the Farmers of Prince Edward Island," the
following directions, which are admirably adapted to this
country, and give also useful information as to the culture
of other green crops :

" Turnips are generally sown in that part of the rotation
which closes one course and commences another ; and in
this Island it will in general be found convenient to sow
them after oats, sown on lea. On newly burnt lands there
are few weeds, and excellent crops may be raised with little
labor, by merely scattering the seed and hoeing it in ; but
with this exception, they should always be sown in drills,
under which system three acres can be cultivated with less
labor than one acre broad-cast. The land intended for
them should be well and deeply ploughed in autumn, and
cross-ploughed in the spring, then harrowed and rolled
to break the lumps. If the land is foul with couch, have
it well cleaned, or the turnip crop will be a failure, or cost
more to keep clean than would have cleaned the land before
they were sown. Next open the drills ; thirty inches apart
is the best distance for ordinary culture, as it gives room
for the plough and horse-hoe to work freely between the
drills without injuring the plants.

" When the drills are opened, then cart h your manure,
which should be short, and make it in small piles, so that
it can be regularly spread in the drills. By making the piles
so that they will spread into the three drills in which the
horse walks and the cart wheels run, you will spread it
more evenly, and with less lal)or, than from the larger piles,
in which I often see it deposited. As soon as the manure

i52

SCIENTIFIC AQRICULTURB.

is spread in the drills, and before the sun can dry it, split
the drills with the plough, which will cover the manure
and make a ridgelet over it, then run a light roller length-
ways along the drills, so as to flatten then on the top, and
drill in the seed at once ; it is very important that it should
be done as soon as the drills are rolled, for the ground is
then fresh and damp, which causes the Seed to vegetate
quickly : whereas if you leave it, the tops of the drills get
dry, the seed is longer coming up, and the plants grow
more slowly. I frequently see persons waiting for days,
Until the whole of the land is prepared, before they sow.
This is a very bad practice, because not only do the drills
become dry, but the weeds begin to shoot before the seed
is sown ; and when the plant comes up, it finds the weeds
up before it, and is consequently smothered, and is much
more difficult to hoe and clean. The least you can do for
the turnip is to give it fair play and a fair start with its
numerous weedy competitors; and, therefore, make it a
rule to sow in the evening, or, at furthest, the next morn-
ing, every drill that has been dunged and covered during
the day. Some spread the manure broad-cast, and plough
it in with the second ploughing, and raise fair crops ; but
by putting it in the drills, the whole strength of the manure
is given to the roots of the turnip, and therefore, must
promote its early growth more than when spread over a
large space of ground. When the manure is ploughed in
broad-cast, I think it should be done in the fall; a method
which seems to produce excellent crops, and saves labor in
the spring, when time is of most value to the farmer.

" As to the best time for sowing Swedes, there is much
difference of opinion ; they may be sown from the 20th of
May to the end of Juno; they continue to increase in
weight until the frost compels us to pull them, and therefore,
the earlier they arc sown, the heavier will be the crop.
When sown in May, I have always found them escape the
fly; but the best protection against this insect is thick
sowing — never sow less than three lbs. of seed to tlm aero,
and you will seldom be without sufficient plants after the
fly has done its work. Aberdeen Yellows may bo sown
from the first to the end of July.

I

k

CROPS. 153

" Hoeing and el«aning arc the most important part of
turnip culture : manure as heavily as you please ; if this
is neglected, or carelessly or imperfectly done, you will
not have u good crop ; a few days' delay, carelessness, or
inattention now, will make a diflference of hundreds of
bushels per acre. There is no crop on your farm which
can so ill bear delay at this time as your turnips, and un-
less you can afford to throw away the labour you have ex-
pended, and to forego the benefit of a good supply of turnips
for your stock, do this when it should he done, and do it
well. If you are short-handed, let every man, woman, and
child, who can lift a hoe or pull a weed, go to work in
earnest, and the job will soon be accomplished ; and what
is more, your children will become expert at turnip culture,
on which all successful farming in this Island will, before
long, depend: and remember that a good turnip-hoer never
takes his eye from the ground, until called to dinner ;
recollect this yourselves, and impress it on the children,
and there will be no stopping to talk, nor ceasing work to
gaze at every passer by, by which so much time is often
lost. The method I have found best in hoeing is this : as
soon as the leaves are between two and three inches long,
run a plough between the drills, taking away the earth on
each side to within about two inches of the plants ; this will
make a little ridgelet between each drill, and cover up all
the weeds : and if the horse-hoe is run through about a
week afterwards, they will be found quite rotten and form
a good manure for the land ; (some use the horse-hoe only,
but if there is much yar and weeds, the plough makes the
best work.) Then set to work with the hand-hoes, and
thin the plants five inches apart : when the plants are a
good size, and the leaves begin to touch each other, a second
hoeing must be given, cutting out every other plant ; this
will leave them ten inches asunder, taking away at the
same time any weeds that are between them. This second
hoeing is very quickly done. If the land is very weedy,
the horse-hoe should be run between the drills once before
the second hoeing and once after, and this will complete
the work.

11

154 SCIENTIFIC AGRICULTURE.

" Besides the manure covered in with the plough, small
quantities of stimulating manures, placed close to the seed,
are of great benefit to the crop ; a small quantity of ashes
run with the hand along the tops of the drills just before
the seed is drilled in, will cause the young plant to grow
more quickly, and get sooner beyond danger from the fly :
twelve or fifteen bushels are suflGicient for an acre ; more
than twenty is waste. When the manure is ploughed in
in the autumn, if you have a compost of mud and lime, or
mud and ashes, to apply to your turnip land, in addition,
the best way of doing it is, after the ground is ploughed in
the spring, cart on and spread twenty to twenty-five loads
of the compost, then harrow and roll, and then throw the
land into ridgelets, with the plough, thirty inches apart ;
this gathers the greater part of the compost which has been
spread into the drills, and within reach of the suckers of
the turnip; then roll the drills and sow the seed. Night
soil and bones are excellent helps to the crop — the mode of
applying them has been already pointed out.

" Pulling. — Few directions need be given about this
part of the business. The tops and tails should be cut oif
close to the turnips, or they will not keep so well. Some
persons advise the tops to be hauled off arid fed to the cattlo
on other fields. I have tried this, and am convinced it is a
very bad practice. In the first place, as food, they are
scarcely worth the labour oi hauling oft'; they will keep
cattle alive, but if they happen to be fat, they will reduce
their condition ; and if the niilcli cows get tlicm, the butter
will be unfit for market. But the great objection to re-
moving them is, that it robs the land of what ought to bo
left to feed the succeeding wheat crop. A heavy crop of
turnips is exhausting. In Britain, a portion of the turnips.
is consumed on the land, by sheep. Our climate will not
permit thi.H ; therefore, as we have to remove the turnips,
we should at least leave the tops. If you wish to feed
them, and there is time to do so before ploughing, let them
he eaten where thcv grew ; or if not, plough them in, and
decaying in the soil, they will enrich the land ; whereas
removing them is not only a waste of labour, but your
wheat crop will reproach you for having done so.

CROPS. 155

" Storing. — 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 par-
titions, 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 labour in carrying
them to the cattle during winter. Some store them in
their cellars, which is the worst place that can be selected,
as they are generally too hot and close to preserve the tur-
nips, too far^rom the barn for convenience, and the gas
which escapes from them renders the air .of the house un-
wholesome.

" The Swedish turnip appears to be the best suited
to this climate, especially on account of its property of
keeping well in winter. The mangel wurzel, however, is,
of all green crops, the best for milch cows. It produces a
large quantity of milk without communicating to it any
disagreeable 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 requires a somewhat stronger
and deeper soil than the turnip, and in light soils the yellow
globe variety will be found more profitable than the common
long red.

156 SCIENTIFIC AGKICULTURE.

" The Carrot is also a most profitable and sure green crop,
especially in the lighter kinds of soil;?, and is admirably
adapted for the winter feeding of working cattle and horses.
The long white is the most productive variety ; the long
orange and Altringham the next ; but the most delicate
and nutritious for table use is the red horn.

" 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 succulent food can be procured for
stock. They 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. The turnip will do much
later, and good Swedes have been raised in this province
from seed sown in the middle of July. It is generally
wiser, however, to sow much earlier, if there be any chance
of protecting them from the turnip beetle or " fly."

"The carrot, parsnip and mangel wurzel suffer little
from insects, and are very sure crops ; but the turnip has
two very troublesome enemies, — the turnip flies (two species
oi Altica'), and the caterpillar of a moth which attacks the
leaves in autumn. Against the ravages of the fly, the
following expedients may be adopted. Firstf — late sowing,
the fly being most destructive in May, and the early part
of June. Serovdh/, — 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 remem-
ber that the fly makes a point of taking its share first,
and consequently he must provide for it if he wishes to
have uiiy left tor himself. Thinlli/, — 'Sowing while the
ground is moist, immediately after the drills are made, and ,
Hclceting, if possible, the comniencemont of moist weather.
Fourthbf, — watt-ring the ground when flu; seed is ,s[)n)utiiig,
witli <liluted urine, soap suds, or guano and Ava((!r, or the
drainingH of u niunurc pile. A puncheon with a hole to

CROPS. 157

let the water run out, placed in a cart with a tight bottom,
and a narrow slit or a row of notches under the the tail-board
to spread the water, makes a good watering machine ; and
in dry weather the benefits in promoting growth and driv-
ing off the fly will well repay the cost. Fifthly, — sprink^
ing 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 maybe
practicable, a crop may always be secured; and if any
vacancies occur, they can bo 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 wea-
ther. Various dressings for the 'seed have been recom-
mended, but these do little to protect the leaves ; and I have
known some of the most offensive of them — as for instance,
codfish oil and sulphur — to fail entirely in driving oft' 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 ^>«Yc7ie«, for a very
obvious reason.

" The worm,or caterpillar,has been found a difficult 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,
ley, lime water, &c., would do something toward diminish-
ing their numbers.

" All the root crops above referred to are exhausting in
so far as the mineral constituents of the soil are con-
cerned ; but they send their roots deeply into the subsoil
and feed on it; their tops may be left to enrich the
soil ; they afford material for making good stable manure
when fed to animals ; and as they are always put in with
a heavy dressing of manure, they leave the land in ordi-
nary circumstances in a better state for grain crops than
before.

158 SCIENTIFIC AGRICULTURE.

§ 9. The Potato.

The potato contains in its tuber a larfrer proportion of
nutriment than the turnip or carrot, chiefly 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 manure usually applied
to the potato, and in soils containing lime it thrives well,
and is less liable to disease than in others. Some persons
suppose that the application 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, when 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 much potash, the lime afibrded
by the sea-weed, is probably of more importance than the
soda. Animal manures affording nitrogen, are also very
important to the vigorous growth of the potato, as to most
other cultivated plants.

As in the present state of the potato, the rot or blight
is the most important subject of inquiry, we may devote
some time to its consideration ; and may begin by stating
the leading i'acts as to its mode of occurrence.

1. The general diffusion and simultaneous occurrcnco
of the discaHo over extensive regions, is a remarkable fact ;
and the exceptions arising from the differences of soil and
other causes, are also very instructive in suggesting reu)e-
dial meuHures. Soineof the»o exceptions will be considered
' lubsequcntly.

CROPS. 159

2. The disease has usually attacked the crop at that
stage of the growth when the tops are fully formed, and
the formation and filling up of the underground tubers are
most rapidly proceeding. Yet early potatoes often pass
this critical period in safety, while those which are late are
attacked ; showing that the weather or temperature acts
with or against the predisposition at this particular stage
of growth, and modifies its influence.

