Elements of agricultural chemistry and geology

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ELEMENTS \

AGRICULTURAL CHEMISTRY

GEOLOGY.

BY

JAMES F. WwW. “JOMNSTON, M.A., F.B.SS. L. & E.

Ionorary Member of the Royal Agricultural Society of England, and
Author of “ Lectures on Agricultural Chemistry and Geology.”

WITH A COMPLETE INDEX,

AMERICAN PREFACH,

BY SIMON BROWN,

~, EDITOR OF THE NEW ENGLAND FARMER. ey

Guy

NEW YORK: | Ne sige,
C.-M SAXTON,
AGRICULTURAL BOOK PUBLISHER.
1853.

Entered according to Act of Congress, in the year 1853, by
Cr M. SAXTON,

RR BES
in the Clerk’s Office of the District Court of the United States for the South-
ern District of New York.

"8. W. BENEDICT,
STEREOTYPER AND PRINTER,
16 Spruce street, N. Y.

PREFACE TO THE AMERICAN EDITION,

eae} Gee

In England, and on the continent of Europe, it has been
long understood among the class who own the soil, and culti-
vate it by the sweat of the brow of other men, and not their
personal labor, that success in husbandry must depend upon
giving to the soil, in some form, what is annually taken away
in cultivated crops.

In America, in the older States, the same truth is at length
reluctantly admitted. The census tables have shown that the
wheat crop of New York, in some counties, has fallen in its
average product so low as ezght bushels to the acre, where for-
merly from thirty to forty were produced. Lands deemed inex-
haustible have been cropped almost to barrenness. Large sec-
tions of territory in Virginia, formerly very productive, by a
course of culture not guided by a correct knowledge of the

“science of Husbandry, have become utterly unproductive, and
been abandoned by the original cultivators. A succession of
tobacco crops raised by shoal plowing without artificial manur-
ing; or a proper rotation with other products, exhausted the
surface soil, and compelled the proprietors to seek fresh fields.
Recently a more thorough and intelligent system, by men who
are both owners of the land and laborers upon it, has shown
‘that it was only with wareasonable demands upon her resources

\

iv ‘ “PREFACE, |

that a generous mother Earth had refused to comply; for the
same lands, by deep plowing and judicious rotation, are yielding
already a rich return for labor and capital to their owners..

In both countries it is now regarded by well-informed men_as
settled, that only labor directed by scientific knowledge can
yield a fair return upon any but new lands, where, as in our
Western States, Nature’s storehouses of fertilizers are yet unex-
hausted. In England the soil is owned by a few, and those
mostly educated men, and they, directly or indirectly, insist
upon systematic and thor ough tillage, as the only means of
deriving profit fr om their capital.

In America, in the free States, the land owner labors with
his own hands, and a‘knowledge of the principles of husbandry
must be generally diffused, that each for himself may apply
them in his own practice. Indeed, it seems peculiarly fitting
that the owner of the soil, who himself performs the labor upon
it, should have corstantly in view the reason for the various
processes he performs in bringing his crops to maturity.

-~No writer, perhaps, of the present day, has succeeded so
well as Mr. Jonnsron, in adapting to the apprehension of the
general reader his teachings‘upon the Science of Agriculture,—
in combining with instructions necessarily abstruse, the practi-
cal ideas which make his theories of manifest present value to
the farmer. His style has the simplicity and directness only.
acquired by those accustomed to speak to practical men. He
announces at once his object,—the advantage to be gained ;
and then tells us in the plainest language how to attain it.

More advancement has been made in Agricultural Chemistry
in the last ten years, than in any other branch of Science, and
no mind is better qualified than Mr. J OHNSTON’s, to seize upon

INTRODUCTION.

Tue scientific principles upon which the art of culture depends,
have not hitherto been sufficiently understood or appreciated
by practical men. Into the causes of this I shall not here in-
quire. JI may remark, however, that if AcricutrureE is ever to
be brought to that comparative state of perfection to which
many other arts have already attained, it will only be by avail-
ing itself, as they have done, of the many aids which science
offers to it. And if the practical man is ever to realise upon
his farm all the advantages which science is capable of placing
within his reach, he must become so far acquainted with the
connection that exists between the art by which he lives and
the sciences, especially of Chemistry, Geology, and Chemical
Physiology, as to be prepared to listen with candor to the
suggestions they are ready to make to him, and to attach their
proper value to the explanations of his various processes which
they are capable of affording.

The following little Treatise is intended to present a familiar
outline of the subjects eated of more at large in my published

vill INTRODUCTION.

Lectures on AcricuLturaL Cuemistry anD Gronocy. What,
in this work, has necessarily been taken for granted, or briefly
noticed, is in the Lecrures, examined, discussed, or more fully
detailed. |

Those who wish to put into the hands of the young a still
more condensed view of the principles of scientific agriculture,
will find it in my Carecuism or AGRICULTURAL CHEMISTRY AND
Gxotocy. ‘To most persons, indeed, it will prove advantageous
to read the Catechism first, and to proceed from it to the Ele
ments, and then to the Lectures.

DurnaM, November 1852.

PREFACE. ) Vv

every new theory and fact, and to combine them all into a har-
monious whole. ’

The present volume pretendsto no great recent discoveries
in Agriculture, but it is believed that in no other work have
the results of experience and theories been more carefully com-

pared. .

The writer, in addition to a complete treatise upon the
Elements of Agricultural Chemistry, suggests modesof thought
calculated to lead the reader constantly to reflection. What
each crop and each rotation of crops takes frem the soil, is
. carefully shown, that so the farmer may be led to inquire how
he can return the elements thus exhausted. Exact analyses are
given of the various substances used as manure, thus giving aid
to answer such inquiries. The structure of the various parts of
plants, the stem, root, and leaves, and their various functions,
are also carefully considered, with a view of ascertaining both
how their growth may be promoted, and to what useful pur-
_ poses they may be applied as manure, when their other uses are
exhausted. |

The structure of the earth, of its various reck formations,
which are the foundation of all soils, is lucidly discussed, giving
an insight into the value of geology as a practical helper in
husbandry—giving us‘at the same time direct instruction in the
best mechanical treatment of the farm, in plowing, subsoiling,
and thorough draining.

‘The reader will find practical advantage in the suggestions of
the author as to adullerations of the various fertilizers now ex-
tensively used in this country, especially of guano. It is believed
that gross impositions are already practiced upon the agricultu-
ral community, in the sale of various articles of little value. It
is only by the aid of scientific men, like our author, that these

Vi ’ PREFACE.

frauds can be detected, and the community be protected from
imposition, while they reap the full advantage to be derived
from the use of those articles when honestly supplied to them
ina pure form. ‘The work is offered to the public, not to su-
persede the truly-scientific and more technical treatise of Stock
hardt in the schools and colleges, not indeed to take the place
of any existing work, even in our libraries, but as containing the
matured results of a carefully-trained mind, which has long
compared the practical notions of the farmer with the theoreti-
cal ideas of the chemist and geologist, and so wrought out a
fund of valuable knowledge for practical men, such as, it is be-
heved, no other book supplies.

Another feature of great value to the work is that it has a
thoroughly-digested analytical and alphabetical index, so that
the editor, or student, in discussing any particular subject here-
in treated, may turn directly to it ; or the farmer, when in doubt
as to the treatment or composition of certain soils, the compost-
ing or application of manures, or the fertilizing properties of the
rocks upon his farm, by the-aid of the index is directly referred
to the subject in question, where he will usually find such plain
and practical suggestions as will enable him to derive important
aid in lis operations. |

Simon Brown.

Boston, 1853.

¢

ELEMENTS

OF

AGRICULTURAL CHEMISTRY

ETC.

CHAPTER I.

Object of the farmer.—What chemistry, geology, and chemical physiology
may do for agriculture.—Distinction between organic and inorganic sub-
stances.—The ash of plants and animals. —Simple and compound bo-
dies.—What elementary bodies are contained in the organic part of
soils, plants, and animals.—Properties of carbon, sulphur, phosphorus,
hydrogen, oxygen, and nitrogen.—Relative proportions of these elemen-
tary bodies contained in plants and animals.—Meaning of chemical com-
bination and chemical decomposition.

Tue object of the practical farmer is to raise from a given
extent of land the largest quantity of the most valuable pro-
duce at the least cost, in the shortest period of time, and with
the least permanent injury to the soil. Chemistry, Geology,
and Chemical Physiology throw light on every step he takes,
mRopeht to take, in order to effect this main object.

SECTION I._-WHAT CHEMISTRY, GEOLOGY, AND CHEMICAL PHYSIO-
Locy MAY HOPE TO DO FOR AGRICULTURE.
4

But there are certain definite objects which, in their connec-—
tion with agriculture, these sciences hope to attain. Thus,
without distinguishing the special province of each, they pro-
pose generally :—

1

2 WHAT CHEMISTRY AND GEOLOGY

_1°. To collect, to investigate, and, if possible, to explarm alt
known facts in. practical jaMegaaidey —This 3 is their first duty—a
laborious, difficult, but important one. Many things which are
received as facts in agriculture, prove to be more or less untrue
when investigated and tested by experiment. Many ascertained
facts appear inexplic
site and contradictory, which known principles clear up and
reconcile—yet there are many more which only prolonged re-
search can enable us to explain !

2°. From observations and experiments made wn the field or im
the laboratory, to deduce principles which may be more or less appla-
cable im all corcumstances—Such principles will explain useful
practices, and confirm their propriety. They will also account
for contradictory results, and will point out the circumstances
under which this or that practice may most prudently and most
economically be adopted.

Armed with the knowledge of such principles, ‘he instructed
farmer will go into his fields as the physician goes to the bed-
side of his patient,—prepared to understand symptoms and
appearances he has never before seen, and to adapt his prac-
tice to circumstances which have never before fallen under his
observation.

To deduce principles from collections of facts is attended
with much difficulty in all departments of knowledge. In agri-
culture it is at present an unusually difficult task. Observations
and experiments in the field have hitherto been generally made
with too little care, or recorded with too little accuracy, to
justify the scientific man in confidently adopting them as the
basis of his reasonings. A new race, however, of more careful
observers, and more accurate experimenters, is now springing
up. By their aid, the advance of sound agriéultural know-
ledge cannot fail to be greatly promoted. “

3°. To suggest improved, and, perhaps, previously wnthought-of
methods of fertilising the alias true explanation of twenty
known facts or results, or useful practices, should suggest nearly

MAY HOPE TO DO FOR pS cunTroRs. 3

as many more. Thus the explanation of old errors will not
only guard the practical man from falling into new ones, but
will suggest direct improvements he would not otherwise have
thought of. So, also, the true explanation of one useful prac-
tice will point out other new practices, which may safely and
with advantage be adopted.

4°, To analyse soils, manures, and vegetable products.—This is
a most laborious department of the duties which agriculture
expects chemistry to undertake in her behalf.

a. Sous.—The kind and amount of benefit to be derived from
the analyses of soils, are becoming every day more apparent. _
We cannot, indeed, from the results of an analysis, prescribe in
every case the kind of treatment by which a soil may at once
be rendered most productive. In many cases, however, certain
wants of the soil are directly pointed out by analysis ; in many
others, modes of treatment are suggested, by which a greater
fertility is likely to be produced,—and, as our knowledge of
the subject extends, we may hope to obtain, in every case,
some useful directions for the improvement or more profitable
culture of the land.

b. Manures—Of the manures we employ, too much cannot
be known. An accurate knowledge of these will guard the
practical man against an improvident waste of any of those
natural manures which are produced upon his farm—thus les-
sening the necessity for foreign manures, by introducing a
greater economy of those he already possesses. It will also
protect him against the ignorance or knavery of the manure
manufacturer. The establishment of such manufactories, con-
ducted by skilful and honorable men, is one of the most impor-
tant practical results to which the progress of scientific agricul-
ture is likely to lead. And if it cannot prevent uns@upulous
adulterators from engaging in this new traffic, chemistry can at
least detect and expose their frauds.

c. Vegetable Products —In regard, again, to the products of
the soil, few things are now more necessary than a rigorous

F

;
4. WHAT CHEMISTRY AND GEOLOGY MAY HOPE TO Do, &c.
&

analysis of all their parts. , If we know what a plant contains,
we know what elementary bodies it takes from the soil, and,
consequently, what the soil must contain, if the plant is to grow
upon it in a healthy manner,—that is, we shall know, to a cer-
tain extent, how to manure it.

On the other hand, in applying vegetable substances to the
feeding of stock, it is of equal importance to know what they
severally contain, in order that a skilful selection may be made
of such kinds of food as may best suit the purposes we intend
them to serve:

5°. To explain how plants grow and are nourished, and how
animals are supported and most cheaply fed.—What food plants
require, and at different periods of their growth, whence they
obtain it, how they take it in, and in what forms of chemical
combination? Also, what kind and quantity of food the
animal requires, what purposes different kinds of food serve in
the animal economy, and how a given quantity of any variety
of food may be turned to the best account? What questions
ought more to interest the practical farmer than these ?

Then there are certain peculiarities of soil, both physical and
chemical, which are best fitted to promote the growth of each
of our most valuable crops. There are also certain ways of
cultivating and manuring, and certain kinds of manure which
are specially favorable to each, and these again vary with every
important modification of climate. Thus chemical physiology
has much both to learn and to teach in regard to the raising
of crops.

So, different kinds and breeds of domestic animals thrive best
upon different kinds of food, or require different proportions of
each, or to have it prepared in different ways, or given at differ-
ent times. Among animals of the same species also, the grow-
ing, the full-grown, the fattening, and the milking animal, re-
spectively require a peculiar adjustment of!food in kind, quan-
tity, or form. All such adjustments the researches of chemistry
and physiology alone enable us accurately to make.

?
«

ORGANIC AND INORGANIC a OF PLANTS, &c. 5

6°. To test the opinions of theoretical men.—Erroneous opinions
lead to grave errors in practice. Such incorrect opinions are
not unfrequently entertained and pr omulgated even by eminent
scientific men. They are in this case most dangerous and most
difficult to overturn ; so that against these unfounded theories
the farmer requires protection, no less than against the quack-
ery of manufactured manures. It is only on a basis of often
repeated, skilfully conducted, and faithfully recorded experi-
ments, made by instructed persons, that true theories can ever
be successfully built up. Hence the importance of experiments in
practical agriculture.

Such are the principal objects which chemistry, aided by geo-
logy and physiology, either promises or hopes to attain. In no
district, however, will the benefits she is capable of conferring
upon agriculture. be fully realised, unless her aid be really sought
for, her ability rightly estimated, and her interference earnestly
requested. In other words, what we already know, as well as
what we are every day learning, must be adequately diffused
among the agricultural body, and in every district means must
be adopted for promoting this diffusion. It is in vain for che-
mistry and the other sciences to discover or suggest, unless her
discoveries and suggestions be fully made known to those whose
benefit they are most likely to promote.

SECTION II.—OF ORGANIC AND INORGANIC MATTER, AND OF THE OR-
GANIC AND INORGANIC PARTS OF ANIMALS, PLANTS, AND SOILS.

~» In the prosecution of his art, two distinct classes of substances
engage the attention of the practical farmer—the living animals
and crops he raises, and the dead soils from which the latter
are gathered. If he examine any fragment of an animal or
vegetable, either living or dead,—a piece of flesh or wood, for
example, Res will observe that it exhibits pores of various
kinds arranged in a certain order ; that it has a a species of inter-
nal structure ; that it has rho parts or organs ; in short,

‘

6 ORGANIC AND INORGANIC PARTS OF PLANTS, &c.

that it is what physiologists term organised. If he examine, in
like manner, a lump of earth or rock, he will perceive no such
structure. To mark this distinction, the parts of animals and
vegetables, either living or dead—whether entire or in a state
of decay—are called organic bodies, while earthy and stony sub-
' stances are called znorganic bodies.

Organic substances are more or less readily burned away and
dissipated by heat in the open air ; inorganic substances are
generally fixed and permanent in the fire.

Now the crops which grow upon the land, as well as the soil
in which they are rooted, contain a portion of both of these °
classes of substances. In all fertile soils there exists from 3 to
10 per cent. of vegetable or other matter, of organic origin. If
we heat a portion of such a soil to redness in the open air, as
in the annexed, (fig. 1,) this organic matter will burn away,
leaving the inorganic or mineral matter behind. By this burn-
ing, most soils are changed in color, but, if previously dried,

Fig. 1.

are not materially diminished in bulk. The inorganic matter
forms by far their largest part.

All vegetables, again, as they are collected for food, lea
when burned, a sensible quantity of zorganic ash ; but of them
it forms only a small part. Wood leaves about g-per cent,
grain 2 or 3 per cent, straw about 5 per cent ;“and only in
rare cases does the ash left amount to 15 or 20 per cent of the
weight of a vegetable substance. Hence, when a hanaful of
wheat, wheat straw, hay, &c., is burned in the-air, a compara-
tively small weight of matter only remains behind. Every one

SIMPLE AND COMPOUND BODIES. T
is familiar with this faet who has seen the small bulk of ash that
is left when weeds, or thorn-bushes, or trees, are burned in the
field, or when a hay or corn stack is accidentally consumed.
Yet this ash is verf important to the plant, and the study of its
true nature throws much light, as we shall hereafter see, on the
practical management of the land on which any given crop is to
be made to grow. It strikes us also as being important in
quantity, when we consider how much may be contained in an
entire crop. Thus the quantity of ash left by a ton of wheat
straw is sometimes as much as 360 lb., and bya ton of oat straw
as much as 200 lb. A ton of the grain of wheat leaves on an
average about 45 lb., of the grain of oats about 9 lb., and of
oak wood only 4 or 5 |b.

Animal substances also leave a proportion of ash when burned
in the air. Dry flesh and hair leave about 5 per cent of their
weight of inorganic ash ; dry bones more than half their weight.

Generally, therefore, the soil contains little organic and much
inorganic or mineral matter—the plant much organic and little
mineral—the animal, in its soft parts, little, in'its hard or solid
parts, much mineral matter,

SECTION IIi.—OF SIMPLE OR ELEMENTARY AND COMPOUND BODIES.

The various kinds of organic and inorganic matter of which
soils, plants, and animals consist, are distinguished by chemists
into two groups. Those which, by the agency of heat, or by
any chemical or other means, can be separated into two or more
unlike kinds of matter, are called compownd bodies—those which
cannot be so separated, are called szmple or elementary bodies.

Gold, iron, sulphur, and pure charcoal are szmple substances.
They cannot by any known means be separated or resolved into
more than one substance.

Wood, flesh, limestone, sand, &e., are compownd substances.
We are acquainted with methods by which they can each be
split up into two or more substances different from each other,

8 PROPERTIES OF CARBON

and from the wood or flesh, &c., from which they are ob-
tained. ;
Of simple or elementary bodies sixty-four are at present
known to chemists. All the other forms of matter which occur
in the animal, vegetable, or mineral kingdoms are compound. |

SECTION IV.—OF THE ELEMENTARY SUBSTANCES OF WHICH THE
ORGANIC PART OF SOILS, PLANTS, AND ANIMALS CONSISTS.

The organic or combustible part of sails, plants, and animals
is composed almost exclusively of four elementary substances,
known to chemists by the names of carbon, hydrogen, oxygen,
and nitrogen. It usually contains also a minute proportion of
sulphur and phosphorus.

Of these, carbon, sulphur, and phosphorus are solid substances ;
while hydrogen, oxygen, and: nitrogen are gases, or peculiar
kinds of air. Their properties are as follows :—

1. Carson.—When wood is burned in a covered heap, as is
done by the charcoal burners,—or is distilled in iron retorts, as
in making wood-vinegar,—it is charred, and is converted into
common wood charcoal. This charcoal is the most usual and
best known variety of carbon. It is black, soils the fingers, and
is more or less porous, according to the kind cf wood from which
it has been formed. Coke obtained by charring or distilling
coal is another variety. It is generally denser or heavier than
charcoal, though usually less pure. Black lead is a third va-
riety, still heavier and more impure. The diamond is the only
form in which carbon occurs in nature in a state of perfect
purity.

This latter fact, that the diamond is pure carbon—that it is
essentially the same substance with the finest and purest lamp-
black—is very remarkable ; but it is only one of the numerous
striking circumstances that every now and then present them-
selves before the inquiring chemist. ,

Charcoal, the diamond, lamp-black, and all the other forths

PROPERTIES OF HYDROGEN. 9

of carbon, burn away more or less slowly when heated to red-
ness Mm the air or in oxygen gas, and are converted into a kind
of gas known by the name of carbonic acid gas. 'The impure
varieties, when burned, ieave behind them a greater or less pro-
portion of ash.

2. SutpHur is a well known solid substance of a light yellow
color, and faint peculiar odor. It burns with a pale-blue
ine, ‘and in burning gives off fumes possessed of a str ong pun-
gent characteristic smell. 4

3. PHospHorvs is a yellowish waxy substance of a peculiar
smell, which smokes in the air, shines in the dark, takes fire by
mere rubbing, and burns with a large bright flame and much
white smoke. Like sulphur, it exists in all plants and animals,
though in comparatively small quantity. Like sulphur, also, it
is employed largely in the arts, especially in the manufacture of
lucifer matches.

4. Hyprocen.—If oil of vitriol (sulphuric acid) be mixed

Fig. 2.

™ i f ihn i cat a3 =

with twice its bulk of water, and be then poured upon iron

filings, or upon small pieces of zinc, the mixture will speedily

begin to boil up, and bubbles of gas will rise to the surface of

the liquid in great abundance. These are bubbles of hydrogen gas.
1*

10 PROPERTIES OF OXYGEN.

If the experiment be performed in a bottle, the hydrogen
whieh is produced will gradually drive out the atmospliewc, air
it contained, and will itself take its place. If a taper be tied
to the end of a wire, and, when lighted, be introduced into the
bottle, (fig. 2,) it will be instantly extinguished ; while the
hydrogen will take fire, and burn at the mouth of the bottle
with a pale yellow flame. If the taper be inserted before the
common air is all expelled, the mixture of hydrogen and com-
mon air will burn with an explosion more or less violent, and
may even shatter the bottle and produce serious accidents.
This experiment, therefore, ought to be made with caution. It
may be more safely performed in a common tumbler, (fig. 3,)

Fig. 3.

covered closely by a plate, till a sufficient quantity of hydrogen
is collected, when, on the introduction of the taper, the light
will be extinguished, and the hydrogen will burn with a less
violent explosion. Or the gas may be prepared in a retort, and
collected over water, as shown in fig. 4.

This gas is the lightest of all known substances, rising through
common air as wood does through water. Hence, when con-
fined in a bag made of silk, or other light tissue, it is capable
of sustaining heavy substances in the air, and even of carrying
them up to great heights. For this reason it is employed for
filling and elevating balloons.

Hee gas is not known to occur any where in nature in
any sensible quantity in a free state. It is very abundant in
water, and in many other substances, in what by chemists is
called a state of combination. (See pages 15 and 24.) )

5. Oxycen.—When strong oil of vitriol is poured upon black

PROPERTIES OF OXYGEN. it

oxide of manganese, and heated in a glass retort, (fig. 4,) or
when a mixture of chlorate of potash with an equal weight of

=

il

a.

Z =|

oxide of manganese, or when chlorate of potash alone, or red
oxide of mercury alone, is so heated—or when saltpetre, or the
black oxide of manganese, is heated alone in an iron bottle,—
in all these cases a kind of air is given off, to which the name
of oxygen gas is given. It is obtained with the greatest ease,
rapidity, and purity, from the mixture of chlorate of potash and
oxide of manganese.

Soja very elegant method of preparing the gas is to put a few

Fig. 5.

grains of red oxide of mercury into a tube, and apply the heat of
a lamp as in fig. 5. Oxygen gas will be given off while minute
globules of metallic mercury will condense on the cool part of
the tube. The presence of oxygen in the tube is shown by in-

12 PREPARATION OF NITROGEN.

troducing into one end of it a half-kindled match, when it. will
be seen to burn up brilliantly.

It is the characteristic property of this gas, that a taper,
when introduced into it, burns with great rapidity, and with ex-
ceeding brilliancy, and continues to burn till either the whole of
the gas disappears or the taper is entirely consumed. In this
respect it differs both from hydrogen and from common air. If
a living animal is introduced into this gas, its circulation and
its breathing become quicker—it is speedily thrown into a fever
—it lives as fast as the taper burned—and, after a few hours,
dies from excitement and exhaustion. This gas is not lighter,
as hydrogen is, but is about one-ninth part heavier than com-
mon air. ?

In the atmosphere, oxygen exists in the state of gas. It
forms about one-fifth of the bulk of the air we breathe, and is
the substance which, in the air, supports all animal life, and the
combustion of all burning bodies. It is necessary also to the
growth of plants, so that were it by any cause suddenly re-
moved from the atmosphere of our globe, every living thing Ww vould
perish, and all combustion would become impossible.

6. Nirrocen.—This gas is very easily prepared. Dissolve a
little green copperas in water, and pour the solution into a flask,
or crystal bottle, provided with a good cork. Add a little of
the hartshorn of the shops (liquid ammonia) till it is quite muddy,
put in the cork tight, and shake the bottle well for five minutes.
Loosen the cork well without removing it, so as to allow air to
enter the bottle. Cork tight again and shake as before. Re-
peat this as often as the loosening of the cork appears to admit
any air, and after finally shaking it, allow it to stand for a few

minutes. The air now in the bottle is nearly pure nitrogen gas.

If a lighted taper be introduced into the bottle it will be
extinguished by this gas, but no other effect will follow. The
gas itself does not take fire as hydrogen does. Or if a living |
animal be introduced into it, breathing will instantly cease, and
it will drop without signs of life.

COMPOSITION OF THE ORGANIC PART OF PLANTS. 18

This gas possesses no other remarkable property. It isa
very little lighter than common air, (as 974 to 100,) and exists
in large quantity in an uncombined state in the atmosphere
only. Of the air we breathe it. forms nearly four-fifths of the
entire bulk—the remainder being oxygen. In the process
above described for preparing the gas, the oxygen is absorbed
by the iron, and the nitrogen left behind.

These three gases are incapable of being distinguished ‘from
common air, or from each other by the ordinary senses ; but by
the aid of the taper they are readily recognised. Hydrogen
extinguishes the taper, but itself takes fire ; nitrogen simply
extinguishes it ; while in oxygen the taper burns rapidly and
with extraordinary brilliancy.

SECTION V.—PROPORTIONS OF THESE ELEMENTARY SUBSTANCES
CONTAINED IN THE ORGANIC PART OF PLANTS AND ANIMALS.

Of the one solid substance, carbon, and the three gases, hy-
drogen, oxygen, and nitrogen, above described, the organic
part of all vegetable and animal bodies is essentially made up.
In those organic substances which contain nitrogen, sulphur
and phosphorus also are present, but generally in minute pro-
portion.

But the organic part of plants contains these four substan-
ces in very different proportions. Thus, of all the vegetable
productions which are gathered as feod by man or beast, in
their dry state, the

Carbon forms nearly one-half by weight,
Oxygen rather more than one-third,
Hydrogen little more than 5 per cent,
Nitrogen from 4 to 4 per cent,

Sulphur 1 to 5 per cent,

Phosphorus about a thousandth part.

This is shown in part by the following table, which exhibits

14 COMPOSITION OF THE ORGANIC PART OF PLANTS.

the actual composition of 1000 Ib. of some varieties of the more
common crops, when made perfectly dry :—

Carbon. Hydrogen. Oxygen. Nitrogen. Ash.

Hay, 458 lb. 50lb. 3871b. 151b. 90]b.
Red Clover Hay, 474 50 378 21 17
Potatoes, . 440 58 447 15 40
Wheat, . 461 58 434 23 24
Wheat Straw 484 53 3893 34 70
Oats, ‘ 507 64 367 22 40
Oat Straw, 501 54 390 4 51

It is to be observed, however, that in drying by a gentle
heat, 1000.lb. of common hay from the stack lost 158 lb. of
water; of clover hay, 210 lb.; of potatoes wiped dry externally,
759 Ib. ;* of wheat, 145 Ib. ; of wheat straw, 260 Ib. ; of oats,
151 Ib. ; and of oat straw, 287 lb. The above table represents
their composition when thus made perfectly dry.

The bodies of animals contain also a large proportion of
water ; but the dry matter of their bodies, as a whole, is dis-
tinguished from that of plants, by containing a larger proportion
of nitrogen, sulphur, and phosphorus. Some parts of the
bodies of animals are particularly rich in these ingredients.
Thus— .

Dry lean muscle contains 12 to 14 per cent of netrogen,

Dry hair or wool about 5 per cent of sulphur ; and

Dry bone about 6 per cent of phosphorus.

But in animals, as in plants, the chief constituents are carbon
and oxygen. Thus, lean beef, blood, white of egg, and the
curd of milk, when-quite dry, consist in 100 parts of about—

Per cent.
Carbon, > : : : - 55
Hydrogen, ; ‘ , : : 7
Nitrogen, ; : : , : 16
Oxogen, with a little sulphur and phosphorus, 22
100

* Potatoes contain about four-fifths of their weight of water, or five tons
of roots contain nearly four tons of water. Turnips contain sometimes up-
wards of nine-tenths of their weight of water.

CHEMICAL COMBINATION AND DECOMPOSITION. 15

SECTION VI.—OF CHEMICAL COMBINATION AND CHEMICAL DECOM-
POSITION.

1°. If the three kinds of air above spoken of be mixed to-
gether in a bottle, no change will take place ; and if charcoal
in fine powder be added to them, still no new substance will be
produced. Or if we take the ash left by a known weight of hay
or of wheat straw, and mix it with the proper quantities of the
four elementary substances—carbon, hydrogen, oxygen, and
nitrogen—as shown in the above table, we shall be unable by
this means to form either hay or wheat straw. The elements
of which vegetable substances consist, therefore, are not merely
mixed together, they are united in some closer and more inti-
mate manner. ‘To this more intimate state of union the term
chemical combination is applied—the elements are said to be
chemically combined.

- Thus, when charcoal is burned in the air, it slowly disappears,
and forms, as already stated, (p. 9,) a kind of air known by
the name of carbonic acid gas, which rises into the atmosphere
and diffuses itself through it. Now this carbonic acid is formed
by the wnzon of the carbon (charcoal) while burning, with the
oxygen of the atmosphere, and in this new air the two elements,
carbon and oxygen, are chemically combined.

Again, if hydrogen be burned in the air by means of a com-
mon gas jet, (see p. 24,) water is formed, and the hydrogen,
and a portion of the oxygen of the atmosphere, disappear to-
gether. The two gases have combined chemically with each other,
and formed water.

2°. On the other hand, if a piece of wood, or bit of straw,
in which the elements are already chemically combined, be
burned in the air, these elements are separated, and made to
assume new states of combination, in which new states they
escape into the air and become invisible. When a substance is
thus changed, and converted or separated into other substances
by the action of heat, or in any other way, it is said to be de-

«

16 CHEMICAL COMBINATION AND DECOMPOSITION.

composed. If it more gradually decay and perish, as animal and
vegetable substances do, by-exposure to the air and moisture,
it is said to undergo slow decomposition.

When, therefore, two or more substances unite together, so -

as to form a third, possessing properties different from both, they
enter into chemical union—they form a chemical combination, or
chemical compound. And when, on the other hand, a compound
body is so changed as to be converted into two or more sub-
stances different from itself, it is decomposed. Thus carbon,
hydrogen, and oxygen undergo a chemical combination in the
interior of the plant during the formation of wood—while wood,
again, is decomposed, when in the retort of the vinegar-maker it
is converted among other substances into charcoal and wood-
vinegar. So the flour of grain is decomposed when the brewer
or distiller converts it into ardent spirits ; and so in the experi-
ment described in section tv. for preparing oxygen gas from red
oxide of mercury, the oxide is decomposed by the heat, and is
resolved into its two constituent elements, oxygen and metallic
mercury.

7

- CHAPTER II.

Forms in which the organic elements, carbon, hydrogen, oxygen, nitrogen,
sulphur, and phosphorus, enter into plants.—Properties of the carbonic,
humic, ulmic, geic, and crenic acids, and of humine and ulmine.—Of water,
and its relations to vegetable life-—Of ammonia, its properties and pro-
duction in nature.—Of other organic alkalies containing nitrogen.—Of
nitric acid, and its production in the air and in the soil.—Composition of
the atmosphere.—Of sulphuric and phosphoric acids.

SECTION I.—FORMS IN WHICH THE ORGANIC ELEMENTS, CARBON,
HYDROGEN, OXYGEN, NITROGEN, &C., ENTER INTO PLANTS.

Ir is from their food that plants derive the carbon, hydrogen,
oxygen, and nitrogen, as well as the sulphur and phosphorus, of
which their organic part consists. This food enters partly by
the minute pores of their roots, and partly by those which exist
in the green parts of the leaf and of the young twig. The roots
bring up food from the soil, the leaves take it in directly from
the air.

Now, as the pores in the roots and leaves are very minute,
carbon (charcoal) cannot enter them in a solzd state ; and as it
does not dissolve in water, it cannot, in the state of simple car-
bon, be any part of the food of plants. The same is true of
sulphur and phosphorus. Again, hydrogen gas neither exists in
the air nor usually in the soil; so that, although hydrogen is
_ always found in the substance of plants, it does not enter them
in the state of gas. Oxygen, on the other hand, exists in the
air, and zs directly absorbed both by the leaves and by the roots
of plants; while nitrogen, though it forms a large part of the
atmosphere, is not known to enter dzrectly into plants in any
considerable quantity.

The whole of the carbon and hydrogen, therefore, and the

18 PROPERTIES OF CARBONIC ACID.

greater part of the oxygen and nitrogen also, enter into plants
in a state of chemical combination with other substances. The
carbon is taken up chiefly in the state of carbonic acid, and of
certain other soluble compounds which exist in the soil; the
hydrogen and oxygen in the form of water; the nitrogen chiefly,
it is supposed, in those of ammonia, of certain other soluble sub-
stances containing nitrogen, and of nitric acid; and the sulphur
and phosphorus in those of sulphuric and phosphoric acids. It
will be necessary, therefore, briefly to describe these several
compounds.

SECTION IJ.—OF THE CARBONIC, HUMIC, ULMIC, GEIC, AND
CRENIC ACIDS.

1. Carsontc Aocrp.—If a few pieces of chalk or lime-stone,
Fig. 6.

or of common soda, be put into the bottom of a tumbler, and a
little spirit of salt (muriatic acid) be poured upon them, a boil-
ing up or effervescence will take place, and a gas will be given off,
which will gradually collect and fill the tumbler; and when pro-
duced very rapidly, may even be seen to run over its edges.

PROPERTIES OF CARBONIC ACID. 19

This gas is carbonic acid. It cannot be distinguished from
common air by the eye; but if a lighted taper be plunged into
it, the flame will immediately be extinguished, while the gas

will remain unchanged. This kind of air is so heavy, that it
may be poured from one vessel into another, and its presence in
the second vessel recognised as before by the use of the taper.
Or it may be poured upon a lighted candle, which it will in-
stantly extinguish, (fig. 6.) This gas has also a peculiar odor,
and is exceedingly suffocating, so that if a living animal be in-
troduced into it, life immediately ceases. It is absorbed by
water—a pint of water absorbing or dissolving a pint of the gas,
and acquiring a faintly acid taste.

This gas derives its name of acid from this taste, which it
imparts to water, and from its property of reddening vegetable
blue colors, and of combining with alkaline* substances to form
_ carbonates. The former property may be shown by passing a
stream of the gas through a decoction of red cabbage—as in

* Acids have generally a sour taste like vinegar, and redden vegetable blues.
Alkalines, again, have a peculiar taste called alkaline, of which the taste of
common soda or of hartshorn are examples; they restore the blue color to
vegetable blues which have been reddened by an acid, and they unite with
acids to form chemical combinations, known by the name of salts or saline
combinations.

90 PROPERTIES OF CARBONIC ACID.

8—when the liquid will gradually become red; the latter, by
putting lime water into the glass instead of the decoction of red
cabbage, when the stream of gas will render it milky, forming
carbonate of lime.

Carbonic acid gas exists in the atmosphere ; it is given off
from the lungs of all living animals while they breathe ; it is
also produced largely during the burning of wood, of coal, and
of all other combustible bodies, so that an unceasing supply of
it is perpetually being poured into the air. Decaying animal
and vegetable substances also give off this gas, and hence it is
always present in greater or less abundance in the soil, and es-
pecially in such soils as are rich in vegetable matter. It is pro-
duced during the fermentation of malt Fquors, or of the ex-
pressed juices of different fruits, such as the apple, the pear, the
grape, or the gooseberry—and the briskness of such fermented
liquors is due to the escape of carbonic acid gas. From fer-
menting dung and compost heaps it is also given off ; and when
put into the ground, farm-yard manure imparts much carbonic
acid to the soil and to the roots of plants.

Carbonic acid consists of carbon and oxygen only, combined
together in the proportion of 28 of the former to 72 of the lat-
ter. Or 100 lb. of carbonic acid contain 28 lb. of carbon and
72 lb. of oxygen. )

It combines with potash, soda, lime, magnesia, ammonia, &c.,
forming carbonates of these bases.

ow

HUMIC AND ULMIC ACIDS. * oF

2. Humic anp Usmic Acrps.—The soil always contains a
portion of decaying vegetable matter, (called humus by some
writers, ) and such matter is always added to it when it is ma-
nured from the farm-yard or the compost heap. During the de-
cay of this vegetable matter, carbonic acid, as above stated, is
given off inlarge quantity, but other substances are also formed
at the same time. Among these are the two to which the
names of humic and wlmic acids are respectively given. Both of
these acids contain much carbon,—they are both capable of en-
tering the roots of plants, and both, in favorable enipesaenees :
help to feed the plant.

In peat bogs two distinct kinds of turf are frequently recog-
nised—a light, porous, brown-colored, and a dense, compact,
black variety. The former abounds in reddish-brown ulmzc, the
latter in brownish-black Awmic acid. These acids may readily —
be extracted from the peat by means of potash, soda, or ammo-
nia, in solutions of which they easily dissolve.

Thus if the common soda of the shops be dissolved in water,
and a portion of a rich vegetable soil, or a bit of peat, be put
into this solution, and the whole then boiled, a brown liquid is
obtained. If to this brown liquid, spirit of salt (muriatic acid)
or vinegar be added till it is sour to the taste, a brown flocky
tasteless powder falls to the bottom. This brown substance is
humic or ulmic or geic acid, or a mixture of all the three. In
our cultivated soils, the humic is more abundant than the ulmic
acid.

The quantity of these mixed acids, extracted in this way from
three rich soils, was respectively 44, 54, and 84 per cent. In
most of our arable soils, however, the proportion present is con-
siderably less.

3. Gxutc Acip.—The geic acid resembles the above acids in
appearance, but contains more oxygen. Like them it exists in
the soil in variable quantity, and may be extracted from it by
solutions of potash, soda, or ammonia, and is thrown down from
these solutions by the addition of an acid.

22, PROPERTIES OF. CRENIC AND APOCRENIC ACIDS.

These three acids have so strong a tendency to.combine with
ammonia, that it is almost impossible to obtain them free from
this substance. In the soil they absorb it whenever it is pre-
sent, and if exposed to the air in a moist state, they drink it in
from the atmosphere, if any happen to be floating in their neigh-
borhood. Hence the utility of partially dried peat for absorb-
ing liquid manure, or for mixing with or covering fermenting
compost heaps. ia

All the three acids above named are sparingly soluble in wa-
ter, and, therefore, in their uncombined state can afford little
direct nourishment to plants. They form compounds with lime,
magnesia, and oxide of iron, which are also very sparingly solu-
ble, and enter little into the roots of plants. They all dissolve
readily, however, when they are combined with potash, soda, or
ammonia. And as the latter substance especially is produced,
and is always present in the soil, and as these acids attract it
very strongly, there is good reason for believing that they are
frequently rendered soluble by it, and that in this way ulmic,
humic, and geic acids ¢ontribute directly to the nourishment of
our cultivated crops?’

4. Crrnic anp Apocrenic Actps.—By these names are dis-
tinguished two other acid substances which exist in the soil, and
in a greater degree, perhaps, and more directly, promote the
growth of plants. They exist in the water of all bogs and mo-
rasses, and are often met with in considerable quantity in the
water of springs, especially in such as form an ochrey deposit
when exposed to the air. They are produced from the humic
and ulmic acids by the absorption of more oxygen from the at-
mosphere, and, like them, eagerly combine with ammonia ; but
they are lighter in color, and much more soluble in water.

When rich soil is boiled in carbonate of soda, as above de-
scribed, and the humic, ulmic, and geie acids are thrown down
by the addition of muriatic acid, the crenic and apocrenie acids
remain still in the solution, and may be separated by further
processes which it is unnecessary here to describe. |

GENERAL OBSERVATIONS. 93

All the above acids, and especially the two latter, exist in
greater or less quantity in the rich brown liquor of the farm-
yard, which is so often allowed to run to waste. They are pro-
duced, also, during the decay of the mixed animal and vegeta-
ble manure we add to the soil, and yield to the plant a portion
of that supply of organic food which it must necessarily receive
from the soil.

5. Humine anp Utnrye are the names given to certain inso-
luble black substances formed in the soil along with the humic
and other acids during the decay of vegetable matter. One of
the ways in which lime acts beneficially upon the soil is supposed
to be by disposing these insoluble matters to enter into new
states of combination, in which they may become soluble, and
thus capable of entering into the roots of plants.*

Of the important substances above described, I may further
remark—

a. That the ulmic acid is the first formed from the decay of
vegetable matter, Hence, in peat bogs the red turf is usually
found nearest to the surface. R

6. That the humid acid is formed from the ulmic by the ab-
sorption of more oxygen from the atmosphere. It consists of
carbon and water only. (See page 50.)

c. That the gcic contains more oxygen than the humic acid,
and is formed from it by the absorption of a further quantity of
oxygen from the air, or from the water with which it is in con-
tact.

d. That the crenic and apocrenic acids contain still more oxy-
gen, and, along with other substances produced in the soil, are
formed by the union of the geic acid with another proportion of
oxygen.

Thus decaying vegetable matter appears first. to form the ul-
mic, next the humic, than the geic, after that the crenic and
apocrenic acids. We do not know how many other compounds

* See in the Chapter “On the Use of Lime,” the sections which treat of
the chemical action of lime when applied to the soil.

24 COMPOSITION OF WATER.

may succeed to these by the union of their elements with more
and more oxygen, before they are entirely resolved into car-
bonic acid,—the final state to which all these changes ultimately
lead.

These excessive absorptions of oxygen by the decaying veg-
etable matter, promote the production of ammonia in the soil,
as well as of nitric acid. This fact will be more clearly ex-
plained in section v1.

SECTION III.—OF WATER, ITS COMPOSITION, AND ITS RELATIONS
TO VEGETABLE LIFE.

If hydrogen be prepared in a bottle in the way already de-
scribed, (p. 9,) and a gas-burner be fixed into its mouth, the

THT

i
Ni

i i I } Hi

hydrogen may be lighted, and will burn as it escapes into the
air, (fig. 9.) Held over this flame, a cold tumbler will become
covered with dew, or with little drops of water. This water is
produced during the burning of the hydrogen ; and as its pro-
duction takes pines 3 in pure oxygen gas as well as in the open

SOLVENT POWER OF WATER. 25

air, which contains oxygen—a portion of the oxygen and hydro-
gen alone disappearing—the water formed must contain the
hydrogen and oxygen which disappear, or must consist of hydro-
gen and oxygen only.

This is a very interesting fact ; and were it not that chemists
are now familiar with many such, it could not fail to appear
truly wonderful that the two gases, oxygen and hydrogen, by
uniting together, should form water—a substance so very dif-
ferent in its properties from either. Water consists of 1 of
hydrogen united to 8 of oxygen by weight ; or every 9 lb. of
water contain 8 lb. of oxygen and 1 lb. of hydrogen.

Water is so familiar a substance that it is umnecessary to
dwell upon its properties. When pure, it has neither color,
taste, nor smell. At 32° of Fahrenheit’s scale, (the freezing
point,) it solidifies into ice ; and at 212° it boils, and is con-
verted into steam. It possesses two other properties, which are
especially interesting in connection with the growth of plants.

Ist. If sugar or salt be put into water, they disappear, or are
dissolved. Water has the power of thus dissolymg numerous
other substances in greater or less quantity. Hence, when the
rain falls and sinks into the soil, it dissolves a portion of the
soluble substances it meets with in its way, both through the
air and through the soil, and rarely reaches the roots of plants
in a pure state. So waters that rise up in springs are rarely
pure. They always contain earthy and saline substances in
solution, and these they carry with them when they are sucked
in by the roots of plants.

It has been above stated, that water absorbs (dissolves) its
own bulk of carbonic acid ; it dissolves also smaller quantities
of the oxygen and nitrogen of the atmosphere ; and hence,
when it meets any of these gases in the soil, it becomes im-
pregnated with them, and conveys them into the plant, there to
Serve as a portion as its food.

In nature, water never occurs in a pure state. It generally

contains both gaseous dnd saline substances in a state of solu-
2,

26 PROPERTIES OF AMMONIA.

tion ; and this, no doubt, is a wise provision by which the food
of plants is constantly renewed and brought within their reach.