3. 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 num
ber of little cells, or bags, filled 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 com-
municating with the eyes or buds on the surface of the
potato. The disease usually commences at the surface,
immediately under the skin, and usually near the eyes, and
penetrates inward along the bundles of vessels. Under
the microscope it is seen to be accompanied by the growth
of a minute parasitic fungus, analogous to that which
causes mildew in wheat, though it has not been certainly
ascertained whether this fungus. originates the disease, or
whether its growth is merely a consequence of the change
of the tissues. It is perhaps most probable that the deve-
lopment of the fungus is favoured by the disease previously
commenced, and it seems certain that in some cases the
disease exists without the fungus. From these 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 best
general view that can be given of such a disease is, that it

W^ SCIENTIFIC A9RICULTURK.

is a mortification of the tissues of the plant, proceeding
from something which has diminished its vital energies, in
such a manner as to allow those changes to go on which
ordinarily would take place only after the death of the
plant.

As to causes, two important truths, deducible from the
facts already stated, at once meet us : ,

1. A disease so general and widely spread, probably
primarily depends on some great, and generally operating,
predisposing cause.

2. Notwithstanding this, it is locally induced or pre-
vented by the action of a great number of secondary causes,
which favor or arrest its development, and which yet can-
not be considered as the primary causes of its appearance.
Let us inquire first, into

The inducing or secondary causes of the disease, and
remedies or palliatives founded on their study.

Most of these causes it will be necessary merely to name,
as the greater number of practical men are well acquainted
with them. The principal are wet and undrained soils, wet
seasons, wet weather after warm and dry weather when
the tops are fully grown, chilly nights succeeding hot days,
rank manure in contact with the roots, want of attention to
keeping the crop well tilled and free from weeds, run-out
seed long cultivated on the same farm. These and similar
causes have evidently had an important influence in locally
developing the disease, but none of them can be its general
cause, since the disease often appears where all are absent,
and these causes were quite as general as now, in former
times, without producing any such consequence as the
potato blight. Some valuable hints, however, as to the
best palliatives or temporary remedies for the disease, can
be derived from these causes, in connection with the expe-
rience of farmers. Of these, the following arc very impor-
tant temporary remedies or palliatives.

1. Early planting, and planting early sorts; because
this gives greater probability of avoiding tho effects of
autumnal chills uii*l rains. This remedy bus been found
very effectual in Nova Scotia.

CHOI'S. 161

2. Change of seed, especially from poor and cold loca-
lities, to richer and milder situations. The Scottish low
country farmers have obtained excellent results by import-
ing seed potatoes from the bleak and poor highland dis-
tricts.

3. 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 pro-
cured from the seed.

4. Planting in dry soils, and underdraining more moist
soils, if necessary to plant in them. The dry, sandy up-
lands of some districts have almost entirely escaped the
disease, when the crop has been put in early.

5. Applying well-rotted manure, and plowing it in, in-
stead 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 reme-
dial agents act by giving the plants a greater 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 o^ mineral manures.
It is generally observed, that the potato has been most
healthy when planted in new, virgin soil, before the un-
skilful agriculturist has extracted from it the stores of
alkaline and other mineral manures remaining in it from
the ashes of the forest. The composition of the ash of the
potato at once explains the reason of this, as the following
table, taken from Johnston, will show :

Ashes in 10,000 lbs. of the roots and stems of the potato.

HOOTS. TOPS.

Potash, 40.28 81.9

Soda, 23.34 0.9

Lime, 3.31 129.7

Magnesia, 3.24 17.0

Alumina, 0.50 0.4

Oxide of iron, 0.32 0.2

Silica, 0.84 49.4

Sulpiiuiic acid, 5.40 4.2

Phosphoric acid, 4.01 19,7

Chlorine, 1.60 5.0

82.83 308.4

162 SCIENTIFIC AGRICULTURE.

Here we have very large proportions of lime and potash ;
the latter forming nearly 50 per cent, of the ashes of the
roots. Now these substances, potash especially, are 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,
gypsum, (sulphate of lime,) common salt, (chloride of so-
dium,) 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 be obtained by planting with no other manure
than a 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. Whenever,
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 pro-
gress of the change arrested by being kept dry ; and that
the diseased spots dried up and lost their putrescent cha-
racter.

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 tliat from sound potatoes. Every farmer
should have a grater or grating machine for potatoes, and
in autumn should prepare u quantity of farina. It is
excellent for children's food, puddings, to mix with flour
for bread, &c. ; and it will keep for several years.

All the above, and probably other ex pod ion ts, liavo been
approved by experience, as useful palliatives. In short,
anythin]; thut tends to plaoo tho plant in a natural and

CROPS. 163

healthy condition, appears to give it a much greater power
of resisting the cause of disease, whatever that may be.*

None of these secondary or partial remedies, howevea,
can be expected to eradicate the disease. They may tem-
porarily prevent it ; or, when present, mitigate its violence,
or diminish the loss resulting from it. But I shall pre- .
sently show, that we have no reason to suppose that any,
or all of them, can effect a perfect cure.

We proceed then, in the next place, to inquire into the

Prwuiry or predisposing cause of the disease, and its
remedies.

Almost every fact that can be collected, seems to indi-
cate that there must be some general cause of this nature,
which began to operate only in modern times ; and which
has, during the last few years, been almost universally
active, but modified by the influences of the secondary
causes above referred to.

The ordinary popular resource in seeking for the origin
of wide-spread epidemics, is to refer them to the atmos-
phere. " It is in the air," appears often to be thought a
satisfactory explanation. If we ask for proof, none can be
obtained either from chemistry or meteorology. If atmos-
pheric, then the cause of the evil is likely at once to be
beyond our cognizance and control ; besides, we are at a
loss, on this hypothesis, to account for the apparently
almost entire limitation of the disease to one cultivated
plant.

On the contrary, every point in the nature of the disease,
and the means hitherto found useful in counteracting it,
indicate that the defect is in the plant itself; that from
some cause its vital force has been weakened, so that pu-
trefactive processes lay hold on the substances which, in a
liealthy state, it could retain unchanged ; and that these
putrefactive changes can be arrested only when the cir-

* To this I may add that when the disease is observed in the
stalks, the potatoes should be dug at once. If they must be left
in tha ground, the stalks should ba pulled out.

164 SCIENTIFIC AGRICULTURE.

cumstances are in all respects healthy ; while unfavorable
circumstances, which in former years produced no eifect,
are now speedily fatal. The occurrence in the diseased
potato or on its surface, of fungi, plant-lice, or other
enemies, does not disprove these views, as these are always
ready to attack tissues previously unhealthy.

Is there then, anything in the past history or present con-
dition of the plant, likely to produce such an effect. I have
long thought that there is such a cause, and shall now pro-
ceed to explain it, in connection with the only means of
counteraction which have suggested themselves.

Of all our crops, the potato alone has been continuously
propagated by natural or artificial division of the plant. The
tuber of the potato is a sort of underground stem, with eyes
or buds intended to produce young shoots in the year fol-
lowing the formation of the tuber, and with a store of starch,
albumen, &c., to nourish these young shoots in the early
stages of their 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
dimini-shes, and at length it will die out ; and if a new plant
occupy its place, it must be a seedling produced from the
balls which have fallen on the spot.

If then, since the potato was introduced into Europe
about 250 years ago, we have been continuing its cultivation
solely by division or separation of the tubers, we have been
perpetuating the life of one individual plant; and wo must
now have potatoes that are the descendants of those import-
ed by Raleigh, not by natural generation through the seed,
but by indefinite division of the plant; a sort of inlinitosimal
fractions by a perpetual division of that now extremely aged
individual potato. Have wo a right to expect that such

CROPS. 165

plants should be healthy ? 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 plants
which, like the potato, have been furnished with tubers to
provide for the continuance of individual 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 ? In
answer to this I may remark, that the disease in question
is, in fact, merely the death and consequent putrefaction of
parts of the tissues of the plant. Further, the analogy of other
vegetables leads us to believe that plants do not always
simply die out under the influences 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 exter-
jially with lichens, mosses, fungi, and excrescences, usually

166 SCIENTIFIC AGKICULTURE.

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 the planted tubers,
apparently because there was not sufiicicnt 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 some worse disease. And now we have
to contend with a mortification of the tissues, not in the
infant stage, but in tl\e period of the plant's fullest vigor
and strength.

It may be objected, that even renewal from the ball has
not been effectual, the seedling varieties having suffered as
well as others. It must be observed, however, that seedling
varieties have generally resisted the disease longer than
others, and that there seems good rcjison to believe that the
disease, like most others that originate, whether in plants
or animals, from long exposure to debilittvting influences,
is more or less contagious. It is quite probable also, that
the seed of plants which have already contracted the disease,
may be itself not quite free from hereditary taint. Renewal
from the seed cannot, therefore, be assumed to have been
fairly tried, unless tlie seedlings have been, at all stages,
completely separated from the old varieties, and unless they
have been derived from healthy plants, or are separated, by
a sufficient number of removes, from their unliealthy pro-
genitors.

I come now to the method which the above views would
lead UH to consider the only certain one, with a view to the
final extirpation of the disease, and it is one re({uiring the
means at the command of the government of a state, or

CROPS. 167

some public body or institution, devoted to agricultural
improvement.

It is to cultivate the potato from the hall, for several
generations continuously, until the hereditary taint is re-
moved, and then to distribute the healthy tubers to such
agriculturists as will jiledge themselves to abandon entirely
the culture of the present exhausted and diseased varieties.

To succeed in the experiment, it should be conducted
on a well-managed model farm, or horticultural garden,
from which the culture of the old varieties should be entirely
excluded, and seed should be obtained from the balls of the
most healthy potatoes.

The ground should be light and dry, and manured with
a mixture of old compost, lime, gypsum, and wood ashes.

The seedlings should be carefully tended and kept very
clean from weeds, and any plant, in which the first signs
of blight appear, should be at once destroyed.

A part of the seedlings should be carefully covered, and
allowed to remain in the ground all winter. The remainder
should be carefully packed in dry sand, in a cool cellar,
keeping the various sorts separate.

In the second year, the same precautions should be used
as to the culture of the best varieties obtained in the first
year, and some of the plants should have the soil washed
away from their roots, and the young tubers picked off, in
order to ensure the production of the balls. After picking
off the tubers, the plants should be carefully earthed up
again.

The seed from the balls of the second year should be sown
in the third year, and the whole process repeated as before.
The tubers obtained from the first sowing should not
be distributed as seed potatoes ; but those from the second
sowing might, if no disease had appeared in the course of
the experiments. If disease had appeared, the process
should again be repeated.

The best varieties obtained from the produce of the third
or second sowings, should be planted out, to furnish seed
tubers, with the same precautions as to manure, &c.

The sound tubers should be given or sold to farmers, who

168 SCIENTIFIC AGRICULTURE,

would pledge themselves to cultivate no other varieties, so
as to Sv.-cure them against contagion.

A national nursery for new varieties of potatoes, on the
above plan, should be kept up in every agricultural country,
so as continually to supply new and sound varieties. Inde-
pendently of the prospect of gradually restoring the potato
culture, the improvement of the sorts cultivated would
amply repay the expense. In the same farm, or garden,
experiments might be tried in the culture of wild varieties,
obtaiued from tlie native country of the potato.