2d. Water, as we have shown above, is composed of oxygen
and hydrogen, and by certain chemical processes it can readily
be resolved or decomposed artificially into these two gases. The
same thing takes place naturally in the interior of the living
plant. The roots and leaves absorb the water; but if in any part
of the plant hydrogen be required for the formation of the sub-
stance which it is the function of that part to produce, a portion
of the water of the sap is decomposed either directly or indi-
rectly, and its hydrogen worked up, while its oxygen is set free,
or converted to some other use. So, also, where oxygen is
required, and cannot be obtained from some more ready source,
water is decomposed, the oxygen made use of, and the hydrogen
liberated. Water, therefore, which abounds in the vessels of
all growing plants, if not directly converted into the substance
of the plant, is yet a ready and ample source from which a sup-
ply of either of the elements of which it consists may at any
time be obtained.

Tt is a beautiful adaptation of the properties of this all-perva-
ding compound—water—that its elements should be so fixedly.
bound together as rarely to separate in external nature, and yet
to be thus at the command and easy disposal of the vital pow-
ers of the humblest order of living plants.

SECTION IV.—OF AMMONIA, ITS PROPERTIES AND PRODUCTION IN
NATURE.

If the sal-ammoniac, or the sulphate of ammonia of the shops,
be mixed with quick-lime, a powerful odor is immediately per-
ceived, and an invisible gas is given off, which strongly affects
the eyes. This gas is ammonia. Water dissolves or absorbs
it in.very large quantity, and this solution of the gas in water
forms the common hartshorn of the shops. ..The white solid

NATURAL PRODUCTION OF AMMONIA. 27

smelling-salts of the shops (carbonate of ammonia) are a com-
pound of ammonia with carbonic acid and a little water.

Ammonia consists of nitrogen and hydrogen only, in the pro-
portion of 14 of the former to 3 of the latter by weight ; or 17
lb. of ammonia ‘contain 14 lb. of nitrogen and 3 Ib. of hydrogen.

The decay of animal substances is an important natural
source of this compound. During the putrefaction of dead ani-
mal bodies, ammonia is invariably given off. From the animal
substances of the farm-yard it is evolved during their decay or
putrefaction, as well as from all solid and liquid manures of ani-
mal origin.

Ammonia is naturally formed, also, during the decay of veg-
etable substances in the soil. This happens in one or other of
three ways.

a. Asin animal bodies, by the direct union of the nitrogen
with a portion of the hydrogen of which they consist.

b. Or by the combination of a portion of the hydrogen of the
decaying plants with the nitrogen of the air.

c. Or when they decompose in contact, at the same time,
with both air and water—by their taking the oxygen of a
quantity of the water, and disposing its hydrogen at the mo-
ment of liberation, to combine with the nitrogen of the air, and
form ammonia.

The production of ammonia by either of the two latter
modes, takes place most abundantly when the oxygen of the air
does not gain very ready access. Such are open subsoils in
which vegetable matter abounds. And thus one of the benefits
which follow from thorough draining and subsoil ploughing is,
that the roots penetrate and fill the subsoil with vegetable mat-
ter, which, by its decay in the confined atmosphere of the sub-
soil, gives rise to this production of ammonia. When thus
formed in the soil, it is at once absorbed and retained by the
humic and ulmic acids already described, renders them soluble,
and enters with them into the roots of living plants.

Ammonia is also formed naturally during the chemical

28 OTHER ORGANIC ALKALIES.

changes that are produced in volcanic countries, through the
agency of subterranean fires. It escapes often in considerable
quantities from the hot lavas, and from crevices in the heated
rocks.

It is produced artificially by the distillation of animal sub-
stances, (hoofs, horns, &c.,) and during the burning, coking,
and distillation of coal. Soot contains much ammonia, while
thousands of tons of that which is present in the ammoniacal
liquors of the gas-works, and which might be beneficially applied
as a manure, are annually carried down by the rivers, and lost
in the sea.

Of the ammonia which is given off during the putrefaction of
animal and vegetable substances, a variable proportion rises
into the air, and floats in the atmosphere, till it is either decom-
posed by natural causes, or is dissolved and washed down by
the rains. In the latter case it sinks into the ground, and finds
its way into the roots of plants. In our climate, cultivated
plants appear to derive a considerable proportion of their nitro-
gen from ammonia. It is one of the most valuable fertilizing
substances contained in farm-yard manure ; and as it is usually
present in greater proportion in the liquid than in the solid con-
tents of the farm-yard, much real wealth is lost, and the means
of raising increased crops thrown away, in the quantities of
liquid manure which are almost everywhere permitted to ran
to waste.

SECTION V.—OF OTHER ORGANIC ALKALIES, AND THEIR INFLUENCE
UPON VEGETATION,

Ammonia has hitherto been considered by chemists as the
only organic substance of a volatile and alkaline nature, which
exercised a sensible influence upon vegetation. But a number
of other organic alkalies, volatile like ammonia, possessed of a
powerful odor, soluble in water, and like it containing nitrogen,
have recently been discovered. Some of these are of such a kind

fe

eae. ».

NITRIC ACID. 29

as to be naturally produced, I believe, during the decay and
fermentation of animal and vegetable substances ; and if so,
they cannot fail to affect the growth of plants.

These alkaline compounds contain carbon in addition to the
hydrogen and nitrogen of which ammonia consists. Hence if
they exist, or are formed in the soil, they will be able to minis-
ter these three elements to the wants of the plant, and in a form
of combination in which they may be more readily converted
into those substances of which the parts of the plant are com-
posed.

_ No experiments have yet been made upon the relations which
these compounds bear to vegetable life, to fertility of soil, or to
fertilizing manures ; but I insert these brief remarks regarding
them in this place from the persuasion, that the study of these
relations will afford the materials for an intricate, perhaps, but
most interesting and important chapter in future histories of the
phenomena of vegetation.

SECTION VI.—OF NITRIC ACID, AND ITS PRODUCTION IN THE AIR
AND IN THE SOIL.

Nitric acid is a powerfully corrosive liquid, known in the shops
by the familiar name of aquafortis. It is prepared by pouring
oil of vitriol (sulphuric acid) upon saltpetre, and distilling the
mixture. The aquafortis of the shops is a mixture of the pure
acid with water.

Pure nitric acid consists of nitrogen and oxygen only, united
in the proportions of 14 of nitrogen, by weight, to 40 of oxygen.
It is very remarkable that the union of these two gases, so
harmless in the air, should produce the burning and corrosive
compound which this acid is known to be.

It never reaches the roots or leaves of plants in this free and
corrosive state. It exists and is produced in many soils, and is
naturally formed in compost heaps, and.in most situations where
animal or vegetable matter is undergoing decay in contact with

30 PROPERTIES OF NITRIC ACID.

the air ; but in these cases it is always found in a state of che-
mical combination. With potash it forms nztrate of potash,
(saltpetre,) with soda, nztrate of soda, with lime, nitrate of lime,
with magnesia, nitrate of magnesia, with ammonia, nitrate of
ammonia, and so on. All these nitrates are very soluble in wa-
ter, and it is generally in the state of-one or other of these com-
pounds that nitric acid exists in the soil and reaches the roots
of plants.

It is well known that saltpetre—called also nitre, or nitrate
of potash—is in India obtained by washing the rich alluvial soil
of certain districts with water, and evaporating the clear solu-
tion to dryness. On the continent of Hurope, artificial nitre-
beds are formed by mixing together earthy matters of various
kinds with the liquid and dung of stables, and forming the mix-
ture into heaps, which are turned over once or twice a year.
These heaps, on washing, yield an annual crop of impure salt-
petre. The soil around our dwellings, and upon which our
towns and villages stand, becomes impregnated with animal mat-
ter of various kinds through defective drainage, and is thus con-
verted into extensive nitre-beds, in which nitric acid and nitrates
are produced in great abundance. ‘The rains that fall and sink
into the soil wash these downwards into the wells, if any are
near. Hence nitrates usually abound in wells which are dug
within the walls of large towns ; and the waters of such wells
are generally unwholesome to man, though they would wonder-
fully nourish plants, if employed for the purposes of irrigation.*

Nitric acid is also naturally formed, and in some countries

* “Tn Leon (Nicaragua) the practice of burying in the churches has al-
ways prevailed, and is perpetuated through the influence of the priests, who
derive a considerable fee from each burial. The consequence is, that the
ground within and around the churches has become (if the term is admissi-
ble) saturated with the dead. The burials are made, according to the amount
paid to the Church, for from ten to twenty-five years, at the end of which

time the bones with the earth around them are removed and sold to the manu- y,

Sacturers of nitre.”—Squier’s Nicaragua, vol. i. p. 384,

*

ee

PRODUCTION OF NITRIC ACID. SE

probably in large quantities, by the passage of electricity through
the atmosphere. The air consists of oxygen and nitrogen maxed
together, but when electric sparks .are passed through a quan-
tity of air, minute portions of the two gases wnife together che-
mically, so that every spark which passes forms a small quantity
of nitric acid. <A flash of lightning is only a large electric
spark ; and hence*every flash that crosses the air produces
along its path a sensible proportion of this acid. Where thun-
der-storms are frequent, much nitric acid, and probably some
ammonia, are produced in this way in the air. They are washed
down by the rains—in which they have frequently been de-
tected—and thus reach the soil, where the acid combines with
potash, soda, lime, &e., and produces the nitrates above men-
tioned.

It has long been observed that those parts of India are the
most fertile in which saltpetre exists in the soil in the greatest
abundance. ‘The nitrates of soda and potash have been found
among ourselves, also, wonderfully to promote vegetation, when
artificially applied to growing crops ; and it is a matter of fre-
quent remark, that vegetation seems to be refreshed and invigo-
rated by the fall of a thunder-shower. ‘There is, therefore, no
reason to doubt that nitric acid is really beneficial to the gene-
ral vegetation of the globe. And since vegetation is most lux-
uriant in those parts of the globe where thunder and lightning
are most abundant, it would appear as if the natural production
of this compound body in the air, to be afterwards brought to
the earth by the rains, were a wise and beneficent contrivance
by which the health and vigor of universal vegetation is in-
tended to be promoted, ay,

It is from nitrie acid, thus universally produced and existing,
that plants appear to derive a large—probably, taking the vege-
tation of the earth as a whole, the largest—proportion of their
nitrogen. In all climates, they also derive a portion of this
element from ammonia, and from other soluble compounds con-

32 COMPOSITION OF THE ATMOSPHERE.

taining nitrogen; but less, probably, from these sources in tropi-
cal than in temperate climates.*

SECTION VII.—OF THE COMPOSITION OF THE ATMOSPHERE.

The air we breathe, and from which plants derive a portion of
their nourishment, consists of a mxture of oxygen and nitrogen
gases, with a minute quantity of carbonic acid, and a variable
proportion of watery vapor. Every hundred gallons of dry air
contain about 21 gallons of oxygen and 79 of nitrogen. . The
carbonic acid amounts only to one gallon in 2500, while the
watery vapor varies from one to two and a half gallons (of
steam) in 100 gallons of common air.

The oxygen of the atmosphere is necessary to the breathing
of animals, to the life of plants, and to the burning of bodies
in the air. The nitrogen serves principally to dilute the strength,
so to speak, of the pure oxygen—in which gas, if unmixed,
animals would live, and combustibles burn with too great ra-
pidity. The small proportion of carbonic acid in the atmo-
sphere affords an important part of their food to plants, and the
watery vapor aids in keeping the surfaces of animals and plants
‘in a moist and pliant state; while, in due season, it descends
also in refreshing showers, or studs the evening leaf with spark-
ling dew.

There is thus in the composition of the atmosphere a beau-
tiful adjustment to the nature and necessities of living beings.
The energy of the pure oxygen is tempered, yet not too much
weakened, by the admixture of nitrogen gas. The carbonic
acid, which, when undiluted, is noxious, especially to animal life,
is mixed with the other gases in so minute a proportion, as to
be harmless to animals, while it is still beneficial to plants; and
when the air is overloaded with watery vapor, it is provided
that it shall descend in rain.

* For fuller information on this point, see the Author’s Lectures on Agri-
cultural Ohemistry and Geology, 2d edition.

SULPHURIC AND PHOSPHORIC ACIDS. 33

But the air contains besides many other substances not essen-
tial to its composition, but which exercise, nevertheless, an
important influence both upon animal and vegetable life. We
have already seen that nitric acid, and probably ammonia, are
produced in it by the agency of electricity, and are brought
down by the rains. ‘There are continually rising into it also
vapors and exhalations of various kinds from the earth’s sur-
face. ‘The sea sends up a portion of its common salt and other
constituents, and the land the numberless forms of volatile
matter which arise from decaying animal and vegetable sub-
stances, from festering marshes, from burning volcanoes, and
from countless manufactories and chemical operations. As the
ocean receives all that water can carry into it, so the atmo-
sphere receives everything that the air can bear up.

And lest these ever-rising exhalations should contaminate the
air, and render it unfit for the breathing of animals, the rains,
as they descend, dissolve, wash out, and bring them back again
to the soil. Thus they purify at once, the atmosphere through
which they fall, and bear refreshment to the land, and the
means of fertility, wherever they come.

SECTION VIII.—OF SULPHURIC AND PHOSPHORIC ACIDS.

We have stated in a previous section that sulphuric and phos-
phoric acids are the chief. forms in which sulphur and phospho-
rus respectively enter into plants. i

1°. SutpHuric Acip—known also as oil of vitriol—is a very

heavy, oily-looking, sour, and corrosive liquid, which becomes
hot when mixed with water, chars and blackens straw or wood
-when immersed in it, and is capable of dissolving many organic
and inorganic substances. It is manufactured by burning sul-
phur in large leaden chambers, and consists of sulphur and
oxygen only—combined with a little water. One pound of
sulphur produces about three pounds of the strongest sulphuric
acid.
9%

34 SULPHURIC AND PHOSPHORIC ACIDS.

This acid combines with potash, soda, lime, magnesia, and
ammonia, and forms sulphates. These sulphates exist in the soil,
and when dissolved by water are conveyed into the sap of plants,
and supply the sulphur which is necessary for the formation
of their growing parts.

The strong acid is now employed largely for dissolving bones
and the fossil phosphates of lime, from which the artificial ma-
nure known as swper-phosphate of lime is manufactured. Ina
diluted state it has been employed with advantage as a steep
for barley, and even as a manure for turnips.

2°, Puospnoric Acip.—lIf a piece of phosphorus be kindled
in the air, it burns with a brilliant flame, and gives off dense
white fumes. These white fumes are phosphoric acid. They
are produced by the union of the burning phosphorus with the
oxygen of the atmosphere. A 100 Ib. of phosphorus, when
burned, form 2274 lb. of phosphoric acid.

If the experiment be performed under a glass, as in the
annexed figure, the white fumes of acid will condense on the
cool inside of the vessel in the form of a white powder, which
speedily absorbs moisture from the air, and runs to a liquid.
This acid is very sour and corrosive. It combines with potash,
lime, &c., and forms phosphates, and in these states of combina-
tion it = in soils and manures, and enters into plants. The
bones of animals contain a large proportion of this acid, chiefly
in combination with lime and magnesia.

Lucifer matches are tipped with a morsel of phosphorus,
which, when rubbed, takes fire and kindles the sulphur. The
white smoke given off by such a match, when first kindled, con-
sists of phosphoric acid.

CHAPTER ITF.

Structure of the stem, root,and leaves of plants—Functions of the root,
the leaves, and tlie stem.—How plants draw their nourishment from the
soil and the air.—Of the substance of plants, and the structure of the
seed or grain.—Of cellulose, starch, sugar, gum, mucilage, and pectose,
or pectic acid.—Of the oil or fat, wax, resin, and turpentine of plants.—Of
gluten, albumen, and casein.—Germination of seeds and growth of plants.
—Mautual transformations of starch, sugar, and cellulose.—Production of
cellular fibre from the organic food of plants.—Necessity of nitrogen, or
substanees containing it, to the growth of plants.—Forms in which nitro-
gen may enter into plants.

From the compound substances described in the preceding
chapter, plants derive the greater portion of the carbon, hydro-
gen, oxygen, and nitrogen, with the sulphur’and phosphorus of
which their organic part consists. The living plant possesses
the power of absorbing these compound bodies, of decomposing
them in the interior of its several vessels, and of re-compownding
their elements in a different way, so as to produce new sub-
stances,—the ordinary products of vegetable life.

Before describing the nature of these new substances, I shall
briefly consider the general structure of plants, and their mode
of growth. |

SECTION I.—OF THE STRUCTURE OF THE STEM, ROOT, AND LEAVES
OF PLANTS.

A perfect plant consists of three several parts:—a root which
throws out arms and fibres in all directions into the soil; a
trunk which branches into the atmosphere on every side ; and
leaves which, from the ends of the branches and twigs, spread
out a more or less extended surface into the surrounding air.

, ;

36 STRUCTURE OF THE STEM AND ROOT OF PLANTS.

Each of these parts has a peculiar structure, and special func-
tions assigned to it.

1°. The stem of any of our common trees consists of three
parts—the pith in the centre, the wood surrounding the pith,
and the bark which covers the whole. The pith consists of a
collection of minute cells, supposed to communicate horizontally
with the external air through the medullary rays and the outer
bark ; while the wood and inner bark are composed of long
tubes bound together in a vertical position, so as to be capable
of carrying liquids up and down between the roots and the
leaves. When a piece of wood is sawn across, the ends of
these tubes may be distinctly seen. The branch is only a pro-
longation of the stem, and has a similar structure.

2°. The root, immediately on leaving the trunk or stem, has
also a similar structure. But as the root tapers away, the pith
disappears—in some, as in the walnut-and horse-chestnut, grad- .
ually—in others immediately. The.bark also thins out, and the
wood softens, till the white tendrils, of which its extremities are
composed, consist only of a colorless spongy mass, full of pores,
and in which no distinction of parts can be perceived. In this
spongy mass the vessels or tubes which descend through the
stem and root lose themselves, and by these tubes the spongy
extremities in the soil are connected with the leaves in the air.

3°. The leaf is an expansion of the twig. The fibres, which
are seen to branch out from the base through the interior of the
leaf, are prolongations of the vessels of the wood, and are con-
nected with similar prolongations of the inner bark, which usu-
ally lie beneath them. The green exterior portion of the leaf is,
in like manner, a continuation of the outer or cellular tissue of
the bark, in a very thin and porous form. The pores, or mouths,
(stomata) contained in the green part, are an essential feature
in the structure of the leaves, and are very numerous. ‘The
leaf of the common lilac contains as many as 120,000 of them
on a square inch of surface. They are generally most numerous
on the under part of the leaf, but in the case of leaves which
float upon water, they are chiefly confined to the upper part.

FUNCTIONS OF THE ROOT. 37

The annexed woodcut shows the appearance of the oval pores
p on the leaf of the garden balsam.~ Connected with these
pores, the green part of the leaf consists ef or contains a collec-

Fig. 11.

tion of tubes or vessels which stretch along the surface of the
leaf, and communicate, as.we have said, with those of the inner
bark.

SECTION II.—FUNCTIONS OF THE ROOT, THE LEAVES, AND THE
STEM.—COURSE AND MOTION OF THE SAP.

Each of these principal parts of the plant performs its pecu-
liar functions.

1°. Functions of the root—The root sends out fibres in every
direction through the soil in search of water and of lguzd food,
which its spongy extremities suck in, and send forward with the
Sap to the upper parts of the tree. It is to aid the roots in
procuring the food more rapidly that in the art of culture such
substances are mixed with the soil as experience has shown to
be favorable to the growth of the plants we wish to raise.

What chemical changes the food is made to undergo in en-
tering or passing along the roots is not yet understood.

2°. £wnetions of the leaf.—tlt is not so obvious to the common
observer that the leaves spread out their broad surfaces into the
air for the same purpose precisely as that for which the roots
diffuse their fibres through the soil ; the only difference is, that
while the roots suck in chiefly quid, the leaves inhale almost

38 FUNCTIONS OF THE LEAF.

solely gaseous food. In the daytime, whether in the sunshine or
in the shade, the green leaves are continually absorbing car bonie
acid from the air, and giging off oxygen gas. That is to say,
they are continually « appropriating carbon from the air.* When
night comes, this process is reversed, and they begin to absorb oxygen
ond to give off carbonic acd. But the latter process does not
#0 on so rapidly as the former ; so that, on the whole, plants,
when growing, gain a large portion of carbon from the air.
. The actual quantity, however, varies with the season, with the
climate, and with the kind of plant. The proportion of its
carbon, which has been derived from the air, is greatly modified,
also, by the quality of the soil in which the plant grows, and
by the comparative abundance of liquid food which happens to
be within reach of its roots. It has been ascertained, however,
that in our climate, on an average, not less than from one-third
to four-fifths of the entire quantity of carbon contained in the
crops we reap from land of average fertility, is really obtained
from the air. ;

We see then why, in arctic climates, where the sun, once risen,
never sets again during the entire summer, vegetation should
almost rush up from the frozen soil; the green leaf is ever
gaining from the air and never losing, ever taking in and never
giving off carbonic acid, since no darkness ever interrupts or
suspends its labors.

How beautiful, too, does the contrivance of the expanded
leaf appear ! The air contains only one gallon of carbonic acid
in 2500, and this proportion has been adjusted to the health
and comfort of animals to whom this gas is hurtful. But to
catch this minute quantity, the tree hangs out thousands of
square feet of leaf—in perpetual motion, through an ever-moving
air ; and thus, by the conjoined labors of millions of -pores, the
substance of whole forests of solid wood is slowly extracted from
the fleeting winds. JI have already mentioned the number of

* Since carbonic acid, as shown in the previous chapter, (p. 20,) consists

only of carbon and oxygen. Of these the leaves retain the carbon and re-
ject the oxygen.

SUBSTANCE OF PLANTS. 39

pores which have been observed on a square inch of leaf ; and
when I add that ona single oak tree seven millions of leaves
have been counted, the multitude of absorbing mouths in a for-
est—like those of the coralline animals in a reef—will appear
equal to the most gigantic effects.

The green stem of the young shoot, and the green stalks of
the grasses, also abound in pores, and consequently absorb car-
bonic acid, and give off oxygen, as the green leaf does ; and
thus a larger supply of food is afforded when the growth is most
rapid, or when the short life of the annual plant demands much
nourishment within a limited time. The yellow and red leaves
and parts of plants give off no oxygen, (Senebier.) .

3°. Functions of the stem —F¥rom the spongy part of the root
the sap ascends through the vessels of the woody stem till it is
diffused over the interior of the leaf by the woody fibres which
the leaf contains. During this passage the substances which the.
sap contains undergo certain chemical changes, which are as yet
not well understood. From the woody fibre, of the leaf—along
the vessels which lie beneath these fibres, and are covered by
the green part of the leaf—and after it has absorbed or given
off the gases which the pores transmit, thé sap is returned
towards the outer part of the stem, and through the vessels of
the inner bark descends again to the root.

4°, Course and motion of the sap.—lIn the living plant, at least
till it has passed maturity, most of the vessels are full of sap,
and this sap is in continual motion upwards within the stem, and
downwards along its surface within the inner bark. In spring
and autumn the motion is more rapid. In winter it is some-
times scarcely perceptible ; yet the sap, except when frozen, is
supposed to be rarely quite stationary in any part of the tree.

SECTION IlI.—OF THE SUBSTANCES OF WHICH PLANTS CHIEFLY
CONSIST, AND OF THE STRUCTURE OF THEIR SEEDS.

t

In the way above described, the perfect plant derives from the

40 SUBSTANCE OF PLANTS.

soil and from the air the food by which it is sustained and ena-
bled to grow. In the substance or stem of plants thus formed,
and in their seeds, various chemical compounds exist, but they
may all be included in three main groups or classes.

When the grain of wheat, barley, oats, rye, Indian corn, &c.,
is sent to the mill to be ground, two products are obtained—the
bran or husk, and the flour. When washed free from flour, the
bran or husk is tasteless, insoluble in water, and woody. It is
the same thing, indeed, for the most part, as the cellular and
fibrous part of wood or straw.

Again, when a portion of the flour is made into dough, and

this dough is kneaded with the hand under a stream of water
upon a piece of muslin, or on a fine sieve, as long as the water
passes through milky—there will remain on the sieve a glutinous
sticky substance resembling bird-lime, while the milky water will
gradually deposit a pure white powder. This white powder is
starch, the adhesive substance which remains on the sieve is glu-
ten. Both of these substances exist, therefore, in the flour ; they
both also exist in the grain.

Further, when bruised wheat, oats, Indian corn, linseed, or
even chopped hay and straw, are boiled in alcohol or ether, a
portion of oil or fat, of wax and of resin, is extracted, and is ob-

THE STARCH GROUP. 41

tained separately by allowing the solution to evaporate to dry-
ness in the air.

Thus, from the seed or grain we have obtained four different
substances—the woody part which covers it, starch, gluten, and
fat. The annexed woodcut shows the position and relative
quantities of the last three substances in the seeds of wheat, bar-

Pig, 13.
Indian corn. Wheat. Barley.

ley, and Indian corn. Thus, a shows the position of the oil in
the outer part of the seed. It exists in minute drops, enclosed
in six-sided cells, which consist chiefly of gluten. 06 the posi-
tion and comparative quantity of the starch, which in the heart
of the seed is mixed with only a small proportion of gluten. ¢
the germ or chit which contains much gluten.

These substances represent the three great classes of organic
bodies of which the bulk of all plants is made up.

The woody matter and the starch represent what is called the
starch group. ‘The gluten represents the gluten or albumen
group. ‘The oil or resin represents the fatty group.

I shall briefly describe these several groups or classes of sub-
stances. :

SECTION IV.—OF THE STARCH GROUP—-WOODY FIBRE, STARCH, GUM,

MUCILAGE, SUGAR, AND PECTOSE, OR PECTIC ACID.
~ :

The starch group comprehends a great number of different
substances, possessing different properties, but all characterised
by this similarity in composition, that they consist of carbon and
water only.

42 CELLULOSE, STARCHES, GUMS AND MUCILAGES.

The following are the principal substances belonging to this
class :—

1°. Cellulose or woody fibre—This forms the walls of the cells
of plants, the fibres of cotton and linen, the woody part of the
husk or covering of the seed, and a es portion of the sub-
stance of wood, hay, straw, ee Jt is insoluble in water, both
in the fresh aaa dry states, but; as it exists in fodder, appears,
after due mastication, to be in some degree soluble in the stom-
achs of animals. It consists of 36 parts by weight of carbon,
and 45 of water.

2°. The starches—There are several varieties of starch besides
that which occurs in the flour of wheat, oats, barley, the pota-
to, &c. These are all insoluble in cold water, but give a jelly
with boiling water. The Iceland moss, and some other lichens,
contain a starch which gives a jelly with boiling water, but
which is somewhat different from that of common starch ; while
the-roots of the dahlia and the dandelion give a starch which
dissolves in boiling water, but does not form a jelly, and falls
again in a powdery state as the solution cools.

Common starch, and that of the dandelion and the lichen,
consist, like woody fibre, of 86 parts of carbon by weight, and
45 of water; that of the dahlia contains a very little more
water.

3°. The gwms.—When common starch is heated in an oven
to 300° F., or when it is mixed with water containing a little
sulphuric acid and gently heated, it is changed into a soluble
gummy adhesive substance, to which the name of dextrin is
given. In this soluble state, starch is supposed to exist abun-
dantly in the sap of plants. The name arabine is given to
gum arabic, which is soluble in cold water, and ceracine to
cherry tree gum, which is insoluble in cold, but dissolves readily
in boiling water. All these three varieties of gum consist, like _
common starch and woody fibre, of 36 parts by weight of car-
bon, united to 45 parts of water.

4°, The mucilages—The name of mucilage is given to gum

CANE AND GRAPE SUGARS. 43

tragacanth, which does not dissolve, but swells out into a jelly
when placed in water—to the adhesive matter which water ex-
tracts from linseed and other oily seeds, and to the jelly which
is obtained from the roots of the orchis, (Salop,) the mallow,
&e. It consists of 48 parts by weight of carbon, and 57 of
water. ,

5°. The sugars.—In the sap of plants several kinds of sugar
occur; but those called cane and grape sugars are the most
aor

Cane sugar exists in the sugar cane, the maple, the beet, the
stalks of corn, and in many other plants. In the ordinary states
of loaf sugar, crystallised sugar, sugar-candy, &c., it consists of
48 parts of carbon by weight, and 66 of water.

Grape sugar exists naturally in the grape, in fruits in general,
and in honey. It is formed artificially when cellulose or starch
is boiled for a length of time in water made slightly sour by
means of sulphuric acid, (oil of vitriol.) It is less sweet than
cane sugar, and in its eerie state consists of 48 of carbon
by weight, and 84 of water.

The following table exhibits the relative composition of these
several substances in a hundred parts, as nearly as it can be
expressed in whole numbers :—

Carbon. Water.

Cellulose or ra Gites ji. : 44. 56
Starch, : : ; é 44. 56
Gum, . ; ; 7 : j 44. 56
Mucilage, . : d 3 46 . got
Sugar of the cane, : ‘ ; 42 58
Sugar of the grape, . : ear 36 64

In stating that these substances consist of carbon and water
only, I have adopted, for the sake of clearness and simplicity, a
mode of expression which has: not yet been shown to be quite
correct. It is not certain that these substances contain water
in the proportions above stated, but they contain hydrogen and
oxygen in the proportions (1 to 8) in which they form water.
For simplicity, therefore, we may suppose these two elementary

44 FATTY SUBSTANCES OF PLANTS.

bodies actually to exist in the vegetable substances above de-
scribed in the form of water.

6°. Pectose and pectic acid——The reader will not fail to be
struck with the remarkable circumstance, that substances so
different as woody fibre, starch, and gum, should yet consist of
the same elements—charcoal and water united together in the
same proportions. In some vegetable substances, however,
which otherwise resemble starch and gum, and may be classed
along with them, the hydrogen and oxygen do not exist exactly
in this proportion. In fleshy fruits, such as the plum, peach,
apricot, apple, pear, &c., and in the bulbs or roots of the turnip,
the carrot, the parsnip, &c., there exists no starch, but in its
stead a substance to which the name of pectose and sometimes
of pectic acid is given. This substance is nearly as nutricious as
starch, and serves the same purposes when eaten. It contains,
however, less hydrogen and more oxygen than starch does, and
changes also more readily into other substances both in the
plant and in the stomach.

SECTION V.—OF THE FATTY SUBSTANCES OF PLANTS.

The fatty substances which occur in plants are of three kinds
—the true fats and oils, the waxes, and the turpentines and
resins. ‘They all agree in containing less oxygen than would be
required to convert their hydrogen into water—less than 8 to 1
by weight.

1°. The true fats which have as yet been found in plants are
divided into two classes—the solid and the liquid fats. «

a. Solid fats—When almond, olive, or linseed oil is exposed
to a very low temperature, a portion of it freezes or becomes
solid. This portion may be separated, and by pressure may be,
in great measure, freed from the liquid portion.

The solid part thus obtained from most vegetable oils is called
margarine, and is identical with the solid part of butter, and of
the fat of man, of the horse, and of some other animals. Some

SUBSTANCES CONTAINING NITROGEN. 45

plants yield a solid fat called stearine, which is the same thing
as the solid fat of the cow, the sheep, the pig, the goat, and
many other animals.

b. To the Liquid fats the name of elaine is given. That
obtained from the oils of almonds, olives, &c., which are called
fat oils, is somewhat different from that of which linseed, wal-
nut, and other drying oils chiefly consist. The liquid oil ex-
pressed from the fat of animals consists chiefly of the former
variety of elaine.

2°, The waxes—Many plants produce wax. It coats the
flowers and leaves of many trees and shrubs, and forms the
beautiful bloom which covers the grape and other fruits. From
these the bees collect it; and though the different varie-
ties of wax differ somewhat in properties, they all agree with
bees-wax in being insoluble in water, partially soluble in alcohol,
nearly without taste and very combustible.

3°. The turpentines and resins abound in trees of the pine
tribe. They are all insoluble in water, but readily soluble in
alcohol; are more combustible than either true fat or wax, and
amen less oxygen than either.

Nothing resembling either wax or resin is found in the bodies
of animals.

SECTION VI.—OF VEGETABLE SUBSTANCES CONTAINING NITROGEN—
THE GLUTEN OR ALBUMEN GROUP.

In washing the dough of wheaten flour, we have seen (p.
40) that a portion remains on the sieve or muslin, to which the
name of gluten is given. This substance contains nitrogen in
addition to the carbon, hydrogen, and oxygen which are present
in the bodies described in the preceding sections, and is the re-
presentative of an entire class of important substances into
which nitrogen enters as a constituent. I shall briefly mention
the most important of these substances.

1°. Gluten.—This is obtained from the dough of wheaten

46 ALBUMEN AND CASEIN.

flour, in the way already described. It is insoluble in water,
partly soluble in alcohol, which extracts from it a fatty oil, and
entirely and easily soluble in vinegar, (acetic acid,) or in solu-
tions of caustic potash or soda. Besides the fatty oil which it
contains, the crude gluten, as it is washed from wheaten

flour, consists of at least two substances,—one soluble in alco-—

hol, (gluéin,) the other insoluble in this liquid, (giuten,) and
which appears closely to resemble coagulated albumen. When
moist, gluten is nearly colorless, and is tenacious and adhesive
like bird-lime : ; but when perfectly dry, it is hard, brittle, and
of a grey or brownish color.

2°, Albwmen.—The white part of eggs is called albumen by

chemists. In the natural state it is a glairy thick liquid, which

can be diffused through or dissolved in water, but which coagu-
lates, or becomes solid and opaque, when heated to about 180°
of Fahrenheit, or nearly to the temperature of boiling water.
In this coagulated state it is insoluble in water, or in alcohol,
but dissolves in vinegar, or in solutions of caustic potash or soda.
When dried it becomes hard, brittle, semi-transparent, and of
a brownish color.

When the expressed juice or sap of plants is “heated, a solid
substance coagulates, and separates from it in opaque white
flocks. This substance possesses nearly all the properties of the
albumen of the egg, and is therefore called vegetable albumen.

Albumen exists in plants not only in the liquid state, as in
the sap of plants, but also in the it eke state. In the
husks and envelopes an of corn for exam-
ple—and in the solid par - of woody 404 herbaceous plants, it
is found in this state in greater or less proportion.

3°. Caseen—When rennet, vinegar, or diluted muriatie
acid is added to milk, it coagulates or cyrdles, and a white curd
separates from the whey. Alcohol or ether extracts the fat or
butter from the eoagulated mass, and leaves pure curd behind.
To this curd chemists give the name of casein. -

When cold water is shaken up with oatmeal for half an hour,

Se ee

GERMINATION OF SEEDS. 47

and is then allowed to subside, the clear liquid becomes troubled
on the addition of a little acid, and a white powder falls, pos-
sessing nearly all the properties of the casein of milk.

The sap of nearly all plants—the expressed juice of the po-
tato, the turnip, and other roots, after being heated to coagu-
late the albumen—and the solution obtained when the meal of
the bean, the pea, and other. legumes, is treated with warm
water—yield, on the addition of an acid, precipitates of this
substance differing but little from one another.

Vegetable casein, therefore, is a constant constituent of our
best known and cultivated plants. To the variety obtained
from the oat the name of avenin has been given, and to that
yielded by the bean, the pea, and the vetch, the name of legumin.

All these substances are combinations of a body called protein,
and are therefore frequently spoken of under the general desig-
nation of proten compounds.* 'They occur mixed in variable
proportions in the different kinds of grain and roots which are
used for food. In addition to carbon, oxygen, and hydrogen,
they all contain, when quite dry, about 16 per cent of nitrogen,
with 1 or 2 per cent of sulphur, and most of them also a small
per-centage of phosphorus.

SECTION VII.—OF THE GERMINATION OF SEEDS AND THE GROWTH
OF PLANTS.

When a seed is committed to the earth, if the warmth and
moisture are favorable, it begins to sprout. It pushes a
shoot upwards, it thrusts a root downwards, but, until the leaf
expands and the root has fairly entered the soil, the young plant
derives no nourishment other than water, either from the earth
or from the air. It lives on the starch and gluten contained in
the seed. But these substances, though capable of being sepa-
rated from each other by means of water, as described in a

* For an account of protein and its compounds, see my Lectures on Agri-
culiural Chemistry, 2a edition, p. 5.

4§ CHANGE OF STARCH INTO SUGAR.

previous section, (p. 40,) are neither of them soluble in water.
Hence they cannot, without undergoing a previous chemical
change, be taken up into the sap and conveyed along the ves-
sels of the young shoot they are destined to feed. But it is so
‘arranged in nature that, when the seed first sprouts, there is
produced at the base of the germ, from a portion of the gluten,
a small quautity of a white soluble substance called dzastase.
This substance exercises so powerful an effect upon the starch
as almost immediately to render it soluble in the sap, which is
thus enabled to take it up and convey it by degrees, just as it is
wanted, to the shoot or to the root.* The starch, when thus
changed and rendered soluble, becomes the substance called
dextrin, which we have already described, (p. 42.)
In the oily seeds which contain no starch, the mucilage and
the oil take the place of starch in nourishing the young sprout.
As the sap ascends it becomes sweet—the dextrin formed
from the starch is further changed into sugar. When the shoot
first becomes tipped with green, this sugar again is changed
into cellulose or woody fibre, of which the APs of perfect
plants chiefly consists. By the time that the food contained in
the seed is exhausted—often long before—the plant is able to
live by its own exertions, at the expense of the air and the soil.
This change of the sugar of the sap into cellular or woody
fibre is observable more or less in all plants. When they are
shooting fastest the sugar is most abundant—not, however, in
those parts which are actually shooting up, but in those which
convey the sap to the growing parts. Thus the sugar of the

* In malting barley, it is made to sprout a certain length, and the growth
is then arrested by heating and drying it. Mashed barley, before sprout-
ing, will not dissolve in water; but when sprouted, the whole of the starch
(the flour) it contains dissolves readily by a gentle heat, and is changed into
soluble dextrin. The diastase formed during the germination effects this.
By further heating in the brewer’s wort, this dextrin is converted into sugar
by the agency of the same diastase, as it is also in the growing plant. We
can thus imitate by art; and, in brewing, we do imitate what takes place
uaturally in the living vegetable.

FORMATION GF CELLULAR FIBRE. 49

ascending sap of the maple and the alder disappears in the leaf
and in the extremities of the twig. Thus the sugar-cane sweet-
ens only a certain distance above the ground, up to where the
new growth is proceeding ; and thus also the young beet and
turnip abound most in sugar—while in all these plants the
sweet principle diminishes as the year’s growth draws nearer to
a close.

In the ripening of the ear, also, the sweet taste at first so
perceptible in young grain gradually diminishes, and finally dis-
appears. The sugar of the sap is here changed into the starch
of the grain, which, as above described, is afterwards destined,
when the grain begins to sprout, to be reconverted into sugar
for the nourishment of the rising germ.

Tn the ripening of fruits a different series of changes presents
itself. The fruit is at first tasteless, then becomes sour, and at
last sweet. In this case, either the acid of the unripe is changed
into the sugar of the ripened fruit, or a portion of the other
constituents of the fruit—its cellulose and pectose—are con-
verted into sugar, and disguise the acid.

SECTION VIII.—HOW THE CELLULAR OR WOODY MATTER OF
PLANTS IS FORMED FROM THEIR ORGANIC FOOD.

The substance of plants—their solid parts, that is—consists
chiefly, as we have already stated, of cellular fibre, the name
given to the fibrous substance of which wood evidently consists.
It is interesting to inquire how this substance can be formed
from the compounds—water and carbonic, humic, ulmic, and
other acids—of which the organic food of plants in a great
measure consists. Nor is it difficult to find an answer.

1°. It will be recollected that the leaf drinks in carbonic
acid from the air, and delivers back its oxygen, retaining only
its carbon, (p. 38.) It is also known that water abounds in
the sap. Hence carbon and water are abundantly present in
the pores or vessels of the green and living leaf. Now, as cel-

3 :

50 FORMATION OF CELLULAR FIBRE.

lulose or woody fibre consists only of carbon and water chemically
combined together, it is easy to see how, when the carhon and
water meet in the leaf, cellular fibre may be produced by their
mutual combination.

2°. If, again, we inguire how this important constituent of
plants may be formed from the other substances, which enter
by their roots—from the humic acid (p. 21) for example—the
answer is equally ready. This acid also consists of carbon and
water only—50 Ib. of carbon with 373 of water forming 873 of
humic acid—so that, when it is conveyed by the roots into the
sap of the plant, all the materials are present from which the
eellular fibre may be produced.

3°. Nor is it more difficult to understand how the starch of
the seed may be converted into sugar, and this again into cel-
lular fibre ; or how, conversely, sugar may be changed into
starch in the ear of corn, or cellular fibre into sugar during the
ripening of the winter pear after its removal from the tree.
Any one of these substances may be represented by carbon and
water only. In the interior of the plant, therefore, it is obvious
that if any one of them is present in the sap, the elements are
at hand out of which any of the others may be produced. In
what way they really are produced, the one from the other,
and by what circumstances these transformations are favored,
-it would lead into too great detail to attempt here to explain.*

We cannot help admiring the varied purposes to which in
nature the same elements are applied,—and from how small a
number of materials, substances the most varied in their pro-
perties are in the living vegetable daily produced.

* For fuller and more precise explanations on these interesting topics,
see the Author’s Lectures on Agricultural Chemistry and Geology, 2d edition,
Part I.

NECESSITY OF NITROGEN TO THE GROWTH OF PLANTS. 51

SECTION IX.—OF THE NECESSITY OF NITROGEN, OR OF SUBSTANCES
CONTAINING IT, TO THE GROWTH OF THE PLANT, AND OF THE
FORMS IN WHICH IT MAY ENTER THE ROOTS.

But a substance containing nitrogen is necessary to the pro-
duction of those beautiful and varied changes which take place
in the sap of the plant at the different stages of its growth.

We have seen that, during germination, the insoluble gluten
of the seed is partly changed into a soluble substance—diastase
—by which the first alteration of the insoluble starch into solu-
ble dextrin is effected. The remainder of the gluten ascends
or descends by degrees with the sap, in some soluble form which
is not yet clearly understood, and, if not actually the cause of
the successive changes which the starch, sugar, and gum of
the sap undergo, it is at least always present when they are
produced.

At every point in the growingshoot and root some compound
of nitrogen must be present, if it is to increase in size,—since
in the interior of every new cell the presence of such a com-
pound in minute quantity can be distinctly recognised. In the
young radicles of the sprouting barley there are 82 per cent. of
a substance containing nitrogen, while the grain itself contains
only-14. This substance seems to preside over the change of
the soluble substances contained in the sap, into the insoluble
fibre of the cell. The change of the sugar and gum of the
sap into the starch of the ear always takes place also in the
presence of a substance containing nitrogen. In the young
seed it is present in much larger proportion than when the seed
is matured. In the pea, when beginning to form in the shell, it
constitutes 48 per cent. of the whole weight, (Payen,) while in
the ripe pea it does not exceed one-half the quantity. ‘

When the starch or sugar undergoes a change, the nitrogen-
ous compound undergoes a simultaneous change ; and as the
transformation of the starch of the seed into the sugar of the

52 FORMS IN WHICH NITROGEN ENTERS INTO PLANTS.

sap is attended by the change of its gluten into diastase and
other soluble compounds, so the converse change of the sugar
of the sap into the starch of the ear is attended by a converse
production of the insoluble gluten of the ripening grain.

It has also been ascertained that the leaves of growing plants
are in the sunshine always giving off nitrogen, in quantity which
varies with the kind, and probably the age, of the plant, and
with the time during which it has been exposed to the sun’s
rays. This nitrogen appears to be derived from gluten and
other nitrogenous (protein) compounds, which are continually
undergoing changes in the sap, and which are*necessary to the |
ordinary processes of vegetable growth.

The necessity of nitrogen to. the growth of the plant in all
its stages is thus fully established ; and hence the utility, estab-
lished by long practical experience, of applying manures in
which nitrogen is contained.

It has not yet been proved in what form of combination
nitrogen is most fitted to promote the growth of our cultivated
crops. It usually finds its way into the roots of plants in the
form of nitric acid, of amnionia, of other organic alkalies con-
taining nitrogen, (p. 30,) or of the compounds of these alkalies
with the humic and ulmic acids, which are so extensively pro-
duced in the soil itself. Animal manures may owe part of their
peculiar beneficial action to their supplying other compounds of
nitrogen—protein compounds, perhaps, in a soluble form—which
the plant, with still less trouble to itself, can convert into por-
tions of its own substance.

The plant grows rapidly by the aid of the ready-formed
gluten of the seed,—why should it not thrive well also by the
aid of similar compounds placed within its reach in the soil and
absorbed by its roots? There seems, indeed, very little solid
foundation for the opinion held by some, that the plants zm owr
cultivated fields derive the whole of their nitrogen from ammonia
‘and nitric acid together—still less that they obtain it from
ammonia alone.

FORMS IN WHICH NITROGEN MAY ENTER ROOTS. 53

The plant that grows on the surface of common vinegar, and
makes it thick and glairy, is formed from the vinegar* itself,
and from a nitrogenous substance resembling gluten, which the
liquid vinegar holds in solution. So the mould which grows on
flour paste is formed from the starch and the gluten of the flour,
and the minute plant which forms the yeast in the brewer’s vat
is produced from the sugar of the wort and the changed gluten
of the barley.’

In all these cases the substance of the plant is formed by the
direct appropriation of compounds, which bear a close analogy
to those of which its own parts consist ; and though the mould
plants above mentioned are very different in kind from those we
raise for food, yet the mode in which they are built up is very
similar to that by which the solid parts of larger plants are
really produced from the substances contained in the sap. If,
then, those substances from which their growing parts are thus
known to be built up can be conveyed directly into the circula-
tion of our cultivated plants by their roots, it is reasonable to
suppose that their growth may be promoted by them at least as
well as if the roots took up only carbonic acid to supply the car-
bon, and ammonia to supply the nitrogen.

In other words, the probabilities are, I think, in favor of the
view that animal or vegetable substances containing nitrogen,
when brought into a soluble state by fermentation, may enter
directly into the roots, and feed our crops, without being first
decomposed either into ammonia or into nitric acid. The subject
is deserving, therefore, of being made matter of direct experi-
ment in the field or garden.

* Pure vinegar, like starch and cellular fibre, consists of carbon and
water alone, 50 of carbon and 56 of water forming 106 of vinegar.

CHAPTER IV.

Of the inorganic constituents of plants.—Potash, soda, lime, magnesia, silica,
alumina, oxide of iron, oxide of manganese, sulphur, sulphuric acid, phos-
phorus, phosphoric acid, chlorine, iodine, fluorine —Immediate source of
these constituents of plants.—The quantity contained in plants, and in
parts of plants, varies with many circumstances.—The composition or
quality of the inorganic constituents in plants.—It varies also with many
circumstances.—Average quantity of each constituent in certain common
crops, and in a series of crops.—Practical deductions from a knowledge
of the inorganic constituents of plants.

SECTION I.—SOURCE OF THE EARTHY MATTER OF PLANTS, AND
; SUBSTANCES OF WHICH IT CONSISTS.

Wuen plants are burned, they always leave more or less of
ash behind. This ash varies in quantity in different plants, in
different parts of the same plant, in different specimens even of
the same kind, and of the same part of a plant, especially if
grown upon different soils ; yet it is never wholly absent.* It
is as necessary to their existence in a state of perfect health, as
any of the elements which constitute the organie or combustible
part of their substance. They must obtain it, therefore, along
with the food on which they live. It is, in fact, a part of their
natural food, since without it they become unhealthy. We shall
speak of it, therefore, as the znorganic food of plants.

We have seen that all the elements which are necessary to
the production of the cellular fibre, and of the other organic —
parts of the plant, may be derived either from the air, from the
carbonic acid and watery vapor taken in by the leaves, or from

* The only known exceptions occur in the mould plants—as in the myco-
derma vini, which grows on puro vinegar, that which grows on soos es of
milk sugar, &c. By these no trace of ash is left.

INORGANIC OR EARTHY MATTER OF PLANTS. 55

the soil through the medium of the roots. In the air, however,
only rare particles of inorganic or earthy matter are known to
float, and these are in a solid form, and therefore unable to en-
ter the minute pores of the leaves. Hence the earthy matter
which constitutes the ash of plants must all be derived from the
soil. |

The earthy part of the soil, therefore, serves a double use. It
is not, as some have supposed; a mere substratum, in which the
plant may so fix and root itself as to be able to maintain its up-
right position against the force of winds and tempests ; but it is
a storehouse of food also, from which the roots of the plant may
select such earthy substances as are necessary to, or are fitted
to promote, its growth.

The ashi of plants consists of a mixture of several, sometimes
of as many as fourteen, different substances. These substances
are the following :—

1. Potash.—The common pearl-ash of the shops is a com-
pound of potash with carbonic acid, or it is a carbouate of potash.
By dissolving the pearl-ash in water, and boiling it with quick-
lime, the carbonic acid is separated, and potash alone, or caus-
tie potash, as it is often called, is obtained.

9. Seda.—The common soda of the shops is a carbonate of
soda. By boiling it with quick-lime, the earbonic acid is sepa-
rated, as in the case of pearl-ash, and pure or caustic soda re-
mains. The proportions to be used are 1 lb. of the carbonate
to a 4 lb. of lime and 10 Ib. of water.

3. Lime —This is familiar to every one as the lume-shells, or
unslaked lime of the lime-kilns. The unburned lime-stone is a
carbonate of lime, the carbonic acid in this case being separated
from the lime by the roasting in the kiln.

4, Magnesia.—This is the calcined magnesia of the shops.
The uncaleined is a carbonate of magnesia, from which heat
drives off the carbonic acid.

5. Silica.—This is the name given by chemists to the sub-
stance of flint, of quartz, of rock crystal, and of siliceous sands

56 OXIDES OF IRON, MANGANESE, &c.

and sandstones. It is particularly abundant in the straws and
grasses, and in the glaze of the bamboo and other canes.

6. Alwmina is the pure earth of alum, obtained by dissolving
alum in water, and adding liquid ammonia (hartshorn) to the
solution. It forms about two-fifths of the weight of porcelain
and pipe-clays, and of some other very stiff kinds of clay. It
exists abundantly in most soils, but as an essential constituent
of plants it has hitherto been met with only in the ash of the
club mosses.

T. Oxide of vron.—The most familiar form of this substance is
the rust that forms on metallic iron in damp places. It is a
compound of iron with oxygen, hence the name ozde.

There are, however, two oxides of iron. The red, which gives
its color to rust and to our red soils, This oxide is insoluble in
water, and has the property of absorbing ammonia to a certain
extent.

The black oxide gives their color to many blue clays. It is so-
luble in weak acids, is produced from the red oxide by the ac-
tion of organic matter in the soil, and is believed, when so pro-
duced, to be very noxious to the roots of plants.

8. Oxide of manganese is a dark brown powder, which con-
sists of oxygen in-combination with a metal resembling iron, to
which the name of manganese is given. It usually exists in
plants and soils in very small quantity only.

9. Sulphur.—This substance is well known. It is present in
nearly all the parts of plants and animals. It exists largely in
mustard seed, is a necessary constituent of the gluten of wheat,
of the white of the egg, of the fibre of beef, and of the curd of
milk, and forms one-twentieth part of the weight of hair and
wool. When sown along with turnip seed, it is said to prevent
the attack of the fly. .

Sulphuric Acid, or oil of vitriol, has been already described.
It forms, with potash, sulphate of potash ; with soda, sulphate of
soda, or Glauber’s salts ; with ammonia, sulphate of ammonia ;
with lime, sulphate of lime, or gypsum ; with magnesia, sulphate

PHOSPHORUS AND CHLORINE. 5T

of magnesia, or Epsom salts ; with alumina, sulphate of alumina,
which exists in alum ; and with oxide of iron, sulphate of «ron,
or green vitriol. When the sulphate of potash is combined with
sulphate of alumina, it forms common alum.

10. Phosphorus and phosphoric acid have been already de-
scribed, (pp. 9 and 33.)

Phosphoric acid forms phosphates with potash, soda, ammonia,
lime, and magnesia. When bones are burned, a large quantity
of a white earth remains, (bone earth,) which is chiefly a phos-
phate of lime, consisting of lime and phosphoric acid, in the
proportion of 484 of phosphoric acid to 514 of lime. Phosphate
of lime is present in the ash of plants generally. Phosphate of
magnesia is contained most abundantly in the ash of wheat,
barley, and other varieties of grain. It exists also in beer, to
the amount sometimes of 100 grains in a gallon.

11. Chlorine.—This is a very suffocating gas, of a pale, yellow-

ish green color, which gives its peculiar smell to chloride of

lime, and is used for bleaching and disinfecting purposes. It is

readily obtained by pouring muriatic acid (spirit of salt) upon

the black oxide of manganese of the shops, contained in a flask,

and applying a gentle heat, as in the annexed figure. If the

flask be of colorless glass, the color of the gas will immedi-
3k

58 IODINE AND BROMINE.

*

ately become perceptible, and its smell will diffuse itself through
the room. This gas is 2} times heavier than common air, and
a burning taper plunged into it is speedily extinguished. In
combination with the metallic bases of potash, soda, lime, and
magnesia, it forms the chlorides of potassium, sodium, ) common
salt), calcium, and magnesium ;* and in one or other of these
states it generally enters into the roots of plants, and exists in
their ash.

Lodine is a solid substance of a grey color and metallic lus-
tre, very much resembling filings of lead. It has a peculiar
odor, not unlike that of chlorine, an acrid taste, and stains the
fingers of a brown color. It is distinguished by two proper-
ties—by heing changed into a beautiful violet vapor when
heated, and by giving with starch a beautiful blue compound.
It occurs in small quantities in sea water, and in marine and
many fresh-water plants. In still smaller proportion, it has
been recently detected in wood ashes and in those of land plants,
and it probably forms a constant though very minute constitu-
ent of all the plants we raise for food.

Like their chlorine, they will obtain it generally from the
soil through their roots, though, as it has been detected in the
atmosphere, they may derive some of this element from the rain
water that falls on their leaves.

Bromine is a dark brownish red heavy liquid, possessed_.of a
strong odor, giving a yellowish red vapor, and coloring
starch yellow. It also exists in sea water, in certain salt
springs, and has been detected in the ashes of certain plants.
It probably accompanies chlorine and iodine into all plants,
tnough the proportion, which is still less than that of iodine,
has hitherto prevented its presence from being detected.

* Potash, soda, lime, and magnesia, are compounds of the metals here
named with oxygen. It isa very striking fact, that the suffocating gas
chlorine, when combined with sodium, a metal which takes fire when
placed upon hot water, should form the agreeable and necessary condiment
common, salt.

VARIATION IN THE QUANTITY OF ASH IN PLANTS. 59

As chlorine forms chlorides, so iodine forms iodides, and bromene
forms bromides with the metals already mentioned. The chlo-
rine is the only one of these three, the presence of which in
plants is at present believed to be of any importance in a prac-
tical point of view.

Fluorine is a very corrosive gas, of which little is yet known.
It exists in small quantity in the teeth and bones, and in the
blood and milk; of animals. Traces of it also have been detect-
ed in the ashes of some plants; so that it is probably necessary
to the growth of both animals and vegetables. With metals,
it forms flworides,; and fluoride of calcium, or fluor spar, is the
best known and most common of its combinations.

Such are the inorganic substances usually found mixed or
combined together in the ash of plants. It has already been
observed, that the quantity of ash left by a given weight of
vegetable matter varies with a great many conditions. This
fact deserves a more attentive consideration.

SECTION II.—OF THE DIFFERENCES IN THE QUANTITY OF ASH
LEFT BY PLANTS, AND BY THEIR SEVERAL PARTS.

1. The quantity of ash yielded by dzfferent plants is unlike.
Thus 1000 lb. of the following vegetable substances, in their
ordinary state of dryness, leave of ash, on an average,

Wheat, about 20 lb. Wheat straw, 50 lb.
Barley, . »-.y, 30 - Barley straw, 50
Oats, - 40 Oat straw, 60
Rye, =e kZOE: Rye straw, 40
Indian corn, 15 Indian corn do.50
Beans, - 30 Pea straw, 50
Peas, aif OO

Meadow hay, - - 50 to 100 lb.

Cloverhay, - - 90

Rye-grass hay, - 95

Potatoes, ah hs 8 to 15

Turnips, - 5to 8

Carrots, oa Ee vo 20T

* See Lectures on Agricultural Chemistry and Geology.

60 VARIATION IN THE QUANTITY OF INORGANIC MATTER, &c.,

So that the quantity of inorganic food required by different
vegetables is greater or less according to their nature ; and if
a soil be of such a kind that it can yield only a small quantity
of this inorganic food, then those plants only will grow well
upon it to which this small supply will prove sufficient. Hence
trees may grow where arable crops fail to thrive, because many
of the former require and contain comparatively little inorganic
matter. Thus the weight of ash left by 1000 lb. of

Elm wood is 19 Ib. Birch wood is 34 Ib.
Poplar? =.-20 Pine, - Igto3
Willow, - 44 Oak, - 2
Beeah, Os 2-7 1s to 6 Ash, - lto6

The elm and the poplar contain about as much inorganic
matter as the grain of wheat, but very much less than any of
the straws or grasses. How much less also does the oak con-
tain than either the elm or the poplar !

2. The quantity of inorganic matter varies in defferent parts
of the same plant. 'This is shown clearly by the different pro-
portions of ash left by the grain and by the straw of our culti-
vated crops, as given in the preceding table. It appears, also,
by the following comparison of the quantities left by 1000 lb. of

the different parts of some of our cultivated plants in their dry
state. Thus—

Roots or tuber. Grain or seed. Straw or stalks. Leaves.

Turnip, . 80 lb. 25 Ib. — lb. 130 lb.
Potato: Wiel (aOR — — ¥F80 *
Wheat, . — 20 ‘ 50." ooo

Pea, . — 1 is Pie uns, | 130,
Tobacco, . a Ag tt 100 * 930 &

In trees, also, the leaves ‘contain a much larger proportion of
inorganic matter than the wood. Thus, 1000 Ib. of the dry
wood and leaves of the following trees left of ash respectively—

Wood. Leaves. Seed.
Willow, : . 43 Ib. 82 Ib. —
Beech, . ‘ Le. aod 4a2,.é —
Siren, *-. ; oe 50 “ —
Paes : ‘aay 20 to 30 50 Ib.

Elm, 45h) gaieoee® 120 Sy) Be

IT VARIES ALSO WITH THE SOIL. 61

It appears, therefore, that by far the largest proportion of
the inorganic matter which is withdrawn from the soil by a crop
of corn is returned to it again, by the skilful husbandman, in
the fermented straw. In the same way also nature, in causing
the trees periodically to shed their leaves, returns with them to
the soil a very large portion of the soluble inorganic substances
which had been drawn from it by their roots during the season
of growth.

Thus an annual top-dressing is naturally given to the land
where forests grow; and that which the roots from spring to
autumn are continually sucking up, and carefully collecting from
considerable depths, winter strews again on the surface in the
form of decaying leaves, so as, in the lapse of time, to form a
rica and fertile soil. Such a soil must be propitious to vegeta-
bie growth, since it contains or is made up of those very mate-
rials of which the inorganic substance of former races of vege-
tables had been almost entirely composed.

8. It varies in quantity en different portions of the same part
of the plant. Thus, if a tall stalk of wheat, oats, or barley
straw be cut into four equal parts, and these be burned sepa-
rately, the lowest portion will generally leave the smallest, the
highest portion the greatest per centage of ash. If the bottom
of the stalk, for example, leave 34 or 4 per cent., the next por-
tion will leave 5 or 6, the third 6 or 7, and the highest perhaps
8 or 9. This is a very interesting and curious fact, not hitherto
noticed by experimenters, though evidently of great interest in
connection with the inorganic food of plants.

In some cases this difference is not observed, while in others
the largest proportion of ash is left by the bottom part of the
straw. These exceptions, however, occur generally in stunted
grain, which has grown upon an unfavorable soil, or has been
injured by the season.

4. The quantity of inorganic matter often differs in different
specimens and varieties of the same plant. Thus 1000 lb. of wheat
straw, grown at different places, gave to four different experi-

62 DIFFERS WITH VARIETY AND SOIL.

menters 48, 44, 35, and 155 lb. of ash respectively. Wheat
straw, therefore, does not always leave the same quantity of
ash. The same is true also of other kinds of vegetable pro-
duce.

This fact, as well as the variation of the quantity of ash with
the part of the plant, is shown by the following table of the
proportions of ash left by the several parts of two different
varieties of oats grown on different soils, (Norton )—

Hopeton oat. Potato oat.
Grain, ; : 2.14 2.22
Pipicheay: tem trae 6.47 6.99
Straw, : : 4.98 8.62
Leaf, Preie 8.44 14.59
Pua. war 4 16.53 18.59

Here not only do the different parts of the same plant, but
similar parts also of different plants of the same species, leave
very different proportions of ash.

To what is this difference owing? Is it to. the nature of the
soil, or does it depend upon the variety of wheat, oats, or other
produce experimented upon? Itseems to depend partly upon both.

a. Variety—Thus on the same field, in Ravensworth Dale,
Yorkshire, on a rich clay soil abounding in lime, the Golden
Kent and Flanders Red wheats were sown in the spring of 1841.
The former gave an excellent crop, while the latter was a total
failure, the ear containing 20 or 30 grains only of poor wheat.
The straw of the former left 165 lb. of ash from 1000 lb., that
of the latter only 120 lb. Something, therefore, depends wpon
the variety.

b. Soi.—Again, 1000 lb. of the straw of the same variety of
oat, grown by the Messrs. Drummond of Stirling in 1841, upon

Aberdeen granite, left 96 lb. of ash.
On clay-slate, Toe. ce,

On*preenstone, : 2° 19. &
On limestone, eae
On gypsum, : 5S j-%
On silicious sand, ae

On light loamy soil, 88 “

GENERAL CONCLUSION. 63

The quantity of ash, therefore, depends in some measure also wpon
the nature of the soil.

5. But the degree of ripeness which a plant has attained has
also an influence on the proportion of ash which it leaves.
Thus the straw of the same wheat grown on the same limestone
soil near Wetherby, in Yorkshire, gave me, when cut five weeks
before it was ripe, 40 lb., and when fully ripe, 55 lb., from 1000
Ib. of dry straw. To compare the ash, therefore, of any two
samples of straw, they ought to be gathered in the same state
of ripeness.

A similar observation also has been made in regard to the
wood of trees. The quantity of ash they leave varies both
with their age and with the season of the year at which they
are burned.

On the whole, the truth, so far as it can as yet be made out,
seems to be this—that every plant must have a certain quantity
of inorganic matter to make it grow in the most healthy manner
—that it is capable of living, growing, and even ripening seed
with much less, and probably with much more, than this quan-
tity—but that those soils will produce the most perfect plants
which can best supply all their wants; and that the best seed
will be raised in those districts where the soil, without being
too rich or rank, yet can yield both organic and inorganic food
in such proportions as to maintain the corn plants in their most
healthy condition.

This latter observation, in regard to the quality of seed, is
of great practical importance, and must be borne in mind when
_we come hereafter to inquire whether seeds can be so prepared
or doctored, by steeping or otherwise, as to grow quicker, with
more certainty, and with greater luxuriance, and to yield larger
returns of grain.

-

64 THE QUALITY OF THE ASH OF PLANTS.

SECTION III.—OF THE COMPOSITION OR QUALITY OF THE ASH OF
PLANTS, AND THE CIRCUMSTANCES BY WHICH IT IS MODIFIED.

But much also depends upon the quality as well as upon the
quantity of the ash. Plants may leave the same weight of ash
when burned, and yet the nature of the specimens of ash—the
kind of matter of which they respectively consist—may be very
different. The ash of one may contain much lime, of another
much potash, of a third much soda, while in a fourth much sili-
ca may be present. Thus 100 lb. of the ash of bean straw have
been found to contain 53 Ib. of potash, while that of barley con-

tained only 9 Ib. in the hundred. On the other hand, 100 Ib.

of the ash of barley straw contain 68 lb. of silica, while in that
of bean straw there are only 7 lb.

The quality of the ash seems to vary with the same conditions
by which its quantity is affected. Thus—

1. Lt varies with the kind of plant.—1000 lb. of the ash of the
gram of wheat, barley, oats, beans, and linseed—of the potato
tuber and the turnip bulb, for example—contain respectively—

3 2 SN ie a,

$24 oe bog) ah Bee

= H = iS ao S gq = =

Bie ch oct: 4 Ge Peete anor ae

Potash, - - - | 237 | 136 | 262 | 220 l g05 336 | 245 | 557 | 419
Soda) -.- - «= | 91) SL} 1116) | 79? 2: te ee ae ee
Lime, - - - | 28; 26] 60) 49 14 58 |147} 20) 136
Magnesia, - - |120| 751100/103| 162 80| 99] 53) 53
Oxide of iron, - - 1 ORS | eee 3 6} 19 a eee Fs
Phosphorie acid, - 1500 | 390/438|495] 449 |380/381/126] 176
Sulphuric acid, -| 8/- 11105| 9) = SB hat en ee
Silica, + - et LA 203 f-27 4 14 12| 57] 427° 79
Chlorine, - - - | — |trace| 3) — 2 7 3| 42] 36
eesti ee
998 | 997 | 9991009) 997 | 995; 994 nal 99

A comparison of the numbers in the first four columns shows
how unlike the quantities of the different substances are which

ns

THE ASH OF GRAINS AND BULB. 65

are contained in an equal weight of the ash of the four varieties
of grain. It is to be remarked, however, that the great differ-
ence in the case of barley arises from the thick husk with which
it is covered, and from which the large per centage of silica is
derived. The sample of oats was taken without the husk.

Beans contain more sulphuric acid, also, than any of the other
grains in the above table, while they are deficient in phosphoric
acid when compared with wheat, barley, or oats. But the most
striking differences appear between the several kinds of grain
and the potato and turnip. In these last the alkaline matter is
very much greater, while the phosphoric acid is much dimin-
ished.

Tt is thus evident that a crop of wheat will carry off from the
soil—even suppose the whole quantzty of ash left by each to be
the same in weight—very different quantities of potash, soda,
lime, phosphoric acid, &c., from what would be carried off by a
crop of beans or of potatoes. It will, therefore, exhaust the soil
more of some, as beans and potatoes will of other substances.
Hence one reason why a piece of land may suit one crop and not
suit another. Hence, also, two successive crops of different
kinds may grow well where it would greatly injure the soil to
take two in succession of the same kind, especially of either
wheat or barley ; and hence we likewise deduce one natural rea-
son for a rotation of crops. The surface-soil may be so far ex-
hausted of one inorganic substance that it cannot afford it in
sufficient quantity to bring a given crop to healthy maturity ;
and yet this substance may, by natural processes, be so far re-
stored again, during the intermediate growth of certain other
crops, as to be prepared in a future season fully to supply all
the wants of the same crop, and to yield a plentiful harvest.

2. The kind of inorganic matter varies with the part of the
plant.—Thus the grain and the straw of the corn-plants contain
very unlike quantities of the several inorganic constituents, as
will appear by comparing the several columns in the following
with those of the preceding table.

66 ASH OF STRAW.

1000 Ib. of the ash of the straw of wheat, barley, oats, rye,
and Indian corn, have been found to contain respectively of—

; ares _, (Indian

Wheat. Barley.| Oats. | Rye. nee,

Potash, - - -|} 125 92 194 173 96
Soda) =" ot y 3 97 3 | 286
Tame,” = Se 67 85 81 90 83
Magnesia, - - 3 50 38 24 66
Oxide of iron, - 13 10 18 14 8
Phosphoric acid, 31 on 26 58 Praise
Sulphuric acid,- 58 10 33 8 7
Chlorine, - - 11 6 32 5 15
Nilica, - - -| 654] 676 | 484] 645 | 270

1000 963 | 1000 | 1000 | 1012
|

——. ____.

The quantities of the several inorganic substances contained
in the above kinds of straw are very different from those con-
tained in the corresponding kinds of grain. Jn this difference
We see one reason why the same soil which may be favorable to
the growth of the straw of the corn plant may not be equally
propitious to the growth of the ear. The straw contains com-
paratively little of some of the ingredients found in the ear, es-
pecially of the lime, magnesia, and phosphoric acid, while the
grain contains a large proportion of these substances. On the
other hand, the straw is rich, and the grain very poor in silica.
It is clear, therefore, that the roots may, in certain plants and
in certain soils, succeed in fully nourishing the straw, while they
cannot fully ripen the ear ; or contrariwise, where they feed but
a scanty straw, may yet be able to give ample sustenance to the
filling ear.*

That similar differences prevail in other orders of plants also,
and that their several parts require, therefore, different propor-

* And occasionally do give; for a plump grain, and even a well-filled ear,
are not unfrequently found where the straw is unusually deficient.

ASH OF THE APPLE TREE AND FRUIT. 67

tions of the several kinds of inorganic food to bring them to
perfection, is shown by the following table.
1000 lb. of the ash of the stem, leaves, and fruit of the apple
tree, (Pyrus spectabilis—Chinese crab,) have been found to
contain respectively, (Vogel, )

Stem. |Leaves| Fruit.

Carbonates of potash and soda, 46 68 | 190

Phosphates of do., - - - | — | trace.| 141
Carbonate of lime, - - - 822 729 | 370
Carbonate of magnesia, - - 49 98 bo
Phosphates of lime and magnesia, 88 105 | 186
Silica, - - - - Sm nee — 37

Deedee 1000-| 979

Thus potash and. phosphoric acid abound most in the fruit
of the apple tree, as they do in the ear of our corn plants, and
are therefore as necessary to their healthy growth and complete
maturity.

3. The quality of the ash varies also with the kind of sow im
which the plant 1s made to grow.—This will be understood from
what has been stated above. Where the soil is favorable, the
roots can send up into the straw everything which the plant re-
quires for its healthy growth, and in the right proportions.
When it is either too poorly or too richly supplied with one or
more of those inorganic constituents which the plant desires,
life may indeed be prolonged, but a stunted or unhealthy crop
will be raised, and the kind, and perhaps the quantity, of ash
left on burning it, will necessarily be different from that left by _
the same species of plant grown under more favoring circum-
stances. Of this fact there can be no doubt, though the extent
to which such variations may take place without absolutely kill-
ing the plant has not yet been made out. That it is considera-
ble is shown by the following table, which exhibits the compo-

68 INFLUENCE OF SOILAGE AND SEASON.

sition of 1000 Ib. of the ash of three samples of wheat grown in
different localities :—

GERMAN.

DutcH. | White. Red.
| somata 0)

Potash, . é ‘ . 64 219 338
Soda, . ; : ; 278 157 ta
Lime, = “. : , ‘ ag 19 31
Magnesia, : 2 - 130 96 136
Oxide of iron, : : 5 14 3
Sulphurie acid, ie as 3 2 4
Phosphoric acid, .. : 461 493 492
Silica, —. : ; : 3 ae

983 1000 1000

Tn the first of these we find little potash, in the last no soda,
while in all nearly half the weight consists of phosphoric acid.

4. It varies also with the period of the plant’s growth, or the
season at which it is reaped—Thus, in the young leaf of the
turnip and potato, a greater proportion of the inorganic matter
consists of potash than in the old leaf. The same is true of the
stalk of wheat; and similar differences prevail in almost every
kind of plant at different stages of its growth.

The enlightened agriculturist will perceive that all the facts
above stated have a more or less obvious connection with the
ordinary processes of practical agriculture, and tend to throw
considerable light on some of the principles by which these pro-
cesses ought to be regulated. One illustration of this is exhib-
ited in the following section.

SECTION IV.—AVERAGE QUANTITY OF INORGANIC MATTER CONTAINED
IN AN ORDINARY CROP, OR SERIES OF CROPS.

The importance of the inorganic matter contained in living
vegetables, or in vegetable substances when reaped and dry,

3 WHAT A WHOLE CROP CARRIES OFF. 69

will appear more distinctly if we consider the actual quantity -
carried off from the soil in the series of crops.
In a four years’ course of cropping, in which the crops gathered
amounted per acre to—
Ist year, Turnips, 20 tons of bulbs and 63 tons of tops.
2d year, Barley, 40 bushels of 63 lb. each, and 1 ton of straw.
3d year, Clover and Rye-Grass, 1% ton of each in hay.
4th year, Wheat, 25 bushels of 60 Ib., and 13 tons of straw.
1°. The quantity of inorganic matter carried off in the four
crops, supposing none of them to be eaten on the land, amounts
to about—

Potash, : : 317 Ib. Sulphuric acid, . 108 Ib.
Soda, ‘ . 54 ‘ Phosphoric acid EG:
Lime, . F a 1 Chlorine, . Bho Og
Magnesia, “.- *. 55 “

Oxide of iron, . aii ’
Silica, : : on6i.* Total, 1284 *

or in all about 11 ewt.; of which gross weight the different sub-
stances form unlike proportions.

2°. A still clearer view of these quantities will be obtained by
a consideration of the fact, that if we carry off the entire pro-
duce, and add none of it again in the shape of manure, we must
or ought, in its stead, if the land is to be restored to its original
condition, to add to each acre every four years—

Dry pearl-ash, : . ; . 465 lb.
Common bone dust, ‘ ‘ : 552 “
Epsom salts, j : : ; page cr
Common-salt, - F , : LEG.
Quick-lime, . : gos Se : TO.

Total, 1529 *

Several observations suggest themselves from a consideration
of the above statements.

First, That if this inorganic matter be really necessary to the
plant, the gradual and constant removal of it from the land
ought, by and by, to make the soil poorer in this part of the
food of plants.

10°.” GENERAL CONSIDERATIONS.

Second, That the more of the crops which grows upon the
land we return to it again in the form of manure, the less will
this deterioration be perceptible.

Third, That as many of these ears gaieapi ghd ocanei ;
potash, soda, Xe.
nure of the fnriteadl so often allowed to run to waste, must
carry with it to the rivers much of the saline matter that okt
to be returned to the land.

Fourth, If the rains also are allowed to run over and wash
the surface of the soil, they will gradually deprive’it of those
soluble saline substances which appear to be so necessary to the
erowth of plants. Hence one important benefit of a system of
drainage so perfect as to allow the rains to sink into the soil
where they fall, and thus to carry down, instead of away, what
they naturally dissolve.

And, lastly, That the utility, and often indispensable necessity,
of certain artificial manures—though, in some districts, perhaps
arising from the natural poverty of the land in some of the
mineral substances which plants require—is most frequently
owing to a want of acquaintance with the facts above stated,
and to the long-continued neglect and waste which has,been the
natural consequence.

In certain districts, the soil and subsoil! contain within them-
selves an almost unfailing supply of some of these inorganic or
mineral substances, so that the waste of them is long in being felt;
in others, again, the land contains less, and therefore becomes
sooner exhausted. This latter class of soils requires a more
careful, and usually a more expensive mode of cultivation than
the first; but both will become at length alike unproductive, if
that which is yearly taken from the soil is not in some form or
other restored to it. ;

One thine is of essential importance to be remembered by the
practical farmer—that the deterioration of land is often an ex-
ceedingly slow process. In the hands of successive generations,
a field may so imperceptibly become less valuable, that a cen-

*

ARTIFICIAL MANURES, WHY NECESSARY. 71

tury even may elapse before the change prove such as to make
a sensible diminution in the valued rental. Such slow changes,
however, have been seldom recorded; and hence the practical
man is occasionally led to despise the clearest theoretical prin-
ciples, because he has not happened to see them verified in his
own limited experience; and to neglect, therefore, the sug-
gestions and the wise precautions which these principles lay
before him. -

The special agriculturai history of known tracts of land of
different qualities, showing how they had been cropped and tilled,
and the average produce in grain, hay, and stock every five
years, during an entire century, would afford invaluable mate-
rials both to theoretical and to practical agriculture.

General illustrations of this sure though slow decay may be
met with in the agricultural history of almost every country.
In none, perhaps, are they more striking than in the older slave
states of North America. Maryland, Virginia, and North Ca-
rolina—once rich and fertile—by a long-continued system of
forced and exhausting culture, have become unproductive in
many places, and vast tracts have been abandoned to appa-
rently hopeless sterility. Such lands it is possible to reclaim,
but at what an expense of time, labor, manure, and skilful
management! It is to be hoped that the newer states will
not thus sacrifice their future power and prospects to present
and temporary wealth—that the fine lands of Ohio, Kentucky,
and the Prairie states, which now yield Indian corn and wheat,
crop after crop, without intermission and without manure, will
not be so cropped till their strength and substance is gone, but
that.a better conducted and more skilful husbandry will con-
tinue, without diminishing the present crops, to secure a per-
manent fertility to that naturally rich and productive country.

SECTION Y.—PRACTICAL DEDUCTIONS TO BE DRAWN FROM A KNOW-
LEDGE OF THE INORGANIC CONSTITUENTS OF PLANTS.

Several important practical deductions are to be drawn from

ye hom PRACTICAL DEDUCTIONS.

what has been stated in regard to the inorganic constituents of
plants.

1°. Why one crop may grow well where another fatls—Sup-
pose, for example, a crop to require a peculiarly large supply
of potash—it may grow well if the soil abound in potash ; but
if the soil be deficient in potash and abound in lime, then this
crop may scarcely grow at all upon it, while another crop to
which lime is especially necessary may grow luxuriantly.

2°. Why mixed crops grow well together—If two crops of
unlike kinds be sown together, their roots suck in the inorganic

Shocahas acid kas eau more lime, magnesia, or
silica. They thus interfere less with each other than plants of
the same kind do—which require the same kinds of food in
nearly the same proportions.

Or the two kinds of crop grow with different degrees of
rapidity, or at different periods of the year ; and thus, while
the roots of the one are busy drawing in supplies of inorganic
nourishment, those of the other are comparatively idle ; and
thus the soil is able abundantly to supply the wants of each as
its time of need arrives.

3°. Why the.same crop grows better on the same soil after long
intervals.—If each crop demands special substances, or these
substances in quantities peculiar to itself, or in some peculiar
state of combination, the chances that the soil will be able to
supply them are greater, the more distant the intervals at
which the same crop is grown upon it. Other crops do not
demand the same substances, or in the same proportions ; and
thus they may gradually accumulate on the soil till it becomes
especially favorable to the particular crop we wish to grow.

4°. Why a rotation of crops is necessary—Suppose the soil
to contain a certain average supply of all*those inorganic sub-
stances which plants require, and that the same corn crop is
erdwn upon it for a long series of years—this crop will carry
off some of these substances in larger proportion than others,

ROTATION OF CROPS : EXHAUSTION. le

so that year by year the quantity of those which are thus
chiefly carried off will become relatively less. Thus at length
the soil, for want of these special substances, will become
unable to bear a corn crop at all, though it may stili contain a
large store of the other inorganic substances which the corn
crop does not specially exhaust. Suppose bean or turnip crops
raised in like manner for a succession of years, they would
exhaust the soil of a different set of substances till it became
unable to grow them profitably, though still rich perhaps in
those things which the corn crop especially demands.

But grow these crops alternately, then the one crop will
draw especially upon one class of substances, the other crop
upon another ; and thus much larger crops of each will be
reaped from the same soil, and for a much longer period of
time.

On this principle the benefit of a rotation of crops in an
important degree depends.*

5°, What is meant by exhaustion—Thus, exhaustion may
either be general, arising from the gradual carrying off of all the
kinds of food on which plants live—or speczal, arising from the
want of one or more of those substances which the crops that
have been long grown upon it have specially required.

To repair the former kind of exhaustion, an addition of ~
many things to the soil may be necessary ;—to repair the
latter, it may be sufficient to add a needful supply of one
or more things only. In showing how this may be most
efficiently and most economically done, chemistry will be of
thé most essential service to the practical man. Before en-
tering further upon this point, however, it will be necessary to
study also the nature of the soil in which plants grow.

* In showing, in the above remarks, how the doctrine of the inorganic
part of plants throws light, among other things, upon the use of a rotation
of crops, the reader will bear in mind that a knowledge of the organic por-
tion of the plant, and of the living functions of each part in each species, is
no less necessary to the full understanding of this intricate subject.

i 4

CHAPTER V.

Of soils —Their organic and inorganic portions.—Saline or soluble, and
earthy or insoluble, matter in soils—Examination and classification of
soils.—Determination of the per-centage of sand, clay, vegetable matter,
and lime.—Diversities of soils and subsoils.

Sorts consist of two -parts; of an organic part, which can
readily be burned away when the soil is heated to redness ; and
of an inorganic part, which is fixed in the fire, and which con-
sists entirely of earthy and saline substances.

SECTION I.—OF THE ORGANIC PART OF SOILS,

The organic part of soils is derived chiefly from the remains
of vegetables and animals which have lived and died in or upon
the soil, which have been spread over it by rivers and rains ; or
which have been added by the hands of man, for the purpose
of increasing its natural fertility.

This organic part varies very much in quantity in different
soils. In some, as in peaty soils, it forms from 50 to’70 per
cent of their whole weight ; and even in rich long-cultivated
soils it has been found, in a few rare cases, to amount to as
much as 25 per cent. In general, however, it is present in
much smaller proportion, even in our best arable lands. Oats
and rye will grow upon a soil containing only 14 per cent, barley
when 2 to 3 per cent are present, while good wheat soils gene-
rally contain from 4 to 8 per cent. The rich alluvial soil of the
valley of the Nile contains only 5 per cent of dry organic mat-
ter. In stiff and very clayey soils, 10 to 12 per cent is some-
times found. In very old pasture-lands, and in gardens, vegeta-
ble matter occasionally accumulates so as to overload the upper
soil.

ORGANIC AND INORGANIC PARTS OF THE SOIL. TD

To this organic matter in the soil the name of humus has
been given by some writers. It contains, or yields to the plant,
the ulmic, humic, and other acids already described, (see Chap-
ter II.) It supplies also, by its decay in contact with the air
which penetrates the soil, much carbonic acid, which is supposed
to enter the roots, and thus to assist the growth of living vege-
tables. During the same decay, ammonia, as we have already
stated, is likewise produced, and this in larger quantity if ani-
mal matter be present in considerable abundance. Other sub-
stances, more or less nutritious, are also formed from the organic
matter in the soil. These enter by the roots, and contribute to
nourish the growing plant, though the extent to which it is fed
from this source is dependent, both upon the abundance with
which these substances are supplied, and upon the nature of the
plant itself, and of the climate in which it grows.

Another influence of this organic portion of the soil, whether
naturally formed in it or added to it as manure, is not to be
neglected. It contains—as all vegetable substances do—a con-
siderable quantity of inorganic, that is, of saline and earthy
matter, which is liberated as the organic part decays. Thus
living plants derive from the remains of former races, buried
beneath the surface, a portion of that inorganic food which can
only be obtained from the soil, and which, if not thus directly
supplied, must be sought for by the slow extension of their roots
through a greater depth and breadth of the earth in which they
erow. The addition of manure to the’soil, therefore, places
within the easy reach of the roots not only organic but also inor-
ganic food.

SECTION II.—OF THE INORGANIC PART OF SOILS.

The inorganic part of soils—that which remains behind, when
everything combustible is burned away by heating it to redness
in the open air—consists of two portions, one of which is scluble
in water, the other insoluble. The soluble consists of sadene sub-
stances, the insoluble of earthy substances.

76 SALINE OR SOLUBLE PART.

1. The saline or soluble portion.—In this country, the surface-
soil of our fields, in general, contains very little soluble matter.
If a quantity of soil be dried in an oven, a pound weight of it
taken, and a pint and a-half of pure boiling rain water poured
over it, and the whole well stirred and allowed to settle, the
clear liquid, when poured off and boiled to dryness, may leave
from 30 to 100 grains of saline mixed with a variable quantity
of organic matter. This saline matter will consist of common
salt, gypsum, sulphate of soda, (Glauber’s salts,) sulphate of
magnesia, (Epsom salts,) with traces of the chlorides of calcium,
magnesium, and potassium, and of potash, soda, lime, and mag-
nesia, in combination with nitric and phosphoric, and with the
humic and other organic acids. It is from these soluble sub-
stances that the plants derive the greater portion of the saline
ingredients contained in the ash they leave when burned.

Nor must the quantity thus obtained from a soil be considered
too small to yield the whole supply which a crop requires. A
single grain of saline matter in every pound of a soil a foot deep,
as equal to 500 1b. on an acre. ‘This is more than is carried off
from the soil in ten rotations, (forty years,) where only the
wheat and barley are sent to market, and the straw and green
crops are regularly, and without loss, returned to the land in
the manure.*

In some countries—indeed, in some districts of our own coun-
try—the quantity of saline matter in the soil is so great as in
hot seasons to form a white incrustation on the surface. It may
often be seen in the neighborhood of Durham; and is more
especially to be looked for in districts where the subsoil is sandy
and porous, and more or less full of water. In hot weather,
the evaporation on the surface causes the water to ascend from
the porous subsoil ; and as this water always brings with it a
quantity of saline matter, which it leaves behind when it rises

. ‘
* A further portion, it will be recollected, is carried off in the cattle that
are sent to market, or is lost in the liquid manure that is wasted, or is washed
out by the rains from the soil or from the manure; all these are here neglected.

SALINE INCRUSTATIONS UPON THE SOIL. TT

in vapor, it is evident that, the longer the dry weather and
consequent evaporation from the surface continue, the thicker
the incrustations will be, or the greater the accumulations of
Saline matter on the surface. Hence, where such a moist and
porous subsoil exists in countries rarely visited by rain, as in the
plains of Peru, of Egypt, or of India, the country is whitened
over in the dry season with an unbroken snowy covering of the
different saline substances above mentioned.

When rain falls, the saline matter is dissolved, and descends
again to the subsoil. In dry weather it re-ascends. Hence the
surface-soul of any field will contain a larger proportion of solu-
ble inorganic matter in the middle of a hot dry season than in
one of even ordinary rain. Hence, also, the fine dry weather
which, in early summer, hastens the growth of corn, and later
in the season favors its ripening, does so probably, among its
other modes of action, by bringing up to the roots from beneath
a more ready supply of those saline compounds which the crop
requires for its healthful growth. In some countries, however,
this saline matter ascends in such quantity as to render the soil
unfit to grow the more tender crops. Thus, on the plains of
Attica, when the rainy season ends, saline substances begin to
rise to the surface in such abundance as by degrees entirely to
burn up or prevent the growth of grass, though abundant wheat
crops are yearly ripened.

2. The earthy or insoluble portion—The earthy or insoluble
portion of soils rarely constitutes less than 95 Ib. in a hundred
of their whole weight. It consists chiefly of szica in the form
of sand—of alwmina mixed or combined with silica in the form
of clay—and of lume in the form of carbonate of lime. It is
rarely free, however, from two or three per cent of oxide of
iron ; and where the soil is of a red color, this oxide is often
present in still larger proportion. A trace of magnesia also -
may be almost always detected, and a minute quantity of phos-
phate of lime. The principal ingredients,- however, of the
earthy part of all soils are sand, clay, and lime ; and soils are

78 SEPARATION OF SAND AND CLAY.

named or classified according to the quantity of each of these
three they may happen to contain.

a. If an ounce of soil be intimately mixed with a pint of
water till it is perfectly softened and diffused through it, and
if, after shaking, the heavy parts be allowed to settle for a few
minutes, the sand will subside, while the clay, which is in finer
particles, and is less heavy—will still remain floating. If the
water and fine floating clay be now poured into another vessel,
and be allowed to stand till the water has become clear, the
sandy part of the soil will be found on the bottom of the first
vessel, and the clayey part on that of the second, and they
may be dried and weighed separately.

b. If 100 grains of dry soil, not peaty or unusually rich in
vegetable matter, leave no more than 10 of clay when treated
in this manner, it is called a sandy soi; if from 10 to 40, a
sandy loam ; if from 40 to 10, a loamy soil; if from 70 to 85, a
clay loam ; from 85 to 95, a strong clay soil ; and when no sand
is separated at all by this process, it is a pure agricultural clay.

c. The strong clay soils are such as are used for making tiles
and bricks ; the pure agricultwral clay is such as is commonly
employed for the manufacture of pipes, (pipe-clay.) This pure
clay is a chemical compound of silica and alumina, in the pro-
portion of about 60 of the former to 40 of the latter. Soils
of pure clay rarely occur—it being well known to all practical
men that the strong clays, (tile clays,) which contain from 5
to 15 per cent of sand,:are brought into arable cultivation
with the greatest possible difficulty. It will rarely, almost
never, happen, therefore, that arable land will contain more
than 30 to 35 per cent of alumina.

d. If a soil contain more than 5 per cent of carbonate of
lime, it is called a marl; if more than 20 per cent, it is a cal-
careous soil. -Peaty sis, of course, are those in which the
vegetable matter predominates very much.

e. The quantity. of vegetable or other organic matter is de-
termined by drying the soil well upon paper in an oven, until it

DIVERSITIES OF SOILS AND SUBSOILS. 79

ceases to lose weight—taking care that the heat is not so great
as to char the paper—and then burning in the open air a
weighed quantity of the dried soil: the loss by burning is
nearly all organic matter. In stiff clays this loss will include
also a portion of water, which is not wholly driven off from
such soils by drying upon paper in the way described.

f. To estimate the lime, a quantity of the soil should be
heated in the air till the organic matter is burned away. A
weighed portion, (200 or 300 grains,) should then be diffused
through half a pint of cold water mixed with half a wine-
glassful of spirit of salt, (muriatic acid,) and allowed to stand
for a few hours, with occasional stirring. When minute bub-
bles of gas cease to rise from the soil, the water is poured off,
the soil dried, heated to redness as before, and weighed : the
loss is nearly all lime.

SECTION III.—QOF THE DIVERSITIES OF SOILS AND SUBSOILS.

Ast. Seas.—Though the substances of which soils chiefly con-
sist are so few in number, yet every practical man knows how
very diversified they are in character—how very different in
agricultural value. Thus, in some of our southern counties,
we have a white soil, consisting apparently of nothing else but
chalk ; in the centre of England a wide plain of dark-red
land ; in the border counties of Wales, and on many of our
coal-fields, tracts of country almost perfectly black ; while
yellow, white, and brown sands and clays give the prevailing
character to the soils of other districts. Such differences as
these arise from the different proportions in which the sand,
lime, clay, and the oxide of iron and organic matter which
color the soils, have been mixed together.

But how have they been so mixed—differently in different
parts of the country? By what natural agency? For what
end ?

2d. Swbsod.—Again, the surface-soil rests on what is usually
denominated the swbscil, This is also very variable in its cha-

80 IMPORTANCE OF THE SUBSOIL.

racter and quality. Sometimes it is a porous sand or gravel,
through which water readily ascends from beneath, or sinks in
from above ; sometimes it is light and loamy, like the soil that
rests upon it ; sometimes stiff, and more or less impervious
to water. )

The most ignorant farmer knows how much the value of a
piece of land depends upon the character of the surface-soil,—
the intelligent improver understands best the importance of a
favorable subsoil. ‘‘ When I eamny. to look at this farm,” said
an excellent agriculturist to me, ‘‘it was spring, and damp,
erowing weather : the grass was beautifully green, the clover
shooting up strong and healthy, and the whole farm had the
appearance of being very good land. Had I come in June,
when the heat had drunk up nearly all the moisture which the
sandy subsoil had left on the surface, I should not have offered
so much rent for it by ten shillings an acre.” He might have
said also, ‘‘ Had I taken a spade, and dug down 18 inches in
various parts of the farm, I should have known what to expect
in seasons of drought.”