The above suggestions are submitted as probably far
superior to any founded on the belief of any one method
or substance being effectual as a cure. Such partial reme-
dies, though they may be temporarily successful in par-
ticular soils or seasons, never can effect the general or per-
manent removal of the evil.*

§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 of 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 Bruns-
wick, existed in Scotland, in connection with this branch
of husbandry, about 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 tlie winter months. The
beef these cattle gave was so poor tliat it took the suit badly,

* The above ezplAnatioB of the Potato rot was first published
bj the author in the Keport of the Agricultunil Hociclies of
liassachuBBctts for 1851. It has since been often r(<))roduced
by variouH writers, and hns been to some citenl rrduced to
pra«ti«« in th» productioa of r\*vr rariftifs of th« potato.

e^ROPS, 169

Vras hard and indigestible, and kept badly in the brine.
Now, the cattle are not killed in the autumn more than at other
seasons. The present modes of husbandry provide winter
food for all the stock the farmer finds it convenient to keep.
When killed, the beef or mutton is now of excellent quaHty ;
large quantities of both are forwarded, 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 hus-
bandry, the most important points to be considered in refer-
ence 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, pos-
sessing 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 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. Circum-
stances may render necessary partial deviations from this
rule ; but the principle should be considered as settled,
that every 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 diflScult as may

12

iTO SCIENTIFIC AamCULTURE. ^

be imagined ; 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 impoverish-
ment results. On the other hand, the grand secret of hope-
lessly 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 Nevi 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 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. Where there is a large
crop to be cut, and few hands, mowing should, if possible, be
commenced he/ore, rather than after the flowering of the
bead, — which is the time when the grass contains the largest
quantity of nutritive matter. It is true, however, that
tew grasses will bear late cutting better than herd'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 requires to be present in the soil,
are very much the same with tho.se 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

Hnccessful culture are as yet very imperfectly known in

this country. The ashes of clover contain largo quantities

<t prjtash, lime, and gypsum. Those substances must

GR0P3. 171

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 trou-
ble. 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 preparing nourishment for the growth and
strengthening of the root; and if cut early with 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 successive rotations, the land becomes
" clover-sick," as it is termed, and the crops fall off. In
Britain, pasturing for several years has been found to cure
this; and manuring with wood ashes, lime composts, and
urine, have also been found beneficial.

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 often attributed to particular varieties of seed ; but they
depend f\r more on the nature of the soil and treatment,
— though of course, some unfavorable seasons occur, in
which no management is altogether cfiectual; and as the
natural life of red clover does not extend beyond two or
three years, it cannot be expected to remain permanently

i'?2 SCIENTIFIC AGRICULTtJldj.

in the land. Shallow undrained poor soils, ■which do not
allow the roots to become large and strong in the first year ;
destruction of the leaves of the first year in autumn ; defi-
ciency 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.

Jackson, in his Agriculture and Dairy Husbandry, states,
that clover may be very successfully sown with flax. This
fact may be useful to some farmers.

The expense of clover seed tends to prevent the poorer
farmers from using it more freely, and hence the land has
generally too little seed to give a good crop in the first
season. There seems no reason to prevent the seed from
being more extensively cultivated in this country. The
directions usually given for this are, to allow cattle to eat
down the leaves in early spring, or to cut the leaves very
early, and then to protect the second growth, and allow it
to ripen its seed. The process for cleaning the seed may
be seen in many agricultural books. This is a subject
deserving the attention of Agricultural Societies, which
might usefully give premiums. for the best and largest
samples.

§11. FhXf Hemp, Broom Com, &c.

The culture of Flax has of late been much recommended,
more especially since the recent scarcity of vegetable fibres
for textile manufactures commenced, and there can be no
doubt tliat it might be made the means of securing a pro-
titiible article of export, as well as of establishing domestic
manufactures. On this subject, we cannot lioro enter into
details which belong to the mechanical part of agriculture,
but may notice a few points connected with thccoiiipusition
and habits of the plant. Flax re(iuircs very frequent
changes of seed. Sowing seed raised in another country,
gives a remarkable stimulus to its productiveiiess. In
Britain, American and Riga seeds arc imported and sown,
and flux growers alwkys prefer this foreign seed, or that

CROPS. 178

which is but one remove from it, to their own. In this
country, where farmers sow seed raised on their farms year
after year, short crops must necessarily be the result. Flax
prefers well-elaborated manure, and must, of course, have
clean land. Its proper place in a rotation is, therefore,
after a well-tilled green crop. A dressing of lime, or wood
ashes, sown with the seed, or after it is up, will be found
very advantageous. I have already stated, that grass and
clover may be sown with flax ; and I may add, that the
Belgian farmers are of opinion that the young grass and
clover are not injurious, but, on the contrary, beneficial to
the flax.

Flax has usually been considered an exhausting crop ;
but the success of clover after it, shews that this is not
strictly true. The fibre and seed of flax probably take
less from the soil than the grain of a wheat crop. The
greater part of the inorganic matter taken from the
soil is contained in the refuse of the dressing ; and if this
be composted 'or otherwise saved, and restored to the soil,
no exhaustion will result. If clover succeed the flax, and
be ploughed down after the second crop, its roots will
replace most of the organic matter abstracted by the flax.
Flax extracts much from the subsoil, and is partial to a
calcareous soil, and much benefitted by lime. When yield
of seed is an object, an abundance of organic manure in
the soil is important ; but for flax of fine quality, if the
inorganic matter required is present, rank manures are
objectionable.

The precise requirements of flax, as to inorganic food,
are shown by the following analysis by Johnston of the
ashes of the flax fibre and of the refuse or poh.

Flax. Fob.

Alkaline salts, chiefly common salt, and

sulphate of Potash

Phosphates, chiefly of Lime and Magnesia.

Carbonate of Lime

Carbonate of Magnesia

insoluble sijicious aiatter

100. 100.

8.93

9.58

17.89

14.12

45.56

51,43

6.38

9.24

21.24

15.63

174 SCIENTIFIC AGRICULTURE.

This table shows how important it is to restore as manure
to the soil the pob oi- Jiossings of the flax, and also that
to restore the fertility of land exhausted by this crop,
lime, bone-earth, and wood ashes would be suitable
manures. Guano would be very valuable in this respect.
It has also been ascertained by Sir R. Kane, that the water
in which flax has been steeped, contains much nitrogenous
matter, and also many saline substances, in solution, and is
most valuable as a liquid manure.

Hemp is also worthy of the attention of farmers, and is
largely cultivated in climates similar to ours. It requires
good soil, and is said to clear the ground of weeds. Grain
and grasses thrive well after it, which would indicate that
it is not a very exhausting crop. The plants are male and
female, the latter of course alone producing seed ; but the
former, which is smaller and more delicate, producing the
best lint. The seed of both sexes must be sown together,
and both may be dressed together, but it is advisable to
have a separate patch, from which most of the male plants
have been thinned out, for seed. The crop, when ripe,
which is known by the disappearance of the farina or bloom
of the male plant, and the partial withering of the leaves,
is pulled like flax, or cut near the ground, and its subsequent
treatment resembles that of flax. After being broken on
a hand-brake, somewhat stronger and larger than that used
for flax, it may be sold to the manufacturers without further
preparation. An acre yields from 6 to 10 cwt. of prepared
hemp. The breaking of hemp furnishes good employmeni
for idle hands in winter. It would probably thrive well
on our dvked marshes and intervales, and on the deeper
loamy uplands. A very particular account of the mode of
preparation, by the Hon. H. Clay, is given in Fcssenden's
American Farmer.

Broom Corn is a crop of profitable culture wherever tho
plimatc is sufficiontly warm, and in many parts of British
America this \n the case. The stalks or their upper parts
HcU profitably lor bropm-makiiig. Tho seeds are ^^aid to be
equal ill value to a crop of oats. It re(juires rich manure,
ttud cleaning with the hoc ; and its general culture resembles

CROPS. 175

that of Indian corn. It is, no doubt, an exhaustitig crop ;
as it grows to a great height, and a considerable part of its
strong woody stalk is sold off the farm. Full directions for
its culture will be found in the American Agricultural
books.

The Chinese sugar cane is a plant similar to Broom Corn
in its culture, and is useful for feeding cattle, and the pro-^
duction of syrup. It grows well on rich loamy soils in
Canada, though its seed does not ordinarily ripen, at least
in Eastern Canada. It sometimes attains the height of
nine feet, and affords much highly saccharine syrup as
well as nutritious food for cattle.

§12. Orchard Culture.

The culture of fruit trees is largely and skilfully practised
in some parts of the country ; but in others it is little
attended to. There can be no question, that wherever
soil and circumstances are favorable, it well deserves atten-
tion, on account of its market value, and its contributioi^
to family comfort and to the beauty of the farm. I shall,
under this head, notice a few requisites for a good orchard,
and the remedies for the more destructive blights and dis-
eases to which fruit trees are liable.

It is of the first importance to have a suitable soil and
exposure. The apple prefers deep loams, or sandy loams ;
— the red loams of parts of the Lower Provinces, and the
deep shingly soils of the inland hills, are especially adapted
to it. The pear does Well in similar soils. The plum does
not object to a stiff clay, and will not grow luxuriantly in
some of the lighter soils, in which the apple flourishes. The
cherry, on the contrary, prefers a light dry soil. Much can
be done, however, by proper drainage and manuring, to
render all ordinary soils suitable to these and other fruit
trees. A good exposure should be selected; and where
there is not natural shelter, belts or rows of trees should be
planted on the sides exposed to the cold winds. Cherry
trees suit well for this purpose ; so do spruces. The butter-
nut tree has also been recommended; and, indeed, any

176 SCIBNUFIC AGBICULTURE.

rapidly-growing tree, suitable to the soil, will serve the pur-
pose. The ground should be well tilled, drained, and ma-
nured. It is folly to plant valuable trees in a poor, cold,
undrained soil ; and it is folly to plant worthless or inferior
trees at all, when good sorts can be procured.

Trees should be lifted with care, so as not to injure the
roots ; as these are all required to nourish the tree. They
should be planted with like care, — spreading out the roots
in a natural form, and trimming off some of the young
shoots from the top. Holes for planting should be made
both larger and deeper than is absolutely necessary ; and
the surface-soil, with compost or rotted manure, should be
turned into the bottom of the hole. If the soil be deep
and dry, the tree may be set pretty deeply ; if cold and
shallow, the tree should be nearer the surface. The earth
should be carefully pressed around the tree ; and a little
straw, or a few sods or some seaweed, laid on the surface,
to preserve the moisture of the soil. Bones, parings of
hides and horns, hair, and similar animal matters, are
excellent and permanent manures for young trees. After
planting, the ground should be kept clean, and regularly
manured with old compost, ashes, ditch cleanings, or ani-
mal matters ; and on no account must it be allowed to
become covered with a tough grass sward, especially in the
case of apple trees. Trees arc often seen growing in old
grass sward, regularly mowed, and seldom or never man-
ured. Such trees must eventually become unproductive
and diseased. Trees extract large quantities of matter
from the soil, and require plentiful manuring, especially
when another crop is being taken from the same soil.
Hence it is a good plan to plant orchards very open, and
to cultivate and manure the ground in regular rotation ;
taking care not to damage the roots unnecessarily, and not
to leave the land long in grass. The apple is much bene-
fitted by frequent stirring of the soil; — stone fruits require
less of this, and are more apt to bo injured by wounds
inflicted on their roots.
^When it is desirable to plant out trees before the ground
is" properly prepared, or when it cannot be tended as it

CROPS. 177

requires, seedlings or slips raay be planted out, instead of
grafted trees ; and such of them as become strong and vigo-
rous, may afterwards be grafted with good sorts. In like
manner, farmers who have young trees of wild or inferior
kinds, may have them headed down and grafted upon ; — if
skilfully done, the grafts soon come into bearing. In
planting, abundance of space should be left for air and light.
When early produce is desired, the trees may be planted at
half the proper distance apart, and each alternate tree may
be forced into early bearing, by root pruning and shorten-
ing-in the branches. These trees may afterwards be cut
out, when they interfere with the others.

Pruning is a most important part of orchard management.
Trees should be kept open, and trained symmetrically, so
as not to permit the branches to interfere with each other,
and to present the greatest possible surface to air and light.
There are various modes of pruning, but all depend on this
principle ; and wall, espalier, round, oval, or conical training
may be preferred, just as one or other may appear, in the
circumstances or situation, to be more or less adapted to
promote access of air and light. The perfection of pruning,
is to study the growth of the tree, and cut out as early as
possible every twig that interferes with the intended plan,
or with the symmetry of the whole. When it becomes
necessary to cut out large branches, more or less permanent
injury to the tree is unavoidable. The cutting off a
large branch is somewhat analogous to the amputation of
a limb in an animal, and more or less deranges the circu-
lation of the whole system. Large limbs should be pruned
in summer ; small twigs may be freely cut in spring.
Experience has shewn, that the dangers of spring pruning,
in the case of considerable limbs, are much greater in stone
fruits than in apples and pears.

On the subjects of grafting and selecting of sorts of
trees, I may refer every beginner in orchard culture to
Cole's American Fruit Book, a cheap and excellent little
work.

The diseases and enemies of fruit trees should be care-
fully studied, both in books and in nature, by every fruit

iti

SCIENTIFIC AGRICULTURE.

cultivator. They are very numerous and troublesome,
though often sufficiently interesting and curious. In the
following remarks, I shall give principally the results of
my own observations in this country ; and it is, of course,
possible that I may have overlooked some pests of the
orchard known to other persons.

1. The Scale Insect or Bark Louse (^Coccus) attacks the
apple tree, and, though not rapidly destructive, much
impairs the vigor and productiveness of, the tree. It is
a small whitish creature, residing under a greyish scale
attached to the bark, and is, in its adult state, quite inca-
pable of locomotion. It appears to subsist by sucking the
juices of the inner bark, to which, when very numerous,
they give an unhealthy brown color. In autumn, the
adult deposits under the scale a number of whitish eggs,
and dies. In spring, the young are hatched on the ap-
proach of warm weather, usually in May, and make their
way to the younger twigs and branches, where they fix
themselves, and acquire a scaly coat, like their parents.
To destroy these insects, the branches should be washed
with lime in early spring. This prevents the young from
extricating themselves from the old scale, or from attaching
themselves ; and they consequently perish. At the same
time, the tree should be well manured, to give a vigorous
growth, and the loose outer bark should be scraped from
the trunk before the lime is applied. In this way, a cure
can be easily effected in the case of small trees.

2. The TeiU Caterpillar, or web-weaving caterpillar,
attacks all kinds of fruit trees. It is the larva of a moth,
ClUioaimpa, which, in autumn, deposits its oggs in a ring
surrounding a branch. In autumn, winter, and early
spring, these deposits of eggs should be searched for and
removed. The trees should also be carefully examined in
spring and summer, and ev( i) little cobweb curtain that
is obsorvcd, should bo cut off, and its inliabiUmts crushed ;
or if it bo too large to permit this to be done without
injury to the tree, the web and insects may be brushed off
with a mop, or broom, dipi>ed in a strong solution of »oft
ooap.

CROPS. 179

3. The Tussock Caterpillar is a creature of gay colors,
and ornamented with long tufts of black hair. It is the
most beautiful of our caterpillars ; and, singularly enough,
in its perfect state, it is one of the plainest of grey moths.
It belongs to the genus Orgyia. The female is an un-
sightly wingless creature, remaining motionless on the spot
where she emerges from the hairy cocoon in which the
full-grown caterpillar envelopes itself, when about to enter
on its torpid or pupa state. Attached to this cocoon, she
deposits a mass of eggs, enveloped in a hard spongy
whitish varnish, intended to protect them from the rains
and storms of winter. Owing to this circumstance, the
eggs are easily observed ; and when seen in autumn or
winter, attached to limbs of trees, fences, or buildings, they
should be brushed down and destroyed. When the cater-
pillars are hatched, if abundant, they soon strip a tree of
its leaves ; and means should at once be resorted to for
their destruction. The best method is to drench the tree
with a solution of whale oil soap, or soft soap, common
soap-suds, or weak potash ley. This may be sprinkled
with a mop of rags, or, better, with a garden syringe.
Small trees may be sufficiently sprinkled with a garden
watering pan. Soap, applied in this way, is a useful
remedy for the attacks of all kinds of caterpillars. Much
injury may also be prevented by smearing Jhe lower part
of the trunks of trees with tar in spring ; as some kinds of
caterpillars, and the canker-worm among the rest, are occa-
sionally hatched on fences, outhouses, &c., and make their
way into the trees by climbing the trunks. American
books say, that the canker-worms may be shaken down
from the tree, and destroyed on the ground. I have not
found this to be the case with the species common here,
as it clings very tenaciously to the limbs. Some other
kinds of caterpillars may, however, be shaken down.

4. The Apple Worm, the larva of a species of moth,
Carpocapsa pomonella, burrows in the apple, devouring a
part of it, and causing it to fall prematurely. On arriving
at maturity, the grub creeps into a crevice or sheltered
place, and spins a neat whitish cocoon, within whi«k it

180 SCIENTIFIC AGBICULTURE. "*

remains till it comes forth in the perfect state. The best
remedy is to pick up and destroy all the fallen apples ;
hogs are sometimes allowed to devour them. If this be
attended to, the numbers of the apple-worm will speedily
be diminished.

5. The Black Wart attacks plum trees, and sometimes
cherry trees ; and, if allowed to proceed unchecked, is a
fatal disease. It seems to be a fungus, analogous to the
*' spunk " and other dry fungi often found on forest trees ;
and it probably diffuses itself by spores, or dust-like seeds,
carried by the wind. Every affected branch should be cut
off so soon as the disease is observed, and should be
burned, or carried to a distance from the orchard. In the
case of plum trees, salt, or pickle — which, in moderate
quantity, is by no means injurious to these trees— should
be scattered around them ; and though it may not wholly
prevent the black wart, it will much mitigate its destruc-
tive effects.

6. The Plum Weevil, or Curculio, is a small beetle,
(Rhi/nchcenus nenvphar) which deposits its eggs in the
young plum. The grubs prey pn the fruit, and cause it
to fall prematurely ; after which they burrow in the ground,
and come forth in the next season as perfect insects, which
creep and fly into the tree. The remedies which have
been found useful, are : — 1. Manuring with salt, which is
said to render^the fruit distasteful to the grub. 2. Pick-
ing up and destroying the fallen fruit. 3. Putting a girdle
of cotton wool or tar around the trunk, which arrests the
beetles in their ascent. 4. Treading flio ground hard
around the tree, which tends to prevent the grubs from
burrowing. Plum trees in light soils, lue more liable to
be attacked by these insects than those in stiff soils.

7. Plant-lice, and Mites. These creatures are often
injurious to fruit trees, especially to the plum, and some-
times kill them. A little red mite, or red " spider," as it
is sometimes called, and two or three species oi' green
and black plant-lice (ajihis) are especially troublesome.
The best mode of dfwtroying these creatures is, to drench
the tree with soap-suds, or ley, or to smoke it with tobacco,

CHOPS. 181

—The larvae of the common little red lady-hugs, (Cocdnetla)
are great devourers of aphides. They are hideous-looking
large-headed grey caterpillars, which, when disturbed, erect
themselves on their tails with a jerk. Their good o&ces
in destroying plant-lice, entitle them to rank as trUe
"farmers' friends."

8. The Cherry Slug is a small slimy dark-colored cater-
pillar, the larva of a little blackish fly (^Selandria Cerasl).
They often appear in cherry trees in considerable numbers,
without doing much injury ; but when very numerous, they
should be destroyed, by dusting the leaves with wood ashes
or lime.

9. Many other creatures might be added to this list of
destroyers. The Apple-tree Borer [Saperda Candida),
and the apple Buprestis, or snapping beetle, devour the
wood of the trunk of the apple tree ; and among the de-
vourers of the leaves may be reckoned different species of
palmer worms or weaver moths, the caterpillars of insects
of the genus ChaitocMlus, as well as many other caterpil-
lars ; but, with the exception perhaps of the Borer, none of
these attain to the destructiveness of those already men-
tioned, in British America. Couper recommends as the
best mode of guarding young trees against the Borer, to
surround their trunks with a band of grafting clay, two
inches thick, from the ground to a height of two feet.*

10. It may be remarked, in general, with respect to all
the enemies of fruit trees, that the orchardist should
encourage all the insectivorous birds, — robins, swallows,
fly-catchers, titmice, wrens, warblers, &c., — to frequent his
orchard. Some of these birds commit occasional depreda-
tions ; but, in the main, they are admirable assistants in
the destruction of noxious insects. Tliey should be pro-
tected from injury ; and the cultivator would do well to
imitate them, in their activity, vigilance, and prying search
for every living thing that shelters itself on bark, leaf, or
limb.

• Canadian Naturalist, Vol. VIII.

CHAPTER XIV.

SUGGESTIONS AS TO PRACTICAL APPLICATIONS.

The young agriculturist has presented to him by the
study of this subject a number of topics of thought and
inquiry, such as the improvement of barren or run-out
soils, the most economical use of manures, the proper suc-
cession of crops on a given soil, and the uses of crops in
feeding. In each of these he may meet with diflBculties as
to the application of the principles and facts stated, and
with objections on the part of practical men. A few exam-
ples of these may be usefully given by way of conclusion.

One of the difficulties is that of obtaining satisfactor/
information as to the soil on which he has to operate. He
can easily ascertain its mechanical quality, and general
feature.s, as argillaceous, silicious, and so on; but its inti-
mate chemical constitution may be involved in doubt. If
he can have a chemical analysis executed by a reliable
practical chemist, this will be one sure means of informa-
tion. 8till in many respects even the most accurate results
of the chemist are not sufficient for practical purposes.
When a good chemical analysis shows the absence or satrciti/
of one or more important ingredients of fertile soils, this is
a fixed and valuable fact. It is, however, just in this nega-
tive direction that an unskilful analysis is most likely to
err. On the other hand, the prrscnce of a substance in the
soil, docs not prove its availabiliti/ for the use of plants,
and there are cases where on this account chemical analysis
gives a much too favorable result. Supposing a good
analysis obtained, the farmer must still satisfy himself
whether the Hubstancos which it show-s arc available. If
no analysis can be obtained, he ntust ascertain the whole
of the facts required in some other way.

PRACTICAL STJGGESTTONS. 18^

The surest mode of testing the soil practically, is by
means of experiments with crops and manures. Let a
given surface of soil be divided into portions, and sown
or planted with several kinds of crops without manure.
This will give an indication, by the yield obtained, as to the
fertility of the soil, relatively to these crops ; and the known
composition and habitudes of these plants will indicate
why one thrives better than another. Large straw and leaf
in wheat or barley, will indicate the presence of silicates and
alkalies ; abundant and healthy seeds that of phosphates.
Large potato tops indicate the presence of potash ; clover is
a test for lime and sulphates, and so on.