But how come subsoils thus to differ—one from the other—
and from the surface-soil that rests upon them? Are there
any principles by which such differences can be accounted for—
by which they can be foreseen—by the aid of which we can
tell what kind of soil may be expected in this or that district,
even without visiting the spot, and on what kind of subsoil it
is likely to rest ?

Geology explains the cause of many of these differences,
and supplies us with principles by which we can predict the
general quality of both soils and subsoils in the several parts
of entire kingdoms ; and where the soil is of inferior quality,
and yet susceptible of improvement, the same principles indi-
cate whether the means of improving it are likely to exist in
any given locality, or to be attainable at a reasonable cost.

It will be proper shortly to illustrate these direct relations of
geology to agriculture. |

“CHAPTER VI.

Direct relations of geology to agriculture.—Origin of soils.—Causes of their
diversity.—Relation of soils to the rocks on which they rest.—Constancy
in the relative position and character of the stratified rocks.—Relation of
this fact to practical agriculture.—Of primary, secondary, tertiary, and
post-tertiary rocks.—Different soils observed upon each of these divisions
along the Atlantic sea-board of North America.

Gronocy is that branch of knowledge which embodies all
ascertained facts in regard to the nature and internal structure,
both physical and chemical, of the solid parts of our globe.
This science has many close relations with practical agriculture.
It especially throws much light on the nature and origin of
soils—on the causes of their diversity—on the agricultural capa-
bilities, absolute and comparative; of different farming districts
and countries—on the unlike effects produced by the same
manure on different soils—on the kind of materials, by admix-
ture with which they may be permanently improved—and on
the sources from which these materials may be derived.

It tells beforehand, also, and by a mere inspection of the
may, what is the general character of the land in this or that
district of a country—whcere good land is to be expected—where
improvements are likely to be effected—of what kind of im-
provements this or that district will be susceptible—and where
the intending purchaser may hope to lay out his money to the
ereatest advantage.

SECTION I.—OF THE CRUMBLING OF ROCKS AND THE ORIGIN OF SOILS.

If we dig down through the soil and subsoil to a sufficient
depth, we always come sooner or later to the solid rock. In
many places the rock actually reaches the surface, or rises in

4%

82 GENERAL COMPOSITION OF ROCKS.

cliffs, hills, or ridges, far above it. The surface (or crust) of
our globe, therefore, consists everywhere of a more or less solid
mass of rock, overlaid by a covering, generally thin, of loose
materials. The upper or outer part of these loose materials
forms the soil.

The geologist has travelled over great part of the earth’s
surface, has examined the nature of the rocks which everywhere
repose beneath the soil, and has found them to be very unlike in
appearance, in hardness, and in composition—in different coun-
tries and districts. In some places he has met with a sandstone,
in other places a limestone, in others a slate or hardened rock
of clay. But a careful comparison of all the kinds of rock he
has observed has led him to the general conclusion that they are
all ether sandstones, limestones, or clays of different degrees of
hardness, or a mixture in different proportions of two or more of
these kinds of matter.

When the loose covering of earth is removed from the sur-
face of any of these rocks, and this surface is left exposed, sum-
mer and winter, to the action of the winds and rains and frosts,
it may be seen gradually to crumble away. Such is the case’
even with many of those which, on account of their greater
hardness, are employed as building-stones, and which, in the
walls of houses, are kept generally dry ; how much more with
such as are less hard, or lie beneath a covering of moist earth,
and are continually exposed to the action of water. The natural
erumbling of a naked rock thus gradually covers it with loose
materials, in which seeds fix themselves and vegetate, and which
eventually form a soil. The soil thus produced partakes neces-
sarily of the chemical character and composition of the rock on
which it rests, and to the crumbling of which it owes its origin.
If the rock be a sandstone, the soil is sandy—if a claystone, it
is a more or less stiff clay-—if a limestone, it is more or less
calecareous—and if the rock consist of any peculiar’ mixture of
those three substances, a similar mixture is observed in the
earthy matter into which it has crumbled.

RELATIONS OF SOILS TO ROCKS. $3

Led by this observation, the geologist, after comparing the
rocks of different countries with one another compared next the
soils of various districts with the rocks on which they immedi-
ately rest. The general result of this comparison has been, that
in almost every country the soils, as a whole, have a resemblance
to the rocks beneath them, similar to that which the loose earth
derived from the crumbling of a rock before our eyes bears to
the rock of which it lately formed a part. The conclusion,
therefore, is irresistible, that soils, generally speaking have been
formed by the crumbling or decay of the solid rocks—that there
was a time when these rocks were naked and without any cover-
ing of loose materials—and that the accumulation of soil has
been the slow result of the natural degradation or wearing
_away of the solid crust of the globe.

SECTION II.—CAUSE OF THE DIVERSITY OF THE SOILS.

The cause of the diversity of soils in different districts, there-
fore, is no longer obscure. If the subjacent rocks in two local-
ities differ, the soils met with there are likely to differ also, and
in an equal degree.

But why, it may be asked, do we find the soil in some coun-
tries uniform in mineral* character and general fertility over
hundreds or thousands of square miles, while in others it varies
from field to field—the same farm often presenting many well-
marked differences both in mineral character and in agricultural
value? <A chief cause of this is to be found in the mode in
which the different rocks are observed to lie—upon or by the
side of each other.+

1. Geologists distinguish rocks into two classes, the stratified
and the wnstratified. The former are found lying over each
_ other in separate beds or strata, like the leaves of a book when

* That is, containing the same general proportions of sand, clay, lime, &,,
or colored red by similar quantities of oxide of iron.
7 For another important cause, see Section IT. of Chapter VIII.

84 STRATIFIED AND UNSTRATIFIED ROCKS.

laid on tts side, or like the layers of stones in the wall of a
building. The latter—the unstratified rocks—form hills, moun-
tains, or sometimes ridges of mountains, consisting of one more
or less solid mass of the same material, in which no layers or
strata are usually anywhere or distinctly perceptible. Thus, in
the following diagram, (No. 1,) A and B represent wnstratzfied
masses, in connection with a series of stratified deposits, 1 2 3,
lying over each other in a horizontal position, On A one kind
of soil will be formed, on C another, on B a third, and on D a
fourth—the rocks being all different from each other.

No: ll.

If from A to D be a wide valley of many miles in extent, the
undulating plain at the bottom of the valley, resting in great
part on the same rock, (2,) will be covered by a similar soil.
On B the soil will be different for a short space ; and again it
will differ at the bottom of the valley ©, and on the first ascent
to A, at both of which places the rock (3) rises to the surface.
In this case the stratified rocks lie horizontally ; and it is the
undulating nature of the country which, bringing different kinds
of rock to the surface, causes a necessary diversity of soil.

2. But the degree of znclination which the beds possess is a
more frequent cause of variation in the characters of the soil
in the same district, and even at very short distances. This
is shown inthe annexed diagram, (No. 2,) where AB CDE
represent the mode in which the stratified rocks of a district
of country not unfrequently occur in connection with each

other.
No. 2.

RNR Ne

Proceeding from EH in the plain, the soil would change when

ORDER OF SUCCESSION CONSTANT. 85

we came upon the rock D, but would continue pretty uniform
in quality till we reached the layer C. Hach of these layers
may stretch over a comparatively level tract of perhaps hun-
dreds of miles in extent. Again, on climbing the hill-side,
another soil would present itself, which would not change till
we arrived at B. Then, however, we begin to walk over the
edges of a series of beds, and the soil may vary with every
new stratum or bed we pass over, till we gain the ascent to A,
where the beds are much thinner, and where, therefore, ‘still
more frequent variations may present themselves.

Everywhere over the British islands valleys are hollowed
out, as in the former of these diagrams, (No. 1,) by which the
different rocks beneath are in different places exposed and dif-
ferences of soil produced ; or the beds are more or less inclined,
as in the latter diagram, (No. 2,) causing still more frequent
variations of the land to appear. By areference to these facts,
therefore, many of the greater diversities which the soils of the
country present may be satisfactorily accounted for.

SECTION III.—OF THE CONSTANCY IN MINERAL CHARACTER, AND
ORDER OF SUCCESSION, WHICH EXISTS AMONG THE STRATIFIED
ROCKS.

Another fact, alike important to agriculture and to geology,
is the natural order or mode of arrangement in which the stra-
tified rocks are observed to occur in the crust of the globe.
Thus, if 1 2 3 in diagram No. 1 represent three different kinds
of rock—a limestone, for example, a sandstone, and a hard clay
rock (a shale or slate) lying over each other in the order here
represented—then, in whatever part of the country, nay, in
whatever part of the world these same rocks are met with,
they will always be found in the same position. The bed 2 or
3 will never be observed to le over the bed 1.

This fact is important to geology, because it enables this
science to arrange all the stratified rocks in a certain invariable

86 DEDUCTIONS FROM THIS.

order—which order indicates their relative age or antiquity—
since that rock which is lowest, like the lowest layer of stones
in the wall of a building, must generally have been the first
deposited, or must be the oldest. It also enables the geologist
on observing the kind of rock which forms the surface in any
country, to predict at once whether certain other rocks are
likely to be met with in that country or not. Thus at C,
(diagram No. 1,) where the rock 3 comes to the surface, he
knows it would be in vain, either by sinking or otherwise, to
seek for the rock 1, the natural place of which is far above it ;
while, at D, he knows that by sinking he is likely to find either
2 or 3, if it be worth his while to seek for them.

To the agriculturist this fact is important, among other
reasons,— |

1. Because it enables him to predict whether certain kinds
of rock, which may be used with advantage in improving his
soil, are likely to be met with within a reasonable distance or
at an accessible depth. Thus, if the bed D (diagram No. 2)
be a limestone, the instructed farmer at K knows that it is not
to be found by sinking into his own land, and therefore brings
it from D; while to the farmer upon C it may be less expen-
sive to dig down to the bed D in one of his own fields, than to
cart it from a distant spot, where it occurs on the surface.
Or, if the farmer requires clay, or marl, or sand, to ameliorate
his soil, this knowledge of the constant relative position of beds
enables him to say where these materials are to be got, or
where they are to be looked for, and whether the advantage to
be derived is likely to repay the cost of procuring them.

9. It is observed that, when the soil on the surface of each
of a series of rocks, such as C or D or E, (diagram No. 2,) is
uniformly bad, 7¢ 2s almost uniformly of better quality at the
point where the two rocks meet. ‘Thus C may be dry, sandy, and
barren ; D may be a cold unproductive clay ; and E a more
or less unfruitful limestone soil ; yet at either extremity of the
tract D, where the soil is made up of an admixture of the

PRACTICAL VALUE OF GEOLOGICAL KNOWLEDGE. 87

decayed portions of the two adjacent rocks, the land may be
of average fertility—the sand of C may adapt the adjacent
clay to the growth of turnips, while the lime of E may cause it
to yield large returns of wheat.* Thus, to the tenant in look-
ing out for a farm, or to the capitalist in seeking an eligible
investment, a knowledge of the mutual relations of geology
and agriculture will often prove of the greatest assistance.
But how little is such really useful knowledge diffused among
either class of men—how little have either tenants or proprie-
tors been hitherto guided by it in their choice of the local-
ities in which they desire to live !

3. The further fact that the several stratified rocks are re-
markably constant in their general mineral character, renders
this knowledge of the order of relative superposition still more
valuable to the agriculturist. Thousands of different beds
are known to geologists to occur on various parts of the earth’s
surface—each occupying its own unv arying place in the series.
Most of these beds also, when they crumble or are worn down,
produce soils possessed of some peculiarity by which their
general agricultural capabilities are more or less affected,—and:
these peculiarities may generally. be observed in soils formed
from rocks of the same age—that is, occupying the same place
in the series—in whatever part of the world we find them.
Hence, if the agricultural geologist be informed that his friend
has bought, or is in treaty for a farm or an estate, and that it
is situated upon such and such a rock, or geological formation,
or is in the immediate neighborhood of such another,—he can
immediately give a very probable opinion in regard to the
agricultural value of the soil, whether the property be in Eng-
land, Australia, or in New Zealand. If he knows the nature
of the climate also, he will be able to estimate with tolerable
correctness how far the soil is likely to repay the labors of
the practical farmer—nay, even whether it is likely to suit
- better for arable land or for pasture ; and if for arable, what

* See p. 84.

$8 AGRICULTURAL VALUE OF GEOLOGY.

species of grain and root crops may be expected to produce
most abundantly.

These facts are so very curious, and illustrate so beautifully
the value of geological knowledge—if not to A and B, the holders
and proprietors of this and that small farm, yet to enlightened
agriculturists, to scientific agriculture in general—that I shall
explain this part of the subject more fully in a separate section.
To those who are now embarking in such numbers in quest of
new homes in our numerous colonies—who hope to find, if not a
more willing, at least a more attainable soil in new countries— -
no kind of agricultural knowledge can at the outset,—I may
say, even through life—be so valuable as that to which the rudi-
ments of geology will lead them. Those who prepare themselves
the best for becoming farmers or proprietors in Canada, in
New Zealand, or in wide Australia, leave their native land in
general without a particle of that preliminary practical know-
ledge which would quality them to say, when they reach the
land of their adoption, “on this spot rather than on that
—in this district, rather than that,—will I purchase my
allotment, because though both appear equally inviting, yet
I know, from the geological structure of the country, that
here I shall have the more permanently productive soil ;
here I am more within: reach of the means of agricultural im-
provement; here, in addition to the riches of the surface, my
descendants may hope to derive the means of wealth from mine-
ral riches beneath.” And this oversight has arisen chiefly from
the value of such knowledge not being understood—often from
the very nature of it being unknown, even to otherwise well-
instructed practical men. It is not to men well skilled merely
in the details of local farming, and who are therefore deservedly
considered as authorities, and good teachers in regard to local
or district practice, that we are to look for an exposition, often
not even for a correct appreciation of those general principles.
on which a universal system of agriculture must be based—
without which, indeed, it must ever remain a mere collection of

SUBDIVISIONS OF STRATIFIED ROCKS. 89

empirical rules, to be studied and laboriously mastered in every
new district we go to—as the traveller in foreign lands must
acquire a new language every successive frontier he passes.
England, the mistress of so many wide and unpeopled lands,
over which the dwellings of her adventurous sons are hereafter
to be scattered, on which their toil is to be expended, and the
glory of their motherland by their exertions to be perpetuated—
England should -especially encourage all such learning, and the
sons of English farmers should willingly avail themselves of
every opportunity of acquiring it.
*

SECTION IV.—OF THE SUBDIVISIONS OF THE STRATIFIED ROCKS,

AND OF OBSERVED DIFFERENCES AMONG THE SOILS THAT REST

UPON THEM.

The thousands of beds or strata of which I have spoken as
lying one over the other in the crust of the globe, have—partly
for convenience, and partly in consequence of certain remarkably
distinctive characters observed among them—been separated by
geologists into three great divisions. The primary are the
lowest and the oldest; the secondary lie over these; and the ¢ertz-
ary are the uppermost, and have been most recently formed. The
sands, gravels, clays, and alluvial deposits, which in many places
overlie the solid rocks and the beds of soft limestone, in many
places formed by calcareous springs, are often spoken of as post-
tertiary.

In some countries, on the surface of which these several
divisions of the strata are seen to succeed each other very closely,
the character of the surface soil and its agricultural capability
are also seen to vary as we pass from the rocks of the one epoch
to those of the other. ‘This is the case, for example, in the more
southernly of the United States of America-which lie along the
Atlantic border. As we walk inland from the sea-shore, we
pass over low and swampy, but rich muddy flats, which yield
large returns of sea-island cotton and rice. As we proceed, the

90 DIFFERENT ROCKS OF THE

ground gradually rises above the sea-level—becomes firmer and
drier—and instead of the swamp willow and cypress, bears the
hickory and the oak. Tobacco and sugar are the marketable
crops on this drier land, and Indian corn the staple food of the
colored population. After twenty miles or so, the edge of this
drier alluvial plain is reached, and we ascend a low escarpment
or terrace of yellow sand. Here we find ourselves amid thin
forests of unmixed natural pine, growing upon a poor sandy
soil; and till we cross this belt and reach a second terrace, few
corn-fields, or attempts at clearing for the purposes of cultiva-
tion meet the eye. The new terrace presents the remarkable
contrast of an open prairie, void of trees, covered with a thin
soil waving with grass, and resting, like our English downs, on
chalk rocks beneath. This tract is dry and deficient in water;
but the thin soil, when turned over, yields crops of corn, and
bears, among others, a variety of hard wheat, known in the
market by the name of Georgian wheat. Still farther on this
prairie is passed, and we ascend hilly slopes, upon which clays
and loams of various qualities and capabilities occur at intervals
intermingled, and broad-leaved trees of various kinds ornament
the landscape. It is a country fitted for general husbandry,
propitious to skill and industry, and, by its climate, adapted to
the constitution of settlers of European blood.

These changes in agricultural character and capability are
coincident with changes in the geological age of the beds which
form its surface. This I have shown in the following section of
the coast-line in question, from the sea to the mountains. The
letterpress below the section indicates the geological formations;
that placed above it indicates, first, the natural vegetation, and
then the kind of husbandry and of labor which are best adapted
to each.

AMERICAN ATLANTIC BORDER. 91

No. 3. Broad-leaved forests.

Oak

Swamp and General husbandry.
willow. hickory.

Dry chalk downs. White labor.
Rice Sugar Pine forests. ‘Treeless prairies. rd
and . and Sandy barrens. ——

cotton. tobacco. Georgian wheat.

Little cultivation.

Colored labor.

Sea. Post-tertiary, Tertiary sands. Secondary Primary metamorphic*

and alluvial. chalk marks. rocks and granite,
In this section the reader will observe a close general relation
between the changes in geological and agricultural character
which appear on the several successive terraces or flats of land
which intervene between the shores of the Atlantic and the slopes
of the Alleghany Mountains. Where the most recent or alluvial
loams and rich clays end, there the tobacco, Indian corn, and even
wheat culture, for the time, end also. The tertiary sands be-
long to a more ancient epoch, and to them are limited, by a
strictly defined boundary on each side, the dark pine forests
which are so striking a feature of the country. On the still
older chalk, again, the treeless prairie and flinty wheat country
is as distinctly limited by the formations on either hand; and
beyond this, again, the changed forests and cultivation of the
higher country are determined by the change in nature and in
age which the rocks of this region exhibit.

* The word metamorphic here used means changed or altered—as clay,
for example, is changed when it is baked into tiles or bricks.

CHAPTER Vil. ,

Subdivisions of the tertiary, secondary, and primary groups of rocks.—
Agricultural relations of the crag and London clay.—Fossil phosphates
of the crag; quantity and value of these.—Soils of the London and
plastic clays——Of the chalk and green-sand.—Ware malt.—Clays of
the Weald and Lias—Rich soils of the new red sandstone.—Contrast
between those of the millstone grit and mountain limestone.—Soils of the
Silurian, Cambrian, and Mica slate rocks. General conclusions as to the
relations of geology to agriculture.

Bur the several great groups of strata, of which we have
spoken under the names of primary, secondary, &c., are them-
selves broken up or subdivided by geologists into a variety of
subdivisions called systems and formations, each of which pos-
sesses its peculiar mineral characters and special agricultural
relations. These, in so far as relates to the geology of our own
country, it will be proper briefly to indicate.

“

SECTION I.—-THE TERTIARY STRATA.

The tertiary strata, as they occur in England, consist chiefly
of the crag, which lies above, and the London and plastic clays,
which follow each other underneath.

1. The Crag consists of a mass of rolled pebbles mixed with
marine shells and corals, and resting upon beds of sand and
marl. It is in places as much as 50 feet in thickness, though
generally of less depth, and forms a strip of flat land, a few
miles in width, along the eastern shores of Norfolk and Suffolk.
The soil is generally fertile, but varies in value from 5s. to 25s. -

an acre of rent.
This crag is chiefly interesting to the agriculturist from its

ty,

NODULES OF PHOSPHATE OF LIME. 93

containing hard, rounded, flinty nodules—often spoken of as
coprolites—in which as much as 50 per cent of phosphate of lime
(bone-earth) is frequently found. These nodules are scattered
through the body of the marls, and through the subsoils of the
fields far inland, and are collected for sale to the manufacturers
of super-phosphate of lime and other artificial manures. Some
parties are said to have dug up as much as 60 or 70 tons a-week.*

2. The London and plastic clays, from 500 to 900 feet thick,
consist of stiff, almost impervious, dark-colored clays—the soils
formed from which are still chiefly in pasture. The lower beds—
the plastic clay—are mixed with sand, and produce an arable
soil ; but extensive heaths and wastes rest upon them in Berk-
shire, Hampshire, and Dorset. The crops of corn and roots
yielded by the stiff clay soils of these strata have hitherto, in
many districts, been found insufficient to pay the cost of raising
them. The drain and the subsoil plough, with lime or chalk—
in which these clays are very deficient, and for the addition of
which they are very grateful—would render them more produc-
tive and more profitable to the farmer.

SECTION II.—THE SECONDARY STRATA.

3. The Chalk, about 600 feet in thickness, lies below the Lon-
don and plastic clays above described. It consists—as shown
in the section No. 4—in the upper part, of a purer chalk with

* The cost of digging up, screening, cleaning, &c., of these nodules, is
about 5s. a ton, and they are delivered on board the vessel at 30s. to 45s.
The quantity of the fossils which is scattered over this part of the county,
and the treasure they are now proving to the owners of the land, may be
judged of from two facts stated by Mr. Herapath, (Jour. Royal Agric. Soc.,
xii. p. 93,) “that £60, £70, and £80, have been repeatedly given for leave
to dig over a two-acre field;” and “that the land itself is actually improved
by the course of treatment to which it is subjected when excavating for the
fossils.

94 THE CHALK AND GREEN-SAND.

No. 4.
Suffolk. - Mouth of the Thames. Kent.

1. London clay. 3. Upper chalk, with flints.
2. Plastic clay. 4. Under chalk, without flints.

layers of flint, (3) ; in the lower, of a marly chalk without
flints, (4.) The soil of the upper chalk is chiefly in sheep-
walks ; that of the lower chalk is very productive of corn. In
some localities, (Croydon,) the arable soils of the upper chalk
have lately been rendered much more productive in corn and
beans by deep ploughing, and thus mixing with the upper soil as
much as 6 or 8 inches of the inferior chalk. Excellent crops of
carrots also have been obtained by deep-forking such land.

The general and comparative agricultural value of the soils
upon the chalk may, to a certant extent, be judged of by the
fact, that, in the lowest-rented counties in England, chalk is the
prevailing rock.

4. The Green-sand, 500 feet thick, consists of 150 feet of
clay, with about 100 feet of a greenish, more or less indurated,
sand above, and 250 feet of sand or sandstone below it. The
upper sand forms a very productive arable soil; but the clay

forms impervious wet and cold lands, chiefly in pasture. The -—

lower sand is generally unproductive.

In the green-sand, both upper and lower, but especially in the
upper, beds of marl occur, in which are found layers of so-called
coprolites and other organic remains, rich in phosphate of lime.
To the presence of these beds is ascribed the fertility of the
soil of the upper green-sand, which in some localities is very
remarkable, and, as at Farnham in Surrey, is found to be espe-
cially favorable to the growth of hops. The organic remains are
in some places so abundant. that, as in the crag, they are sought

FERTILITY OF MIXED SOILS. 95

for and dug up, as a natural source of the phosphate of lime,
usually supplied to the soil directly in the form of bones.

It is an important agricultural remark, that where the plastic
clay comes in contact with the top of the chalk, an improved
soil is produced ; and that where the chalk and the green-sand
mix, extremely fertile patches of country present themselves.

The following imaginary section shows the relative positions
of these two fertile strips of country, above and below the chalk.

At the contact with the plastic clay it is particularly adapted
for the growth of barley, which, for quality and malting proper-
ties, is not excelled by any in a kingdom. In Essex, barley
grown on this soil is principally sold to maltsters at Stortford,
&e.; and when malted, is sold again in London under the name
of Ware malt. This name is derived from Ware in Hertford-
shire, a market town standing on a similar soil.

No. 5.
Wheat and hop land. Barley soils.

Piastic Ciay:

Upper
Green-Sand.

The soils at the contact of the chalk and upper green-sand
are celebrated for their crops of wheat, in producing which the
phosphates in the marls of the upper green-sand are supposed to
have some influence. —

5. The Wealden formation, which succeeds the green-sand, is
nearly 1000 feet thick, and consists of 400 feet of sand, covered
by 300 of clay, resting upon 250 of marls and limestones.
The clay forms the poor, wet, but improvable pastures of Sus-
sex and Kent. These clays, In many places, harden like a
brick when dried in the air ; and clods which have lain long in
the sun, ring, when struck, like a piece of pottery. By drain-
ing alone, their produce has been raised from 16 to 40 bushels
of wheat an acre. On the sands below the clay rest heaths
and brushwood ; but where the marls and limestones come to

x

96 THE WEALDEN AND OXFORD CLAYS.

the surface, the land is of better quality, and is susceptible of

profitable arable culture.
6. In the Upper oolite, of 600 feet in thickness, we have a

bed of clay (Kimmeridge clay) 500 feet thick, covered by 100.

feet of sandy limestones. The clay lands of, this formation are
difficult and expensive to work, and are therefore chiefly in old
pasture. The sandy limestone soils above the clay are also
poor ; but where they rest immediately upon, and are inter-
mixed with, the clay, excellent arable land is produced.

T. The Middle oolite, of 500 feet, consists also of a clay,
(Oxford clay,) dark blue, adhesive, often rich in lime, and
nearly 400 feet thick, covered by 100 feet of limestones and
sandstones. These latter produce good arable land where the
lime happens to abound, but the clays, especially while un-
drained, form close heavy compact soils, most difficult and ex-
pensive to work. In wet weather they are often adhesive like
bird-lime, and in dry summers become hard like stone, so as to

require a pick-axe to break them. They have therefore hitherto.

been very partially brought into arable culture. _The extensive
pasture-lands of Bedford, Huntingdon, Northampton, Lincoln,
Wilts, Oxford, and Gloucester, rest chiefly upon this clay ; as
do also the fenny tracts of Lincoln and Cambridge. ~The use
of burned clay upon the arable land has, in some parts of this
clay district, been of much advantage.

8. The Lower or Bath oolite, of 500 feet in thickness, con-
sists of many beds of limestone and sandstone, with about 200
feet of clay in the centre of the formation. The soils are very
various in quality, according as the sandstone or limestone pre-
dominates in each locality. The clays are chiefly in pasture :
the rest is more or less productive, easily worked, arable land.
In Gloucester, Northampton, Oxford, the east of Leicester,
and in Yorkshire, this formation is found to lie immediately
beneath the surface, and a little patch of it occurs also on the
south-eastern coast of Sutherland.

9. The Zzas is an immense deposit of blue clay, from 500 to

i i

THE COAL MEASURES. OT

1000 feet in thickness, which produces cold, blue, unproductive
clay soils. It forms a long stripe of land, of varying breadth,
which extends, in a south-western direction, from the mouth of
the Tees, in Yorkshire, to Lyme Regis, in Dorset. It is chiefly
in old, and often very valuable pasture. An efficient system of
drainage will by-and-by convert much of this clay into most
productive wheat land.

10. The New red sandstone, though only 500 fect in thickness,
forms the surface of nearly the whole central plain of Eng-
land, and stretches northwards through Cheshire to Carlisle
and. Dumfries. It consists of red sandstones and red marls,
the soils produced from which are easily and cheaply worked,
and form some of the richest and most productive arable lands
in the island. This is in some degree indicated by the fact that
the three highest-rented counties in England rest chiefly upon
this rock. In whatever part of the world the red soils of this
formation have been met with, they have been found to possess
in general the same valuable agricultural capabilities.

11. The Magnesian limestone, from 100 to 500 feet in thick-
ness, is covered by a stripe of generally poor thin soil, extend-
ing from Durham to Nottingham, capable of improvement as
arable land by high farming, but bearing naturally a poor pas-
ture, intermingled with sometimes magnificent furze.

12. The Coal measures, from 300 to 3000 feet thick, consist
of beds of grey sandstone, and of dark blue shale, or har-
dened clay, intermingled (inter-stratified) with beds of coal.
Where the sandstones come to the surface, the soil is thin, poor,
hungry, sometimes almost worthless. The shales, on the other
hand, produce stiff, wet, almost unmanageable @ays—not un-
workable, yet expensive to work, and requiring draining, lime,
skill, capital, and a zeal for improvement to be applied to them,
before they can be made to yield the remunerating crops of
corn they are capable of producing. The blaes or shales of
this formation, when dug out of cliffs or brought from coal-
mines, may be Jaid with advantage on loose sandy soils, and

5

Ly

98 MILLSTONE GRIT.

even, it is said, on the stiff whitish clays almost destitute of
vegetable matter, which, as in Lanarkshire, occasionally -occur
on the surface of our coal-fields.

13. To the fillstone grit, of 600 feet or upwards in thick-
ness, the same remarks apply. It lies below the coal, but is
often only a repetition of the sandstones and shales of the
coal measures, and forms in many cases soils still more worth-
less. Where the sandstones prevail, large tracts lie naked, or
bear a thin and stunted heath. Where the shales abound, the
naturally difficult_soils of the coal shales again recur. The
rocks of this formation generally approach the surface, around
the outskirts of our coal-fields.

This arises from the circumstance that our coal measures
often lie in basin-shaped deposits, from beneath each edge of
which, the millstone grit and mountain limestone rocks rise up
to the surface. This is illustrated by the annexed section, (No.
6,) across a part of Lancashire, in which | represents the coal
measures ; 2 the coarse sandstones, &c. of the millstone grit ;
3 a thick shale-bed, which often overlies the thick masses of
mountain limestone represented by 4.

No. 6.
Pendle hill. Boulsworth hill.
1803. 1689.

The traveller passes off the poor, often cold and wet, clay
soils of the coal measures, on to the equally poor lands of
the millstone grit, and over its top, as at Pendle hill, descends
upon the sweet herbage and rich dairy pastures of the moun-
tain limestone at 4. :

The section shows also how in this country the millstone grit

&

OLD RED SANDSTONE SOILS. 99

often rises into high hills. These are then covered with poor
heaths and worthless moors, while limestone hills of equal
height bear green herbage to the very top.

14. The Mowntain limestone, 800 to 1000 feet thick, is a hard
blue limestone rock, separated here and there into distinct beds
by layers of sandstones, of sandy slates, or of bluish-black
shales like those of the coal measures. The soil upon the
Jimestone is generally thin, but produces a naturally sweet
herbage, everywhere superior in value to that which grows on
the sandier soils of the millstone grit. When the limestone
and clay (shale) adjoin each other, as where 3 and 4 in the
section meet, arable land occurs, which is naturally productive
of oats, and where the climate is favourable, may, by skilful
treatment, be converted into good wheat land. In the north
of England—in Derbyshire, for example, and among the York-
shire dales—a considerable tract of country is covered by
these rocks ; but in Ireland they form nearly the whole of the
interior of the island.

15. The Old red sandstone varies in thickness from 500 to
10,000 feet. It possesses many of the valuable agricultural
qualities of the new red, (No. 10,) consisting, like it, of red
sandstones and red marls, which crumble down into rich red
soils. Such are the soils of Brecknock, Hereford, and part of
Monmouth ; of part of Berwick and Roxburgh ; of Hadding-
ton and Lanark ; of southern Perth ; of either shore of the
Moray Firth ; and of part of Sutherland, Caithness, and the
Orkney islands. Jn Ireland, also, these rocks abound in Tyrone,
Fermanah, and Monahan; in Waterford, in Mayo,, and in
' Tipperary. In all these places the soils they form are generally
the best in their several neighborhoods. Here and there,
however, where the sandstones are harder, more silicious and
impervious to water, tracts, sometimes extensive, of heath and
bog occur ; while in others the rocks have crumbled into hun-
gry sands, which swallow up the manure, and are expensive to
maintain in arable culture.

100 THE PRIMARY STRATA

SECTION III. THE PRIMARY STRATA.

The primary stratified rocks, which lie underneath all those
already described, are separable into three natural divisions ;
the Selwrzan* above, which contain the remains of animals in
a fossil state ; the Cambriant below, in which no animal
remains have yet been discovered ; and, lowest of all, the
mica slate and gneiss rocks, which, exhibit marks of change or
alteration by the agency of heat. Hence these last are often
spoken of as metamorphic, or changed rocks.

16. The Upper Silurian system is nearly 4000 feet m thick-
ness, and forms the soils which cover the lower border counties
of Wales. It consists of sandstones and shales, with occasional
limestones ; but the soils formed from these beds take their
character from the general abundance of the clay. They are
cold—usually unmanageable muddy clays ; with the remarkably
inferior agricultural value of which the traveller is immediately
struck, as he passes westward from the red sandstones of.
Hereford to the Upper Silurian rocks of the county of Radnor.

17. The Lower Silurian rocks are many thousand feet in
thickness, and in Wales lie to the west and north of the Upper
Silurian rocks. They consist, on the upper part, of about
25,000 feet of sandstone, on which, when the surface is not
naked, barren heaths alone rest.

_. Beneath these sandstones lie 1200 feet of sandy and earthy
limestones, from the decay of which, as may be seen on the
southern edge of Caermarthen, fertile arable lands are produced.

The high land, which stretches across the whole of southern
Scotland, from St. Abb’s head to Portpatrick, including the
Lammermuir hills, so far as they have yet been examined, con-
sists of strata belonging to the upper part of the Lower Silu-
rian, and the lower part of the Upper Silurian. The soils in

* Or older Palaiozoic, as containing evidences of most ancient life.
+ Or Azvic, from containing no traces of life.

CAMBRIAN SYSTEM, MICA SLATE, AND GNEISS. — 101

general are of inferior quality, the slaty rocks crumbling with
difficulty, and being poor in lime. Cold and infertile farms
cover the higher grounds, and wide heathy moors and bogs.

18. The Cambrian system—meaning by this term unaltered
rocks, containing no fossils—is at present a subject of dispute
among geologists, and its limits even in our own island are not
well defined. It is probably many thousand feet in thickness—
lies beneath the Lower Silurian—and in its agricultural re-
lations has much resemblance to these rocks. It consists in
great part of slaty rocks, more or less hard, which often crum-
ble very slowly, and almost always produce either poor and
thin soils—or cold, difficultly manageable clays, expensive to
work, and requiring high farming to bring them into profitable
arable cultivation. In Cornwall, western Wales, the mountains
of Cumberland ; in the mountains of Tipperary, in the extreme
south of Ireland, on its east coast, and far inland from the bay
of Dundalk, such slaty rocks occur, though the limits of the
two formations have not been everywhere defined. Patches of
rich, well-cultivated land occur here and there in these districts,
with much also that is improvable ; but the greater part is
usurped by worthless heaths and extensive bogs. On the dif-
ficult soils of those formations—-thinly peopled, inhabited by
small farmers with little capital, and therefore hitherto neglected
—imuch improvement is now here and there appearing ; and
the introduction of the drain promises to make much corn
grow, where little food, either for man or beast, was previously
produced. ‘These rocks in general contain little lime, and
therefore, after the drain, the addition of lime is usually one of
the most certain means of increasing the productiveness of the
soils formed from them.

19. The Micaslate and Gneiss systems are of unknown
thickness, and consist chiefly of hard and slaty rocks, crumb-
ling slowly, forming poor, thin soils, which rest on an imper-
vious rock, and which, from the height to which this formation
generally rises above the level of the sea, are rendered more

102 GENERAL CONCLUSIONS.

unproductive by an unpropitious climate. They form extensive
heathy tracts in Perth and Argyle, and on the north and west
of Ireland. Here and there only—in the valleys or sheltered
slopes, and by the margins of the lakes—spots of bright green
meet the eye, and patches of a willing soil, fertile in corn.

SECTION IV.—GENERAL CONCLUSIONS AS TO THE RELATIONS OF
GEOLOGY TO AGRICULTURE.

A careful perusal of the preceding sketch of the general
agricultural capabilities of the soils formed from the several
classes of stratified rocks, will have presented to the reader
many illustrations of the facts stated in the previous chapter.
He will have drawn for himself—to specify a few examples—
the following among other conclusions :—

1. That some formations, like the new red sandstone, yield
a soil almost always productive ; others, as the coal measures
and millstone grits, a soil almost always naturally unproduct-
ive ; and others, again, like the mountain limestones, a short
sweet herbage, grateful to cattle, and productive of butter
and cheese.

2. That good—or better land, at least, than generally pre-
vails in a district—may be expected where two formations, or
two different kinds of rock, meet. As when a limestone and
a clay mingle their mutual ruins for the formation of a com-
mon soil.*

3. That in almost every country extensive tracts of land, on
certain formations, will be found laid down to natural grass, an
consequence of the original difficulty and expense of working. Such
are the Lias, the Oxford, the Weald, the Kimmeridge, and the
London clays. In raising corn, it is natural that the lands
which are easiest and cheapest worked should be first sub-
jected to the plough. It is not till implements are improved,
skill increased, capital accumulated, and population presses, that

* See diagram No. 5, p. 95.

ROTATIONS OFTEN PRESCRIBED BY THE SOIL. 103

the heavier lands in a country are rescued from perennial grass,
and made to produce that greatly increased amount of food for
both man and beast, which they are easily capable of yielding.

4. That the rotations adopted in a district, though faulty,
and, in the eyes of improved agriculture, deserving of condem-
nation, are often not only determined, but rendered necessary
by the natural structure of the country. When cold clays re-
fuse to bear even average crops of any other kinds than wheat
and beans, the old European rotation of wheat, beans, fallow—
which in this country has prevailed, in many places, since the
times of the ancient Britons—becomes almost a necessity to the
farmer. It is unfair to blame his rotations, or accuse him of
prejudice and ignorance in clinging to them, till the natural
condition of the land has been altered by art, so as to fit it for
the profitable growth of other crops.

The turnip and barley soils of Great Britain are in many dis-
tricts, it may be, but indifferently farmed; and the State has
reason to complain of much individual neglect® of known and
certain methods of increasing their productiveness. But the
great achievement which British agriculture has now to effect, as to
subdue the stubborn clays, and te convert them into, what many of
them are yet destined to become, the richest corn and green-crop bear-
ing lands in the kingdom.

5. That there are larger tracts of country still—such as rest
on the slates of the Lower Silurian and Cambrian systems, for
example—from which the efforts of the enlightened agriculturist
have hitherto been withheld, in consequence of the apparent
hopelessness of ever bringing them into profitable culture. Over
these tracts, however, there are large portions which will pay
well for skilful improvement. Make roads and drains, bring in
lime, and manure well. You will thus improve the soil, gradu-
ally ameliorate the climate, make modern skill and improvements
available, obtain a remunerating return for labor economically
expended, and for capital judiciously invested, and you will at the
Same time increase the power and the resources of the country.

CHAPTER VIII.

Poor soils of the granites and fertile soils of the trap rocks, and of the modern
lavas.—Composition of felspar and hornblende.—Accumulations of trans-
ported sands, gravels, and clays.—Their influence on agricultural capa-
bility—Mlustration from the neighborhood of Durham.—Importance of
surface or drift geology to agriculture.—General uniformity in the agri-
cultural character of the rocks and soils on geological formations of the
same age.—Exceptions among the Silurian rocks.— Use of geological maps
in reference to agriculture.

Ir was stated in a preceding chapter that rocks are divided
by geologists into the stratified and the wnstratified.* The stra-
tified rocks cover by far the largest portion of the globe, and
form the great ¥ariety of soils, of which a general description
has just been given. The unstratified rocks are of two kinds—
the granites and the trap rocks; and as a considerable portion
of the area, especially of the northern half, of our island is covered
by them, it will be proper shortly to consider the peculiar char-
acters of each, and the differences of the soils produced from them.

SECTION I.—POOR SOILS OF THE GRANITES, AND FERTILE SOILS OF
THE TRAP ROCKS AND MODERN LAVAS.

1. The Granites consist of a mixture, in different proportions,
of three minerals, known by the names of quartz, felspar, and
mica. The latter, however, is generally present in such small
quantity, that in our general description it may be safely left

* The unstratified are often called crystalline rocks, because they fre-
quently have a glassy appearance, or contain regular crystals of certain
mineral substances; often also igneous rocks, because they appear all to have
been originally in a melted state, or to have been produced by fire.

-

POOR GRANITE SOILS. 105

out of view. Granites, therefore, consist chiefly of quartz and
felspar, in proportions which vary very much; but the former,
on an average, constitutes perhaps from one-third to one-half of
the whole.

Quartz has already been described as being the same sub-
stance as flint, or the silica of the chemist. When the granite
decays, this portion of it forms a more or less coarse silicious
sand.

Felspar is a white, greenish, or flesh-colored mineral, often
more or less earthy in its appearance, but generally hard and
brittle, and sometimes glassy. It is scratched by quartz, and
thus is readily distinguished from it. When felspar decays, it
forms an exceedingly fine tenacious clay, (pipe-clay.)

Granite generally forms hills, and sometimes entire ridges of
mountains. When it decays, the rains and streams wash out
the fine felspar clay, and carry it down into the valleys, leaving
the quartz sand on the sides of the hills. Hence the soil in the
bottoms and flats of granite countries consists of a cold, stiff,
wet, more or less impervious clay, which, though capable of
much improvement by draining, often bears only heath, bo&, or
a poor and un-nutritive pasture. The hill sides are either bare,
or are covered with a thin, sandy, and ungrateful soil, of which
little can be made without the application of much skill and
industry. Yet the opposite sides of the same mountains often
present a remarkable difference in this respect; those which are
most beaten by the rains having the light clay most thoroughly
washed from their surfaces, and being therefore the most sandy
and barren.

2. The Trap rocks, comprising the green-stones and basalts—
both sometimes called whin-stones—consist éssentially* of felspar
and hornblende or augite. In contrasting the trap rocks with
the granites, it may be stated generally, that while the granites

* The reader is referred for more precise information to the Author's
“LECTURES,” 2d edition.

5

106 COMPOSITION OF FELSPAR AND HORNBLENDE.

consist of felspar and quartz, the traps consist of felspar and
hornblende (or augite.) In the traps, both the felspar and the
hornblende are reduced, by the action of the weather, to a more
or less fine powder, affording materials for a soil ; in the granites,
the felspar is the principal source of the fine earthy matter they
are capable of yielding. If we compare together, therefore, the
chemical composition of the two minerals, (hornblende and fel-
spar,) we shall see in what respect these two varieties of soil
ought principally to differ. Thus they consist respectively of—

Felspar. Hornblende.
Silica, : - - - 65 42
Alumina, - - - 18 14
Potash and soda, - - 17 trace
Lime, - - - - trace. 12
Magnesia, - - - do. 14
Oxide of iron, - - - do. 143
Oxide of manganese, - - do. 3

100 97

A remarkable difference appears thus to exist, in chemical
composition, between these two minerals—a difference which
must affect also the soils produced from them. <A granate soil, in
addition to the silicious sand, will consist chiefly of silica, alu-
“mina, and potash, derived from the felspar. A trap soil, in addi-
tion to the silica, alumina, and potash from its felspar, will
generally contain also much lime, magnesia, and oxide of iron,
derived from its hornblende. If the variety of trap consist
chiefly of hornblende, as is sometimes the case, the soil formed
from it will derive nearly 2} cwt. each of lime, magnesia, and
oxide of iron, from every ton of decayed rock. A hornblende
soil, therefore, contains a greater number of those inorganic
substances which plants require for their healthy sustenance, and,
therefore, will prove more generally productive than a soil of
decayed felspar. But when the two minerals, hornblende and
felspar, are mixed together, as they are in the variety of trap
called green-stone, the soil formed from them must be still more

~~, oe

FERTILITY OF TRAP AND GREEN-STONE SOILS. 107

favorable to vegetable life. The potash and soda, of which the
hornblende is nearly destitute, is abundantly supplied by the fel-
spar; while the hornblende yields lime and magnesia, which are
known to exercise a remarkable influence on the progress of
vegetation.

This chemical knowledge of the nature and differences of .the
rocks from which. the granite and trap soils are derived, explains
several interesting practical observations. ‘Thus it shows—

a. That while granite soils, in their natural state, may be
eminently unfruitful, trap soils may be eminently fertile ; and
such is actually the result of observation and experience in
every part of the globe. Unproductive granite soils cover nearly
the whole of Scotland, north of the Grampians, as well as large
tracts of land in Devon and Cornwall, and on the east and west
of Ireland. On the other hand, fertzle trap soils extend over
thousands of square miles in the lowlands of Scotland, and in the
north of Ireland; and where in Cornwall they occasionally mix
with the granite soils, they are found to redeem the latter from
their natural barrenness.