If the soil has proved itself poor for all or any of the
crops tried, it may again be tested with the manures
which it may be supposed to want, and the results compared
with those of the same crop on an unmanured patch. This
may be done on a small scale; using superphosphate of
lime, wood ashes, gypsum, peat compost, or other substances
in given quantities per acre. The results sliould be
observed for two or three years, as the effects of some of
these substances may be more or less permanent.

Such trials, judiciously made on a small scale, with
reference to chemical principles, will eventually give
information which may be applied to the whole farm. No
expensive failures will be made, and the improvements
will carry their own evidence with them. The result of
such experiments may be further tried by observation of the
natural herbage or forest of the ground, and of the results
of the culture of different crops or the application of dif-
ferent manures on the farm in the course of its culture.
The trials which may be made on neighboring farms
having similar soil, are also to be observed in this way.
Supposing the experimenter and observer to be a person
of sound judgment, and to have mastered the elements
of agricultural chemistry, the conclusions reached will
assuredly be a safe guide for practice.

It may be useful to state, by way of contrast, some of the
errors which proceed from inattention to, or ignorance of,
scientific principle^.

1S4

SCIBNTIFIC AGRICULTURE.

Liebig, the great Grerman chemist, had maintained the
importance of mineral manures to the growth of wheat. In
this he was right, but the most silly uses have been made
of his statements. Mineral manures have been prepared,
containing in due proportion the substances required for
the ashes of a crop of wheat, and it has been supposed that
this must necessarily be the proper manure to apply for
the culture of this plant. But nothing can lead to greater
mistakes in practice than this notion. If the land
already contains the materials of many crops of wheat in
an available state, then the addition of a small dressing of
these can scarcely give any appreciable result. If it want one
or two of them, then these alone will be of service, the
others may be dispensed with. If it is utterly barren, then
the quantity of such material which should be applied
must be vastly greater than that required for one or two
crops. Thus the use of such a manure can be profitable
only in certain circumstances, which must be ascertained
in the first instance.

To determine the precise value of such mineral manures,
Messrs. Lawes and Gilbert, two eminent English agricultu-
rists, undertook a series of experiments extending over ten
years. Unfortunately, however, they proceeded without
thinking of one of the most important conditions of the
experiment. This was that the soil experimented on should
be destitute or deficient of the materials added to it. On
the contrary they selected a spot which, as the experiments
themselves showed, possessed already enough of mineral
manure for several crops of wheat. On this account, as
might have been expected, small quantities of mineral
manures produced scarcely any improvement of the crop.
Any school-boy, who had studied the elements of agricul-
tural chemistry, could have told the experimenters this
before they began. Yet these costly experiment's were
made, and the results paraded as conclusive evidence of tho
worthlessQOSB of mineral manures, when in reality they
only proved the incompetence of the experimenters for the
work they had uiulertaken. Many trials made on a small
scale fail from a similar cause.

PRACTICAL SUGGESTIONS. 185

Again : It must be taken into account that a manure
of the greatest value on one soil may be quite useless on
another. A farmer cultivating a soil deficient in lime,
is induced to apply a large dressing of this substance.
The results are extraordinary, because previously the
crops were stinted of this material, and it was per-
haps wanted also to promote necessary changes in the soil.
He announces to others the great effects produced ; and
another farmer cultivating a highly calcareous soil, straight-
way applies lime, but without any beneficial effect, since
the land has already enough of it. He of course condemns
lime, and with it the book-farming which has led him to
waste his labor and money. An inland farmer uses
salt with advantage ; and another, living on the sea coast,
where the spray, carried by the winds, sufficiently salts the
soil, tries it, and finds it worse than useless. Such want of
attention to the circumstances of individual cases vitiates
a great part of the correspondence of agricultural journals,
and renders it valueless, unless commented on by an
enlightened editor, or read by persons who understand the
reasons of the success or failure in each particular instance.

Farther, a mineral or artificial manure, very useful at
first, may in time fail to have any effect, or may even
exhaust the soil. Take the instance of gypsum already
referred to. When applied to soils deficient in sulphates,
it produces magical effects ; but if trusted to as the only
manure, it ceases to do good, and the land appears
poorer than ever. It is then decried as a stimulant, and
abandoned in digust. The same result in the case of
lime originated the English proverb that it makes rich
fathers and poor sons. This must necessarily happen in
the case of all partial or special manures. In an article
written several years ago, for an agricultural journal, the
case was put in the following way : Let us suppose that
any cultivated crop requires from the soil equal quantities
of three substances, which we may call A, B, and C, and
that the soil of a field is capable of supplying in one year
lA, 2B, 3C, the plant, requiring equal quantities, can
only avail itself of lA, IB, IC, while IB and 20

13

186 SCrENTIFIC AGRICULTURE.

remain as surplus or go to waste. Let the fanner now
apply annually lA to the field as manure, the plant now
takes 2A, 2B, 2C, and the crop may be doubled. But
it is evident that the increased crop exhausts B and C
more rapidly than the previous small crop. Hence perhaps
in a few years the proportions in the soil are reversed, and
it can yield only IB, and 2A, and 2C to the crops. The
crop will now fall to its originally small amount, and it is B
that must be added to supply this new deficiency ; any
quantity of A doing no good when applied. This simple
consideration explains many results otherwise puzzling, and
we may add that the only manures which really contain
the whole of the food of plants, are those aflForded by
the liquid and solid products of the stable, and animal
and vegetable substances of similar composition. Other
manures are in their nature special and partial, and though
their application achieves some of the greatest and
most profitable triumphs of scientific agriculture, their
misapplication through ignorance of the chemical composi-
tion of crops, soils, and manures, does very much to bring
the whole scientific theory of agriculture into most unde-
served contempt with practical men. It is hard that
science should bear the blame of errors which arise only
from the want of it ; yet this must be the case until farm-
ers and agricultural writers familiarize themselves so far
with the principles of chemistry as to be able to understand
the meaning of the experiments which they make, and the
results at which they arrive.

In conclusion, the young farmer must be cautioned
against supposing that this little book contains the whole
theory of agriculture. On many important subjects, as for
instance the applications of physiology to the feeding and
ore of animals, it has not entered ; and of those to wliich
it has adverted, it has given merely the elements. It may,
in a subject advancing so rapidly, and to which the writer
oannot give undivided attention, have failed to nftach to
some facts or principles their true value. Tlic subject is a
large one, affording ample scope for all the obstirvation,
thought, and reading which the professional farmer oun

PRACTICAL SUGGESTIONS. 187

devote to it. Having mastered the elements as given in
the foregoing pages, he should provide himself with 'good
books and journals treating of the subject, and thus go on to
make himself so familiar with all its details, that he will be
at home in every part of his profession, and able to state a
good reason for all that he does.

So doing, the young farmer will be enabled to avoid the
misfortunes which arise on the one hand from the apathy
and listlessncss of ignorance, and on the other from the
rash experiments of half knowledge. He will be able to
avail himself of all that is new and valuable in improvements
introduced abroad. He will cultivate an enlightened
regard fyr the resources and privileges of his country, and
will despise the croakings of those who condemn climate
and soil when they should condemn themselves. He
will regard agriculture as truly a learned profession,
requiring, for its successful prosecution, enlarged general
intelligence and acquaintance with scientific principles.
He will regard it also as a profession more intimately con-
nected than any other, with those great natural processes
by which God provides out of the earth food for every liv-
ing thing, and with all that is beautiful and attractive in
the face of external nature, — a profession therefore, worthy
of thought and study, and leading to love of country and
of home, and to the cultivation of those tastes and habits
that make home agreeable and happy. Such views will make
him disposed rather, by persevering and intelligent industry
and care to build up his own prosperity and that of his
native land out of the rich resources which it possesses,
than to throw himself on the uncertain chances of emigra-
tion, or to abandon agriculture for some other calling per-
haps less conducive on the whole to his own interests or
those of his country.

APPENDIX

I. APPLICATION OF METEOROLOGY TO AGRICULTURE:

The importance of foresight of the weathei* to the farmer
is often very great ; and many observant farmers acquire,
by experience, a knowledge of the signs of change appli-
cable to their own locality which is almost unerring. To
those who have not this skill the barometer is a very useful
instrument. Its fall and rise indicate with great certainty
the approach of stormy or fine weather, and may be safely
relied on for regulating farm operations. Cheap barome-
ters applicable to farm use may be obtained of the philo-
sophical instrument makers or hardware merchants of most
of the large towns.

Some useful guidance in farm work may also be obtained
by a study of the results of the observations of meteorolo-
gists. A few of these results I shall present in the follow-
ing tables, as specimens of the information of this kind
which has been collected. For the first table I am indebted
to Dr. Smallwood, Professor of Meteorology in McGill
College.

I. AVERAGE NUMBER OF RAINY DAYS AND HOURS OP
RAIN IN EACH MONTH, from Ut jlpril to 1st December.

Rainy. Durat. of Rain.

Days. h. m.

April 8.2 46.16

May 11.0 48.28

June 12.3 49.19

July 10.3 32.55

August 11.0 37.56

September 11.5 67.39

October 12.1 62.00

November 8.2 47.08

The above table represents the mean of twenty vears.
It indicates the amount of rainy weather that may be ex-
prcM'd in each month. It applies specially to the vicinity
of Montreal.

APPENDIX.

189

For comparison, I add a similar table prepared by Henry

Poole, Esq., for Pictou, Nova Scotia, which is nearly in
the same latitude with Montreal, but eleven degrees farther
east.

II. RAINY DAYS AT ALBION MINES, PICTOU— MEAN
OF TEN YEARS.

Nights. Days. Quant. Inch-
December 5.5 12 4.8198

January 5 11 3.3814

February 4 9 3.2673

March.' 4 10 4.3963

April 4.3 8.3 2.6500

Total for five non-working months. .22.8 50.3 18-5148

Nights. Days. Quantity.

May 4 9.6 2.8976

June 5 9 2.1338

July 5 10 3.0052

August 5 9 4.5006

September 4 8 3.1520

October 6 9 5.6016

November 4.5 11 4.3984

Total for seven working months. ..33.5 115.8 47.2040

The following table from the records of the Magnetic
Observatory, Toronto, I owe to the kindness of Professor
Kingston, Director of the Observatory. It applies to a
large district of Upper Canada.

III. RAINY DAYS AND AMOUNT OF RAIN AT TORONTO.

Average No. of

Average dura-

Average depth

Month

Rainy Days.

tion in Hours.

in Inches.

1840—1862.

1854— 18G2.

1840—1862.

March

6.0

36.59

1.548

April

9.5

44.14

2.398

May

11.3

57.22

3.241

June

11.9

40.23

3.100

July

10.0

34.14

3.490

August

10.2

35.52

2.951

September

11.2

40.31

3.973

October

11.7

47.42

2.485

November

10.0

63.08

3.140

December

5.3

32.44

1.545

190 APPENDIX.

The following table, by Dr. Small WOOD, indicates the
temperature of the year in the middle part of Canada, and
shows the mean of 20 years' observations.

IV. MEANS AND EXTREMES OF TEMPERATURE, AND
PERIODS AFFECTING VEGETATION.

Month of January 13°26

" February 13^21

" March 25044

'■ April 40<^12

" May 55070

" June 62011

'' July... 74°78

" August 61°'21

" September 58°r2

" October 46°04

" November 31°49

" December IS^SO

Mean of the year 41^50

Highest temperature observed lOQo 5

Lowest -43° 6

Earliest frost of Autumn, August 18th.

Latest frost of Spring, June IGth.

Latest ploughing, December 10th. •

Earliest snow, October 10th.

Latest snow, May 20th.

Highest temperature of the ground at 18 inches

in depth 67o

Lowest do do 32"

Number of days of rain 87

Number of days of snow 46

Number of fair days 2:t2

Number of days of thunder and ligbtniQg 16

Amount of rain in inches 47.224

Amount of snow in inches. 79.600

Another point of interest to the fanner is the compara-
tive periods of rotation in different places and seasonfi.

APPENDIX.

191

V. COMPARATIVE TABLE OF PERIODS OF VEGETA-
TION.

Plants.

Lower Ca-
nada, by Dr.

New Brunswick,
by Professor

Scotland, by H.
Stevens.

Smallwood.

Johnston.

Barley sowed

15 to 16 May

10 May to 15 June

April and May.

reaped

15tol6Aug.

20Aug.to25Sept.

days in ground

92

96

Spring Wheat

sowed

1 to 8 May

15 April to 1 June

8 to 26 March.

reaped

1 to 8 Sept.

10Aug.to20Sept.

26Aug.to30Sept.

days in ground

123

110

153 to 186.

Oats sowed

1 to 8 May

April and May.

January.

reaped

10 August

Aug. and Sept.

days in ground

97

110

Indian Corn

sowed

20 June

15 May to 1 June

reaped

29 Sept.

1 Sept. to Oct. 2

days in ground

101

117

Buckwheat

sowed

20to29June

1 to 30 June

June.

reaped

18 Sept.

1 to 25 Sept.

September,

days in ground

90

93

120.

Potatoes planted

20 to 26 May

10 April to 20 June

March & ApriL

dug

29 Sept.

Sept. and Oct.

October.

days in ground

131

150

150.

This table might be greatly extended by adding the
periods of other cultivated plants. Its value is limited by
the great local variety that occurs in these respects, owing
to differences of soil, drainage, exposure, and elevation.
One object in presenting it here is to indicate to farmers
the utility of carefully noting these points for each year, in
connection with the results of more or less early sowing,
the character of the season, the effects of manures, and of
different methods of tillage and of drainage.

192 APPENDIX.

II. DIRECTIONS FOR PERFORMING EXPERIMENTS ILLUS-
TRATIVE OP THE SUBJECT.

A teacher who has hiitiself studied the elements of chem-
istry, can readily illustrate its applications to agriculture
by experiments, which Will greatly add to the interest of
the subject. Cheap sets of apparatus for this purpose
are prepared by the manufacturers of chemical apparatus,
and are very convenient; but with a little ingenuity
and practice, all that is necessary can be done with a few
phials and other ordinary vessels, and the chemicals which
can be procured in any druggist's shop. The following
directions are taken with slight modifications from John-
ston's Catechism of Agricultural Chemistry. They relate
to the illustration of the elements and food of plants, as
stated in chapters 4th and 5th of this manual.

1. OXTQEN.

The least troublesome mode of preparing oxygen, is to
rub together in a mortar equal weights of chlorate of potash
and black oxide of manganese, to put the mixture into a
common Florence flask, and apply the spirit lamp. With
the !>id of a glass tube, bent by means of the spirit lamp,
and adapted by means of a cork to the mouth of the flask,
the gas may be collected over water in wide-mouthed
phials or receivers. Half a teacupful of the mixture will
be found sufficient to fill several small receivers with the
gas. For details of the manipulation see section 8th
below.

Oxygen gas may also bo prepared by mixing sulphuric
acid (oil of vitriol,) with black oxide of manganese in fine
powder, in a retort, and applying the licat of a lamp ; or
by rubbing together in a mortar equal weights of oxide of
copper and chlorate of potash, putting the niixtun' into a
BmuU retort, and applying the lamp as before. The last
if) the quickest method of the three.

The properties of oxygen may be very well shown with-

APPENDIX.

1^3

out the necessity of collecting the gas. Thus, the mixture
of chlorate of potash and oxide of copper above described,
may be put into an open tube, and the flame of a lamp
applied for a few minutes ; when a bit of red hot charcoal,
or a match, of which a spark is still red at the extremity,
will burn brilliantly if introduced.

2. Hydrogen.

Fig. 1.

Take a beer or champagne glass (Fig. 1),
put into it some pieces of zinc or iron
filings, and pour over them a small quan-
tity of oil of vitriol (sulphuric acid) di-
luted wim twice its bulk of water, and
cover the glass for a few minutes. On
putting in a lighted taper, an explosion
will take place. The teacher may re-
peat the same experiment in a phial,
into the cork of which he has introduced
a common gas jet (Fig. 2). After a
short time, when the hydrogen gas pro-
duced has driven out all the common
air from the bottle, a light may be ap-
plied to the jet, when the gas will take
fire and burn. The cork and jet may
now be taken out of the bottle, and a
lighted taper introduced into it, when
the taper will be extinguished, while
the gas itself will take fire and burn at
the mouth of the bottle. Lastly, if the
teacher possesses a small balloon, he
may fill it with the gas by attaching it
to the mouth of the bottle, and may thus show that the
gas is so light that it will carry heavy bodies up with it
through the air.

3. Nitrogen.

Place a piece of phosphorus in a small tin cup, and cause
it to float in water, in a shallow basin or deep plate ; ignite

194 APPENDIX.

the phosphorus and insert over it a receiver or wide-
mouthed bottle with its mouth below the surface of the
water ; the burning phosphorus consumes the oxygen of
the enclosed air, and forms white fumes of phosphoric acid,
which are rapidly absorbed by the water. At the close of
the operation, the water will be found to have risen and
filled one-fifth of the vessel, and the remaining gas will be
nitrogen. This experiment shows very prettily the com-
position of atmospheric air, and affords, with little trouble,
a supply of nitrogen for showing its properties.

4. Chlorine.

This gas is readily preparec^ by pouring muriatic acid
on black oxide of manganese in a retort, and applying a
gentle heat. It should be collected over hot water.

An easier mode of showing some of the properties of
this gas, is to put a little dry chloride of lime into the
bottom of a tall glass, and pour upon it strong sulphuric
acid. Chlorine gas will be given off, and will gradually fill
the lower part of the glaSvS, and the boys may then be
made to smell it, and it may be shown, — 1st, That a taper
burns in it with a smoky flame and is soon extinguished.
2nd. That it is much heavier than common air, by pour-
ing it from one glass to another, or upon the flame of a
candle. 3rd. That phosphorus takes fire in it of its own
accord. 4th. . That it gives a red color to a solution of
iodide of potassium when poured upon its surface, or a
purple color if a little dissolved starch be previously mixed
with the solution of the iodide. Otlj. That the color of
rod cabbage or red tape is discharged by it. It is not
absolutely necessary for the teacher to make all these
cxporimcntB, but they are very simple ; and they are likely
fio to impress the knowledge of this gae, cbloraiie, upon
the mind of the pupil, that he will never forget it.

A very neat method is to put the mntorinls into a flask
with bent tube, as for the preparation of oxygen ; j)asa the
end of tlie tube to tJie bottom of a tall wide-mouthed phial
or jar, and the chloriao, being hoavior than air, will gr»-

APPINDIX. 195

daally fill the vessel, in which the experiments mentioned
may be readily performed. The operator should care-
fully avoid inhaling any of the gas, and the flask should
be removed from the room as soon as the experiments are
performed.

5. Carbonic Acid.

The teacher may prepare carbonic acid gas, by pouring
dilute muriatic acid upon bits of limestone, or of the com-
mon soda of the shops, in a tall covered beer glass. He
can show that a burning taper is extinguished by this gas ;
but that it does not, like hydrogen, take fire itself; — that
it is so heavy that it may be poured from one glass to
another ; and that when poured from a large tumbler a
common candle may be put out by it.

6. Phosphoric Acid.

If the teacher can obtain a piece of phosphorus, he may
show how it burns with white fames in the air, and may
collect these white fumes — which are phosphoric acid —
by holding over them a cold glass or metal plate, or he
may simply burn the phosphorus in a little cup under a
tumbler.

A still simpler way of making his pupils acquainted
with phosphorus and phosphoric acid, is to take a common
lucifer match, of the variety that kindles without explosion,
and to rub the end of it on the sand-paper so gently as not
to kindle it. If it be now brought near the nose the smell
of phospliorus will be perceived. If it be again rubbed so
as to take fire, it will burn with a white flame, and will for
a short time give a white smoke. 7%is white smoke is
phosphoric acid.

7. Properties op Acids and Alkalies.

Prepare a dilute solution of sulphuric acid (oil of vitriol),
or muriatic acid. By tasting a rod dipped in it, the

196

APPENDIX.

sour taste characteristic of acids will be -perceived. By
pouring a little of it into an infusion of red cabbage or
of violets or of litmus, this will be reddened. By pouring
it upon common carbonate of soda the carbonic acid of that
substance will be expelled, and a sulphate or chloride will
be the result, which may be seen in a crystalline state, as
a salt, by evaporating it to dryness.

Make a strong solution of potash or soda, and add this
to the cabbage infusion which has been reddened by the
acid, and its blue color will be restored, and by adding
more it will become green. Similar changes of color are
produced by acids and alkalies in the juice of beets or blue-
berries or of the purple dahlia.

8. Modes op Preparing and Collecting Gases.

Figure 1 shows how this may be done over water, with
a flask or bottle and a bent tube (a), a flat basin (h) for
a cistern, and a tumbler or wide mouthed phial (c) for a
receiver. This last must be filled with water and inverted,
and a little shelf of bent iron or tin may be placed in the
water for it to rest on. When full, a plate or saucer may be
placed under it, and it may stand aside till others are filled,
taking care to leave a little water in the saucer to prevent
the escape of the gas.

Fig. 4.
Fig. 3.

APPENDIX. 197

When heat must be applied, as in preparing oxygen, a
flask which will endure this without cracking must be
used, and a lamp applied as in Fig. 5. A stand to support
the flask may be made with an iron rod fixed upright in
a block of wood, and furnished with rings of wire having
the ends twisted round the rod spirally.

9. Soluble Organic Matters in the Soil.

An interesting experiment in illustration of these is the
following : — Take a small quantity of vegetable mould,
place it in a flask with some water and a little potash or
soda, and boil it for some time. When cool, filter it
through blotting paper placed in a funnel, and a clear brown
solution will be obtained, illustrating the solution of the
vegetable acids of the soil (humic and ulmic acids) by the
aid of an alkali, and also the character of the dark colored
waters of bogs and swamps. Then to a portion of this
solution add a little hydrochloric acid. This will com-
bine with the alkali, taking it from the organic acid ; and
this last becoming again insoluble will float up to the top
as a grayish scum, which, if collected and dried, may be
regarded as pure humus or vegetable mould.

10. Chemical Analysis.

The analysis of soils is a tedious and difficult operation,
requiring, on the part of the operator, not only a large
acquaintance with chemistry, but much skill and practice,
pure chemical tests, and somewhat expensive apparatus.
Neither the farmer nor the teacher can therefore, in ordin-
ary circumstances, be an analytical chemist. Since, how-
ever, it may sometimes be desirable to ascertain in a rude
way the general composition of soils and manures, I give
here the following simple processes, principally from Pro-
fessor Norton :

The mechanical texture of a soil is ascertained by simply
washing with water. Dry the soil ; weigh a portion, say
a pound or half-pound, boil in water, and stir thoroughly.