But while such is the general rule in regard to these two
classes of soils, it happens on some spots that the presence of
other minerals in the granites, or of hornblende or mica in
larger quantity than usual, gives rise to a granitic soil of average”
fertility, as is the case in the Scilly Isles. In like manner, the
trap rocks are sometimes, as in parts of the Isle of Skye, so
peculiar in their composition as to condemn the land to almost
hopeless infertility.

b. Why in some districts the decayed traps, under the local
names of Rotten rock, Marl, &c., are dug up, and applied with
advantage, as a top-dressing, to other kinds of land. They
afford supplies of lime, magnesia, &c., of which the soils they
are found to benefit may be naturally deficient. And as, by
admixture with the decayed trap, the granitic soils of Cornwall
are known to be improved in quality, so an admixture of decayed

108 LIMING OF TRAP SOILS.

granite with many trap soils, were it readily accessible, might
add to the fertility of the latter also,

c. Why the application of lime in certain trap districts adds
nothing to the fertility of the land. The late Mr, Oliver of
Lochend informed me that he had never known a case in which
the application of lime within five miles of Edinburgh had done
any good. This he accounted for from the vast number of
oyster shells which are mixed with the town dung laid on by the
Edinburgh farmers. Another important reason, however, is the
abundance of lime contained in the trap rocks from which the
soils are formed, and of which they contain so many fragments.
A piece of decaying trap I lately picked up on the north side
of the Pentland hills, on the farm of Swanstone, was found in
my laboratory to contain as much as 16 per cent of carbonate
of lime.

d. Why, as in many parts of the counties of Ayr and Fife,
the application of lime is found to be useful when the trap soils
are first broken up or reclaimed, but to produce little sensible
benefit for twenty or thirty years afterwards, however frequently
applied. In these cases the lime has been washed out of-the
surface soil, and from the thoroughly decayed parts of the trap,
so that, when first broken up, lime is necessary to supply the
deficiency. But the constant turning up of the soil by the after-
cultivation exposes fresh portions of trap to the air, the decay
of which annually supplies a quantity of lime to the soil from the
rocky fragments themselves, and renders further artificial appli-
cations less necessary. I have picked up a piece of decaying
trap, of which the outer portion contained scarcely any lime,
while the central kernel contained a large proportion. The
plough and harrow break up such decaying masses, and expose
the undecomposed kernels to the weathering action of the atmo-
sphere, and to the roots of the growing crops.

3. The Lavas which often cover large tracts of country, where
active or extinct volcanoes exist, are composed essentially of the
same mineral substances as the trap rocks. These latter, indeed,

APPARENT DIFFICULTIES. 109

are in general only lavas of a more ancient date. Like the
traps, the lavas not unfrequently abound in hornblende or augite,
and consequently in lime. They also crumble, with various
degrees of rapidity, when exposed to the air, and in Italy and
Sicily often form soils of the most fertile description. Like the
traps also, when in a decayed state, they may be advantageously
employed for the improvement of less fruitful soils. In St.
Michael’s, one of the Azores, the natives pound the volcanic
matter and spread it on the ground, where it speedily becomes
a rich mould, capable of bearing luxuriant crops.

SECTION II.—OF THE SUPERFICIAL ACCUMULATIONS OF TRANSPORTED
MATERIALS ON DIFFERENT PARTS OF THE EARTH’S SURFACE, AND
THEIR RELATIONS TO THE SOIL.

It is necessary to guard the reader against disappointment
when he proceeds to examine the relations which exist between
the soils and the rocks on which they lie, or to infer the quality
_of the soil from the known nature of the rock on which it rests
—in conformity with what has been above laid down—by ex-
plaining another class of geological appearances, which present
themselves not only in our own country, but in almost every
other part of the globe.

The unlearned reader of the preceding section and chapter
may say—I know excellent land resting upon the granites, fine
turnip soils on the Oxford or London clays, tracts of fertile fields
on the coal measures, and poor gravelly farms on the boasted
new red sandstone: I have no faith in theory—I can have none
in theories which are so obviously contradicted by natural ap-
pearances. Such, it is to be feared, is the hasty mode of rea-
soning among too many locally* excellent practical men—

* By locally excellent, I mean those who are the best possible farmers on
their own districts and after their own way, but who would fail in other
districts requiring other methods. To the possessor of agricultural princi-
ples, the modifications required by difference of crop, soil, and climate,

4

11Oh LOOSE, TRANSPORTED MATERIALS.

familiar, it may be, with many useful and important facts, but
untaught to look through and beyond isolated facts to the
principles on which they depend.

Every one who has lived long on the more exposed shores of
our island, has seen that, when the weather is dry, and the sea-
winds blow strong, the sands of the beach are carried inland and
spread over the soil, sometimes to a considerable distance from
the coast. In some countries this sand-drift takes place to a
very great extent, travels over a great stretch of country, and
gradually swallows up large tracts of fertile land, and converts
them into sandy deserts.

Again, most people are familiar with the fact, that during
periods of long continued rain, when the rivers are flooded and
overflow their banks, they not unfrequently bear with them loads
of sand and gravel, which they carry far and wide, and strew at
intervals over the surface soil.

So the annual overflowings of the Nile, the Ganges, the Mis-
sissippi, and the river of the Amazons, gradually deposit accu-
mulations of soil over surfaces of great extent;—and so also the
bottoms of most lakes are covered with thick beds of sand, gravel
and clay, which have been conveyed into them from the higher
grounds by the rivers which flow into them. Over the bottom
of the sea also, the ruins of the land are spread. Torn by the
waves from the crumbling shore, or carried down from great
distances by the rivers which lose themselves in the sea, they
form beds of mud, or banks of sand and gravel of great extent,
which cover and conceal the rocks on which they lie.

To these and similar agencies, a large portion of the existing
dry land of the globe has been, and is still, exposed. Hence,
in many places, the rocks and the soils naturally derived from
them are buried beneath accumulated heaps of layers of sand,
gravel, and clay, which have been brought from a greater or
less distance, and which have not unfrequently been derived

readily suggest themselves, where the mere practical man is bewildered,
disheartened, and in despair.

CIRCUMSTANCES TO BE CONSIDERED. lll

from rocks of a totally different kind from those of the districts
in which they are now found. On these accumulations of trans-
ported materials, a soil is produced which often has no relation
in its characters to the rocks which cover the country, and the
nature of which soils, therefore, a familiar acquaintance with
the rocks on which they immediately rest would not enable us to
predict.

To this cause is due that discordance between the first indi-
cations of geology, as to the origin of soils from the rocks on
which they rest, and the actually observed characters of those
soils in certain districts—of which discordance mention has heen
made as likely to awaken doubt and distrust in the mind of the
less instructed student, in regard to the predictions of agricul-
tural geology. There are several circumstances, however, by
which the careful observer is materially aided in endeavoring to
understand what the nature of the soils is likely to be in any
given district, and how they ought to be treated even when the
subjacent rocks are thus overlaid by masses of drifted materials.
Thus—

1. It not unfrequently happens that the materials brought
from a distance are more or less mixed up with the fragments
and decayed matter of the rocks which are native to the spot,
—so that, though modified in quality, the soil nevertheless
retains the general characters of that which is formed in other
places from the decay of these rocks alone.

2. Where the formation is extensive, or covers a large area,
—as the new red sandstones and coal measures do in this coun-
try, the mountain limestones in Ireland, and the granites in the
north of Scotland,—the transported sand, gravel, or clay,
strewed over one part of the formation, has not unfrequently
been derived from the rocks of another part of the same for-
mation ; so that, after all, the soils may be said to be produced
from the rocks on which they rest, and may be judged of from
the known composition of these rocks.

3. Or if not from the rocks of the same formation, they

112 SOILS OVERLAP THEIR NATURAL LIMITS.

have most frequently been derived from those of a neighboring
formation—from rocks which are to be found at no great distance
geologically, and generally on higher ground. Thus the ruins
of the millstone-grit rocks are in this country often spread over
the surface of the coal measures—of these, again, over the
magnesian limestone—of the latter over the new red sand-
stone, and so on. The effect of this kind of transport of the
loose materials upon the character of the soils is merely to
overlap, as it were, the edges of one formation with the proper
soils of the formations that adjoin it, in the particular direction
from which the drifted materials are known to have come.

It appears, therefore, that the occurrence on certain spots, or
tracts of country, of soils that have no apparent relation to the
rocks on which they immediately rest, tends in no way to
throw doubt upon, to discredit or to disprove, the conclusions
drawn from the more general facts and principles of geology.
It is still generally true that soils ave derived from the rocks on
which they rest. The exceptions are local, and the difficulties
which these local exceptions present, require only from agricul-
tural geologists a more careful study of the structure of each
district—of the direction of the highlands—the nature of the
slopes—the course and width of the valleys—and the extent of
the plains,—before they pronounce a decided opinion as to the
degree of fertility which the soil either naturally possesses, or
by skilful cultivation may be made to. attain.

‘It is not to be denied, however, that the practical importance
of these local exceptions is becoming every day more manifest,
and the necessity more apparent for a careful recording and
mapping of them in the interests of agriculture. Riding over
the country, for example, due north from the city of Durham,
a distance of about three miles, till we are stopped by a bend
of the river Wear, the superficial covering, so far as it can be
seen, is represented by the subjoined section.

a”

DRIFT COVERING NEAR DURHAM. 113

No. 1.
Kimbles-
Red Hills. worth.
B Bishop’s
Ach Grange.
Es
bs 88
he a
é 2 ae
Pe) eG

1. Yellow unstratified hard clay with small stones and
boulders, forming cold impervious clay soils, 3 to 40 feet.

2. Yellow sand, loose, with fragments of drifted coal and
sandstone gravel and botilders, forming potato, sete and light
turnip soils, 10 to 100 feet.

3. Blue unstratified clay, with boulders—often wanting—10
to 30 fest.

4. The coal measures lying beneath.

All the country being covered, as this section represents,
with from 30 to 120 feet of superficial sands and clays, it is
obvious that it can be of comparatively little use to me to know
that the sandstones and shales of the coal measures lie far
below ; and though I know that the sands and clays are all
derived from the crumbled beds of the coal measures, yet they
give me no information respecting the sandy nature of the soils
near Kimblesworth, or that they are cold and clayey about
Bishop’s Grange. The nature of the soil in each portion of the
district—and the same is true of a large portion of the county
of Durham—depends upon whether the clay or the sand comes
to the surface. This can only be shown upon special maps, rig-
orously prepared for the purpose ; and these the progress of
scientific agriculture will soon render indispensable.

SECTION III.—GENERAL UNIFORMITY IN THE AGRICULTURAL CHAR-
ACTER OF THE ROCKS AND SOILS ON GEOLOGICAL FORMATIONS OF
THE SAME AGE,

And yet there is a wonderful degree of general uniformity in

114 UNIFORMITY IN THE AGRICULTURAL CHARACTER

the mineral character and agricultural capabilities of the same
geological formation in different countries, even when they lie at
great distances from each other. I have already alluded, for
example, in a preceding chapter,* to the natural dryness of the
belt of chalk which runs along the Atlantic border of the
United States. The scarcity of water experienced by those
who residé upon it is often great. Every one knows that the
same is true of our own chalk region in England, and that this
very materially affects its agricultural capabilities. It is famil-
iar to every one also, that in very many places wells are sunk
through it with the view of reaching water, and that in London
ereat depths are gone to, and at a vast expense, through the
London clay and the chalk, before water can be obtained. In
the Paris basin the chalk is equally dry ; and there are very
few who have not read of the remarkably deep well at Grenelle
in the neighborhood of Paris, which, like the less profound
London wells, has been sunk to the sands below the chalks, and
with similar success.

So, in the remote State of Alabama, on this formation, water
is only to be obtained by sinking through the chalk ; and there
also this circumstance modifies in a wonderful degree the gene-
ral dispositions of rural economy. ‘Three years ago there were
already about 500 wells in that State, sunk to a depth of from
400 to 600 feet, there being one generally upon each plantation.
And thus, while the climate there, as elsewhere, determines the
general character of the vegetable produce, and what kind of
plants under the meteorological conditions can arrive at perfec-
tion, yet the geological structure determines, and enables us to
judge beforehand, to a certain extent, whether or not any crops
shall be able to grow at all, and of the kind of plants suitable
to the climate, which can be profitably cultivated, under the
circumstances of soil and dryness, which that geological structure
implies.

* See the diagram in ry

OF SOILS OF THE SAME FORMATION. 115

I may here remark, that, in this case of Alabama, the geo-
logical structure determines more. In such a climate, and with
a soil so naturally arid, abundant water is indispensable ; but
this can only be obtained by deep boring, performed at a great
expense. The geological conditions, therefore, confine the pos-
sibility of cultivation to men of large means, and, in present
circumstances at least, necessarily exclude all petty farming and
the subdivision of the land into small holdings. They deter-
mine, in other words, the social condition of the people. This
single illustration is enough of itself to satisfy any impartial
person of the close general relation which exists between the
geological character and the agricultural capability of a coun-
try, and of the broad general deductions in regard to its possible
future prosperity—in a rural sense—which may be drawn from
a knowledge of its geology. I believe it is partly under the
influence of this conviction that the Senate and Congress of the
United States have so often and so cordially voted large sums
of money for the purpose of investigating and mapping the
main geological features of the new States and territories which
from time to time have been admitted into the Union.

Geological maps, such as those now referred to, indicate with
more or less precision the extent of country over which the
chalk, the red sandstone, the granites, &c., are found immedi-
ately beneath the loose materials on the surface. Such maps,
therefore, are of great value in indicating also the general qual-
ity of the soils over the same districts. It may be true, as I
have above explained, that here and there the natural soils are
masked or buried by transported materials—yet the polztical
economist may, nevertheless, with safety estimate the general
agricultural capabilities and resources of a, country by the study
of its geological structure—the capitalist judge in what part of
it he is likely to meet with an agreeable or profitable investment
—and the practical farmer in what country he may expect to
find land that will best reward his labors, that will admit of
the kind of culture to which he is most accustomed, or, by the

116 GEOLOGY NOT PERFECT.

application of better methods, will manifest the greatest agri-
cultural improvement.

There are many cases also in which geology, leaving the hum-
bler task of explaining why certain regions exhibit, or are capa-
ble of exhibiting, singular natural fertility, or the reverse,
advances to the higher gift of prediction. United theory and
observation enable it not only to point out where rich and
desirable lands are sure to be found—to inform the statesman
as to the true value of regions still wild and neglected—to
direct the agricultural emigrant in the choice of new homes—
but looking far into the future, to specify also the kind of popu-
lation and the processes of industry which will hereafter prevail
upon it—the comparative comfort, wealth, numbers, and even
morality, of its future people.

That there are certain cases in which geology finds herself at
fault, or her general deductions unsupported by the reality, is
only a proof that it is a part of human science, rapidly pro-
gressive, but still full of imperfections.

CHAPTER IX.

2

Of the physical, chemical, and botanical relations of soils—Physical proper-
ties. — Density, absorbent, and evaporative powers, capillary action,
shrinkage, absorption of moisture from the air, and of heat from the sun.
—Functions of soils in reference to vegetation.—Chemical composition and
analysis of soils.—Comparative composition of certain fertile and barren
soils.—Importance of certain forms of organic matter to the fertility of a
soil—The black earth of central Russia.—Direct relation between the
character of the soil and the kind of plants that naturally grow upon it.

Sorts formed, as we have described, from the ruins of crumb-
led rocks, more or less sorted and drifted by water, possess
three classes of properties, intimately related to each other,
and to their special agricultural value. These are their phy-
sical, chemical, and botanical properties. A brief consideration
of these will form the subject of the present chapter.

SECTION I.—OF THE PHYSICAL PROPERTIES OF SOILS.

1°. Density.—Some soils are heavier and denser than others,
sands and marls weighing most and dry peaty soils the least.
This density is of so much practical importance, that treading
with sheep and other stock is resorted to in many districts,
with the view of rendering the land more solid ; or heavy
rollers are passed over it, to prepare a firm seed-bed for the
corn. Also, in reclaiming peaty soils, it is found highly bene-
ficial to increase their density by a covering of clay or sand, or,
‘as in Ireland, of limestone gravel.

2°, Absorption of water— Again, some soils absorb the
rains that fall, and retain them in larger quantity and for a
longer period than others. Strong clays absorb and retain
nearly three times as much water as sandy soils do, while peaty

118 PHYSICAL PROPERTIES OF SOILS.

soils absorb a still larger proportion. Hence the more fre-
quent necessity for draining clayey than sandy soils ; and hence
also the reason why, in peaty land, the drains must be kept
carefully open, in order that the access of springs and of other
water from beneath may be as much as possible prevented.

3°. The capillary action of soils also differs.. Some, when
immersed in water, will become moist, or attract the water
upwards for 10 or 12 inches, some as many as 16 or 18 inches,
above the surface of the water. This property is of great
importance in reference to the growth of plants—to the rising
of water to the surface of land which rests upon a wet subsoil
—to the necessity for thorough drainage—to the general
warmth of the soil, and so on.

4°. Evaporative power—When dry weather comes, soils lose
water by evaporation with different degrees of rapidity. In
this way a silicious sand will give off the same weight of water,
in the form of vapor, .in one-third of the time necessary to
evaporate it from a stiff clay, a peat, or a rich garden mould,
when all are equally exposed to the air. Hence the reason
why plants are so soon burned up ina sandy soil. Not only
do such soils retaen less of the rain that falls, but that which is
retained is also more speedily dissipated by evaporation.
When rains abound, however, or in very moist seasons, these
Same properties of sandy soils enable them to dry quickly, and
thus to sustain a luxuriant vegetation at a time when plants
will perish on clay lands from excess of moisture.

5°. Shrinkage-—In drying under the influence of the sun,
soils shrink in, and thus diminish in bulk, in proportion to the
quantity of.clay or of peaty matter they contain. Sand
scarcely diminishes at all in bulk by drying, but peat shrinks
one-fifth in bulk, and strong agricultural clay nearly as much.
The roots are thus compressed and the air excluded from them,
especially in the hardened clays, in very dry weather, and thus
the plant is placed in a condition unfavorable to its growth.
Hence the value of proper admixtures of sand and clay. By

TEMPERATURE OF A SOIL, 119

the latter (the clay) a sufficient quantity of moisture is re-
tained, and for a sufficient length of time; while by the former
the roots are preserved from compression, and a free access of
the air is permitted.

6°. Absorption of moisture from the air.—In the hottest and.
most drying weather, the soil has seasons of respite from the
scorching influence of the sun. During the cooler season of
the night, even-when no. perceptible dew falls, it has the power
of again extracting from the air a portion of the moisture it
had lost during the day. Perfectly pure sand possesses this
power in the least degree ; it absorbs little or no moisture
from the air. <A stiff clay, on the other hand, will, in a single
mght, absorb sometimes a 30th part of its own weight, and a dry
peat as much as a 12th of rts weaght ; and, generally, the quan-
tity thus drunk in, by soils of various qualities, is dependent
upon the proportions of clay and vegetable matter they seve-
rally contain. We cannot fail to perceive from these facts,
how much the productive capabilities of a soil are dependent
upon the proportions in which its different earthy and vegetable
constituents are mixed together. ;

1°. The temperature of a sovl, or the degree of warmth it
is capable of attaining under the influence of the sun’s rays,
materially affects the progress of vegetation. Every gardener
knows how much bottom heat forces the growth, especially of
young plants ; and wherever a natural warmth exists in the
soil, independent of the sun, as in the neighborhood of vol-
canoes, there it exhibits the most exuberant fertility. One
main influence of the sun in spring and summer is dependent
upon its power of thus warming the soil around the young
roots, and rendering it propitious to their rapid growth. But
the sun does not warm all soils alike—some become much
hotter than others, though exposed to the same sunshine.
When the temperature of the air in the shade is no higher
than 60°, or 70°, a dry soil may become so warm as to raise the
thermometer to 90° or 100°. Mrs. Ellis states, that among

120 INFLUENCE OF THE SUN.

the Pyrenees the rocks actually smoke after rain, under the -
influence of the summer sun, and become so hot that you can-
not sit down upon them. In Central Australia, where the
thermometer is sometimes as high as 132° F. in the shade, and
157° in the sunshine, the ground becomes so hot that it kindles
matches that fall on it, and burns the skin off the dogs’ feet.
In wet soils the temperature rises more slowly, and rarely
attains the same height as in a dry soil by 10° or 15°. Hence
it is strictly correct to say, that wet soils are cold; and it is
easy to understand how this coldness is removed by perfect
drainage.* Dry sands and clays, and blackish garden mould,
become warmed to nearly an equal degree under the same sun ;
brownish-red soils are heated somewhat more, and dark-colored
peaty soils the most of all. It is probable, therefore, that the
presence of dark-colored vegetable matter renders the soil
more absorbent of heat from the sun, and that the color of the
dark-red marls of the new and old red sandstones may, in
some degree, aid the other causes of fer tility in the soils which
they produce. .

In reading the above observations, the practical reader can
hardly fail to have been struck with the remarkable similarity
in physical properties between stiff clay and peaty soils.
Both retain much of the water that falls in rain, and both
part with it slowly by evaporation. Both contract much in
drying, and both absorb moisture readily from the air, in the
absence of the sun. In this similarity of properties we see
not only why the first steps in improving both kinds of soil
must be very nearly the same, but why, also, a mixture either
of clay or of vegetable matter will equally impart to a sandy
soil many of those elements of ried ter bag which they are
alike possessed.

-* See the succeeding Chapter.

CHEMICAL COMPOSITION AND ANALYSIS OF SOILS. 121

SECTION Il.—OF THE CHEMICAL COMPOSITION AND ANALYSIS OF
SOILS.

Soils perform at least three functions in reference to vege-
tation. They serve as a basis in which plants may fix their
roots and sustain themselves in their erect position—they supply
food to vegetables at every period of their growth—and they
are the medium in which many chemical changes take place,
that are essential to a right preparation of the various kinds
of food which the soil is destined to yield to the growing
plant.

We have spoken of soils as consisting chiefly of sand, lime,
and clay, with certain saline and organic substances in smaller
and variable proportions. But the study of the ash of plants
(see chap. iv.) shows us that a fertile soil, besides its organic
matter, must of necessity contain an appreciable quantity of
twelve or fourteen different mineral substances, which, in most
cases, exist in greater or less relative abundance in the ash both
of wild and of cultivated plants.

Two well-known geological facts lead to precisely the same
conclusion. We have seen that the soils formed from the un-
stratified rocks—the granites and the traps—while they each
contain certain earthy substances in proportions peculiar to
themselves, yet contain also in general, especially the trap
soils, a trace of most of the other kinds of matter which are
found in the ash of plants. Again, it is equally certain that
the stratified rocks are only the more or less slowly accumu-
lated fragments and ruins of more ancient stratified or unstra-
tified masses, which, under various agencies, have gradually
crumbled to dust, been strewed over the surface in alternate
layers, and have afterwards again consolidated. The reader
will readily grant, therefore, that in all rocks, and consequently
in all soils, traces of every one of these substances may gene
rally be presumed to exist.

6

122 GENERAL COMPOSITION OF SOILS.

Actual chemical analysis confirms these deductions in regard
to the composition of soils. It shows that, in most soils, the
presence of all the constituents of the ash of plants may be de-
tected, though in very variable and sometimes in very minute
proportions ; and, following up its investigations in regard to
the effect of this difference in their proportions, it establishes
certain other points of the greatest possible importance to agri-
cultural practice. Thus, it has found, for example—

1. That as a proper adjustment of the proportions of clay,
sand, and vegetable matter, is necessary in order that a soil
may possess the most favorable physecal properties, so the
mere presence of the various kinds of food, organic and inor-
ganic, in a soil, is not sufficient tomake it productive of a given
crop, but that they must be present in such quantity that the
plant shall be able readily—at the proper season, and within
the time usually allotted to its growth—to obtain an adequate
supply of each.

Thus a soil may contain, on the whole, far more of a giyen
ingredient, such as potash, soda, and lime, than the crop we
have sown may require, and yet, being diffused through a large
quantity of earth, the roots may be unable to collect this sub-
stance fast enough to supply the wants of a rapidly growing
plant. To such a soil it will be necessary te add a further por-

- tion of what the crop requires.

Again, a crop of winter wheat, which remains nine or ten
months in the field, has much more leisure to collect from the
soils those substances which are necessary to its growth than a
crop of barley, which in cold climates like that of Sweden is
only from 6 to 74 weeks in the soil, and which in warm
countries like Sicily may be reaped twice in the year. Thus a
soil which refuses to yield a good crop of the quick-growing
barley may readily nourish a crop of slow-growing wheat.

2. That when a soil is particularly poor in certain of these

“substances, the valuable cultivated corn crops, grasses, and

USE OF CHEMICAL ANALYSIS TO AGRICULTURE. 123

trees, refuse to grow upon them in a healthy manner, and to
yield remunerating returns. And,

3. That when certain other substances are present in too
great abundance, the soil is rendered equally unpropitious to
the most important crops.

In these facts the intelligent reader will perceive the founda-
tion of the varied applications to the soil which are everywhere
made under the direction of a skilful practice—and of the diffi-
culties which, in many localities, lie in the way of bringing the
land into such a state as shall fit it readily to supply all the
wants of those kinds of vegetables which it is the special ob-
ject of artificial culture easily and abundantly to raise.

Chemical analysis is a difficult art—one which demands much
chemical knowledge, as well as skill in chemical practice;
(manipulation, as it is called,) and calls for both time and per-
severance—if valuable, trustworthy, and minutely correct results
are to be obtained. I believe it is only by aiming after such
minutely correct results that chemical analysis is likely to throw
light on the peculiar properties of those soils which, while they
possess much general similarity in composition and physical pro-
perties, are yet found in practice to possess very different agri-
cultural capabilities. Many such cases occur in every country,
and they present the kind of difficulties in regard to which
agriculture has a right to say to chemistry—‘‘ These are mat-
ters which I hope and expect you will satisfactorily clear up.”
But while agriculture has a right to use such language, she has
herself preliminary duties to perform. She has no right in one
breath to deny the value of chemical theory to agricultural
practice, and in another to ask the sacrifice of time and labor
in doing “her chemical work. Chemistry is a wide field, and
many zealous lives are now being spent in the prosecution of it,
without at all entering upon the domain of practical agriculture.
It may be that here and there it may fall in with the humor or
natural bias of some one chemist to apply his knowledge to this»
most important art; but hitherto the appreciation of such efforts

=

124 CLAY AND SAND IN SOILS.

has, except by a limited few, been so small—the reception of
scientific results and suggestions by the agricultural body gene-
rally so ungracious—that little wonder can exist that so many
chemists have quitted the field in disgust—that the i herp of
capable men should studiously avoid it.

SECTION IIJ.——-COMPARATIVE COMPOSITION OF FERTILE AND
e BARREN SOILS.

With the view of illustrating the deductions which, as above
stated, may be drawn from an accurate chemical analysis, I
shall exhibit the composition of three different soils, as deter-
mined by Sprengel, a German agricultural chemist.

No. 1 is a very fertile alluvial soil from East Friesland, for-
merly overflowed by the sea, but for sixty years cultivated with
corn and pulse crops, without manure.

No. 2 is a fertile soil near G6ttingen, which produces excel-
lent crops of clover, pulse, rape, potatoes, and turnips, the two
last more especially when manured with gypsum.

No. 3 is a very barren soil from Luneberg.

When washed with water in the manner described in page
76, they give respectively, from 1000 parts of soil—

No. 38°“ SNo: 2! No. 3.

Soluble saline matter, ; : 18 1 1
Fine clay and organic matter, . 937 839 599
Silicious sand, . : ; : 45 160 400
1000 ~~ 1000 1000

The most striking distinction presented by these numbers is
the large quantity of saline matter in No. 1. This soluble mat-
ter consisted of common salt, chloride of potassium, sulphate of
potash, and sulphate of lime, (gypsum,) with traces of sulphate
of magnesia, sulphate of iron, and phosphate of soda. The
presence of this comparatively large quantity of these different
saline substances—originally derived, no doubt, in great part

COMPOSITION OF CERTAIN SOILS BY ANALYSIS. 125

from the sea—was probably one reason why it could be so long
cropped without manure.

The unfruitful soil is much the lightest (in the agricultural
sense) of the three, containing 40 per cent of sand; but this is
not enough to account for its barrenness, many light soils con-
taining a larger proportion of sand, and yet being sufficiently
fertile.

The finer portions, separated from the sand and soluble mat-
ter, consisted, in 1000 parts, of—

Organic matter, : ; : : 97 50 40
Silica, ‘ , F , ‘ . 648 833 7178
Alumina, . P 3 4 3 57 51 o7
Lime, eee rey Aare ey CAT ee 5g 18 4
Magnesia, . - : : : ; 8} 8 1
Oxide of iron, . : : ; : 61 30 81
Oxide of manganese, . : - : 1 3 $
Potash, . ; . : : j 2 trace. trace.
Soda, ; ; . ‘ c : 4. do. do.
Ammonia, ‘ ; 2 : trace. do. do.
Chlorine, . : : ; ; ‘ 2 do. do.
Sulphuric acid, . , ¢ : ‘ 2 a do.
Phosphoric acid, sitet aos wei ants 45 1j do.
Carbonic acid, . ; : : 40 45 do.
Loss, . : : : : ; : 14 — 43

1000 1000 1000

1. The composition of No. 1 illustrates the first of the general
deductions stated in the preceding section—that a considerable
supply, namely, of adl-the species of inorganic food is necessary
to render a soil eminently fertile. Not only does this soil contain
a comparatively large quantity of soluble saline matter, but it
contains also nearly 10 per cent of organic matter, and what,
in connection with this, is of great importance, nearly 6 per
cent of lime. The potash and soda, and the several acids, are
also present in sufficient abundance.

2. In the second—a fertile soil, but one which cannot dispense
with manure—there is little soluble saline matter, and in the
insoluble portion we see that there are mere ¢races only of

126 PRACTICAL DEDUCTIONS.

potash, soda, and the important acids. Jt contains also only 5
per cent of organic matter, and less than 2 per cent of lime;
which smaller proportions, together with the deficiencies above
stated, remove this soil from the most naturally fertile class to
that class which is susceptible, in hands of ordinary skill, of
being brought to, and kept am, a very productive condition.

3. In the fine part of the third soil, we observe that there
are many more substances deficient than in No. 2. The organic
matter amounts apparently to 4 per cent, and there seems to be
nearly half a per cent of lime. But it will be recollected that
this soil contains 40 per cent of sand, (p. 125;) or that in every
hundred of soil there are only 60 of the fine matter, of which
the composition is presented in the table;—or 100 Ib. of the
native soil contain only 24 lb. of organic matter and § lb. of
lime.

But all these wants would not alone condemn the soil to
hopeless barrenness, because, in favorable circumstances, they
might all be supplied by art. But the oxide of iron amounts to
8 per cent of this fine part of the soil; a proportion of this sub-
stance which, in a soil containing so little lime and organic mat-
ter, appears, from practical experience, to be incompatible with
the healthy growth of eultivated crops. This soil, therefore,
requires, not only those substances of which it is destitute, but
such other substances also, or such a form of treatment, as shall
prevent the injurious effects of the large portion of oxide of iron
it contains.

In these three soils, therefore, we have examples, fifst, of one
which contains within itself all the elements of fertility; second,
of a soil which is destitute, or nearly so, of certain substances
required by plants, which, however, can be readily added by the
ordinary manures in general use, and to which the elements of
gypsum are especially useful, in aiding it to feed the potato and
the turnip; and third, of a soil not only poor in many of the
necessary species of the inorganic food of plants, but too rich

THE BLACK EARTH OF RUSSIA. 127

in one (oxide of iron) which, when present in excess, is usually
prejudicial to vegetable life.

This illustration, therefore, will aid the general reader in
comprehending how far rigid chemical analysis is fitted to
throw light upon the capabilities of soils, and to direct agricul-
tural practice.

SECTION IV.—IMPORTANCE OF CERTAIN FORMS AND QUANTITIES OF
ORGANIC MATTER TO THE FERTILITY OF A SOIL.

The black earth of Russia.—The Tchornor Zem, or black earth
of Central Russia, illustrates, in a very striking manner, the
fact, that the kind and quantity of the organic matter which a
soil contains are scarcely less influential upon its fertility than
the mineral constituents to which, in the last section, I prin-
cipally adverted. This remarkable black soil, ‘‘the finest in
Russia, whether for the production of wheat or grass,” covers
an area of upwards of 60,000 square geographical miles, and is
said to be everywhere of extreme and of nearly uniform fer-
tility. It nourishes a population of more than twenty millions
of souls, and yet annually exports upwards of fifty millions of
bushels of corn. This black earth stretches into Hungary, and
forms the largest extent of fertile soil possessing common and
uniform qualities which is anywhere known to exist. Its origin
and chemical composition, therefore, have naturally engaged
the attention both of scientific and of practical observers.

Its depth varies from 1 or 2 to 20 feet ; when moist, it is
jet black, and when dry, of-a dark brown. This dark color,
from which it derives its name, is due to the presence of or-
ganic, chiefly vegetable matter, in a peculiar decomposed state,
minutely divided and cneinintcly mixed with mineral matter.
Of the weight of the dry soil, it forms, in different samples,
from 6 to 18 per cent. This vegetable matter is distinguished
by two circumstances.

1. That it is in an exceedingly minute ati of division, and

128 ANALYSIS OF THE BLACK EARTH,

is intimately mixed with finely-divided mineral matter. The
black earth, therefore, forms a comparatively free and open
soil, into which the air penetrates and the roots of plants
descend freely.

2. It contains in a state of combination a considerable pro-
portion of nitrogen. In different samples this constituent has
been found to vary from 24 (Payen) to eight per cent (Schmidt)
of the weight of the organic matter. Through the action of
the air, this nitrogen will favor the production in the soil of
nitric acid, ammonia, and other soluble compounds containing
nitrogen, which I have already described as propitious to the
growth of plants.

But in this black earth the composition of the mineral or
inorganic part is also such as to promote fertility. In one
of the richest varieties, in which the organic matter amounted
to 18 per cent, the mineral matter was found to consist of—

Per cent.
Potash, ‘ : ; : : : 5.81
Soda, : ; : ; : : 2.31
Lime, : - : A : i 2.60
Magnesia, 5 : 0.95
Alumina and oxide of iron, with traces of
phosphoric i Pegg 17.32
Silica, of which 7 or 8 per cent were soluble, 70.94
99.95

We see in this analysis an abundant supply of those mineral
substances which appear to be so necessary to the healthy
growth of plants.

The general results of our analytical examination of soils,
therefore, are chiefly these—

a. That a due admixture of organic matter is favorable to
the fertility of a soil.

6. That this organic matter will prove the more valuable in
proportion to the quantity of nitrogen it holds in combination.

c. That the mineral part of the soil must contain all those
substances which are met with in the ash of the plant, and in

AND CAUSES OF ITS FERTILITY. 129

such a state of chemical combination that the roots of plants
can readily take them up in the requisite proportion.

It is to the long accumulation of the remains of forests, or
other abundant ancient vegetation, that the color of the Black
earth, and its richness in organic matter, is, with the greatest
probability, ascribed.

SECTION V.—OF THE DIRECT RELATION THAT EXISTS BETWEEN THE
CHARACTER OF THE SOIL AND THE KIND OF PLANTS THAT NATU-
RALLY GROW UPON It.

The importance of a minute study of the chemical composi-
tion of soils will, perhaps, be most readily appreciated by a
glance at the very different kinds of vegetables which, under
the same circumstances, different soils naturally produce ; in
other words, by a glance at their botanical relations.

There are none so little skilled in regard to the capabilities of
the soil, as not to be aware that some lands naturally produce
abundant herbage or rich crops, while others refuse to yield a
nourishing pasture, and are deaf to the often-repeated solicita-
tions of the diligent husbandinan. There exists, therefore, a
universally understood connection between the kind of soil and
the kind of plants that naturally grow upon it. It is interest-
ing to observe how close this relation in many cases is.

1. The sands of the sea-shore, the margins of salt lakes and
the surfaces of salt plains, like the Russian steppes, are distin-
guished by their peculiar tribes of salt-loving plants—by varie-
ties of salsola, salicornia, &c. The Triticum junceum (sea
wheat) grows on the seaward slopes of the downs at no great
distance from the sea. The drifted sands more removed from
the beach produce their own long, waving, coarser grass,—the
Arundo arenaria, (sea bent,) the Elymus arenarius, (sea lime
grass,) and the Carex arenarius, (sand sedge,) the roots of
which plants bind the shifting sands together. The beautiful

6%

130 PLANTS SELECT THE SOILS

sea pink spreads itself over the loose downs—while further
inland, and as the soil changes, new vegetable races appear.

2. The peaty hills and flats of our island naturally clothe
themselves with the common ling, (Calluna vulgaris,) the fine-
leaved heath, (Erica conerea,) and with the cross-leaved heath,
(Erica tetralix.) When drained and laid down to grass, or
when they exist as natural meadows, they produce one soft
woolly grass almost exclusively—the Holcws lanatus. After
they are limed, these same soils become propitious to green
crops and produce much straw, but refuse to fill the ear. The
grain is thick-skinned, and therefore light in flour. There is a
greater tendency to produce cellular fibre, and the insoluble
matter associated with it, than the more useful substances starch
and gluten.

3. On the margins of water-courses in which silica abounds,
the mare’s tail (Aquisetum) springs up in abundance ; while, if
the stream contain much carbonate of lime, the water-cress
appears and lines the sides and bottom of its shallow bed, some-
times for many miles from its source.

4. The Cornish heath (rica vagans) shows itself rarely
above any other than the serpentine rocks; the red broom-
rape, ( Orobanche rubra, ) only on trap or basaltic rocks ; the
Anemone pulsatilla on the dry banks of chalky mounds, as in
the neighborhood of Newmarket ; the lady’s slipper on ealca-
reous formations only ; the Medicago lupulina on soils which
abound in marl ; while the red clover and the vetch delight in
the presence of gypsum, and the white clover in that of alka-
line matter in the soil.

So the red and white fire-weeds, Epilobiwm coloratum, and
Evrichtites. berecifolius, cover with their bright blossoms every
open space in the North American woods, over which the fires,
so frequent there, have run during the previous year. The
ashes of the burned trees and underwood are specially grateful
to the seeds of these plants, which in vast quantities he dor-
mant in the soils.

ON WHICH THEY PREFER TO GROW. 13]

5. The clays, too, have their likings. The Rest harrow,
(Ononis arvensis, ) delights in the weald, the gault, and the
plastic clays, but passes by the green-sand and chalk soils, by
which these clays are separated from each other. The oak, in
like manner, characterises the clays of the weald ; while the
elm flourishes, in preference, on the neighboring soils of the
green-sand formation.

6. Then, again, plants seem to alternate with each other on
the same soil. Burn down a forest of pines in Sweden, and
one of birch takes its place for a while. The pines after a
time again spring up, and ultimately supersede the birch. The
same takes place naturally. On the shores of the Rhine are
seen ancient forests of oak from two to four centuries old, gra-
dually giving place at present to a natural growth of beech,
and others where the pine is succeeding to both. In the Pala-
tinate, the ancient oak-woods are followed by natural pines;
and in the Jura, the Tyrol, and Bohemia, the pine alternates
with the beech.

These and other similar differences are believed to depend in
great part upon the chemical composition of the soil. The slug
may live well upon, and therefore infest, a field almost deficient
in lime ; the common land snail will abound at the roots of the
hedges only where lime is plentiful, and can easily be obtained
for the construction of its shell. So it is with plants. Hach
grows spontancously where its wants can be most fully and
most easily supplied. If they cannot move from place to place
like the living animal, yet their seeds can lie dormant, until
either the hand of man or the operation of natural causes pro-
duces such a change in their position, in reference to light,
heat, &., as to give them an opportunity of growing—or in
the composition and physical qualities of the soil itself, as to fit
it for ministering to their most important wants.

And such changes do naturally come over the soil. The oak,
after thriving for long generations on a particular spot, gradu-
ally sickens; its entire race dies out, and other races succeed it.

132 PLANTS SICKEN ON SOME SOILS.

Has the operation of natural causes gradually removed from
the soil that which favored the oak, and introduced or given
the predominance to those substances which favor the beech or
the pine? On the light soils of the state of New Jersey the
peach tree used to thrive better than anything else, and large
sums of money were made from the peach grounds in that
state. But of late years they have almost entirely failed. In
Scotland, the Scotch fir has been known at once to die out over
an area of 500 or 600 acres—and the forests of larch are now
in many localities exhibiting a similar decay. This decay is
often, I believe, owing to the presence of noxious matters in
the subsoil, but it is due in some cases also to a natural change
in the composition and character of the several soils, which has
taken place since the peach, the fir, and the larch trees were
first planted upon them.

In the hands of the farmer, the land grows sick of this crop

—it becomes tired of that. These facts may be regarded as
indications of a change in the chemical composition of the soil.
This alteration may proceed slowly and for many years; and
the same crops may still grow upon it for a succession of rota-
tions. But at length the change is too great for the plant to
bear; it sickens, yields an unhealthy crop, and ultimately refuses
altogether to grow.

The plants we raise for food have similar likes and dislikes
with those that are natur ally produced. Onsome kinds of food
they thrive; fed with others, they sicken or die. The soil must
therefore be prepared for their special growth.

In an artificial rotation of crops we only follow nature. One
kind of crop extracts from the soil a certain quantity of all the
inorganic constitnents of plants, but some of these in much
larger proportions than others. A second kind of crop carries
off, in preference, a large quantity of those substances of which
the former had taken little; and thus it is clearly seen, both
why an abundant manuring may so alter the composition of the
soil as to enable it to grow almost any crop; and why, at the

ee

AGRICULTURE A CHEMICAL ART. lee

same time, this soil may, in succession, yield more abundant
crops, and in greater number, if the kind of plants sown and
reaped be so varied as to extract from the soil, one after the
other, the several different substances which the manure we
have originally added is known to contain.

So with regard to the organic matter which soils contain.
That form of organic food which suits one, may not equally favor
another species of plant, and thus, at different times, different
species may be most suited to the chemical condition of the
same field.

The management and tilling of the soil, in fact, is a branch
of practical chemistry which, like the art of dyeing, of lead-
smelting, or of glass-making, may advance to a certain degree
of perfection without the aid of pure science, but which can
only have its processes explained, and be led on to shorter, more
simple, more economical, and more perfect processes, by the
aid of scientific principles.

wa

CHAPTER X.

Of the general improvement of the soil, and how the prudent man will
commence such improvement.—Mechanical methods of improving the
soil.—Draining, cause of the benefits produced by it—Draining of appa-
rently dry land.—Summary of the economical advantages of draining.— -
Depth to which drains ought to be dug.—Effects produced by the rains
as they descend through the soil.

THE soil, in its natural condition, is possessed of certain ex-
isting and obvious qualities, and of certain other dormant capa-
bilities. How are the existing qualities to be improved,—the
dormant capabilities to be awakened ?

SECTION I.—-OF THE GENERAL IMPROVEMENT OF THE SOIL, AND HOW
THE PRUDENT MAN WILL COMMENCE SUCH IMPROVEMENT.

There are few soils to which something may not still be done
in the way of improvement, while by far the greatest breadth
of the land, in almost every country, is still susceptible of ex-
tensive amelioration. In its present condition, the art of culti-
vating the land in England generally, differs from nearly all
other arts practised among us in this—that he who undertakes
it later in life, who brings to it a mind already matured, a good
ordinary education, a sound judgment, and a fair share of pru-
dence, who turns to it as a new pursuit, is often seen to take
the lead among the agriculturists of the district in which he
settles. He comes to the occupation free from the trammels of
old customs, old methods, and old prejudices, and hence, is free
to adopt a sounder practice and more rational methods of cul-
tivation. Such men, from lack of prudence or other causes,
have not always prospered in their worldly affairs, but they

GENERAL IMPROVEMENT OF SOILS. 135

have in very many districts been the beginners of agricultural
improvements, the introducers of better systems of culture, and
consequently public benefactors to the country.

What ought to be the course of sach a man in embarking
any serious amount of capital in this new pursuit ? What that _
of an intelligent practical farmer on establishing himself in a
new district?

Suppose them to be equally well read in the theory and in
the general practice of agriculture, they will—

1. Examine the quality of the land, its soil and its subsoil,
the exposure and the climate, the access to markets and to ma-
nures ; and generally, they will inquire what, in that district,
are the more common sources of disappointment to the indus-
trious farmer.

2. Consider what, in the abstract, theory would indicate as
the most proper treatment for such land so situated, and the
amount of produce it ought to yield.

3. Inquire what is the actual produce of the land, what the
actual practice in the district, and especially the cause or rea-
son of any local peculiarities in the practice which may be
found to prevail. There are often good reasons for local pecu-
liarities which new settlers injure themselves by overlooking,
and find out too late for their own interest. The prudent man
may look with suspicion upon such local customs, but he will
be satisfied that there is no sufficient reason for their adoption,
before he finally reject them to follow the indications of theory
alone.

In illustration of this I may mention, that a friend of mine
in Ayrshire, in agreeing to become the tenant*of a farm which
appeared to have been exhausted by the previous occupant,
founded his hopes of success on ploughing deeper, and thus
bringing a new soil to the surface, and his anticipations have
not been disappointed by the result. On the other hand, I
know of an instance in Berkshire, where, under the direction of
a new agent, deeper ploughing was introduced, and the crops

136 IMPROVEMENT BY DRAINING.

proved in consequence almost an entire failure. In this case
sound theory indicated a deeper ploughing, but local experience
had proved that shallow ploughing alone could preserve the
crops from the fatal ravages of insect tribes. The local custom
_ here, therefore, was founded upon a good reason, one sufficient
to deter the prudent man from hasty or extensive experiments,
though not enough to prevent him from seeking out some method
of so extirpating the insect destroyers from his land, as to enable
him afterwards to avail himself of its greater depth of soil.

Suppose it now to be determined that the land is capable of
being made to yield a larger produce, the questions recur—what
is the kind of improvement for which this land will give the
best return? how is this improvement to be best, most fully,
and at the same time most economically brought about?

All soils may be arranged into one or other of two classes.

1., Those which, like No. 1, (p. 125) contain in themselves
an abundant supply of all those things which plants require,
and are therefore fitted chemically to grow any crop.

2. Those which, like Nos. 2 and 3, (p. 126) are deficient in
some of those substances on which plants live, and are there-
fore not fitted to grow, perhaps, any one crop with luxuriance.

Both of these classes of soils, as they are naturally met with,
are susceptible of improvement, the former by mechanical
methods chiefly, the latter by mechanical partly, but chiefly by
chemical methods. In the present chapter we shall consider the
mechanical methods of improving the soil.

SECTION II.—OF IMPROVING THE SOIL BY DRAINING, AND THE CAUSES
OF THE BENEFITS PRODUCED BY IT,

The first step to be taken in order to increase the fertility of
nearly all the improvable lands of Great Britain, is to drain
them. The advantages that result from draining are manifold.

1°. The presence of too much water in the soil keeps it con-
stantly cold. The heat of the sun’s rays, which is intended by

EFFECTS OF DRAINING. 137

nature to warm the land, is expended in evaporating the water
from its surface ; and thus the plants never experience that
genial warmth about their roots which so much favors their
rapid growth.

The temperature which a dry soil will attain in the summer
time is often very great. Sir John Herschel observed, that at
the Cape of Good Hope the soil attained a temperature of 150°
Fahrenheit, when that of the air was only 120° ; and Hum-
boldt says, that the warmth of the soil between the tropics
often rises to from 124° to 136°, (see p. 119.)

When the land is full of water, it is only after long droughts,
and when it has been thoroughly baked by the sun, that it be-
gins to attain the temperature which dry land under the same
sun may have reached, day after day, probably for weeks before.

2°, Where too much water is present in the soil, also, that
portion of the food of the plant which the soil supplies is so
much diluted, that either a much greater quantity of fluid
must be taken in by the roots—much more work done by them,
that is—or the plant will be scantily nourished. The presence
of so much water in the stem and leaves keeps down ¢hezr tem-
perature also, when the sunshine appears—an increased evapo-
ration takes place from their surfaces—a lower natural heat, in
consequence, prevails in the interior of the plant, and the
chemical changes, on which its growth depends, proceed with
less rapidity.

3°. By the removal of the water, the physical properties of
the soil, also, are in a remarkable degree improved. Dry pipe-
clay can be easily reduced to a fine powder, but it naturally,
and of its own accord, runs together when water is poured
upon it. So it is with clays in the field. When wet, they are
close, compact, and adhesive, and exclude the air from the
roots of the growing plant. But remove the water and they
gradually contract, crack in every direction, become thus open,
friable, and mellow, more easily and cheaply worked, and per-
vious to the air in every direction.

138 DRAINING OF LIGHT gOILs.

4°. The access of this air is essential to the fertility of the
soil, and to the healthy growth of most of our cultivated
crops. The insertion of drains not only makes room for the
air to enter by removing the water, but actually compels the
air to penetrate into the under parts of the soil, and renews it
at every successive fall of rain. Open such outlets for the
water below, and as this water sinks and trickles away, it will
suck the air after it, and draw it into the pores of the soil
wherever itself has been.

Vegetable matter becomes of double value in a soil thus
dried and filled with atmospheric air. When drenched with
water, this vegetable matter either decomposes very slowly, or
produces acid compounds more or less unwholesome to the
plant, and even exerts injurious chemical reactions upon the
earthy and saline constituents of the soil. In the presence of
air, on the contrary, this vegetable matter decomposes rapidly,
‘produces carbonic acid in large quantity, as well as other com-
pounds on which the plant can live, and even renders the inor-
ganic constituents of the soil more fitted to enter the roots,
and thus to supply more rapidly what the several parts of the
plant require. Hence, on dry land, manures containing organic
matter, (farmyard manure, &c.,) go farther or are more profit-
able to the farmer.

5°. Nor is it only stiff and clayey soils to which draining
can with advantage be applied. It will be obvious to every
one, that when springs rise to the surface in sandy soils, a
drain must be made to carry off the water ; it will also readily
occur, that where a sandy soil rests upon a hard or clayey
bottom, drains may likewise be necessary ; but it is not un-
frequently supposed, that where the subsoil is sand or gravel,
thorough draining can seldom be required.

Every one, however, is familiar with the fact, that when
water is applied to the bottom of a flower-pot full of soil, it
will gradually find its way towards the surface, however light
the soil may be. So it isin sandy soils or subsoils in the open

SOIL LIABLE TO BE BURNGD UP. _ 139

field—all possess a certain power of sucking up water from
beneath, (p. 118.) If water abound at the depth of a few
feet, or if it so abound at certain seasons of the year, that
water will rise towards the surface; and as the sun’s heat
dries it off by evaporation, more water will follow to supply its
place. This attraction from beneath will always go on when
the air is dry and warm, and thus a double evil will erisue—
the soil will be kept moist and cold, and instead of a constant
circulation of air downwards, there will be a constant current
of water wpwards. Thus will the roots, the under soil, and
the organic matter it contains, be all deprived of the benefits
which the access of the air is fitted to confer, and both the
crops and the farmer will suffer in consequence.* The remedy
for these evils is to be found in an efficient system of drainage.

6°. It is a curious and apparently a paradoxical observation,
that draining often improves soils on which the crops are
liable to be burned wp in seasons of drought. Yet, upon a
little consideration, the fact becomes very intelligible. Let
a bbe the surface of the soil, and c d the

‘ level at which the water stagnates, or below
« which there is no outlet by drains or natural
é

openings. The, roots will readily penetrate
to c d; but they will in general refuse to descend farther,
because of the unwholesome substances which usually collect
in water that is stagnant. Let a dry season come, ands their
roots having little depth, the plants will be more or less speed-
ily burnt up. And if water ascend from beneath the line ¢ d,
to moisten the upper soil, it will bring with it those noxious
substances into which the roots have already refused to pen-
etrate, and will cause the crop to droop and wither. But put

* A few miles south of the town of Elgin in Morayshire, I was shown a
tract of land on which the crops were usually three weeks later than on
another tract, separated from it by a small stream. Beneath the former
was a pan at the depth of 3 feet, which prevented the surface-water
from sinking beyond that level, and thus retarded the growth of the crop.

140 REMOVAL OF OCHREY MATTER

ina drain, and lower the level of the water toe f, and the
rains will wash out the noxious water from the subsoil, and the
roots will descend deep into it; so that if a drought again
come, it may parch the soil above c d, as before, without in-
juring the plants, since now they are watered and fed by the
soil beneath, into which the roots have descended.

7°. In many parts of the country, and especially in the red-
sandstone districts, the oxide or rust of iron abounds so much
in the soil, or in the springs which ascend into it, as gradually
to collect.in the subsoil, and form a more or less impervious
layer or pan, into which the roots cannot penetrate, and
through which the surface-water refuses to pass. Such soils
are benefited, for a time, by breaking up the pan where the.
plough can reach it; but the pan gradually forms again at a
greater depth, and the evils again recur. In such cases, the
insertion of drains below the level of the pan is the most cer-
tain mode of permanently improving the soil. If the pan be
now broken up, the rains sink through into the drains, and
gradually wash out of the soil the iron which would otherwise
have only sunk to a lower level, and nome again formed itself
into a solid cake.

8°. It is not less common, even in rich and fertile districts,
to see crops of beans, or oats, or barley, come up strong and
healthy, and shoot up even to the time of. flowering, and then
begin to droop and wither, till at last they more or less com-
pletely die away. So it is rare in many places to see a second
year’s clover crop come up strong and healthy. These facts
indicate, in general, the presence of noxious matters in the
subsoil, which are reached by the roots at an advanced stage
of their growth, but into which they cannot penetrate without
injury to the plant. The drain calls in the aid of the rains of
heaven to wash away these noxious substances from the soil,
and of the air to change their nature, and this is the most
likely, as well as the cheapest, means by which.these evils can
be prevented.

AND OF SALINE INCRUSTATIONS. 14]

9°. Another evil in some countries presents itself to the prac-
tical farmer. Saline substances are in certain quantity bene-
ficial, nay, even necessary to the growth of plants. In excess,
however, they are injurious, and kill many valuable crops. I
have already adverted to the existence of such saline substances
in the soil, and to the fact of their rising in incrustations to the
surface (p. 76) when droughts prevail.

In some countries, as in the plains of Athens, and near the
city of Mexico, they come to the surface in such quantity as
actually to kill the more tender herbage, and to permit only the
stronger plants to grow. In the plains of Athens, when the
rainy season ends, a rapid evaporation of water from the surface
begins. The water, as it rises from beneath, brings much saline
matter with it. This it leaves behind as it ascends in vapor,
and thus at length so overloads the surface-soil that tender grass
refuses to grow, though the stronger wheat plant thrives well
and comes to maturity.

This result could scarcely happen if an outlet beneath were
provided for the waters which fall during the rainy season.
These would wash out and carry away the excess of saline mat-
ter which exists in the under soil, and would thus, when the dry
weather comes, prevent it from ascending in such quantities as
to injure the more tender herbage.

It may be objected to this suggestion, that drains in such
countries would render more dry a soil already too much parched
by the hot suns of summer. It is doubtful, however, if this
would really be the case. Deep drains, as in the case above
explained, (6°,) would enable the roots to penetrate deeper, and
would thus render them more independent of the moisture of
the surface-soil.

10°. On this subject I shall add one important practical re-
mark, which will readily suggest itself to the geologist who has
studied the action of air and water on the various clay-beds
that occur here and there, as members of the series of stratified
rocks. There are no clays which do not gradually soften under

/

142 DEPTH OF DRAINS.

the wnited influence of air, of frost, and of runnimg water. It rs
false economy, therefore, to lay down tiles of the common horse-shoe
form without soles, however hard and stiff the clay subsoil may
appear to be. In the course of ten or fifteen years, the stiffest

clays will generally soften so much as to allow the tile to sink to.

some extent—and many very much sooner. The passage for
the water is thus gradually narrowed; and when the tile has
sunk a couple of inches, the whole may have to be taken up.
Thousands of miles of drains have been thus laid down, both in
the low country of Scotland and in the southern counties of
England, which have now become nearly useless. The extend-
ing use of the pipe-tile will, it is to be hoped, gradually lessen
the chances of pecuniary loss, which the above practice involves.

SECTION III.—SUMMARY GF THE ECONOMICAL ADVANTAGES OF
DRAINING.

The economical advantages of draining in such soils as we
possess are chiefly these :—

1. Stiff soils are more easily and more cheaply worked.

2. Lime and manures have more effect, and go farther.

3. Seed-time and harvest are earlier and more sure.

4. Larger crops are reaped, and of better quality.

5. Valuable crops of wheat and turnips are made to grow
where scanty crops of oats were formerly the chief return.

6. Naked fallows are rendered less necessary, and more pro-
fitable rotations can be introduced.

T. The climate is improved, and rendered not only more suited
to the growth of crops, but more favorable to the health of man
and other animals.

SECTION IV.—OF THE DEPTH TO WHICH DRAINS OUGHT TO BE DUG.

Much has lately been written in regard to the depth to which
drains ought to be dug in a. system of thorough drainage. It is

_

ADVANTAGES OF DRAINING. 143

difficult, perhaps impossible, to establish any empirical or gene-
ral rule upon this subject; but there are certain indisputable
points which will serve to guide the intelligent farmer in most
cases which are likely to. occur.

1°. It is acknowledged, as a general rule, to-be of great im-
portance, that the soil should be deepened—that it should be
opened up, for the descent of the roots, to the greatest depth to
which it can be economically done. Now, by the use of the sub-
soil plough or the fork, the soil can be stirred to a depth of
from 22 to 24 inches. The tile—or the top of the drain, if made
of stones—should be at least three inches clear of this disturb-
ance of the upper soil; and as most tiles will occupy at least 3
inches, we reach 30 inches as the minimum depth of a tile drain,
and about 3 feet as the minimum depth of a stone drain, in
which the layer of stones has a depth of not more than 9 inches.

2°, Where the outfall is bad, and a depth of 30 or 36 inches
cannot be obtained, the drains should be made as deep as they
can be made to run and deliver water.

3°. The roots of our corn and other crops will, in favorable
circumstances, descend to a depth of 4 or 5 feet. They do so
in quest of food, and the crop above ground is usually the more
luxuriant the deeper the roots are enabled to penetrate. It is,
therefore, theoretically desirable to dry the soil to a greater
depth even than 3 feet, where it can be done without too great
an outlay of money.

4°, The question of economy, therefore, is one of great im-
portance in this inquiry. In some places it costs as much to
dig out the fourth or lowest foot as is paid for the upper three;
and this additional cost is, in many localities, a valid reason for
limiting the depth to 30 inches, or 3 feet.

5°. But the question of economy ought to be disregarded,
and deeper drains dug where springs occur beneath, or where,
by going a foot deeper, a bed or layer is reached in which much
water is present. The reason of this is—that though water
may not rise from this wet layer in such quantity as actually to

144 ’ RAINS WARM THE SOIL.

run along the drains, yet it may do so in sufficient abundance to
keep the subsoil moist and cold, and thus to retard the develop-
ment of the crops that grow on its surface.

The above circumstances appear sufficient to guide the prac-
tical man in most cases that will present themselves to him. No
uniform depth can be fixed upon; it must be modified by local
circumstances.

In regard to the distance apart at which drains should be
placed, experience appears to be the only satisfactory guide.
This says, as yet, that 18 to 21 feet are safe distances, and that
drains placed at greater distances are doubtful, and may fail to
dry the land.

SECTION V.—EFFECTS PRODUCED BY THE RAINS AS THEY DESCEND
THROUGH THE SOIL.

The most important immediate effect of thorough-drainage
is, that it enables the rain or other surface water to descend
more deeply and escape more rapidly from the soil. . It may be
interesting to specify briefly the benefits which are known to
follow from this descent of the rain through the soil.

1°. It causes the air to be renewed.—It is believed that the
admission of frequently renewed supplies of air into the soil is
favorable to its fertility. This the descent of the rain pro-
motes. When it falls upon the soil it makes its way into the
pores and fissures, expelling of course the air which previously
filled them. When the rain ceases, the water runs off by the
drains ; and as it leaves the pores of the soil empty above it,
the air follows, and fills with a renewed supply the numerous
cavities from which the descent of the rain had driven it.
Where land remains full of water, no such renewal of air can
take place.

2°. It warms the under soil—As the rain falls through the
air it acquires the temperature of the atmosphere. If this be
higher than that of the surface soil, the latter is warmed by it;

{
:
|

RAINS WASH OUT NOXIOUS MATTER. 145

and if the rains be copious, and sink easily into the subsoil,
they will carry this warmth with them to the depth of the
drains. Thus the under soil in well drained land is not only”
warmer, because the evaporation is less, but because the rains
in the summer season actually bring down warmth from the
heavens to add to their natural heat.

3°. It equalises the temperature of the soil during the season of
growth—The sun beats upon the surface of the soil, and gra-
dually warms it. Yet, even in summer, this direct heat descends
only a few inches beneath the surface. But when rain falls
upon the warm surface, and finds an easy descent, as it does in
open soils, it becomes itself warmer, and carries its heat down
to the under soil. Then the roots of plants are warmed, and
general growth is stimulated.

It has been proved, by experiments with the thermometer,
that the under as well as the upper soil is warmer in drained
than in undrained land, and the above are some of the ways by
which heat seems to be actually added to soils that have been
thoroughly drained.

4°, It carries down soluble substances to the roots of plants.—
When rain falls upon heavy undrained land, or upon any land
into which it does not readily sink, it runs over the surface, dis-
solves soluble matter, and carries it into the nearest ditch or
brook. Rain thus robs and impoverishes such Jand.

But let it sink where it falls—then whatever it dissolves it
will carry downwards to the roots—it will distribute uniformly
the saline matters which have a natural tendency to rise to the
surface, and it will thus promote growth by bringing food every-
where within the reach of plants.

5°. It washes noxious matters from the wnder soil—In the sub-
soil, beyond the reach of the air, substances are apt to collect,
especially in red-colored soils, which are injurious to the roots
of plants. These the descent of the rains alters in part and
inakes wholesome, and in part washes out. The plough may
then safely be trusted deeper, and the roots of plants may

T

146 PROPORTION OF RAIN EVAPORATED.

descend in search of food where they would previously have
been destroyed.

It is true that, when heavy rains fall, they will also wash out
of the soil and carry into the drains substances which it would
be useful to retain. Upon this fact some have laid unnecessary
stress, and have adduced it as an argument against thorough-
drainage. But if we balance the constant benefit against the
occasional evil, I am satisfied, as experience indeed has shown,
that-the former will greatly preponderate.

6°. It brings down fertilising substances from the air.—Besides,
the rains never descend empty-handed. They constantly bear
with them gifts, not only of moisture to the parched herbage,
but of organic aa saline food, by which its growth is promoted.
Ammonia and nitric acid, ae 33,) together with the many
exhalations which are daily rising from the earth’s surface,
come down in the rains.; common salt, gypsum, and other saline
substances derived from the sea, are rarely wanting ; and thus,
the constant descent from the heavens may well be supposed to
counterbalance the occasional washings from the earth.

T°. Much of the rain is evaporated.—And lastly, in answer to
this objection, it is of importance to state, that in our climate a
very large proportion of the rain that falls does not sink through
the soil, even where there are drains beneath, but rises again
into the air in the form of watery vapor. Experiments in Man-
chester have shown, that of 31 inches of rain which fall there
in ayear, 24 are evaporated ; while in Yorkshire, of 244 inches
of rain which fall, only 5 inches run off through pipes laid at a
depth of 2 feet 9 inches, the rest being evaporated. There-is
little cause, therefore, for the fear expressed by some, that the
draining of the land will cause the fertility in any perceptible
degree to diminish in consequence of the washing of the descend-
ing rains. They may, as I have said, improve the subsoil by
washing hurtful substances out of it ; but, in general, the soil
will have extracted from the water which filters through it all
the valuable matter it holds in solution before it has reached the
depth of a 3-feet drain.

CHAPTER XI.

Mechanical methods continued.—The subsoil-plough and the fork.—How
they act in improving the soil—Experiments on the profit of subsoiling.—
How deep ploughing and. trenching improve the soil—Chemical and
other effects of common ploughing.—Improvement of the soil by mixing.

Arter the land has been laid dry by drains, other mechanical
modes of improvement can be employed with advantage. Even
the ordinary methods of mechanical culture become more useful,
and the benefits which in favorable circumstances are derived
from turning up the soil are greater and more manifest. These
facts will appear by a brief consideration of the effects produced
by ploughing to various depths, and the causes from which they
arise. ;

SECTION I.—USE OF THE SUBSOIL-PLOUGH. HOW IT ACTS IN IMPROV-
ING THE SOIL.

The subsoil-plough is an auxiliary to the drain—it stirs and
opens the under soil without mixing it with the upper or imme-
diately active soil. Though there are few subsoils through
which the water will not at length make its way, yet there are
some so stiff, either naturally or from long consolidation, that
the good effect of a well-arranged line of drains is lessened by
the slowness with which they allow the superfluous water to pass
through them. In such cases, the use of the subsoil-plough is most
advantageous in loosening the under layers of soil, and in allow-
ing the water to find a ready escape downwards to either side,
until it reaches the drains.*

‘ ’
* For a fuller discussion of the benetits of drainage, see the Author's
Lectures.

148 HOW THE SUBSOIL-PLOUGH ACTS.

It is well known that if a piece of stiff clay be cut into the
shape of a brick, and then allowed to dry, it will contract and
harden—it will form an air-dried brick, almost impervious to
any kind of air. Wet it again, it will swell and become still
more impervious. Cut up wizle wet, it will only be divided into
so many pieces, each of which will harden when dry, or the
whole of which will again attach themselves and stick together
if exposed to pressure while they are still wet. But tear it
asunder when dry and it will fall into many pieces, will more or
less crumble, and,will readily admit the air into its inner parts.
So it is with a clay subsoil.

After the land is provided with drains, the subsoil being very
retentive, the subsoil-plough is used to open it up—to let out
the water and let in the air. If this is not done, the stiff under
clay will contract and bake as it dries, but it will neither suffi-
ciently admit the air, nor open so free a passage for the roots.
Let this operation, however, be performed when the clay is still
too wet, a good effect will follow in the first instance; buat after
a while the cut clay will again cohere, and the farmer will pro-
nounce subsoiling to be a useless expense on his land. Defer
the use of the subsoil-plough till the clay is dry—it will then
tear and break instead of cutting it, and its openness will remain.
Once give the air free access, and, after a time, it so modifies
the drained clay that it no longer has an equal tendency to
cohere.

Mr. Smith of Deanston very judiciously recommended that
the subsoil-plough should never be used till at least a year after
the land has been thoroughly drained. This in many cases will
be a sufficient safeguard—will allow a sufficient time for the
clay to dry: in other cases, two years may not be too much.
But this precaution has by some been neglected; and, subsoil-
ing being with them a failure, they have sought, in some sup-
posed chemical or other quality of their soi, for the cause of a
want of success which is to be found in their own neglect of a
most necessary precaution.. Let not the practical man be too

:

RESULTS OF EXPERIMENTS. 149

a
hasty in desiring to attain those benefits which attend the adop-
tion of improved modes of culture; let him give every method a
fair trial; and above all, let him make his trial wn the way and
with the precaution recommended by the author of the method, before
he pronounces its condemnation.

SECTION II._-EXPERIMENT ON THE PROFITS OF SUBSOILING.
USE OF THE FORK.

The benefits of subsoil ploughing having’ been sometimes
called in question, and there being even some cases on record
in which positive injury has been said to follow from the prac-
tice, I introduce the following numerical results observed on
two farms in the neighborhood of Penicuik, a few miles from
Edimburgh.

1°, Mr. Wilson of Eastfield, Penicuik, made an experiment,
after thorough drainage, upon two portions of land under each
of three crops, and found the effects in the first year after sub-
soil ploughing, compared with ordinary ploughing, to be as
follows :

TURNIPS. |—————-———| POTATOES.

Grain. | Straw.

tons. cwt.| qrs. cwt. | tons. cwt.

Ploughed to 8 inches, - - | 20 i Ty 28 6 144
Subsoiled to 15 inches, Sa ae dee 85 SOR bh oe
Difference, - G6. 10 ; 83 154

From this table, the effects of subsoiling to a depth of 15,
above that of ploughing to a depth of 8 inches, appears to have
been to increase the turnip crop by 64 tons, the potatoes by 15
ewt., and the barley by 7 bushels of grain and 8 ecwt..of straw.

2°. Mr. Maclean of Braidwood, near Penicuik, made a sim-

150 USE OF DEEP PLOUGHING.

ilar experiment with turnips and barley, with the following
results :—

BARLEY.
TURNIPS. - -
Grain. | Straw.
tons. cwt. qrs. stones.
Ploughed 8 inches deep, - -| 19 15 63 1683
Subsoiled to 15 inches, - -| 23 17 1g 2063

Difference, - - 4 2 1 | 38

The turnip crop, in this experiment, was increased 4 tons ;
and the barley crop by 6 bushels of grain and 38 stones of
straw.

It has been observed, also, that the effects of the subsoiling do
not cease with the first crop. In one case, in which an accurate
~ account of the produce was kept, the profit was estimated at 6s.
an acre, for five successive years after the operation. There is
reason, therefore, to anticipate general good from the careful
introduction of this practice ; though it is exceedingly desirable,
at the same time, that the causes of its failure, wherever it is
found to fail, should be rigorously investigated. _

The use of the fork, instead of the subsoil-plough, has lately
been recommended as a more efficient, and even a more econom-
ical method of opening up the under soil. The upper soil of 9
to 12 inches is thrown forward with a spade, and the under soil,
to a depth of 15 inches further, is stirred and turned over with _
a three-pronged fork. I have seen it in operation ; and it cer-
tainly does appear to loosen and open up the under soil more
effectually than the subsoil plough can do, and to a depth which
few subsoil-ploughs are yet able to reach.

SECTION III.—HOW DEEP PLOUGHING AND TRENCHING IMPROVE THE
y SOIL.

1°, Deep ploughing, like subsoiling, aids the effect of the

LIME AND CLAY SINK. 151

drains, and so far—where it goes nearly as deep—even more
completely effects the same object. But, independently of this,
it has other uses and merits, and, where it has been successfully
applied, has improved the land by the operation of other causes.

Subsoiling only lets out the water, and allows access to the
air and rains, and a free passage to the roots. Deep ploughing,
in addition to these, brings new earth to the surface, forms thus
a deeper active soil, and more or less alters both its physical
qualities and its chemical composition.

If the plough be made to bring up 2 inches of clay or sand,
it will stiffen or loosen the soil, as the case may be ; or it may
affect its color or density. It is clear and simple enough, there-
fore, that by deep ploughing, the physical properties of the soil
may be altered. ;

But there are certain substances contained in every soil,
whether in pasture or under the plough, which gradually make
their way down towards the subsoil. They sink till they reach
at last that point beyond which the plough does not usually pen-
etrate. Every farmer knows that lime thus sinks. In peaty
soils top-dressed with clay, as is done in Lincolnshire, the clay
thus sinks. In sandy. soils, also, which have been clayed, the
clay sinks: and in all these cases, I believe, the sinking takes
place more rapidly when the land is laid down to grass. Where
soils are marled, the marl sinks ; and the rains, in like manner,
gradually wash out that which gives their fertilising virtue to
the large doses of chalk which in some districts are spread upon
the land, and render necessary a new application to renovate its
productive powers.

If this be the case with earthy substances such as those now
mentioned, which are, for the most part, insoluble in water, it
will be readily believed that those saline ingredients of the soil
which are easily soluble, will be still sooner washed out of the
upper and conveyed to the under soil. Thus the subsoil may
gradually become rich in those substances of which the surface
soil has been robbed by the rains. Bring up .a portion of this

152 BRINGING UP THE SUBSOIL.

subsoil by deep-ploughing, and you restore to the surface soil a
part of what it has been gradually losing—you bring up what
may probably render it more fruitful than before. Such is an
outline of the reasons in favor of deep ploughing.

In Germany, theory has pointed out the growing of an occa-
sional deep-rooted crop in light soils to effect the same end. The
deep roots bring up again to the surface the substances which
had naturally sunk.

But suppose the land to have originally contained something
noxious to vegetation, which in process of time has been wash-
ed down into the subsoil, then to bring this again to the sur-
face would be materially to injure the land. This also is true,
and a sound discretion must be employed, in judging when and
where such evil effects are likely to follow.

Such cases, however, are more rare than many suppose.
There are few subsoils which after a year’s draining, a full and
fair exposure to the winter’s frost will not in a great degree de-
prive of all their noxious qualities, and render fit to ameliorate
the general surface of the poorer lands. If the reader doubt
this fact, let him visit Yester, and give a calm consideration to
the effects produced by deep ploughing on the home farm of the
Marquis of Tweeddale. Let him also study the practice of
deep ploughing, as it is followed by the Jersey farmers, and ho
will be still further persuaded of the value of deep-ploughing,
in some localities at least.

In many cases the farmer fears, as he does in some parts of
the county of Durham, to bring up a single inch of the yellow
clay that lies beneath his surface soil. In the first inch lodges,
among other substances, the iron worn from his plough, which,
in some soils, and after a lapse of years, amounts to a conside-
rable quantity. Till it is exposed to the air, this iron is hurt-
ful to vegetation ; and one of the benefits of a winter’s expo-
sure of such subsoils to the air arises from the effect produced
upon the iron they contain.

It is the want of drainage, however, and of the free access

COMMON PLOUGHING. 153

of air, that most frequently renders subsoils for a time injurious
to vegetation. Let the lands be well drained—let the subsoils
be washed for a few years by the rain water passing through
them—and there are few of those which are clayey in their na-
ture that may not ultimately be brought to the surface, not
only with safety, but with advantage to the upper soil.

2°. Trenching with the spade more fully and effectually per-
forms what the trench-plough is intended to do. The spade
more completely turns over the soil than the plough does; and,
in the hands of an industrious laborer, many think it the more
economical instrument of the two.

SECTION IV.—CHEMICAL AND OTHER EFFECTS OF COMMON PLOUGHING,

Other benefits, again, attend upon the ordinary ploughings,
hoeings, and working of the land. Its parts are more mi-
nutely divided—the air gets access to every particle—it is ren-
dered lighter, more open, and more permeable to the roots.
The vegetable matter it contains decomposes more rapidly by a
constant turning of the soil, so that wherever the fibres of the
roots penetrate, they find organic food provided for them, and
an abundant supply of the oxygen of the atmosphere to aid in
preparing it. The production of ammonia and of nitric acid
also, (see pages 26 to 32,) and the absorption of these and of
watery vapor from the air, take place to a greater extent the
finer the soil is pulverised, and the more it has been exposed to
the action of the atmosphere. All soils contain, likewise, an
admixture of fragments of those minerals of which the granitic
and trap rocks are composed, which, by their decay, yield new
supplies of inorganic food to the growing plant. The more
frequently they are exposed to the air, the more rapidly do
these fragments crumble away and decompose. The general
advantage, indeed, to be derived from the constant working of
the soil, may be inferred from the fact, that Tull reaped

twelve successive crops of wheat from the same land by the
7%

154 MIXING THE SOIL

repeated use of the plough and the horse-hoe. There are few
soils so stubborn as not to show themselves grateful in pro-
portion to the amount of this kind of labor that may be be-
stowed upon them.

It is chiefly because the fede or the fork divides and
separates the soil more completely, or to a greater depth, that
larger crops have been obtained in many districts by the in-
troduction of spade husbandry than by the ordinary mode of
culture with the plough. But all these benefits, which a
thorough working of the soil is fitted to confer, are only fully
realised where the land is naturally dry, or by artificial drain-
age has been freed from superfluous water.

SECTION V.—OF THE IMPROVEMENT OF THE SOIL BY MIXING,

It has been already shown that the physical properties of
the soil have an important influence upon its average fertility.
The admixture of pure sand with clay soils produces an alter-
ation which is often beneficial, and which is almost wholly
physical. The sand opens the pores of the clay, and makes it
more permeable to the air.

The admixture of clay with sandy or peaty soils, however,
produces both ‘a physical and a chemical alteration. . The clay
not only consolidates and gives body to the sand or peat, but
it also mixes with them certain earthy and saline -substances,
useful or necessary to the plant, which neither the sand nor
peat might originally contain in sufficient abundance. It thus
alters its chemical composition and fits it for nourishing new
races of plants.

Such is the case also with admixtures of marl, of shell-sand,
and of lime. They slightly consolidate the sands and open the
clays, and thus improve the mechanical texture of both kinds
of soil; but their main operation is chemical ; and the almost
universal benefit they produce depends mainly upon the new
chemical element they introduce into the soil.

WITH CLAY, SAND, &c. 155

It is a matter of almost universal remark, that in our cli-
mate, soils are fertile—clayey or loamy soils, that is—only
when they contain an appreciable quantity of lime. In what-
ever way it acts, therefore, the mixing of lime in any of the
forms above: mentioned, with a soil in which little or no lime
exists, is one of the surest practical methods of bringing it
nearer in composition to those soils. from which the largest
returns of agricultural produce are usually obtained. Some of
the chemical effects of lime upon the soil will be explained in a
subsequent chapter.

CHAPTER XII.

Improvement of the soil by planting and the growth of wood.—Influence of
the Scotch fir and the larch on the value of pasture.—Causes of such
influence of growing trees.—Improvement by laying down to grass.—Ob-
served facts —Forms which the improvement assumes.—In what way
pastures generally increase in value by age.—Agency of roots, of insects,
and of winds.—Why rich pasture, when ploughed up, is difficult to
restore.

THERE are certain modes of improving the soil, which, though
involving only simple mechanical operations on the part of the
improver, produce their effects through the agency of refined
scientific causes. Such are the improvements produced by
planting and laying down to grass. These, therefore, I shall
briefly consider in the present chapter.

SECTION I.—IMPROVEMENT OF THE SOIL BY PLANTING, AND HOW
IT IS EFFECTED.

*

It has been observed that lands which are unfit for arable
culture, and which yield only a trifling rent as natural pasture,
are yet in many cases capable of growing profitable plantations,
and of being greatly increased in permanent value by the pro-
longed growth of wood. Not only, however, do all trees not
thrive alike on the same soil, but all do not improve the soil on
which they grow in an equal degree.

Under the Scotch fir, for example, the pasture which springs
up after a lapse of years is not worth 6d. more per acre than
before the land was planted ;—under the beech and spruce, it is
worth even less than before, though the spruce affords excelent
shelter ;—under the ash, it gradually acquires an increased value

eee a

IMPROVEMENT BY PLANTING. 157

of 2s. or 3s. per acre. In oak copses, it becomes worth 5s. or
6s., but only during the last eight years (of the twenty-four)
before the oak copse is cut down. But under the larch, after
the first thirty years, when the thinnings are all cut, land not
worth originally more than Is. per acre becomes worth 8s. to
10s. per acre for permanent pasture.*

1. The main cause of this improvement is to be found in the
nature of the soil, which gradually accumulates beneath the
trees by the shedding of their leaves. The shelter from the sun
and rain which the foliage affords, prevents the vegetable mat-
ter which falls from being so speedily decomposed, or from
being so much washed away, and thus pérmits it to collect in
larger quantities in a given time than where no such cover ex-
ists. The more complete the shelter, therefore, the more rapid
will the accumulation of soil be, in so far as it depends upon
this cause.

2. But the quantity of leaves which annually fall, as well as
the degree of rapidity with which, under ordinary circumstances,
they undergo decay, have also much influence upon the extent
to which the soil is capable of being improved by any given
species of tree. ‘The broad leaves of the beech and oak decay
more quickly than the needle-shaped leaves of the pine tribes,
and this circumstance may assist in rendering the larch more
valuable as a permanent improver.

3. We should expect, likewise, that the quantity and quality
of the inorganic matter contained in the leaves (p. 60)—brought
up year by year from the roots, and strewed afterwards uni-
formly over the surface where the leaves are shed—would ma-
’ terially affect the value of the soil they form. The dry leaves
of the oak, for example, contain about 5 per cent of saline and
earthy matter, while those of the Scotch fir contain less than 2
per cent; so that, supposing the actual weight of leaves which
falls from each kind of tree to be equal, we should expect a

* The result of trials made on the mica slate and gneiss soils (see page
101) of the Duke of Atholl.

158 HOW FALLEN LEAVES FERTILIZE.

greater depth of soil to be formed in the same time by the oak
than by the Scotch fir. The leaves of the larch in the dry
state contain from 5 to 6 per cent of saline matter, so that they
may enrich the surface on which they fall in at least an equal
degree with those of the oak. Much, however, depends upon
the annual weight of leaves shed by each kind of tree, in regard
to which we possess no precise information.

The improvement of the land, therefore, by the planting of
trees, depends in part upon the quantity of organic food which
the trees can extract from the air, and afterwards drop in the
form of leaves upon the soil, and in part upon the kind and
quantity of znorganic matter which the roots can bring up from
beneath, and in like manner strew upon the surface. The quan-
tity and quality of the latter will, in a great measure, determine
the kind of grasses which will spring up, and the consequent
value of the pasture in the feeding of stock. In the larch
forests of the Duke of Atholl, the most abundant grasses that
spring up are said to be the Holcus mollis, and the Holeus
lanatus (the creeping and the meadow soft grasses.)

The action of a tree, therefore, in improving the soil, is two-
fold.

1°. It causes vegetable matter to accumulate on the surface; —
and,

2°. It brings up from beneath certain substances which are
of vital importance to the growth of plants, but of which the
upper soil may have been deficient.

In a previous chapter I have described the black earth of
Central Russia, which presents probably the most remarkable
example now existing of the fertilising effect of a long-con-
tinued growth of trees. The cotton soil of Central and South-
ern Hindostan owes its richness to a similar cause.

LAYING DOWN TO GRASS. 159

SECTION II.—IMPROVEMENT OF THE SOIL BY LAYING DOWN TO GRASS,
FACTS WHICH HAVE BEEN ASCERTAINED.

On this subject, two facts seem to be pretty generally
acknowledged.

First, That land laid down to artificial grasses for one, two,
three, or more years, is in some degree rested or recruited, and
is fitted for the better production of after crops of corn.
Letting it lie a year or two longer in grass, therefore, is one of
the received modes of bringing back to a sound condition
a soil that has been exhausted by injudicious cropping.

Second, That land thus laid down with artificial grasses
diminishes in value again after two, three, or five years—more
or less—and only by slow degrees acquires a thick sward of
rich, nourishing natural herbage. Hence the opinion that grass
land improves in quality the longer it is permitted to lie—the
unwillingness to plough up old pasture—and the comparatively
high rents which, in some parts of the country, old grass land is
known to yield.

Granting that grass land does thus generally increase in value,
three important facts must be borne in mind before we attempt
to assign the cause of this improvement, or the circumstances
under which it is likely to take place for the longest time and to
the greatest extent.

1. The value of the grass in any given spot may increase for
au indefinite period, but it will never improve beyond a certain
extent—it will necessarily be limited, as all other crops are, by
the quality of the land. Hence the mere laying down to grass
will not make all land good, however long it may lie. The ex-
tensive commons, heaths, and wastes, which have been in grass
from the most remote times, are evidence of this. They have,
in most cases, yielded so poor a natural herbage as to have
been considered unworthy of being enclosed as permanent pas-
ture.

160 NATURE OF THE IMPROVEMENT.

2. Some grass-lands will retain the good condition they thus
slowly acquire for a very long period, and without manuring—in
the same way, and upon nearly the same principle, that some rich
corn-lands have yielded successive crops for 100 years without
manure. The rich grass-lands of England, and especially of
Treland, many of which have been in pasture from time imme-
morial, without receiving any known return for all they have
yielded, are illustrations of this fact.

3. But others, if grazed, cropped with sheep, or cut for hay,
will gradually deteriorate, unless some proper supply of manure
be given to them—which required supply must vary with the
nature of the soil, with the kind of stock fed upon it, and with
the kind of treatment to which it has been subjected.

SECTION III.—FORM WHICH THE IMPROVEMENT ASSUMES, AND HOW
IT IS BROUGHT ABOUT.

In regard to the acknowledged benefit of laying down to grass,
then, two points require consideration.

1°. What form does it assume—and how is it effected ?

The improvement takes place by the gradual accumulation
of a dark-brown soil rich in vegetable matter, which soil thick-
ens or deepens in proportion to the time during which it is
allowed to lie in grass. It is a law of nature, that this accu-
mulation takes place more rapidly in the temperate than in
tropical climates, and it would appear as if the consequent
darkening of the soil were intended, among other purposes, to
enable it to absorb more of the sun’s warmth, and thus more
speedily to bring forward vegetation where the average tempe-
rature is low and the summers comparatively short.

If the soil be very light and sandy, the thickening of the
vegetable matter is sooner arrested ; if it be moderately heavy
land, the improvement continues for a longer period; and some
of the heaviest clays in England are known to bear the richest —
permanent pastures.

HOW IT IS BROUGHT ABOUT. 161

The soils formed on the surface of all our rich old pasture
lands thus come to possess a remarkable degree of uniformity
—hboth in physical character and in chemical composition.
This uniformity they gradually acquire, even upon the stiff clays
of the lias and Oxford clay, which originally, no doubt, have
been left to natural pasture—as many clay lands still are—
from the difficulty and expense of submitting them to arable
culture. .

2°. How do they acquire this new character, and why is it
the work of so much time ?

a. When the young grass throws up its leaves into the air,
from which it derives so much of its nourishment, it throws
down its roots into the soil in quest of food of another kind.
The leaves may be mown or cropped by animals, and carried
off the field ; but the roots remain in the soil, and, as they die,
eradually fill its upper part with vegetable matter. On an
average, the annual production of roots on old grass-land is
equal to one-third or one-fourth of the weight of hay carried
off *—though no doubt it varies much, both with the kind of
grass and with the kind of soil. When wheat is cut down, the
quantity of straw left in the field, in the form of stubble and
roots, is sometimes greater than the quantity carried off in the
sheaf. Upon a grass field two or three tons of hay may be
reaped from an acre, and therefore, from half aton to a ton of
dry roots is annually produced and left in the soil. If anything
like this weight of roots die every year, in land kept in pasture,
we can readily understand how the vegetable matter in the soil
should gradually accumulate. In arable land this accumulation
is prevented by the constant turning up of the soil, by which
the fibrous roots, being exposed to the free access of air and
moisture, are made to undergo a more rapid decomposition.

b. But the roots and leaves of the grasses contain earthy
and saline matters also. Dry hay leaves from an eighth to a

* See the Author’s Lectures on Agricultural Chemistry and Geology, 2d
edition.

162 CIRCUMSTANCES BY WHICH IT IS PROMOTED.

tenth part of its weight of ash when burned. Along with the
dead vegetable matter of the soil, this inorganic matter also
accumulates in the form of an exceedingly fine earthy powder;
hence one cause of the universal fineness of the surface-mould
of old grass-fields. The earthy portion of this inorganic mat-
ter consists chiefly of silica, lime, and magnesia, with scarcely
a trace of alumina ; so that, even on the stiffest clays, a sur-
face soil may be ultimately formed, in which the quantity of
alumina—the substance of clay—is comparatively small.

c. There are still other agencies at work, by which the sur-
face of stiff soils is made to undergo a change. As the roots of
the grasses penetrate into the clay, they more or less open up a
way into it for the rains. Now, the rains in nearly all lands,
when they have a passage downwards, have a tendency to carry
down the clay along with them. ‘They do so, it has been ob-
served, on sandy and peaty soils, and more quickly when these
soils are laid down to grass. Hence the mechanical action of
the rains—slowly in many localities, yet surely—has a tendency
to lighten the surface soil, by removing a portion of its clay.
They constitute one of those natural agencies by which, as
elsewhere explained, important differences are ultimately estab-
lished, almost everywhere, between the surface crop-bearing
soil and the subsoil on which it rests.

d. But further, the heats of summer and the frosts of winter
aid this slow alteration. In the extremes of heat and of cold,
the soil contracts more than the roots of the grasses do; and
similar, though less visible, differences take place during the
striking changes of temperature which are experienced in our
climate in the different parts of almost every day. When the
rain falls, also, on the parched field, or when a thaw comes on
in winter, the earth expands, while the roots of the grasses re-
main nearly fixed; hence the soil rises up among the leaves,
mixes with the vegetable matter, and thus assists in the slow
accumulation of a rich vegetable mould.

The reader may have witnessed in winter how, on a field or

EFFECT OF EARTH-WORMS AND WINDS. 163

by a way-side, the earth rises above the stones, and appears in-
clined to cover them ; he may even have seen, in a deserted
and undisturbed highway, the stones gradually sinking and dis-
appearing altogether, when the repetition of this alternate
contraction and expansion of the soil for a succession of winters
has increased, in a great degree, the effects which follow from a
single accession of frosty weather.

So it is in the fields. And if a person skilled in the soils of
a given district can make a guess at the time when a given
field was laid down to grass, by the depth at which the stones
are found beneath the surface, it is partly because this loosen-
ing and expansion of the soil, while the stones remain fixed,
tends to throw the latter down by an almost imperceptible
quantity every year that passes.

e. Such movements as these act in opening up the surface
soil, in mixing it with the decaying vegetable matter, and in
allowing the slow action of the rains gradually to give its
earthy portion a lighter character. But with these, among
other causes, conspires also the action of living animals. Few
persons have followed the plough without occasionally observ-
ing the vast quantities of earth-worms with which some fields
seem to be filled. On a close-shaven lawn, many have noticed
the frequent little heaps of earth which these worms during
the night have thrown out upon the grass. These and other
minute animals are continually at work, especially beneath an
undisturbed and grassy sward—and they nightly bring up from
a considerable depth, and discharge on the surface, their bur-
den of fine fertilismg loamy earth. Each of these burdens is
an actual gain to the rich surface soil; and who can doubt
that, in the lapse of years, the unseen and unappreciated
labors of these insect tribes must both materially improve its
quality and increase its depth ? *

* In the Prize Essays of the Highland Society, (vol. 1. p. 191,) the reader
will find the testimony of a practical man that such was in reality the case,
as observed by himself on part of his own farm in Roxburgshire.

164 FOREST TREES ENRICH THE SOIL.

f. In most localities, also, the winds may be mentioned among
the natural agencies by which the soil on grass lands is slowly
imgroved. They seldom sweep over any considerable extent of
arable land without bearing with them particles of dust and
sand, which they drop in sheltered places, or leave behind them
when sifted by the blades of grass, or by the leaves of an ex-
tensive forest. In hot summers, in dry springs, and even in
winter, when the snow is drifting, the ploughed lands and dusty
roads are more or less bared of their lighter particles of soil,
which are strewed by the winds as a natural top-dressing over
the neighboring untilled fields.

In some countries the agency of the winds is more conspicuous
than among ourselves. Thus on the banks of the Kuruman and
Orange rivers in South Africa, the winds blow during the spring
months—August to November in that climate—from the Kula-
gare desert, bearing with them light particles of dust, which
make the air seem as if dense with smoke, and which are so ex-
quisitely fine as to penetrate through seams and cracks which

are almost impervious to water.* Forest trees and waving |

erass sift this thick air and enrich the soils on which they grow
by the earthy particles they arrest.

In countries where aetive volcanoes exist, these also exercise
an appreciable influence of a similar kind upon the surface soil.
Showers of dust and ashes are sprinkled widely over the land,
by which its natural agricultural capabilities are materially in-
terfered with. Vesuvius is said, in this way, to scatter its ashes
over the adjoining country, so as, on an average, to destroy the
crop every eighth year. But to this circumstance the remarka-

I have lately seen a notice from the Carlisle Journal of a bowling-green

at Penrith, (45 yards by 32,) from which, after watering with a solution of _

corrosive sublimate, eleven stones of worms were this year gathered, and
four years ago twenty stones. The labors of such a number of animals must
produce in time a very sensible effect.