198 APPENDIX.

The sand will settle first, and when it is at the bottom, the
liquid above, holding the clay, &c., in suspension, may be
poured oflE" into another vessel. A few repetitions of this
will leave nothing but clean sand and gravel, if the soil
contain any. This may be dried and weighed, and the
quantity will indicate to which of the classes already referred
to (loams, clays, &c.,) the soil belongs. An examination of
the small stones and coarser grains of sand, to ascertain
whether these be granite, trap, sandstone, &c., may be use-
ful in forming an estimate of the qualities of the soil.

The following course may be adopted, in case more
information is desired, regarding the especial constituents
of a soil :

1. Take a weighed half-pound or pound of the soil, and
boil it in water for some hours : rain water is purest. Then
pour it upon a filter of coarse porous paper, of the kind
that dru^ists use for their filtrations. The mode of man-
aging this operation may be seen in any druggist's sl^pp.
If the liquid does not come through clear at first, it must
be refiltercd till it is quite clear. The solution thus obtained
is evaporated to dryness, and the solid residue burned. It
will blacken at first, by the burning of its organic matter,
but afterwards will become white again.

a. It may now be weighed on a small apothecaries'
balance, and the weight gives the per centage of inorganic
matter soluble in water, that exists in the soil.

h. This portion consists, in many soils, for the most
part of sulphates or carbonates of potash and soda. There
is also commonly present some chloride of sodium, or com-
mon salt.

These are all valuable constituents of a soil ; and hence,
whon an experiment of this kind shows such soluble matter
to abound, it may be inferred that the soil is well supplied
with an importjint portion of its requisite substances.

c. The part soluble in water is commonly not large : it
amounts to not more than from ono to three per cent, in
many ezoeUent soils.

2. Take another woishcd portion of soil, or the same
whioh has already boen Soile^ in water, and heat it with

APPENDIX. 199

some muriatic acid (hydrochloric acid), diluted by two or
three times its bulk of water. After standing a few hours,
put this also upon a filter, and wash the acid liquid through.

a. Wash the residue upon the filter with successive
portions of clear water, until it no longer tastes acid ; it
may then be burned until all of the organic part is consumed,
and weighed when it is cool. This weight gives the per
centage of insoluble silicious matter in the soil.

b. To the filtered acid solution is first added ammonia
(common aqua ammonia3,) till it is no longer acid but alka-
line ; a flocculent precipitate then immediately falls, being
iron and alumina. If it is of a deep red color, then iron
predominates ; and the contrary if it is nearly white. If
the precipitate has a whitish green color, and reddens
when exposed to the air, then the soil contains the pro-
toxide of iron, in place of the peroxide. The first, it will be
remembered, was spoken of as injurious to plants. It is
for this reason important to know which oxide is present.

If it is shown by the above test to be the protoxide,' the
solution must be boiled again with an addition of a little nitric
acid : this will convert all of the iron into protoxide, and it will
thus remain upon the filter; the protoxide would have
been partially washed through. Another filtering is now
necessary. This should be done as soon as the precipitate
has settled, and while the liquid is warm, so that it may
filter more rapidly. The whole operation should be done
in the shortest practicable time, and the liquid covered
as far as possible from access of air.

From the apparent quantity of the iron and alumina,
as weighed after burning, may be judged with tolerable
accuracy the proportion present in the soil.

c. If the soil contained much lime, effervescence would
have been seen at first, when the acid was added ; this is
supposing the lime contained to be carbonate, or in com-
bination with carbonic acid, that being the most common
form. If it is not present as carbonate, or if this is in so
small quantity as not to show any action with acid, there
are still means for its easy and certain detection. To the
solution previously rendered alkaline by ammonia, and

200 APPENDIX.

already filtered to separate iron and alumina, is to be added
a little common oxalic acid. If there be even the smallest
weighable quantity of lime present, a white powdery preci-
pitate will begin to fall ; from the quantity of this may be
estimated roughly the proportion of lime in the soil.

All of the above important points, it will be noticed, may
be determined without any necessity for expensive materials
or apparatus, by a person of ordinary intelligence. Easy
as those things seem, however, in the description, so many
difficulties will be found in practice, as will give the operator
some conception of the care and study involved in a com-
plete and detailed analysis ; one by which it is intended to
ensure the greatest possible degree of accuracy.

I have not mentioned any tests for the presence of phos-
phoric acid, and other of the less abundant substances ;
because their detection and separation are so difficult, that
the inexperienced beginner would only run into every
description of error while looking for them.

It is not a hard matter for the farmer to arrive at the
probable value of a marl, with quite a tolerable degree of
accuracy. A weighed portion must be taken, and diluted
muriatic acid added from time to time, until all eflFervcs-
cence has ceased. The mixture is then boiled, or at least
well heated, and thrown upon a filter. The insoluble residue
which remains upon the filter, must be washed clean from
acid, dried and weighed ; this is chiefly silica. Its weight,
subtracted from the original weight taken, will, in most
cases, give nearly the amount of carbonate of lime that has
been dissolved out by the acid. Small quantities of other
substances have been dissolved at the same time, which
have been mentioned in a previous chapter, as important
to the value of the marl ; but they are only to be separated
by an instructed chemist.

The presence of gypsum in a marl, itc, may be ascer-
tained in the following manner : Stir a portion of the sub-
(ttanco in water, and allow it to sUmd for a few hours.
Then filter off the water, and add a few drops of solution
of nitrate of baryta. If gypsum be present, a white powder
will fall t«) the bottom, and the (juantity of gypsum present
uiay bo estimated from itii amount.

APPENDIX. 201(

III. Rotation op Crops tor Canada.

Under this head I think that an important benefit will
be conferred by republishing the substance of the recom-
mendations published many years ago by Mr. William
Boa, of St. Laurent, and which have been of the utmost ser-
vice to the cause of agricultural improvement throughout
British America.

1. Requisites of a Good System.

1st. It ought to be economical, and not require more capital
than the actual system, or rather than the present absence of
system, requires. It is undoubtedly of great advantage to apply
capital to the land, but this advantage is in general beyond the
reach of our farmers, as their means are not sufficient.

2nd. It ought to restore fertility to the soil, and maintain it
by the products of the land itself. Manures got from other
quarters than the farm itself, are always expensive, and, at a
distance from town, are often not to be had at all.

3d. It ought to be simple and of easy application.

4th. Finally, it ought to have experience clearly in its favor.

2. Rotation of Crops.

There are tAVO sorts of reasons in favor of the plan of rotation
of crops.

1st. Because different plants draw from the soil different sorts
of food, so that one plant will grow freely in a soil which is
worn-out as regards another.

2nd. Because the crops being various, the occasional failure
of one is not so much felt, seeing that the others furnish subsist-
ence sufficiently without it.

The cultivation of a fair proportion of al! the varieties of
crops which Providence permits to grow readily, ought there-
fore to be considered as the best means of averting a famine ;
and what intelligent farmer, with the case of Canada and
Ireland before him, would wish to be limited to the culture of
wheat and potatoes only.

3. Plan of the Rotation.

Divide the arable portion of the farm, whatever may be its size,
into six parts, as equal as possible, with a direct communication
from the barn-yiird to each field, and from one field to the other,

14

202 APPENDIX.

go that the cattle may pass from one to the other -when required.
This division into six fields, may require on most farms new
fencing, and it will be proper, beforehand, to see how this can
be done with the least possible expense. I shall now suppose
the farm prepared to receive the application of this system, and
that is the one which I have found the best for even the poorest
settler.

Ist. Root crops, such as potatoes, carrots, beets, parsnips,
&c., [turnips and also flax] and in cases where the land is not
BuflBciently open for a crop of this kind, the field must be left in
fallow. ,

2d. Crop of Wheat or Barley .

3d. Crop of Hay.

4th. Pasture.

5th. Pasture.

6th. Crop of Oats or Peas.

In beginning the application of this system, that field of the
aeries which is in best condition for a Root crop, should be
called field A

The best for Wheat or Barley B

That which is actually in Hay C

The Pasture fields D & E

That which is best for Oats or Peas F

Each field for the first year ought to be appropriated to the
crops above mentioned, and after the fashion now in use among
the farmers of Lower Canada, except in the case of field A. By
this plan they will at all events still get as much from their
five Gelds as they get at present.

The culture of field A and of crop No. 1, come up together for
the first year, and ought to be the object of special attention, as
this is, in fact, the key to the whole system ; for the good cul-
ture of this field has for its object, and ought to have for its
effect, not only a good crop for the first year, but also to im-
prove the land for the five other years of this Rotation of Crops.

In the following year, the cultivation of the different crops
will be according to the following order :

Crop No. 2 in the field A
Do. "3 " B

Do. "4 "0

Do. "6 " D

Do. "6 " K

Do. " I " F

and 80 on, changing each year until the seventh, when crop No.
1 will come buck to field A, and the whole will then bo in a
good state of fertility, and free from weeds. The above system
has been proved to be capable of restoring old land, and extir-
pating all weeds.

In order to render the thing more simple and easy of coniprehen-

APPENBIX. 20^

sion, 1 shall suppose myself to be again obliged to begin with a
worn-out firm in the autumn. The first thing that I should
do, would be to divide the land into six fields, by proper fences,
to prevent the cattle going from one field to the other ; and I
would then take for field A, that which appeared best for green
crops or root crops ; I would collect all the manure which I
could find in or out of the barns, I would take out the flooring
of the cow-house, stable and piggery, and I would take out as
much of the soil underneath as I could get, for this soil is the
essence of manure, one load of it being as good as four or five
loads of common dung. The portion thus removed, ought to
be replaced by an equal quantity of ordinary soil, or, if it be
possible, of bog earth, which might be removed when necessary
afterwards.

The dung and other manure thus collected, should be placed
on the field A in September, or the beginning of October, spread
with care (as far as it will go), and covered up in a shallow
furrow. Manure aids the decomposition of straw and the weeds
of the soil, and frees it from these plants, which thus help to
keep the soluble portion of the manure, until its juices become
necessary for the crops of the succeeding years. The greater
variety there is in the crops of this field, the better it will be,
provided the soil is suitable for them. Thus this field ought,
as nearly as possible, to look like a kitchen garden. -^ .

4. Crop \st. — Root or Chxen Crop.

Under the actual circumstances of the country, I would par-
ticularly call the attention of farmers to the cultivation of the
carrot as being one well adapted to our soil and climate.

The land which has been manured in the fall, as above de-
scribed, ought to be ploughed at least twice in the spring, the
one furrow across the other, and both as deep as possible. It
is then to be harrowed until it is properly mellow. You then
make with the plough two furrows, distant two feet, or two
feet three inches from each other, taking care to raise the soil
as much as possible between each. You pass the roller over
this ploughed portion, and then with the corner of a hoe, make
a small furrow or drill along the top of the rows : drop the seed
into this furrow, and pass the roller over it again : this last
operation will cover the seed suflRciently.

If you can get a seed-sower, that will simplify matters consi-
derably. A roller is essential in the culture of root crops
which spring from small seeds, but it can be readily got by all
farmers. A log of twenty inches diameter, and five feet long,
with a pole fixed at each end, will do the business admirably.