* Moffat’s Missionary Labors, p. 333. .

ALL LAND REQUIRES ADDITIONS. 165

ble general richness of the soil is ascribed—(Mont.) So does
good arise from seeming evil.

There are natural causes, then, which we know to be at work,
that are sufficient to account for nearly all the facts that have
been observed in regard to the effect of laying land down to
grass. Stiff clays will gradually become lighter on the surface,
and, if the subsoil be rich in all the kinds of inorganic food
which the grasses require, will go on improving for an indefinite
period without the aid of manure. Let them, however, be de-
ficient in, or let them gradually become exhausted of any one
kind of this food, and the grass lands will either gradually.dete-
riorate after they have reached a certain degree of excellence,
or they must be supplied with that one ingredient, that one kind
of manure of which they stand in need. It is doubtful if any
pasture lands are so naturally rich as to bear to be cropped for
centuries without the addition of manure, and at the same time
without deterioration. Where they appear to be so, they pro-
bably receive from springs, from sea-drift, or from some other
unobserved source, those perennial supplies which reason pro-
nounces to be indispensable.

On soils that are light, again—which naturally contain little
clay—the grasses will thrive more rapidly, and a thick sward
will be sooner formed, but the tendency of rains to wash out the
clay may prevent them from ever attaining that luxuriance which
is observed upon the old pastures of the clay lands.

On undrained heaths and commons, and generally on any soil
which is deficient in some fertilising element, neither abundant
herbage, nor good crops of any other kind, can be expected to
flourish. Laying such lands down, or permitting them to remain
in grass, may prepare them for by-and-by yielding one or two
average crops of corn, but cannot be expected alone to convert —
them into valuable pasture.

Finally, plough up the old pastures on the surface of which
this light and most favorable soil has been long accumulating,
and the heavy soil from beneath will be again mixed up with it,

166 NATURAL GRASSES CHANGE.

the vegetable matter will disappear rapidly by exposure to the
air during the frequent ploughings; and, if again laid down to
grass, the slow changes of many years must again be begun
through the agency of the same natural causes, before it become
capable a second time of bearing the same rich herbage it was
known to nourish while it lay undisturbed.

Many have supposed that, by sowing down with the natural
grasses, a thick and permanent sward may at once be obtained;
and on light loamy land, rich in vegetable matters, this method
may, to a certain extent, succeed; but, on heavy land, in which
stiff clay abounds and vegetable matter is defective, disappoint-
ment will often fgllow the sowing of the most carefully selected
seeds. By the agency, among other causes, of those above
adverted to, the soil gradually changes, so that it is unfit, when
first laid down, to bear those grasses which, ten or twenty years
aftegwards, will spontaneously and luxuriantly grow upon it.
Nature is not regulated by one principle in the growth of corn

and by another in growing grass; the apparent difference in her
procedure arises from real differences in our practice.

CHAPTER XIII.

Chemical methods of improving the soil—Use of manures.—Objects of the
farmer.— Vegetable manures.—Green manuring.—Use of sea-weed.—Dry
vegetable substances.— Straw.— Sawdust.— Bran.— Brewers’ grains.—
Malt-dust.—Rape-dust.—Hemp, poppy, cotton, and cocoa-nut cakes.—Use
of peat.—Peat composts and tanners’ bark.—Use of vegetable substances
decomposed by art.—Charred peat, wood charcoal, soot, coal-dust, and
coal-tar.—Relative fertilising and money values of different vegetable
manures.

None of the methods of improving the soil which have been
described in the preceding chapter are purely mechanical. They
all involve, as I have shown, some chemical alterations also,
which are to be explained only by a knowledge of chemical
principles. But the manuring of the land is more strictly a
chemical operation, and may therefore with propriety be sepa-
rated from those methods of improvement which involve at the
same time important and expensive mechanical operations.

In commencing the tillage of a piece of land, the conscien-
tious farmer may have three objects in view in regard to it.

1. He may wish to reclaim a waste, or to restore a neglected
farm to an average condition of fertility.

2. Finding the land in this average state, his utmost ambition
may be to keep it in its present condition; or, .

3. By igh farming he may wish to develop all its capabili-
ties, and to increase its permanent productiveness in the great-
est possible degree.

The man who aims at the last of these objects is not only the
best tenant and the best citizen, but he is also his own best

168 WHAT IS A MANURE.

friend. The highest farming, skilfully and prudently conduct-
ed, is also the most remunerating.*

But whichever of these tliree ends he aims at, he will be un-
able to attain it without a due knowledge of the various
manures it may be in his power to apply to his land—what
these manures are, or of what they consist—the general and
special purposes they are.each fitted or intended to serve—
which are the most effective for this or that crop, and why
they are so—how they are to be obtained in the greatest
abundance, and at the Jeast cost—how their strength may be
economised— and in what state and at what season of the year
they may be most beneficially applied to the land. Such are a
few of the questions which the skilful farmer should be ready
to ask himself, and should be able to answer.

By a manure is to be understood whatever is capable of
feeding or of supplying food to the plant. And as plants re-
quire earthy and saline as well as vegetable food, gypsum and
nitrate of soda are as properly called manures as farmyard
dung, bone-dust, or nightsoil.

Manures naturally divide themselves into such as are of vege-
table, of animal, and of mineral origin. I shall consider these
different kinds of manure in successive chapters.

SECTION I.—OF THE USE OF VEGETABLE MANURKS.

There are two purposes which vegetable manure is generally

* A singular illustration of this fact is mentioned as observed in Hol-
stein, where marl is extensively applied to the land. Those fields which
are marled yield a much larger produce than before, while the adjoining
fields, which are left unmarled, give a less return than when all were un-
marled; so that the holder of the latter is compelled to improve by marl-
ing his fields also.—SPRENGEL.

It is also a curious but important observation, that when light lands,
poor in vegetable matter, are reclaimed from a state of waste, they pay
better for the manure added to them every succeeding year; that is, the
richer in organic matter they become.—VoN VOGHT.

VEGETABLE MANURES. 169

supposed to serve when added to the soil—it loosens the land,
opens its pores, and makes it lighter; and it also supplies
organic food to the roots of the growing plant. It serves, how-
ever, a third purpose. It yields to the roots those saline and
earthy matters, which it is their duty to find in the soil, and
which exist in decaying plants in a state more peculiarly fitted
to enter readily into the circulating system of new races.

Decayed vegetable matters, therefore, are in reality mixed
manures, and their value in enriching the land must vary con-
siderably with the ‘znd of plants, and with the parts of those
plants of which they are chiefly made up. This depends upon
the remarkable difference which exists in the quantity and hind
of the inorganic matter contained in different vegetable sub-
stances, as indicated by the ash they leave, (see pages 59 to
69.) Thus if 1000 lb. of the sawdust of the willow be fer-
mented and added to the soil, they will enrich it by the addi-
tion of only 4} Ib. of saline and earthy matter, while 1000 lb.
of the dry leaves of the same tree, fermented and laid on, will
add 82 lb. of inorganic matter. Thus, independent of the
effect of the organic matter in each, the one will produce a
very much greater effect upon the soil than the other.*:

There are several states in which vegetable matter is collect-
ed by the husbandman for the purpose of being applied to the
land—such as the green state, the dry state, that state of im-
perfect natural decay in which it forms peat, and the decom-
posed state of charcoal, &c., to which it has been reduced by

art.
SECTION II.—OF GREEN MANURING, AND OF THE USE OF SEA-WEED.

When grass is mown in the field, and laid in heaps, it speed-

* It is owing, in part, to this large quantity of saline and other inorganic
inatters which they contain, that fermented leaves alone form too strong a
dressing for flower borders, and that gardeners therefore generally mix them
up into a compost.

8

170 GREEN MANURING.

ily heats, ferments, and rots. But, if turned over frequently and
dried into hay, it may be kept for a great length of time without
undergoing any material alteration. The same is true of all
other vegetable substances—they all rot more readily in the
green state. The reason of this is, that the sap or juice of the
geeen plant begins very soon to ferment in the interior of the
stem and leaves, and speedily communicates the same condition
to the moist fibre of the plant itself. When once it has been
dried, the vegetable matter of the sap loses this easy tendency
to decay, and thus admits of long preservation.

The same rapid decay of green vegetable matter takes place
when it is buried in the soil. Hence the cleanings and scour-
ings of the ditches and hedge-sides form a compost of mixed
earth and fresh vegetable matter, which soon becomes capable
of enriching the ground. When a green crop is ploughed into
a field, the whole of its surface is converted into such a compost
—the vegetable matter in a short time decays into a light,
black mould, and enriches in a remarkable degree, and fertilises
the soil.

This is one reason why the success of wheat after clover, or
of oats after lea, depends so much on the ground being well
covered when first ploughed up.

1°. Green manuring —Hence the practice of green manuring
has been in use from very early periods. The second or third
crop of Zucerne was ploughed in by the ancient Romans—as it
still is by the modern Italians. In Tuscany, the whete lupzn is
ploughed in—in parts of France, the bean and the vetch—in
Germany, borage—and upon sandy soils in Holstein, spurry.
The Madia sativa has lately been tried as a green manure in
Silesia. It is sown in June, and is ploughed in, when two feet
high, in October. Sheep do not eat it; so that if a flock of
sheep be turned in, they eat up the weeds and trample down the
madia, after which it is easily ploughed in. In a month it is
rotten, and the land may be cross-ploughed, and the winter corn
sown. :

TURNIP LEAVES AND POTATO TOPS READILY DECAY. 171

In French Flanders, two crops of clover are cut, and the third
_is ploughed in. In some parts of the United States, the clover
is never cut, but is ploughed in as the only manure ; in other
parts, the first crop is cut and the second ploughed in. In some
of the northern States, Indian corn is sown upon poor lands, at
the rate of 4 to 6 bushels an acre, and two or sometimes three
such crops are turned in during the summer. In north-eastern
China, a species of coronilla and a trefoil are specially sown and
grown in ridges, as a manure for the rice crop. They are
ploughed and harrowed in before the young rice plants are put
into the flooded land.

In Sussex, and in parts of Scotland, turnip seed has been
sown at the end of harvest, and after two months again ploughed
in, with great benefit to the land. Weld mustard, also, which
grows so abundantly as a weed on many of our corn-fields, is
not unfrequently raised for ploughing in green. White mustard
is sown in Norfolk, and ploughed in as a preparation for wheat ;
sometimes, also, on the stubble, as a preparation for turnips. It
is said to destroy the wire-worm. Turnip leaves and potato tops
decay more readily and more perfectly, and are more enriching
when buried in the green state. It is a prudent economy, there-
fore, where circumstances admit of it, to bury the potato tops
on the spot from which the potatoes are raised.* Since the
time of the Romans, it has been the custom to bury the cut-
tings of the vine stocks at the roots of the vines themselves ;
and many vineyards flourish for a succession of years without
any other manuring. In the Weald of Kent the prunings of
the hop-vine, chopped and dug in, or made into a compost and
applied to the roots of the hop, give a larger crop, and with
half the manure, than when they are burned or thrown away,
as is usually done.

* By taking off the blossoms of potatoes—besides the usual increase of
crop—the tops keep green till the potatoes are lifted. Thus much green
matter is obtained; and if this be made into manure, and applied to the
next potato crop, it is said to raise the largest produce of tubers.

172 USE OF SEA-WEED.

Buckwheat, rye, winter tares, clover, and rape, are all occa-
sionally sown in this country for the purpose of being ploughed
in. This should be done when the flower has just bagow to open, |
and, if possible, at a season when the warmth of the air and the |
dryness of the soil are such as to facilitate decomposition.

That the soil should be richer in vegetable matter after this
burial of a crop than it was before the seed of that crop was
sown, and should also be otherwise benefited, will be understood
by recollecting (see page 36) that perhaps three-fourths of the
whole organic matter we bury has been derived from the air—
- that by this process of ploughing in, the vegetable matter 1s
more equally diffused through the whole soil, than it could ever
be by any merely mechanical means—and that by the natural
decay of this vegetable matter, ammonia and nitric acid are, to
a greater extent, (page 26 and 29,) produced in the soil, and
its agricultural capabilities in consequence materially increased.
Indeed, a green crop ploughed in is believed, by some practical men,
to enrich the soil as much as the droppings of cattle from a quantity
of green food three times as great.

These considerations, while they explain the effect and illus:
trate the value of green manuring, will also satisfy the intelligent
agriculturist that there exist methods of improving his land
without the aid either of town or of foreign manures—and that
he overlooks an important natural means of wealth who neglects
the green sods and the crops of weeds that fiourish by his hedge-
rows and ditches. Left to themselves, they will ripen their
seeds, and sow them annually in his fields; collected in compost
heaps, they will materially add to his yearly crops of corn.

2°. Use of sea-weed.—Among green manures, the use of fresh
sea-ware deserves especial mention, from the remarkably fertilis-
ing properties it is known to possess, as well as from the great
extent to which it is employed on all our coasts. The agricul-
tural produce of the Isle of Thanet, in Kent, is said to have
been doubled or tripled by the use of this manure; the farms on
the Lothian coasts let for 208. or 80s. more rent per acre when

SPECIAL ACTION OF SEA-WEED. 173

they have a right of way to the sea, where the weed is thrown
ashore ;* and in the Western Isles the sea-ware, the shell-marl,
and the peat-ash, are the three great natural fertilisers, to which
the agriculture of this remote region is indebted for the com-
parative prosperity to which it has in some of the islands already
attained.

The common red tangle, which grows farther out at sea, is in
some districts preferred as a manure to the other varieties of
sea-weed, when applied green or made into compost. At Oban,
on the west coast of Scotland, the fishermen bring it in their
boats and sell it on the shore at a shilling a cart. One cart is
there reckoned equal to two of farmyard dung for raising pota-
toes. Used alone for this crop, it gives a good return, but gen-
erally of inferior quality. On the south-east coast of Fife,
where the sea-weed is laid on the stubble at the rate of 20 carts
an imperial acre, ploughed in, and the turnips afterwards raised
with half dung, the clover is saad never to fail. Laid on bean-
stubble, and ploughed in, 27 cart-loads gave in Suffolk, (1819,)
three times as much wheat as 5 bushels of salt and 15 loads of
farmyard manure per acre.

Sea-weeds decompose with great ease when collected in heaps
or spread upon the land. During their decay they yield not
only organic food to the plant, but saline matters also, to which
much of their efficacy both on the grass and the corn crops is
no doubt to be ascribed. |

Especially to this saline matter may be ascribed the benefi-
cial influence of sea-weed on garden asparagus, originally a sea-
side plant, and upon fruits like raspberries, which contain much
alkaline matter.

* Tn this locality 16 loads of sea-weed are reckoned equal to 20 tons of
farmyard manure. In the Island of Lewis 20 tons of sea-ware, which would
yield half a ton of*kelp, are considered to be ample manure for a Scotch acre,

+ The potatoes are said to be of better quality when the sea-weed is put
into the soil and covered with a layer of earth, upon which the potatoes are
to be planted.

174 DRY VEGETABLE MATTER FOR MANURING.

The value of sea-weed as a manure may be understood from
the fact that the fucws saccharinus leaves, when dry, 28°6 per
cent of ash, and contains i
compounds. In its recent state it contains 76 per cent of water,
(PAvEN. ) |

SECTION IIJI.—OF MANURING WITH DRY VEGETABLE MATTER.

1. Straw.—Almost every one knows that the sawdust of most
common woods decays very slowly—so slowly, that it is rare to
meet with a practical farmer who considers it worth the trouble
to mix sawdust with his composts. This property of slow decay
is possessed in a certain degree by all dry vegetable matter.
Heaps of dry straw when alone, or even when mixed with
earth, will ferment with comparative difficulty, and with great
slowness. It is necessary, therefore, to mix it, as is usually
done, with some substance that ferments more readily, and
which will impart its own fermenting state to the straw. Ani-
nal matters of any kind, such as the urine and droppings of
cattle, are of this character ; and it-is by admixture with these
that the straw which is trodden down in the farmyard is made
to undergo a more or less rapid fermentation.

The object of this fermentation is twofold—first, to reduce the
particles of the straw to such a minute state of division, that
they may admit of being diffused through the soil ; and second,
that the dry vegetable matter may be so changed by exposure
to the air and other agencies, as to be fitted to yield without
difficulty both organic and inorganic food to the roots of the
plants it is intended to nourish.

Differences of opinion have prevailed, and discussions have
taken place, as to the relative efficacy of long and short, or of
half fermented and of fully rotten dung. But if it be added
solely for the purpose of yielding food to the plant, or of prepar- -
ing food for it, the case is very simple. The more complete the
state of fermentation, if not carried too far, the more immediate

LOSS OF WEIGHT BY FERMENTATION. 175

will be the agency of the manure—hence the propriety of the
_ application of short dung to turnips and other plants it is desir-
able to bring rapidly forward ; but if the manure be only half
decayed, it will require time in the soil to complete the decom-
position, so that its action will be more gradual and prolonged.

Though in the latter case the immediate action is not so per-
ceptible, yet the ultimate benefit to the soil, and to the crops,
may be even greater, supposing them to be such as require no
special forcing at one period of the year. This is easily under-
stood. While it is undergoing fermentation in the farmyard,
the straw loses part of its substance—either in the state of
gaseous matter, which escapes into the air—or of saline matter,
which is washed out in the liquid form. ‘Thus, after complete
fermentation, the quantity of matter present is really less, and
consequently, when added to the soil, though the zmmediate
effect upon the crop be greater, the whole effect may also be
very considerably less.

This will appear more clearly when it is considered that the
quantity of recent dung—mixed straw and cow dung—is by
experiment equal on an average to 2 or 2} times that of the
dry food and fodder taken together, while, when fully rotten,
the weight of the dung may be no greater than that of the dry
food and fodder consumed by the cattle.

Thus it has been found that one ton (20 ewt.) of dry food
and straw gives a quantity of farmyard dung which weighs,

When recent, : : : : 46 to 50 ewt.
After 6 weeks, . : ‘ 2 40 to 44
After 8 weeks, . ‘ ‘ , 38 to 40
When half rotten, ¢ ; : 30 to 35
When fully rotten, : . ; 20 to 25

A part of this loss may, no doubt, be ascribed to the evapora-
tion of a portion of the water of the recent dung ; but the
larger part is due to an actual escape of the substance of the
manure itself. The farmer, therefore, who applies the manure
from a given weight of food and straw, in a fresh state, adds

176 SAWDUST AND BRAN.

more to his land than if he first allows it to become perfectly
fermented. Were he to chop his straw, and put it in as it
comes fresh from the field, he would add still more ; but its ac-
tion as a manure would be slower, and while it would benefi-
cially open stiff and heavy soils, it would injure others, by
rendering them too light and porous.

2. Sawdust.—With a view to this slow amelioration, dry
vegetable matter of any kind may, if in a sufficient state of di-
vision, be added with benefit to the soil. Even sawdust,
applied largely to the land, has been found to improve it,—
little at first, more during the second year after it was applied,
still more during the third, and most of all in the fourth season
after it was mixed with the soil. That any dry vegetable mat-
ter, therefore, does not produce an immediate effect, ought not
to induce the practical farmer to despise the application to his
land—either alone or in the form of a compost—of everything
of the kind he can readily obtain. If his fields are not already
very rich in vegetable matter, both he and they will be ulti-
mately benefited by such additions to the soil.

Saturated with ammoniacal liquor, or with liquid manure,
sawdust has been profitably used, and without further addition,
in the raising of turnips. It may also be charred either by
burning, or by alternate layers of quick-lime, and thus benefi-
cially applied.

3. Bran.—The bran and pollard of wheat are highly recom-
mended as manures. Drilled in with the turnip seed at the rate
of 5 or 6 cwt. an acre, at a cost of £1 2s. 6d., it brought the
young plants rapidly forward, and gave one-third more in ©
weight of bulbs than the other parts of the field, which had
been treated in the same way in every respect, except that no
addition of bran had been made to them. If moistened with
urine and slightly fermented, the action of bran would no
doubt’ be hastened and rendered more powerful.

The husk of the oat, hitherto wasted at many of the oatmeal

MALT AND RAPE DUST. LTT

_ mills in the north, might also be beneficially fermented and em-
ployed as a manure.

4. Brewers’ grains, though usually given as food to fattening
cattle or to milch cows, are by some of the farmers in Norfolk
employed as a manure. They are supposed to pay best when
mixed with farmyard manure.

5. Malt-dust—cummins, or combings—consists of the dried
sprouts of barley, which, when the sprouted seed is dried in the
process of malting, break off and form a coarse powder. This
is found to be almost equal to rape-dust in fertilising power.
One hundred bushels of barley yield 105 to 110 of malt and 4
to 5 of dust. In this neighborhood (Durham) it is sold at one
shilling a bushel.

Applied in the dry state, malt-dust decomposes slowly, and
from its extreme lightness is applied with difficulty, as a top-
dressing. If it be moistened with liquid manure and laid in
heaps for a few days till it heat and begin to ferment, it may
be used either as a top-dressing for grass, clover, and young
corn, or it may be drilled in with the seed. It may also in this
state be employed with advantage without any other manure
for the turnip or potato crop; but the turnip-seed should not be
brought into immediate contact with it in the drills.

Malt-dust leaves, when dry, 8 per cent of ash, and contains
23 per cent of protein compounds, (Payen.) This composition
explains both its fertilising action when applied to the soil, and
its nourishing effects when given to cattle or sheep along with
turnips. | :

6. LRape-dust.—It is from the straw of the corn-bearing plants,
or from the stems and leaves of the grasses, that the largest
portion of the strictly vegetable manures applied to the soil is
generally obtained or prepared. But the seeds of all plants are
much more enriching than the substance of their leaves and
stems. ‘These seeds, however, are in geueral too ya uable for
food to admit of their application as a manure. Still the re-

fuse of some—as that of different kinds of rape-seed after the
8>*

178 HEMP, POPPY, AND COTTON CAKES.

oil is expressed, and which is unpalatable to cattle—is applied
with great benefit to the land. Drilled in with the winter or
spring wheat, or scattered as a top-dressing in spring at the
rate of 5 ewt. an acre, it gives a largely increased and remune-
rating return. Applied at a cost of 40s. per acre to wheat, it.
has been known to increase the produce 10 bushels an acre
(from 29 to 39 bushels) and to give one-fifth more straw. Nor
is the practice recent, for the application of it in this way, and
at a cost of 40s to 42s. an acre, was common in Norfolk in the
time of Arthur Young, (1770,) eighty years ago.

In some districts it is used largely, and without admixture,
for the raising of turnips. It is applied with equal success to
the cultivation of potatoes, if it be put in the place of a part
only of the manure. If used alone it is apt to give very large
and luxuriant tops, with only an inferior weight of tubers. It
is safer, therefore, to mix it with other manure; and generally
it may be substituted for it at the rate of about 1 ewt. of rape-
dust for each ton of farmyard manure.

1. Hemp, poppy, and cotton cakes—the refuse of crushed
hemp, poppy, or cotton seed—may be used for similar purposes,
and in the same way, as rape-cake.

8. Cocoa-nut cake, left by the expressed cocoa-nut, is also a
valuable manure, and has alone been found to produce large
crops of potatoes.

These different kinds of cake all contain a large per-centage
of nitrogen, (4 to 43 per cent,) or, in other words, of protein
compounds. ‘These ferment very easily, promote growth ra-
pidly, and give to the manures that contain them peculiar
fertilising virtues.

SECTION IV.—OF THE USE OF PEAT, PEAT COMPOST, AND TANNER’S
BARK.

1. Natural peat—In many parts of the world—and in none
more abundantly, perhaps, than in some parts of our own islands

PEAT, NATURAL AND FERMENTED. 179

—vegetable matter continually accumulates in the form of peat.
This peat ought to supply an inexhaustible store of organic
matter for the amelioration of the adjacent soils. We know
that by draining off the*sour and unwholesome water, and
afterwards applying lime and clay, the surface of peat bogs may
be gradually converted into rich corn-bearing lands. It must,
therefore, be possible to convert peat itself by a similar process.
into a compost fitted to improve the condition of other soils.

2. Fermented peat—The late Lord Meadowbank, who made
many experiments on this subject, found, that after being par-
tially dried by exposure to the air, peat might be readily fer-
mented, and brought into the state of a rich fertilising compost,
by the same means which are adopted in the ordinary ferment-
ing of straw. He mixed with it a portion of animal matter,
which soon communicated its own fermenting quality to the sur-
rounding peat, and brought it readily into a proper heat. He
found that one ton of hot fermenting manure, mixed in alternate
layers with two of half-dried peat, and covered by a layer of
the same peat, was sufficient to ferment the whole. He observed
afterwards, also, that the vapors which rise from naturally
fermenting farmyard manure or animal matters, would alone
produce the same effect upon peat, placed so as readily to
receive and absorb them.

As ammonia is one of the compounds specially given off by
putrefying animal substances, it is not unlikely that a watering
with ammoniacal lguor would materially prepare the peat for
undergoing fermentation. At all events, it seems possible to
prepare any quantity of valuable peat compost by mixing the
peat with a little soil, and with a still smaller quantity of fer-
mented manure than was employed by Lord Meadowbank, pro-
vided the liquid manure of the farmyard be collected into a
cistern, and be thrown at intervals, by means of a pump, over
the prepared heaps.

After being partially dried, natural peat may be very benefi-

180 PEAT COMPOST : CHARRED PEAT.

cially employed in absorbing the liquid manure of the farmyard,
or in mixing with the contents of the tanks.

3. Mr. Fleming’s peat convpost—Many other ways of working
up peat have been suggested, such as adding lime, salt, and
other substances, to aid the fermentation. The most successful
of these mixtures with which I am acquainted is one which has
been used with much advantage on the home farm of Mr. Flem-
ing of Barochan. This compost consists of—

Sawdust, or dry earthy peat, 40 bushels.

Coal-tar, - - - - 20 gallons.
Bone-dust, - < > . 7 bushels.
Sulphate of soda, - - lat MAE 1 cwt.
Sulphate of magnesia, aiid wicatc . de
Common salt, - - - - rR: 1%
Quick-lime, - - - ° 20 bushels.

These materials are mixed together and put into a heap, and
allowed to heat and ferment for three weeks, then turned, and
allowed again to ferment, when the compost is ready for use.

Compared with farmyard manure and guano, this mixture
gave on hay and turnips—

1°. On hay per imperial acre.

Produce. Cost.
Nothing, : - 416 stones.
Guano, 3 ewt. : - Tea. $7 50
Compost, 40 bushels, a 5 00

2°. On turmps, (Jones’ yellow top.)

Produce. Cost.
Farmyard manure, 28 yards, 26 tons.
Guano, 5 ewt. : : aed $12 50
Compost, 64 bushels, : tS eae 1 16

According to these results, this compost is superior even to
guano. ‘The experiments, however, require repetition, and the
results will no doubt vary with the kind of soil and of crop to
which the compost is applied.

4. Charred peat——By being built up and charred or half
burned in covered heaps, peat may be obtained in a state in

———— oer rhe

USE OF CHARCOAL POWDER. 181

which it is easily reduced to powder. In this powdery state, it
has been used alone for turnips, at the rate of 50 bushels an
acre, and was found to give as good a crop as 50 carts of farm-
yard dung. Something of this action, however, may have de-
pended upon the nature of the soil, and upon the kind of peat.
Charred peat forms, likewise, an excellent absorbent for the
liquids of the dicsensiai and the stable, and for drying up dis-
solved bones.

5. Tanners’ raencraens may here advert also to the use of tan-
ners’ bark, a form of vegetable matter which, like sawdust and
peat, is difficult to work up, and is therefore often permitted
largely to go to waste. Like peat it may be dried and burned
for the ash, which is light, portable, and forms a valuable top-
dressing. But the economist will prefer to ferment it in a
compost, in the way above described for peat. An occasional
watering of the compost with the liquid manure of the farm-
yard will bring it into a heat, and when the ammoniacal liquor
of the gas-works can be procured at a cheap rate, it may be
employed for a similar purpose. The hard thick fragments of
bark, however, cannot be so soon decomposed as the already
finely divided peat, and must be expected therefore to demand
more time. With lime it may, like sawdust or peat, be reduced
and charred.

SECTION V.—MANURING WITH ARTIFICIALLY DECOMPOSED VEGETABLE
SUBSTANCES—-CHARCOAL, SOOT, COAL-TAR, &e.

When wood and other vegetable substances are heated in
close vessels they are converted into charcoal. Coal, which is
of vegetable origin, deposits in our chimneys, when burned,
large quantities of soot ; and when distilled in gas-retorts it
yields, besides gas, a quantity of coal-tar and other products.
All these substances have been tried and recommended as ma-
nures.

1°, Charcoal powder possesses the remarkable properties of

182 EXPERIMENTS WITH SOOT.

absorbing noxious vapors from the air and from the soil, and of
extracting unpleasant impurities as well as saline substances
from water, and of decomposing many saline compounds. It
also sucks into its pores much oxygen and other gases, from the
air. Owing to these and other properties, it forms a valuable.
mixture with liquid manure, nightsoil, farmyard manure, ammo-
niacal liquor, or other rich applications to the soil. It is even
capable itself of yielding slow supplies of nourishment to living
plants ; and it is said in many cases, even when unmixed, to be
used with advantage as a top-dressing in practical agriculture.*
In moist charcoal the seeds of the gardener are found to sprout
with remarkable quickness and certainty ; but after they have
sprouted, they do not continue to grow well in charcoal alone.
Drilled in with the seed, charcoal powder is said greatly to
promote the growth of wheat.

2°. Soot, whether from the burning of wood or of coal, con-
sists chiefly of a finely divided charcoal, possessing the proper-
ties above mentioned. It contains, however, ammonia, gypsum,
nitric acid, and certain other substances in considerable quan-
tity, to which its well-known effects upon vegetation are chiefly
to be ascribed. In many localities it increases the growth of
the grass in a remarkable degree, and as a top-dressing to
wheat and oats, it sometimes produces effects equal to those
which follow the use of the nitrates of potash or soda.t

Thus wheat and oats dressed with soot, in comparison with
undressed, gave the following return of grain—

Wheat. Oats.
Undressed, : : 44 bushels, 49 bushels.
Dressed, , ‘ HAeh hy 55
Increase, . 10 6

* This may no doubt be in part owing to its aiding the production, as all
porous substances do, of ammonia in its interior, and hence of apocrenate of
ammonia (p. 23) in the soil, but in part also to its power ef. decomposing
other substances.

+ Journal of the Royal Agricultural Society of England, ii. p. 259.

COAL DUST AND COAL TAR. 183

It acts also upon root crops—56 bushels of soot mixed with 6
of common salt having produced larger crops of carrots than 24
tons of farmyard manure, with 24 bushels of bones.*

I have lately examined several varieties of soot, and find
that it contains from 18 to 48 per cent of mineral matter, con-
sisting of earthy substances from the coal carried up into the
chimney by the draught, and of gypsum and sulphate of mag-
nesia derived from the lime of the flue and the sulphur of the
coal. It contains besides from 1 to 2 per cent of ammonia,
_ chiefly in the state of sulphate. These proportions of ammonia,
‘calculated in the state of sulphate of ammonia, are equal to
from 54 to 12 per cent of the whole weight of the soot. It is
not wonderful, therefore, that its effects should resemble, and
even rival, those of the nitrate of soda and of the sulphate of
ammonia.

- When applied to grass in spring it is said to give a peculiar
bitterness to the pasture, and even to impart a taste to the
milk. Hence, in large towns, the. cow-feeders of the milk-
dairies are unwilling to purchase early grass which has been
manured with soot.

3°. Coal-dust—In the county of Durham the dust of com-
mon coal, such as is sifted out at the mines as too small for
burning, has been spread upon poor, cold, arable land, and as
a top-dressing upon old pastures, with manifest advantage.
Something will, no doubt, depend both upon the quality of the
coal and upon the kind of land to which it is applied.

4°, Coal-tar applied to the wheat-stubble with a water-cart,
at the rate of 180 gallons to the imperial acre, and allowed to
remain two or three months before it is ploughed in, is said
greatly to benefit the after crop of roots. It has been tried
on a sandy loam, and on a deep clay. It has also been used
in the form of compost.

* Journal of the Royal Agricultural Society of England, iv. p. 270.

184 DIFFERENT VEGETABLE MANURES.

SECTION VI.—RELATIVE FERTILISING AND MONEY VALUES OF
DIFFERENT VEGETABLE MANURES.

There are two principles on which the relative values of dif-
ferent vegetable substances, as manures, may be estimated, ;—
first, by the relative quantity and kind of enorganic matter they
respectively contain ; and second, by the relative proportions of
nitrogen present in each. j

1. Valued according to the quantity of inorganic matter they
contain, the worth of the several kinds of straw, hay, &c.,
would be represented by the following numbers : A ton weeght
of each substance; when made into manure—provided nothing
is washed out by the rains—will return to the soil the following
quantities of inorganic matter in pownds :-

Wheat-straw, : A Y ; 70 to 360
Oat-straw, . - : : : 100 to 180
Hay, , ; : : - 100 to 200
Barley-straw, : : : : 100 to 120
Pea-straw, . : A eet 2 100 to 110
Bean-straw, : ‘ “i : 100 to 130
Rye-straw, . : : : : 50 to 100
Dry potato-tops, : - : ; 400
Dry turnip-tops, * : 2 370
Rape, and other cakes, : : ; 120
Malt-dust, . . ‘ 4 4 180

Dried sea-weed, : ; ; ; 560

Generally, perhaps, these numbers will give the reader a tolera-
bly correct idea of the relative permanent effects of the above
different kinds of vegetable matter, when laid upon the soil.
But a reference to the facts stated in pp. 64 to 73, in regard to
the qualty of the inorganic matter contained in plants, will sat-
isfy him that the effect of these manures on particular crops is
not to be judged of solely by the absolute quantity of earthy
and saline matter they contain. What the turnip-top, for
example, or the bean-stalk, returns to the soil, may not be
exactly what will best promote the growth of wheat.

EFFECTS OF THEIR NITROGEN ON THEIR VALUE. 185

2. On the other hand, if the fertilising value of vegetable
substances is to be calculated from the relative quantities of ni-
trogen they severally contain, we should place them in the fol-
lowing order ;—the number opposite to each substance repre-
senting that weight of it in pounds which would produce the
same effect as 100 pounds of farmyard mantre, consisting of
the mixed droppings and litter of cattle. (Bovussineattr.)

Equivalent
quantities in
pounds.

Farmyard manure, . , : P 100
Wheat-straw, : . : 80 to 170
Oat-straw, . ‘ - é E 150
Barley-straw, : : 4 2 180
Buckwheat-straw, . : : P 85
Pea-straw, . , i - . 45
Wheat-chaff, ; 3 E ‘ 50
Green grass, ‘ ; ‘ : 80
Potato-tops, ; : : ; 75
Fresh sea-weed, ? : : ‘ 80
Dried sea- -weed, f ‘ ‘ 20
Bran of wheat or Indian corn, ; ‘ 26
Malt-dust, . : : 13
Rape, and other cakes, : ‘ : 8

Fir sawdust, ; : : : 250

Oak sawdust, : = : ; 180
Coal-soot, . -. ‘ ‘ 20 to 30

This table again presents the same substances in a somewhat
different order of value ; showing, for example, not only that
such substances as rape-dust, malt-dust, and soot, should pro-
duce a much more remarkable effect upon vegetation than the
same weight even of farmyard manure, but also that certain
dry vegetables, such as bran, chaff, and pea-straw, will yield,
when not unduly fermented, a more enriching manure than the
straw of barley, oats, or wheat. It agrees also with the known
effect of green manuring upon the land, since 80 pounds of
meadow grass ploughed in should, according to the table, be equal
in virtue to 100 of farmyard manure.

Some writers ascribe the entzre action of these manures to the

186 GENERAL CONCLUSIONS.

nitrogen they contain. This, however, is taking a one-sided
view of their real natural operation. The nitrogen, during their
decay, is liberated chiefly in the form of ammonia,—a compar-
atively evanescent substance, producing an immediate effect in
hastening or carrying farther forward the growth of the plant,
but not remaining permanently in the soil. The reader, there-
fore, will form an opinion consistent alike with theory and with
practice, if he concludes—

1. That the zmmediate effect of vegetable manures in hasten-
ing the growth of plants is dependent, in a great degree, upon
the quantity of nitrogen they contain and give off during their
decay in the soil ; but—

2. That their permanent effect and value is to be estimated
chiefly by the quantity and quality of the inorganic matter they
contain—of the ash they leave when burned.

The effect of the nitrogen may be nearly expended in a sin-
gle season; that of the earthy and saline matters may not he
exhausted for several years.

Nor is the carbon of vegetable substances without its im-
portant uses to vegetation. From the statements contained in
the earlier chapters of the present work—especially in reference
to the production of ammonia and nitric acid in the soil,
through the agency of decaying carbonaceous matter—it may
be inferred that, however much influence we may allow to the
uitrogen and to the earthy matter of plants in aiding the
growth of future races, the soundest view is that which con-
siders each of the elements present in decayed or decaying plants to
be capable erther of ministering to, or of preparing food for, such
as are still alive. We may not be able as yet to estimate the
precise importance of each element to any particular kind of
crop or soil, or so to adjust the quantities of each in our
manures, as to promote the growth of that crop upon that soil,
in the greatest possible degree, yet the principle itself is a
sound one, and will hereafter guide us to safe and correct
results. e

|
:
:

a

CHAPTER XIV.

Animal manures.—Flesh, fish, shell-fish_—Insects.—Blood.—Animalised
chareoal.—Skin, horn, hair, wool—Woollen rags.—Shoddy.—Horn-saw-
dust, and hoof parings.—Cause of the fertilising influence of these ma-
nures.—Composition and use of bones and horn-flints.—Preparation of
dissolved bones.—Comparative experiments witli crushed and dissolved
bones.—Why solution in acid makes bones more active-—Comparative
action of flesh, blood, horn, woollen rags and bones.—Use of the liquid
excretions of animals.—Urine of man, the cow, the horse, and the pig.—
Construction of liquid-manure tanks.—Urate.—Sulphated arine.

THE animal substances employed as manures consist chiefly
of the flesh, blood, bones, horns, and hair of sea and land ani-
mals, and of the solid and liquid excrements of land animals
and birds.

SECTION I.—OF FLESH, FISH, BLOOD, AND SKIN, AND OF THEIR USE
AS MANURES.

Animal substances, in general, act more powerfully as ma-
nures than vegetable substances; it is only the seeds of plants
which can be at all compared with them in efficacy.

1. The flesh of animals is rarely used as a manure, except in
the case of dead horses or cattle which cannot be used for
- food.

2. Fish are, in this country, chiefly applied in the form of
the refuse of the herring and pilchard fisheries, though occa-
sionally such shoals of sprats, herrings, dog-fish, and even
mackerel, have been caught on our shores, as to make it neces-
sary to employ them as manure. These recent animal sub-
stances are found to be, for the most part, too strong when
applied directly to the land; they are usually, therefore, made

188 FISH AS A MANURE.

into a compost, with a large quantity of soil. Five barrels of
fish, or fish refuse, made into twenty loads of compost, will be
sufficient for an acre.

On the coast of Norfolk, large quantities of sprats are used as a
manure for the turnip crop. They are sold for about 8d. a bushel.
A ton and a half, mixed with twelve to fifteen cwt. of mould
taken from the head of the field, makes a compost which is suffi-
cient for an imperial acre, and is said never to fail. On the
shores of Aberdeenshire, dog-fish are caught and applied as a
manure.

In Rhode Island and the adjoining States, considerable quan-
tities of manure are made by mixing the fish called menhaden,
of which large numbers are taken in the bays, with peat or
swamp mud, in the proportion of one load of fish to ten of peat
or mud. As many as 750 tons of this fish have been taken at
a single haul, and sold to the farmers at about 2s. 6d. the thou-
sand fish, or waggonload.* On the coasts of Connecticut large
quantities of fish, called white fish, are caught and sold for
manure, at the rate of about a dollar (4s.) a thousand, weigh-
ing 15 or 20 cwt. They are either laid on the land and ploughed
in, or are made into acompost. In the north of China, prawns
and other kinds of fish are collected and employed for manuring
purposes. .

The refuse of the fish oils, of the fat of animals that has been
melted for the extraction of the tallow, of skins that have been
boiled for the manufacture of glue—as also horns, hair, wool,
woollen rags, and all similar substances, when made into com-
posts—exercise, in proportion to their weight, a much greater
influence upon vegetation than any of the more abundant forms
of vegetable matter.

3. Shell-fish, when they abound on our coasts, have been found
to be capable of economical application to the land, even for
raising turnips and potatoes. They are mixed with a little

* See the Author’s Notes on North America, vol. ii p. 231.

ee

INSECTS AND BLOOD. 189

earth into a rich compost, and allowed slightly to ferment. If
the means of crushing them be at hand, their value is by this
process considerably increased. On the northern shores of the
Solway, near Annan, the common mussel is found in such quan-
tities in some places, that, when the tide recedes, a cart-load
ean be raked out of the sand in so short a time as to make it
a very economical manure. The Rev. Mr. Gillespie of Cum-
mertrees informs’ me, that 700 cart-loads were collected and
applied to the raising of turnips during the year 1844. They
are used without other manure, at the rate of about 50 bushels
to the Scotch acre. On the coasts of Lincolnshire, also, they
are met with in some places in large quantities, and collected
for use aS a manure.

4. Even the bodies of insects in many parts of the world form
important manures. In warm climates, a handful of soil some-
times seems almost half made up of the wings and skeletons of
dead insects : in Hungary and Carinthia the peasant occasionally
colleets as many as 30 cart-loads of dead marsh-flies in a single
year ; and in the richer soils of France and England, where
worms and other insects abound, the presence of their remains
in the soil must aid its natural productiveness.

5. Blood is in this country very seldom applied to the land
directly. Like the other parts of animals, however, it makes
an excellent compost. In Northamptonshire, such a compost is
made by mixing about 50 gallons of blood with 8 bushels of
peat-ashes and charcoal powder, and allowing the mixture to
stand for a year or two. On light soils, this compost raises
excellent turnips when applied alone, at the rate of 6 quarters
(48 bushels) per imperial acre—or of 2 quarters with 12 tons
of farmyard dung. As a top-dressing to young wheat, 20 or 30
bushels an acre greatly increase the crop. On heavy and wet
lands, its effects are less perceptible. In that part of England
the blood is contracted for at the rate of 3d.a gallon. In some
countries the blood is dried, and in the state of powder is applied
as a top-dressing to the growing crops. In this state it is sold

190 WOOLLEN RAGS AND SHODDY.

in Paris at about 8s. a cwt.—a moderate price, if it be tolera-
bly dry. Samples prepared in London, and containing still 22
per cent of water, have also been valued at £8 or £9 a ton.
But this mode of using blood is not very widely adopted.

6. Animalised charcoal—As blood comes from the sugar re-
fineries, however—in which, with lime-water and animal char-
coal, it is employed for the refining of sugar—it has obtained
a very extensive employment, especially in the south of France.
This animal black, or animalised charcoal, as it is sometimes
called, contains about 20 per cent of blood, and has risen to
such a price in France that the sugar refiners actually sell it
for more than the unmixed blood and animal charcoal originally
cost them. This has given rise to the manufacture of artificial
mixtures of charcoal, fecal matters, and blood, which are also
sold under the name of animalised charcoal. A great disad-
vantage attending the use of these artificial preparations is,
that they are liable to be adulterated, or, for cheapness, pre-
pared in a less efficient manner.

1. Skin.—Fragments of skin are sometimes used as @ ma-
nure. The parings of skins from the tan-works are Boiled by
the glue-makers, and the insoluble refuse is sold as a manure.
This refuse, in the form of compost, ought to nourish the crops
very much. When used alone for potatoes, it is said to make
them wazy on soils where, with other manures, they grow mealy
and dry.

SECTION II.—OF HAIR, WOOL, WOOLLEN RAGS, SHODDY, HORN-SAW-
DUST, AND HOOF-PARINGS.

1. Horn, har, and wool, depend for their efficacy precisely on
the same principles as the blood and flesh of animals. They
differ chiefly in this, that they are dry, while blood, flesh, and
fish contain about 80 per cent of their weight of water.
Hence, one ton of horn-shavings, of hair,* or of dry woollen

* In China, the hair, which every ten days is shaven from the heads of the
entire population, is collected and sold for manure throughout the empire.

NITROGEN IN ANIMAL MANURES. 191

rags, ought tu enrich the soil as much as 4-to 5 tons of blood.
In consequence, however, of their dryness, the horn and wool
decompose much more slowly than the blood. Hence the effect
of soft animal matters is more immediate and apparent, while
that of hard and dry substances is less visible, but continues
for a much longer period of time.

2. Woollen rags, when made into a compost and fermented,
form an excellent manure for potatoes or turnips. In the hop
countries, they are buried at the roots of the hop plants with
great advantage. They sell at about £5 aton. On the sandy
land in Wiltshire, they are frequently used as a manure for
turnips.

3. Shoddy, or mill-waste-—the waste of the woollen and
cloth mills of Yorkshire—is nearly the same thing as hair and
woollen rags. It sells at about £2 a ton, and is extensively
used by the farmers of Kent and Northampton.