Carrot seeds (and you may say the same of the other seeds),
ought to be soaked in rain, or soft water, until they are about
to sprout, and then rolled in quick-lime until the grains are dry

204 APPENDIX.

enough not 4.0 stick to each other. When there is no lime,
wood ashes will do as well. A pound of seed, if it be good (and
you ought always to try it before sowing), will be sufficient for
one acre of land. By the above plan, the young plant will
come up before the weeds, so that it will be easy to distinguish
the rows of carrots before the weeds appear : this renders the
cleaning comparatively easy, since it may be done (except the
thinning) by means of a cultivator. This cultivator is an in-
strument which every settler ought to have, and which, like
tuose already mentioned, is ext^mely simple in its construction.
It is made of three bars of wood joined in front, an J separated
behind, according to the width of the furrows which you wish
to clean. This instrument, called the horse-hoe or drill-har-
row, or cultivator, is drawn by one horse, and has handles to it
like a plough, only lighter. A man or a boy may guide it, so
as not to touch the rows of carrots or other crops, but only to
raise the soil to a greater or less depth, at pleasure. As soon
as the weeds appear, you draw this harrow between the rows,
so as to bring the soil as close as possible to the young carrots,
but without touching or covering them. This process will
keep the plants sufficiently clean until the time for thinning
them and leaving them four or five inches apart from one an-
other ; soon afterwards you may plough between the rows thus
harrowed and raised. These operations do good to the plant,
by permitting air and moisture to have access, and by facilita-
ting evaporation. My plan for gathering the carrots in autumn,
is to pass the plough along the right side of the plants as close
as possible without injuring them : this frees them on one side,
and the stem is strong enough to allow us to haul up the roots
by it afterwards.

This method of culture requires a good deal of labor, but the
return is more than enough to recompense the farmer.

When we consider the large amount of nutritive matter con-
tained in this root, and ite general application to all tho living
things on a farm, its culture cannot be too strongly recom-
mended, besides it is relished by all animals, especially by work-
ing horses, to which it may be given instead of Oats.

I have dwelt particularly upon the culture of tlio Carrot, be-
cause the same method applies to the culture of all tlie root
crops, which can be advantageously grown in this climate, such
as Parsnips, Heets, Mangels and Turnips.

Parsnips will grow in a close soil, almost in clay, and do not
require cellars, since they will remain uninjured all winter in
the ground. In this case you will have them in tlic spring,
affording a new and succulent food, at a time when it is most
necessary. Every animal will oat parsnips with rolisli, and
cows fed upon thorn yield a very rich milk.

lieels and Mangels liave the samu value as a crop, and as food

APPENDIX. 205

Ibr milk cattle ; but I do not consider them to be so good for
fattening cttle.

[In spring, all the manure made during the past winter should
be carted to the field, placed in a heap, and twice turned. All
bones should be gathered and broken up with a hammer ; all
coal and wood ashes, scrapings of sewers, the dung from the
fowl house, and the contents of the privy, should be collected
and made into a compost, with dry loam or bog earth.

The above manure may be used for that portion of the field
devoted to cabbage, potatoes, and turnips. It should be put in
the bottom of the drill on which the above are to be planted or
sown.

When the ground is properly ploughed and harrowed, and a
sufficient quantity of sound seed sown, — say, at least, four pounds
to the acre, — the turnip crop is as certain as any other.

The sowing of turnip seed should be commenced early in
June, and may be continued up to 20th July. If the fly takes
the first sowing, a second will be likely to succeed.

The turnips, when well up, and getting strong, should be
thinned out to a foot apart, and the hoe and cultivator passed
through them at least twice before they meet in the drills.]

If the land is too heavy for root crops, beans and green peas
will suit for No. 1, taking care to sow them in drills, and to
prepare the land as above described for root crops.

If it be thought absolutely necessary to summer-fallow, — that
is, to plough without sowing, — which only happens when the
soil is so hard and heavy that it cannot be pulverized in any
other way, you ought not to spread the manure on the land in
the preceding fall ; but plough the land, and ridge and furrow
it with as much care as for a crop. You need not touch it
aq:ain before the month of June ; when you mUst plough it again,
and harrow it, so as to render it even, and destroy the roots
of the weeds. You may then draw the furrows in a straight
line, giving them a uniform breadth, and so as to facilitate
drainage. About the middle of July, you must plough it again,
and sow it with plenty of buckwheat. At the end of Septem-
ber, plough it again, having previously spread it with dung.
In this case, the buckwheat is ploughed under with the manure,
apd serves greatly to increase the latter. The land thus pre-
pared, ought to be sown with wheat in the ensuing spring, and
you may add a little timothy and clover. A bushel of timothy
will suffice for four or five acres, and three or four pounds of
clover to each acre.

5. Succeeding Groj^s of the Rotation.
I have now done all that I can for field A. I have weeded
and manured it as well as I can ; and after having taken the
crop of roots, and the crop of wheat or barley, next year, I leave

206 AtPiiNDix.

this field to rest until the other fields have been improved in the
same way, and according to the method above described. When
this shall hare been effected, — that is to say, in the space of
six years, — the worst will be over, and the battle may be
considered as gained. The fields will then be in a clean and
fertile condition, and their value will consequently be greatly
increased. The farm of 70 or 80 acres, which at first only
sustained three or four miserable cows, and perhaps no more
than an equal number of sickly sheep, will be capable in less
than ten years, of furnishing an abundant subsistence for ten or
twelve cattle, and other stock in the same proportion.

One of the great advantages of this system of rotation of crops
is, that the pastures, which in summer furnish summer-feed for
the stock, are in due pi-oportion to the quantity of roots and hay
destined to winter-feed them, and in due proportion to the straw
which the grain-crops yield for their bedding. I will observe
here, that farmers — except those who live near towns, where they
can easily procure manures — ought never to sell a single load
of their hay, straw, or roots ; since the whole ought to be con-
sumed on the farm, with the view of procuring a sufiiciency of
manure therefrom, whereby the fertility of the soil is to be sus-
tained. But if the farmer is not to sell hay, or straw, or roots,
what is he to sell ? I answer, the third of the land being, under
this system, appropriated to grain crops, he will always be able
to sell a large part of them. The half of the farm being in hay
and pasture, will allow it to produce a large quantity of butter,
cheese, butchers' meat and wool ; and to sell a considerable part
of these, after having supplied the wants of the family. It may
be said, that six years is a long time to wait for the renovation
of the whole farm , but I will reply, that I know of no other
means by which it may be done in less time, from its own re-
sources ; and it is worthy of observation, that the land is improv-
ing every year. The produce is larger, even for the first year,
under this system than it is under the present method of culture ;
and, from year to year, the land is improving, field by field, and
is producing more and more, so as to i)ay the farmer better than
it does at present, and to recompense him doubly afterwards,
when the whole shall have been improved under a system of
rotation.

It may be objected, that two years of pasture is along tinieoj^
rest for the land ; but you will observe, that the land does not
remain unproductive during this period of repose. This plan
not only contributes to re-establish tlie almost exhausted fertility
of the soil, but it is also the best means of furnishing the farmer
with the first necesBaries of life, and the articles whicli, so to
■peak, will most readily find an outlet in our markets, — such aa
birt'f, lard, mutton, butter, cheese, wool, and other products
already named.

APPENDIX. 207

Manures are of the first importance to the farmer, and he must
do everything in his power to increase their amount. The system
here proposed, is calculated so as to increase the quantity of
manure in proportion as the soil becomes improved. As already
said the farmer ought not to sell a pairticle of his hay or straw,
because these are the principal materials for manure ; and, con-
sequently, it is infinitely worse to sell the manure itself. The
manure, thus economized, will suflBce each year for the field
which is to receive the root crop (No. 1).

After the crop of oats (No. 6), the land is not yet exhausted,
and might even yield another grain crop. It is better, however,
to preserve this fertility when acquired, than to be obliged to
bring it back.

In this short treatise, it is impossible for me to mention one
hundredth part of the means which we have of increasing our
stock of manure. I shall content myself with alluding to the
rich deposits of bog-mould which we possess, and the limestone,
which can be had every where. The very weeds, which are the
curse of our fields, may be converted into good manure.

6. Farther results of Experience.

Mr. Boa has kindly favored the writer with some fur-
ther results of his experience in rotation farming, and
especially in relation to the relative effects of different
green crops. His results in this respect quite accord with
what might have been inferred from the composition of the
ashes of these plants, and point to the proper manures to
counteract the special effects produced on the soil by cer-
tain given crops. The following is an extract : —

I have said that the culture of crop No. 1 in the field is the
key to the whole system. Now, as I have always considered
the cultivation of this field as rather a means than an end, I
have paid particular attention to the effect the several green
crops have upon the following grain crop, say wheat or barley.
I have found mangel wurzel to be the worst of all the green crops
cultivated for the grain crop. The seed comes up aa well after
it as any of the other crops, but as soon as the roots begin to
strike, and the plants begin to tiller, it evidently falls behind
and keeps behind. The crop is always thinner ; is about eight
days later in ripening than on potato-land ; the straw Is always
soft, of a dull color, and affected with rust.* Although this is
a bad crop to precede wheat or barley, I am not prepared to
aay that it is a great exhauster of the soil ; for in some experi-
ments I have made, I have found the clover crop which followed

• This is probably an effect of the large removal of potash by mangel
wurzel. Wood ashes applied with the wheat might be a remedy.

^OS APPENDIX.

it, to be as mucb superior .as the grain crop was inferior. Tur-
nips have mlich the same effect as mangels, when carrierl off the
land, which is generally the case here.

The grain crop, especially wheat, does better after horse-
beans than any other crop, if the beans are sown in drills, and
manured with the same quantity of stable manure as thf^other
green crops ; but clover seeds do not take well, and do not
thrive after them ; but timothy grass does well. Potatoes, car-
rots, and Indian corn are nearly alike favorable to grain and
grass. I find carrots thrive best when manured with composi
containing a large proportion of swamp muck. They appear to
detest lime. I have sown them twice on a piece of land that
got a strong dose of lime some years ago, and got very poor,
scrubby crops of carrots. Last spring I sowed hemp on the
same piece of ground, without giving it any manure, and the hemp
grew over twelve feet high. It appears to feed and thrive well
on what is poison to the carrot. I have introduced hemp as a
crop for the last two years. I know now from the trials made
with it, that this country can produce as good hemp, if pro-
perly managed, as any other country ; and that it will pay the
farmer better than wheat or barley, as things go at present.
A good crop will yield over half a ton of fibre per acre, and
fifteen or sixteen bushels of seed. I sold the fibre, of my croj)
of 1862, at eight cents per pound, and have been offered five
cents per pound for the seed of the crop of 1863. The place of
hemp in the rotation, should be as a green crop, as it is an
extirpator of weeds ; but it must be harvested before the seed is
ripe, or it will leave its seed -on the ground, and prove a weed
itself in the next crop, if wheat or barley. When cut before
ripe, the fibre is much finer that when it has ripened its seed.
When seed is intended, it should be sown in drills or narrow
beds, 80 that the male plants can be pulled as soon as they have
Blied their pollen, without trampling or breaking down the
female plants, which must be left standing to ripen the seed.

Mr. Boa also states his experience in the case of the
wheat midge and potato blight, which accords very closely
with the views given above under those heads, and would
have been inserted in confirmation of these views had it
arrived in time. He further refers to the results obtnined
in rotation farming since the publication of his pamphlet ;
and shows that, when fairly tried, it has produced the best
effects. He remarks, however, tliat it must be adapted to
different soils, as the number of years covered by the rota-
tion may be varied from six to twelve, under diileront
ciroumBtances.

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