4. Horn-sawdust and hoof-parings—The small dust, parings,
turnings, and siftings of horn from the shops of the comb-makers,
as well as the hoofs of cattle, are now sold to the prussiate of
potash manufacturers at the rate of about £2 aton. If they
were free from admixture, they should be worth to the farmer
about the same price as woollen rags. They are usually mixed
with much sand and dust—amounting sometimes to 50 or 60
per cent of their whole weight. In this state they are not
worth more than two-fifths of the price of dry hair or woollen
rags. They may be used instead of bones for the turnip or
potato crop, but should be made into a fermented compost
before they are employed as a top-dressing.

SECTION II.—CAUSE OF THE FERTILISING INFLUENCE OF THE ABOVE
ANIMAL MANURES.

The fertilising influence of the parts of animal bodies, described
in the preceding sections, depends mainly upon their consisting,
for the greater part, of substances very rich in nitrogen. Thus—

192 HORN AND BONES.

. Percentage of
nitrogen,
Dry blood, flesh, and fish contain about . ; 154
Dry skin, hair, wool, horns, and hoofs, . - 16 to 17%

But these two classes of substances differ much in the quan-
tity of water they contain—

Percentage

of water.
Blood, fish, and flesh, contain . ; : 78 to 82
Hair, wool, and horn, . : : : 10 to 15

Skin and hoofs vary much in dryness, and therefore the aver-
age proportion of water in them cannot be estimated.

The special differences of the above substances as manures
depend mainly upon those differences in the proportion of water.
Blood, fish, and flesh decompose rapidly, act quickly; and pro-
mote growth speedily. Wool, hair, and horn take a long time
to rot, are not so well adapted, therefore, for promoting speedy
growth, but by their gradual decay are better fitted to afford
prolonged nourishment to a crop which continues long in the
ground, or permanently to enrich a soil which has been exhausted
by too severe cropping.

The mineral matter contained in these substances is small in
quantity, and therefore of comparatively little influence upon
their manuring value. Dry blood and flesh leave about 4 per
cent of ash, while wool, hair, and horn leave only 1 or 2 per
eent. The ash of flesh and fish consists almost entirely of phos-
phates, and that of blood in great part of common salt. This
may influence their respective action upon plants—as the fact
that hair contains 5 per cent of sulphur may also modify the
action of this substance as a manure. (See p. 000.)

SECTION IV.—COMPOSITION OF BONES AND THE PITH OF HORNS, AND
THEIR VALUE AS MANURES.

1. Bones, while they resemble hair and horn in being dry,

HORN, FLINT OR PITH. 193

differ from them in containing a large quantity of earthy matter,
and hence they introduce a new agent to aid their effect upon
the soil. Thus, the bones of the cow consist in 100 Ib. of—

Phosphate of lime, . - : ‘ . 553
Phosphate of magnesia, : : : 2
Soda and common salt, : ; : ; 2s
Carbonate of lime, . Fs - - “ an
Fluoride of calcium, : ‘ 3
Gelatine (the substance of horn). : ; 334
100.

While 100 lb. of dry bone-dust, therefore, add to the soil as
much organic animal matter as 33 Ib. of horn, or as 300 to 400
Ib. of blood or flesh, they add at the same time two-thirds of
their weight of inorganic matter, consisting of lime, magnesia,
soda, common salt, and phosphoric acid (in the phosphates )—
all of which, as we have seen, must be present in a fertile soil,
since the plants require a certain supply of them all at every
period of their growth. These substances, like the inorganic
matter of plants, may remain in the soil, and may exert a be-
neficial action upon vegetation after all the organic or gelati-
nous matter has decayed and disappeared.

2. Lorn funts,or piths, resemble bone very much in compo-
sition. They contain a little more animal matter, and from
their softness and porosity are more difficult to crush in the
mill. For the same reason, however, they decay more rapidly
in the soil, and act more immediately than bones. They boil
down, however, more readily than bones, and are therefore
largely used for making the size used in stiffening calicoes.
For this purpose they are sold by the comb-makers at about
£4 a ton.

When they are not in demand for this purpose they may be
very usefully employed as a manure.

A sample of the pith, as it is sold in the market, gave to

Professor Norton in my laboratory—
9

194 PREPARATION OF DISSOLVED BONES.

Water, (lost at 2129,) ; 10.31
Phosphates of lime and magnesia, ; 46.14
Carbonate of lime, : : : Utes
Gelatine, (organic matter,) . ‘ : 35.84
100.

SECTION V.—PREPARATION OF DISSOLVED BONES. COMPARATIVE EX-
PERIMENTS WITH CRUSHED AND DISSOLVED BONES. WHY THIS
SOLUTION MAKES BONES MORE ACTIVE.

For the purpose of bringing bones into a state in which the
substances they contain can be more readily taken up by the
roots of plants, and at the same time more uniformly distri-
buted through the soil, the method has been adopted of dis-
solving them in sulphuric acid. For this purpose, the bone-dust
is mixed with one-half its weight, and sometimes with its own
weight of sulphuric acid (the oil of vitriol of the shops,)
previously diluted with from one to three times its bulk of
water. Considerable effervescence takes place at first, from
the action of the acid upon the carbonate of lime in the bones;
but, after two or three days, with occasional stirring, the bones
are entirely dissolved or reduced. The solution or paste may
now be dried up with charcoal powder, with dried or charred
peat, with sawdust, or with fine vegetable soil, and applied
with the hand or with the drill to the turnip crop; or it may
be diluted with 50 times its bulk of water, and let off into the
dvills with a water-cart. Applied either way, the effect is
much more striking than when the same weight of bone-dust is
apes in the ordinary form. 'Thus—

. At Gordon Castle (Mr. Bell) the following results were
eee —

Manure per Imperial Acre. Cost. Poder ry
14 yards farmyard dung

@ bpackals inoue: si £3 0 0 ($15.00) 12 tons.

3 ewt. guano, i tal 9.25) 11°2
16 bushels bones, E160 9.00) 11 os

EXPERIMENTS WITH DISSOLVED BONES. 195

Produce of Bulbs,

Manure per Imperial Acre. Cost. - Dale’s Hybrid

2 bushels bones,
83 lb. sulphuric acid, £0 11 6 ($2.88) 12°2
400 gallons water,
8 bushels bones,
83 lb. sulphuric acid — 1 5 0. ( 6,25) PEG res
sown with the hand.

The largest produce was here obtained, when the dissolved
bones were applied with a water-cart, and at a cost of eleven
shillings per acre.

6. Again, on the farm of Sherriffstoun in Meee fine (Mr.
M‘William,) the following comparative results were obtained in
1843 :—

1. Swedish Turnips.

Cost per Produce in Bulbs per
shbess held Imperial ‘Acre.

75 lb. (1°6 bushels) bones,

46 lb. acid, £0.9.-3 ($2.31) 175 tons.
400 gallons water, )
The same with 200 gallons 0 9 3 (231) 18:5

water, ;

440 lb. (9°5 bushels) bones,

an ee Liivae. 9 ¢,648) Wiis 4

2. Common Turnaps.

170 lb. (3°2 bushels) bones,

92 lb. acid, £017 6 ($4.38) 6" “tons
400 gallons water,

16 bushels bones,

46 lb. acid, 2, 2° @ (6:50) 13°5

10 gallons water,

In all these cases the smaller quantity of bones, when dis-
solved in acid and applied in a liquid state, gave a heavier
return of bulbs than the larger quantity when drilled in dry.
Even the watering of the large quantity of bones with a portion
of acid, did not make their effect. on the crop equal to that of
the small quantity of dissolved bones.

i

196 INFLUENCE OF THE SULPHURIC ACID.

Mr. Hannam obtained, by the use of crushed and dissolved
bones upon turnips, the following results :—

Bones. Tons. cwts.
bushels, crushed, gave e 10 3 per imperial acre.
2 ‘dissolved, ae i 92i4b2 it
2 ie x, EL. 15
4 ior et!
4 14 6
4 ais A yee |
8 ie A pb Rw
8 . 15 2
8 16 1

We can explain this superior action of dissolved bones by the
fact, that the dissolving separates their particles completely from
each other, diffuses them more completely through the soil, and
presents them to a larger surface of the turnip roots, and in a
state in which they can be more readily absorbed. The sul-
phuric acid also may have some effect, since we know that sul-
phur, in some form, is necessary to the growth of all our crops.
I have indeed been informed of a case at Balcarras, in Fifeshire,
where diluted sulphuric acid applied alone to the drills produced
an excellent crop of turnips ; and of another in Dumfriesshire,
where steeping the seed-corn in diluted sulphuric acid added
many bushels to the crop of barley.

Though the immediate effect of a small quantity of bones on
the first crop is made so much greater by this mode of applying
them, it is not to be expected that the effect upon the after
crops should be as beneficial as when a larger quantity of bones
is applied in the ordinary method.

. SECTION VI.—COMPARATIVE ACTION OF FLESH, BLOOD, HORN, WOOLLEN
RAGS, AND BONES.

From what has been stated in the preceding sections the
reader will gather these general conclusions—
1, That animal substances which, like flesh and blood, con-

GENERAL CONCLUSIONS. 19%

tain much water, decay rapidly, and are fitted to operate amme-
diately and powerfully upon vegetation, but are only temporary
or evanescent in their action. (P. 192.)

2. That when dry, as in horn, hair, and wool, they decom-
pose—and consequently act—more slowly, and continue to ma-
nifest an influence, it may be, for several seasons.

3. That bones and horn flints act like horn, in so far as their
animal matter is concerned, and, like it, for a longer or shorter
timé, according as they have been more or ‘ess finely crushed;
but that they ameliorate the soil by their earthy matter for a
still longer period—permanently improving the condition, and
adding to the natural capabilities of the land.

4, That the action of bones may be rendered more imme-
diate and striking by bringing them into a minute state of di-
vision,—as by dissolving them in diluted sulphuric acid, or by
fermenting them in a mixture of moist sand or soil—but that,
like flesh and blood, their effect, by that means, is likely to be
rendered less permanent.

£

SECTION VII.—OF THE URINE OF ANIMALS, AND THE MEANS OF
PRESERVING AND APPLYING IT. URATE. SULPHATED URINE, &e.

Practical men have long been of opinion that the digestion
of food, either animal or vegetable,—its passage through the
bodies of animals—enriches its fertilising power, weight for
weight, when added to the land. Hence in causing animals to
eat up as much of the vegetable productions of the farm as
possible—of the straw and turnip-tops, for example, as well as
of the grain and bulbs—it is supposed that not only isso much
food saved, but that the value of the remainder in fertilising
the land is greatly increased. In a subsequent section we shall
see how far theory serves to throw light upon these opinions.

The digested animal substances usually employed as manures:
are—the urine of man, of the cow, and of the sheep; the solid
excrements of man (nightsoil,) of the horse, the cow, the

198 THE URINE OF MAN.

sheep, and the pig, and the droppings of pigeons and other
birds. The liquid manures act chiefly through the saline sub-
stances which they hold in. solution, while the solid manures
contain also insoluble matters which decay slowly in the soil,
and there become useful only after a time. The former, there-
fore, will influence vegetation more powerfully at first; the
action of the latter will be less evident, but will continue to be
sensible for a much longer period of time.

1. The urine of man.—Human urine consists, in 1000 parts
of—

Water, ; : d : - s : 932
Urea, and other organic matters containing nitrogen, 49
Phosphates of ammonia, soda, lime, and magnesia, . 6
Sulphates of soda and ammonia, : ; : : 7
Sal-ammoniac, and common salt, . : : , 6

1000

1000 Ib. of urine, therefore, contain 68 lb. of dry fertilising
matter of the richest quality, worth, at the present rate of sell-
ng artifical manures wn this country, at least 10s. a cwt. As
each full-grown man voids about 1000 lb. of urine in a year, the
national waste incurred in this form amounts, at the above va-
luation, to 6s. a head. And if 5 tons of farmyard manure per
acre, added year by year, will keep a farm in good heart, 4
ewt. of the solid matter of urine would probably have an equal
effect ; or the urine alone discharged into the rivers by a popu-
lation of 10,000 inhabitants would supply manure to a farm of
1500 acres, and would yield a return of 4500 quarters of corn,
or an equivalent produce of other crops. Mr. Smith of Deans-
ton considered the urine of two men to be a sufficient manuring
for an acre of land, and that when mixed with ashes, it would
produce a fair crop of turnips.*

An important chemical distinction exists between the urine
of man and that of the cow, the horse, and the sheep. It con-
tains, as is shown in the previous page, about 6 per cent of

* Report of Committee on Metropolitan Sewerage.

URINE OF THE COW. 199

phosphates, while these compounds are entirely absent from the
urine of the other animals. The presence of the phosphoric
acid contained in these phosphates, adds very much to the ma-
nuring value of human urine.

If milk or lime be mixed with fermenting human urine, this
phosphoric acid is precipitated with a portion of the animal
matter. Dr. Stenhouse found a precipitate of this kind, when
dried at 212°. F., to contain 40 per cent of phosphoric acid
and of organic matter, including about 1 per cent of ammonia.
By the use of this method, an important part of the fertilising
ingredients of human urine may be separated in a solid state.
It has recently been adopted with some success for the purpose
of separating the fertilising matters contained in» sewage
water.

2. Pig’s wrine-—The urine of the pig resembles that of man,
in containing a considerable proportion of phosphorie acid. In
this respect it is more valuable as a manure than those of the
horse, the cow, and the sheep.

3. The wrine of the cow is said to contain less water than
that of man, though of course much must depend upon the
kind of food with which it it is fed. Considering, then, the
large quantity of liquid manure that is yielded by the cow
(1200 or 1500 gallons a-year,) we may safely estimate the
solid matter given off by a healthy animal in the form of urine
in twelve months, at about 1000 lb. in weight—worth, 2f 2
were in the dry state, from £4 to £5 sterling. In the liquid
state, the urine of one cow, collected and preserved as it is in
Flanders, is valued in that country at about £2 a-year. Any
practical farmer may calculate for himself, therefore, how much
real wealth, taking it even at the Flemish value, is lost in his
own farmyard—how inuch of the natural means of reproduc-
tive industry passes into his drains, or evaporates into the
air.

This liquid manure is very valuable, when collected in tanks,
for watering the manure and compost heaps, and thus hasten-

=

200 CONSTRUCTION OF LIQUID-MANURE TANKS+#

ing their decomposition. It may also be sprinkled directly
upon the fields of grass or of clover, and upon the young corn,
—or the young green crop (turnips, &c.) may be watered with
it, with the best effects. It must, however, be permitted to
stand till fermentation commences, and must afterwards be
diluted with a considerable quantity of water, before it will be
in the best condition for laying upon the land. This dilution,
indeed, where the receiving tanks are large enough, should be
made at an earlier period, for it has been found that, when un-
mixed with water, cows’ urine, which is six weeks old, contains
only one-sixth part of the ammonia retained by the same urine
when.it has been previously diluted with an equal bulk of
water. Sulphuric acid may also be added to fix the ammonia.*

4. Of the construction of liquid-manure tanks—There are four
practical points which are worthy of attention in the construc-
tion of tanks for liquid manure.

a. They ought to be well puddled with clay behind the stone
or brick work, to prevent any loss or escape of the liquid.

6. They ought to be covered over, and the closer the better.
In Germany they are usually vaulted. From close tanks the
sun, rain, and air, are in a great measure excluded, and the fer-
mentation is slower, and the loss of ammonia in consequence
considerably less.

c. They should be divided by a wall, into at least two com-
partments, capable of holding each a two or three months’ sup-
ply. When the first of these is full, the stream is turned into
the second, and by the time it is also full, the contents of the
first are ripe, or in a fit state for putting upon the land. The

* To saturate and fix the whole of the ammonia capable of being formed
in the urine of a single cow of average size, would require about %00 Ib. of
the common strong sulphuric acid of the shops, or nearly 60 Ib. a month,
costing 9s. One-third or one-fourth of this quantity, however, added to the
liquid-manure tank, would be sufficient to prevent any very sensible loss.
Mr. Kinninmonth found 750 gallons of cows’ urine so treated, with about

15 lb. of acid, equal in increasing the produce of hay to 2} ewt. of guano,
or 1 cwt. of nitrate of soda.

ee see a

« URATE AND SULPHATED: URINE. - 201

liquid ought always to be in a state of fermentation before it is
applied either to grass or to any other crop. This double tank
also enables the farmer to collect and preserve his liquid during
the three months of winter, when it cannot be applied, and to
have a large supply in a fit state for putting on when the young
grass or corn begins to shoot.

The liquid as it comes from the cattle ought to be mixed in
the tank with at least its own bulk of water. By this means a
considerable loss of ammonia is prevented which would other-
wise escape from the urine during fermentation ; and it is pre-
vented from burning the grass, which in very dry seasons it is
apt to do when put on without dilution. This necessarily
involves larger cisterns, and more labor in carrying out the
liquid ; but experience seems to say that the additional profit
exceeds considerably the additional expense.

5. Urate-—Among other methods of obtaining the virtues of
animal urine in a concentrated form, burnt gypsum is mixed
with it in the state of powder in the proportion of 10 Ib. to
every T gallons, allowing the mixture, occasionally stirred, to
stand some time, pouring off the liquid, and drying the gypsum.
This is sold by manure manufacturers under the name of wrate.
It never can possess, however, the virtues of the urine, since it
does not contain the soluble saline substances, which the gypsum
does not carry down with it. Except the gypsum, indeed, 100
lb. of urate contain no greater weight of saline and organic
matter than ten gallons of urine. If it be true, then, as the
manufacturers state, that 3 or 4 ewt. of urate are sufficient
manure for an acre, the practical farmer will, I hope, draw the
conclusion,—not that it is well worth while to venture his money
in buying this urate, and trying it upon his land, but that a far
more promising adventure will be to go to some expense in say-
ing his own liquid manure, and after mixing it, if he think
proper, with the burned gypsum, to lay it abundantly upon all
his fields.

' 6. Sulphated urine—<A better method than that of using
gr

202 AMMONIACO-MAGNESIAN PHOSPHATE.

gypsum has been lately adopted by several manure manufac-
turers. They-mix as much sulphuric acid with the urine as is
sufficient to combine with and fix the whole of the ammonia
which may be produced during the decomposition of the urine.
The mixture is then evaporated to dryness, and is sold and
applied to the land in the state of a dry powder.

This sulphated urine, containing as it does all the saline sub-
stance of the liquid urine, with the addition of sulphuric acid,
ought to prove a most valuable manure. If prepared from |
human urine, it will promote the growth of nearly all crops ;
but, from the sulphuric acid it contains, it may exercise a special
influence on beans, peas, and clovers. As a top-dressing it may
be applied alone ; but when used for root-crops, it ought to be
mixed with and to take the place of not more than one-half of
the farmyard manure usually applied. Used in this way, at a
cost of £2 an acre, Mr. Finnie of Swanston obtained, in 1843,
four tons of turnips per imperial acre more than from an equal
cost of guano.

As a top-dressing for wheat, and probably also for other corn
crops, this sulphated urine may be advantageously mixed with
an equal weight of sulphate of soda or of common salt, with at
least as much wood ashes, if they can be had, and with half its
weight of dissolved bones. The soda salts are especially desir-
able where the land lies remote from the sea.

1. Ammoniaco-magnesian phosphate—Boussingault fixes the
ammonia and phosphoric acid of human urine by adding to it,
after it has acquired an ammoniacal odor, a solution of sul-
phate or muriate of magnesia, when the double phosphate of
magnesia and ammonia falls to the bottom of the liquid.
About 7 Ib. of this salt are obtained from 100 lb. of urine;
and it has been ascertained to possess powerful fertilising pro-
perties.*

* In reference to liquid manures, IJ strongly recommend to my readers,
the “Minutes of Information collected on the Practical Application of

Sewer Water, and Town Manures, to Agricultural Purposes,” published by -
the General Board of Health.

CHAPTER XV.

Animal manures continued.—Solid excretions or droppings of animals.—
Nightsoil.— Poudrette.—Taffo.—Cow, horse, and pigs’ dung.—Droppings
of birds.—Pigeons’ dung.—Guano.—African and American varieties.—
Their composition, and fertilising values ——Their durability —Adultera-
tion of, how to test or select a good sample, quantity imported, and va-
lue to the nation.

Tue solid excretions of animals are not less valuable as ma-
nures than their urines, and in almost every country are much
more generally employed.

SECTION I.—OF NIGHTSOIL, POUDRETTE, AND TAFFO ; AND OF COW,
HORSE, AND PIGS’ DUNG.

1. Nightsou is probably the most valuable of all the solid
animal manures. It variesin richness with the food of the in-
habitants of each district,*—chiefly with the quantity of ani-
mal food they consume,—but when dry, few other solid manures,
weight for weight, can be compared with it in general efficacy.
It contains much soluble and saline matter, and as it is made
up from the constituents of the food we eat, of course it con-
tains most of those elementary substances which are necessary
to the growth of the plants on which we principally live.

2. Poudrette—Attempts have been made to dry nightsoil so

* This is said to be so well known in some of the towns in the centre of
Europe, where a mixed population of Protestants and Roman Catholics live
together, that the neighboring farmers give a larger price for the house-
dung of the Protestant families. In Persia, the nightsoil of the Russian
families is, for a similar reason, preferred to that of the less flesh-eating
Mahometans.

204 COW, HORSE AND PIGS’ DUNG.

as to render it more portable,—to destroy its unpleasant smell,
so as to reconcile practical men to a more general use of it,—
and, by certain chemical additions, to prevent the waste of am-
monia and other volatile substances, which are apt to escape
and be lost when this and other powerful animal manures begin
to putrefy. In Paris, Berlin, and other large cities, the night-
soil, dried first in the air with or without a mixture of gypsum
or lime, then upon drying-plates, and finally in stoves, is sold
under the name of poudrette, and is extensively exported in»
casks to various parts of the country. It is said to be equal
in efficacy to 30 times its bulk of horse or street manure, and
is applied at the rate of from 15 to 35 bushels an acre.

In London, also, nightsoil is dried with various admixtures;
and in some of our other large towns an animalised charcoal is
prepared by mixing and drying nightsoil with gypsum and or-
dinary wood charcoal, in fine powder. Charred peat would
answer well for such a purpose.

Few simple and easily attainable substances would make a
better compost with nightsoil, and more thoroughly preserve
its virtues, than half-dried peat, saw-dust, or rich vegetable
soil, mixed with more or less marl or gypsum. It is impossible
to estimate the proportion of waste which this valuable manure
undergoes by being allowed to ferment, without mixture, in the
open air.

3. Taffo—aIn China nightsoil is kneaded into cakes with
clay, which are dried in the air, and, under the name of taffo,
form an important article of export from all the large cities of
the empire. In Persia it is dried in’ the sun and powdered.
Mixed with twice its bulk of dry soil, it is then used for raising
the finest melons.

4. Cow, horse, and pigs’ dung. So much of the saline and
soluble organic matters in the excretions of the cow pass off in
the liquid form, that its dung is correctly called cold, since it
does not readily heat and run into fermentation. Mixed with
other manures, however, or well diffused through the soil, it

DROPPINGS OF BIRDS. 205

aids materially in promoting vegetation. The horse being fed
generally on less liquid food, and discharging less urine, yields
a hotter and richer dung, which is admirably fitted for bringing
substances into a state of fermentation, but answers best for
the land when mixed with other varieties of manure. The
dung of the pig is soft and cold like that of the cow, contain-
ing, like it, at least 15 per cent of water. As this animal lives
on more, varied food than any other which is reared for the use
of man, the manure obtained from it is also very variable in
quality. Applied alone, as a manure to roots, it is said to give
them an unpleasant taste, and to injure the flavor even of the
tobacco plant. It answers well for hemp and for hops; but
when mixed with other manures, it may be applied to any crop.
In some districts pigs’ dung is considered one of the richest
and most valuable that can be applied to the land. But the
most generally useful manure is obtained by mixing all these
varieties together, as is usually done in the manure-heaps of
our larger farmers.

SECTION II._—DROPPINGS OF BIRDS. PIGEONS’ DUNG AND GUANO.
AFRICAN AND AMERICAN VARIETIES—THEIR COMPOSITION AND FER-
TILISING EFFECTS.

1. Pigeons’ dung.—The dung of nearly all birds is distin-
guished by eminent fertilising properties. Some varieties are
stronger than others, or more immediate in their action, and
all are improved for the use of the farmer by being some time
kept, either alone or in compost. In Flanders the manure of
one hundred pigeons is considered to be worth 20s. a-year for
agricultural purposes. In Catalonia, Arragon, and some other
parts of Spain, pigeons’ dung is sold as high as 4d. a pound,
for applying, when mixed with water, to flower-roots, melons,
tomatos, and other plants.*

* The estimation in which it was held in ancient Palestine may be in-
ferred from the statement, that, during a siege of Samaria, the fourth part

206 GUANO AND FARMYARD DUNG.

The dung of birds possesses the united virtues of both. the
liquid and solid excretions of other animals. It contains every
part of the food of the bird, with the exception of what is abso-
lutely necessary for the support and for the right discharge of the
functions of its own body. It is thus fitted to return to the

plant a greater number of those substances on which plants live, —

than either the solid or the fluid excrements of other animals ;
in other words, to be more propitious to vegetable growth.

2. Guano is the name given by the natives of Peru to the
dung of sea-fowl, which in former periods used to be deposited
in vast quantities on the rocky shores and isles of the Peruvian
coast. The numerous shipping of modern times has disturbea
and driven away many of the sea-fowl, so that much less of
their recent droppings is now preserved or collected. Ancient
heaps of it, however, mixed with feathers and fragments of
bone, still exist in many places, more or less covered up with
drifted sand, and also more or less decomposed. These are now
largely excavated, especially on the Chincha islands, for expor-
tation, not only to different parts of the coast of Peru,—as
seems to have been the case from the most remote periods,—but
also to Europe, and especially to England. It is at present sold
in this country at a price which varies from £8 to £11 a ton.

Guano was also imported, for a few years, (1843 to 1847,)
in large quantities from the island of Ichaboe, and from other
places on the west coast of Africa. The quality of the African
was not equal, however, to that of the guano brought from
Peru. It contained more water, and was in a more advanced
stage of decomposition. The known sources of supply from this
quarter are now nearly exhausted ; and with the exception per-
haps of a little from Saldanha Bay, there is none of it now in

of a cab of doves’ dung was sold for 5 pieces of silver.—2 Kings vi. 25.
I may state, however, that what is here translated doves’ dung, was con-
sidered by Linnzus to mean the bulbous root of the Ornithogallum umbel-
latwm, still eaten in Palestine, and forming part of the food of some of the
tribes of Hottentots at the Cape of Good Hope. .

FERTILISING EFFECT OF GUANO. 207

the market. Its price varied with the quality, from £3 to £8
a ton.

Guano is capable of entirely replacing farmyard dung,—that
is to say, turnips and potatoes may be manured successfully with
guano alone. It may be used either as a top-dressing to the
young corn and grass ; or it may be put in with the turnip-sced,
or with the potato cuttings, being previously mixed with a quan-
tity of fine dry soil, charcoal powder or gypsum. It may also
be mixed with water, and used as a liquid manure. It is
applied in various proportions, from one to three, four, or five
hundred weights per acre. Three cwt. of guano, without other
manure, gave Mr. Fleming of Barochan 183 tons of potatoes
per acre ; and 5 cwt., with 20 bushels of wood ashes, gave him
32 tons of yellow turnips.

The application of guano to the sugar cane has largely
increased the produce of sugar, both in the British West India
Islands and in the Mauritius.

When applied in too large a quantity, the effect both upon
the turnip and upon the after corn-crop is of a very hurtful
kind. This is very strikingly shown hy the following results
of an experiment made in Ross-shire (in 1843'and 1844) with
4,8, and 16 ewt. respectively to the Scotch acre :-—

yor eae Effect on the Turnip Crop On De er cnaee --
|
4 ewt. Good turnips, 18 tons. Good Wheat.
San Very indifferent, 14 tons. Inferior.
Grew up wonderfully, { Q i
; Stubble black, grain
16 looked beautiful, but dark, and not larger

there was Jittle bulb.

| Protece Toone than small rice.

3. The fertilising effects of guano depend mainly upon the
quantity of ammonia which already exists in it, or which may
be formed in it by its further decomposition, and upon the pro-

208 COMPOSITION OF GUANOS.

portion of phosphates which are present in it. Of these the
former is the more valuable ingredient of the two—that is to
say, it would cost the farmer most money to buy it in -a sepa-
rate state, at its present price. The phosphates, in like man-
ner, would cost more to buy in the shape of bones or of sugar-
refiners’ refuse, (animal charcoal,) than any of the other
ingredients which the guano contains—the ammoniacal matter
excepted.

4. Composition.—The following table exhibits the composi-
tion of four samples of guano, two from the South American
and two from the African coast. These analyses do not enter
much into details, but they are sufficient for ordinary purposes
—as guides, that is, to the practical man.

SoutH AMERICAN. AFRICAN.
Peruvian. | Bolivian. | Ichaboe. aa
Water, - | 109 | 681. | eu at eee
Organic matter at 53.17 | 55.52 | 4661 | 2214
Gompnbe. , aes t 4.63 | 6.31 | 12.92 5.78
Carbonate of lime, - 4.18 3.87 0.27 1.49
ap ipsa = 23.54 | 25.68 22.40 50.22
ieee ae t ane age 0.52 2.02
~ 100. foo | “Sods | aie

These analyses are not to be considered as doing more than
generally representing the difference between the African and
American guanos. The several cargoes, both of African and
of American, which used to arrive in this country, differed much
among themselves. As I have already stated, the importation |
of Afri ican guano has now almost entirely ceased.

PERMANENCE OF THEIR ACTION. 209

It is one of the valuable qualities of guano, that it contains
a mixture of so many of these substances on which plants live.
The only ingredient in which it is manifestly defective is potash
—of which it usually contains less than 1 per cent ; and hence
an admixture of wood ashes, and especially of leached or washed
wood ashes, would be likely to improve its action upon the
crops, in such soils as do not naturally abound in potash.

5. Lobos Islands guano, which is at this moment attracting
so much of the attention of politicians, is said to be the pro-
duce of the seal or sea-wolf, and to be from 25 to 33 per cent
less valuable than the guano of the Chincha islands.

6. British guano—The successful employment of foreign
guano has caused the droppings of pigeons, sea-fowls, and bats,
to be sought for in the caves along our east and west coasts, and
in our western islands. I have examined several samples from
both coasts ; but though they may prove valuable manures in
the immediate neighborhood where they are found, they are not
rich enough to pay the cost of collection and transport to any
considerable distance.

T. Is guano permanent in its action 2—This is a question which
the practical man naturally asks when he is about to employ it
to a large extent. Hxperience seems to show that its beneficial
action extends to at least two crops, when it is applied in proper
quantity. Theory also indicates, that though the action of the
ammoniacal salts may be more or less exhausted in a single sea-
son, yet that the effect of the phosphates and other saline sub-
stances it contains—which is very important—will continue
beyond one year. But the kind and quality of the guano will
materially affect the length of its action.

In general, however, it may be said, that as guano resembles
bones very much in its composition, a as bones are known to
benefit the crops in an entire rotation, so ought guano also.
The chief difference between bones and guano is this—that the
guano contains ammonia ready formed, or forming, so to speak
—while the bones contain gelatine, which forms ammonia only

210 ADULTERATION OF GUANO.

after it has fermented. The ammoniacal part of the one, there-
fore, will act early, of the other after a longer period—while
the permanent effects of the remaining ingredients of both will
be very much alike if they are laid on in nearly the same
proportions.

SECTION JII.—ADULTERATIONS OF GUANO——HOW TO SELECT A SAM-
PLE OF GOOD QUALITY—NATIONAL VALUE OF THIS MANURE.

1. Adulterations of guano.—In consequence of the high price
of guano, the great demand for it, and the ease with which the
unwary farmer may be imposed upon, guano is adulterated with
various substances, and to a great extent. Impositions even
have been practised by selling as genuine guano artificial mix-
tures, made to look so like guano that the practical man in
remote districts is unable to detect it. A sample of such pre-
tended guano, which had been sold in the neighborhood of Wig-
town, and had been found to produce no effect upon the crops,
when examined in my laboratory, was found to contain, in the
state in which it was sold, more than half its weight of gypsum—
the rest being peat or coal ashes, with a little common salt, sul-
phate of ammonia, and either dried urine or the refuse of the
glue manufactories, to give it a smell. I could not satisfy
myself that it contained a particle of real guano. Burnt earth
and brick-dust are now prepared of various shades, and in fine
powder, in special manufactories, for the purpose of mixing with
guano and with artificial manures. These facts show how
important it is that the farmer should possess some means of
readily, and at a cheap rate, testing the costly manures he
employs.*

* “ Four vessels recently sailed hence for guano stations ballasted with
gypsum, or plaster of Paris. This substance is intended for admixture with
guano; and will enable the parties to deliver from the vessel a nice-looking
and light-colored article. Parties purchasing guano are very desirous of
having it delivered from the vessel, as they believe they obtain it pure. The

HOW TO SELECT A GOOD GUANO. 211:

2. In selecting a good guano, the following simple observations
will aid the practical man.

a. The drier the better—there is less water to pay for and to
transport.

b. The lighter the color, the better also. It is the less com-
pletely decomposed.

c. If it has not a strong ammoniacal smell, it ought to give
off such a smell when a spoonful of it is mixed with a spoonful
of slaked lime in a wine glass.

d. When put into a tumbler with water, stirred well about,
and the water and fine matter poured off, it ona to leave little
sand or stones.

e. When heated to redness in the air till all the animal mat-
ter is burned away, the ash should nearly all dissolve in dilute
muriatic acid. The insoluble matter is useless sand or earthy
adulterations.

f. In looking at the numbers in a published analysis of a
Peruvian guano, those representing the water should be small ;
the organic matter containing ammonia should approach to 50
or 60 per cent ; the phosphates should not much exceed 20 per
cent ; and the common salt and sulphate of soda ought not to
form much more than 5 or 6 per cent of the weight of the guano.
in Saldanha Bay guano the proportion of phosphates was much
greater, and of organic matter less.

3. The national valwe of guano, and the consequent import-
ance of preventing adulteration as far as possible, may be judged
of from three important facts.

a. From the amount of the importation of it into this coun.
try, which, during the last ten years, has been as follows :—

favorite material for the adulteration of guano, at the present moment, is
umber, which is brought from Anglesea in large quantities. The rate of
admixture, we are informed, is about 15 cwt. of umber to about 5 ewt. of
Peruvian guano, from which an excellent-looking article, called African
guano, is manufactured.”—Liverpool paper.

212 YEARLY IMPORTATION OF GUANO.

Years. Tons. Years. Tons.
Gee 2,881 1847, . 82,000
pean. . 20,398 jet te . 41,414
1945; 3,002 1849) 4) geese
ee ae . 104,354 hla) eer . 116,925
1845, . age soot Ui veet yo . 245,016
tee . 89,203

b. That the quantity imported in 1851 would sell for upwards
of two millions sterling, and with good management ought to
produce two or three times its own value in grain or other vege-
table food. In other words, such a yearly supply of guano is
equal to the importation of foreign grain and other produce to
the value of from four to six millions sterling.

c. It also serves as a stimulus, while it supplies one of the |

requisites, to the general introduction of improved methods of
agricultural practice.

CHAPTER XVI.

Relative theoretical values of different animal manures.—Chemical distinc-
tion or difference between animal and vegetable manures.—Cause of this
difference.—Effects of respiration.—Coldness of the droppings of the cow,
and poorness of the manure from growing stock.—Improvement of the
land by eating off with sheep.

SECTION I.—-OF THE RELATIVE THEORETICAL VALUES OF THE DIFFER-
ENT ANIMAL MANURES.

Tue fertilising power of animal manures, in general, is de-
pendent, like that of the soil itself, upon the happy admixture
they contain of a great number of those substances which are
required by all plants in the universal vegetation of the globe.
Nothing they contain, therefore, is without its share of influ-
ence upon their general effects ; yet the amount of nitrogen
present in each affords one of the readiest and most simple
tests by which their relative agricultural values, compared
‘ with those of vegetable matters, and with each other, can be
pretty nearly estimated.

In reference to their relative quantities of nitrogen, there-
fore, they have been arranged in the following order—the num-
ber opposite to each representing the weight in pounds, which
is equivalent to, or would produce the same sensible effect upon
the soil as 100 lb. of farmyard manure:—

Farmyard manure, : 100

Solid excrements of the cow, ‘ ; 125
ee (a horse, : J 73
Liquid excrements of the cow, . ; 91
———_—— horse, . : 16
Mixed excrements of the cow, . 98
———_—__——— horse, s 54

—— sheep, : 36

pig, . 64

214 RELATIVE VALUES OF ANIMAL MANURES.

Dry flesh, : ove yeep ee ‘ 3
Pigeons’ dung, . : : ; 5
Flemish liquid manure, : : 200.
Liquid blood, . ’ ° : 15
Dry blood, aint il : : 4
Feathers, : ty 5 x 3
Cow hair, : - ls ‘ 3
Horn shavings . ‘ ; : 3
Dry woollen rags, : é : 25

_ It is probable that the numbers in this table do not err very
widely from the true relative values of these different manures,
in so far as the organic matter they severally contain is con-
cerned. The reader will bear in mind, however— :

1. That the most powerful substances in this table, woollen
rags for example—2% Ib. of which are equal in virtue to 100
Ib. of farmyard manure—may yet show less zmmedzate and sen-
sible effect upon the crop than an equal weight of sheep’s
dung, or even of urine. Such dry substances, as I have said,
_are long in dissolving and decomposing, and continue to evolve
fertilising matter, after the softer and more fluid manures have
spent their force. Thus, while farmyard manure or rape-dust
will immediately hasten the growth of turnips, woollen rags
will come into operation at a later period, and will prolong
their growth into the autumn. ; :

2. That besides their general relative value, as represented
in the above table, each of these substances has a further spe-
cial value not here exhibited, dependent upon the kind and
quantity of the saline and other inorganic matters which
they severally contain. ‘Thus three of dry flesh are equal to
five of pigeons’ dung, in so far as the organic part is concerned;
but the latter contains also a considerable quantity of bone
earth and of saline matter which is present only in minute
quantity in the former. Hence pigeons’ dung will benefit ve-
getation in circumstances where dry flesh would in some degree
fail. So the liquid excretions contain much important saline
matter not present in the solid excretions-—not -present either
in such substances as horn, wool, and hair-—and, therefore,

DIFFERENCE IN ANIMAL AND VEGETABLE MANURES. 215

each must be capable of exercising an influence upon vegeta-
tion peculiar to itself.

Hence the practical farmer sees the reason why no one simple
manure, such as hair or flesh, can long answer on the same land ;
and why, in all ages and countries, the habit of employing maxed
manures and artificial composts has been universally diffused.
When mixed manures are not employed, the kind of manure
which has been used must, after a time, be changed. A species
of rotation of manures must, in fact, be introduced, in order
that a second or third species of manure may give to the land
those substances with which the first was unable to supply it.

¢

SECTION II.—CHEMICAL DISTINCTION OR DIFFERENCE BETWEEN
ANIMAL AND VEGETABLE MANURES.

In what do animal manures differ from vegetable manures ?
What is the cause of this difference? How does the digestion
of vegetable matter improve its value as a manure ?

1. The characteristic distinction between animal and vegetable
manures is this—that the former contain a much larger
proportion of nitrogen than the latter. This will be seen at
once, by comparing together the tables given in the preceding
pages, (184 and 212,) in which the numbers given represent
the relative agricultural values of different vegetable and
animal substances compared with that of farmyard manure.
The lowest numbers represent the highest value, and the largest
amount of nitrogen, and these low numbers are always opposite
to the purest animal substances.

2. In consequence of their containing so much nitrogen,
animal substances are further distinguished by the rapidity with
which, when moist, they putrefy or run to decay. During this
decay, the nitrogen they contain gradually assumes the form of
ammonia, which is perceptible by its smell, and which, when
proper precautions are not taken, is apt, in great part, to escape
into the air. Hence the loss which occurs when manure is

216 CAUSE OF DIFFERENCE BETWEEN THE MANURES.

fermented too completely, or without proper. precautions to
prevent the escape of volatile substances. And as animal
manure, when thus over-fermented, or permitted to give off its
ammonia into the air, is, found to be less active upon vegetation
than before, it is reasonably concluded that to this ammonia,
and the compounds formed along with it, or to the substances
from which they are produced, the peculzar virtue of animal
manures, when rightly prepared, is in a great measure to be
ascribed.

Vegetable substances in general do not decay so rapidly, and
emit little odor of ammonia when fermenting. When prepared
in the most careful way, also, vegetable manure does not exhibit
the same immediate and remarkable action upon vegetable
growth as is displayed by almost every substance of animal
origin. There are exceptions, indeed, to this general rule, since
the crushed seeds of plants—rape-dust for example—produce an
effect on many crops little inferior to that of animal manures.
They, in fact, resemble animal substances very closely in their
chemical composition.

SECTION IIJ.—CAUSE OF THE DIFFERENCE BETWEEN ANIMAL AND
in VEGETABLE MANURES. EFFECTS OF RESPIRATION.

Whence do animal substances derive all this nitrogen? Ani-
mals live only upon vegetable productions containing little
nitrogen ; can they then procure all they require from this
source alone? Again, does the act of digestion produce any
chemical alteration upon the food of animals so as to render
their excretions a better manure, richer in nitrogen than the
substances on which they feed? Does theory throw any light
upon the opinion generally entertained among practical men
upon this point ?

These two apparently distinct questions will be explained by
a brief reference to one common natural principle.

1. Animals have two necessary vital functions to perform—to

5

EFFECTS OF ANIMAL DIGESTION. 217

breathe and to digest. Both are of equal importance to the
health and general welfare of the animal. The digester (the
stomach) receives the food, melts it down, extracts from it those
substances which are best suited to supply the wants of the
body, and sends them forward into the blood. The breathers
(the lungs) sift the blood thus mixed up with the newly-digested
food, combine oxygen with it, and extract carbon—which car-
bon, in the form of carbonic acid, they discharge by the mouth
and nostrils into the air.

Such is a general description of these two great processes ;
their effect upon the food that remains in the body, and has to
be rejected from it, is not difficult to perceive.

Suppose an animal to be full grown. Take a full-grown man.
All that he eats as food is intended merely to renovate or
replenish his system, to restore that which is daily removed from
every part of his body by natural causes. Jn the full-grown
state, everything that enters the body must come out of the body in
one form or another. The first part of the food that escapes is
that portion of its carbon that passes off from the lungs during
respiration. This portion varies in weight in different individuals
-—chiefly according to the quantity of exercise they take. From
5 to 9 ounces a-day is the average quantity given off from the
lungs of a full-grown man, though in periods of violent bodily
exertion, 13 to 15 ounces of carbon are breathed out in the
form of carbonic acid.

Suppose a full-grown man to eat a pound and a half of bread,
and a pound of beef in 24 hours, and that he gives off by respi-
ration 8 ounces of carbon (3500 grains’ during the same time.
Then he has

Carbon. Nitrogen.
Taken in his food, about 4500 grains, and 500 grains, while
He has given off in res- ; soi
piration, 3500 and little or no nitrogen.
. *
Leaving to be’ converted
into his own substance, + 1000 grains and 500 grains.
or to be rejected, .

218 VALUE OF THE DUNG.

Our two conclusions, therefore, are clear. The vegetable
food, by respiration, is freed from a large portion of its carbon,
which is discharged into the air, while nearly the whole of the
nitrogen remains behind. In the food consumed, the carbon
was to the nitrogen as 9 to 1; in that which remains in the
body after respiration has done its work, the carbon is to the
nitrogen in the proportion of only 2 to 1.

It is out of this residue, v2ch in nitrogen, that the several
parts of animal bodies are built up. Hence the reason why
they can be formed from food poor in nitrogen, and yet be them-
selves rich in the same element.

It is this same residue also, which, after it has performed its
functions within the body, is discharged again in the form of
solid and liquid excretions. Hence the greater richness in ni-
trogen—in other words, the greater fertilising power possessed
by the dung of animals than by the food on which they live.

2. It must also be borne in mind, that the digested food con-
tains all the saline matter, as well as nearly all the nitrogen,
which had entered the stomach of the animal. Weight for
weight, therefore, the dung must be richer also in saline matter
than the vegetable food, and therefore must be more fertilising
in its effects upon the land. In an experiment made on the
food and dung of the horse, it was found that while in the dry
food the carbon was to the saline matter as 6 to 1, it was in
ie dry dung only as 2 to 1.

. Two other remarks I may here add, because of their
‘hen est to the practical man.

a. The manure of the cow, taking it mixed, is not so rich in
nitrogen as that of man. It is true that the cow, owing to its
larger bulk and larger lungs, gives off perhaps eight or nine
times as much carbon by respiration as an active full-grown
man. But the weight of its daily food still farther exceeds that
of a healthy man. Suppose the daily food of a cow to weigh
ten times as much as the food we have supposed: a man to eat,
and to contain carbon and nitrogen in nearly the same propor-

DUNG OF FULL-GROWN ANIMALS. 219

tions—and that it gives off 60 ounces of carbon each day from
its lungs—then we have
Carbon. Nitrogen.

In the food, . 45,000 grains. 5000 grains.
Given off by the Ings 7 28,0000 °° % rain

Tou be ultimately rejected, 19,000 “ Pa se 018 ie

In the mixed manure rejected by such a cow, therefore, the
carbon would be to the nitrogen in the proportion of about 4
to 1; while in nightsoil it was, according to our former suppo-
aia. as2tol. Thus the mixed dung and urine of the cow
is less rich as an cmmediately acting manure than the mixed
nightsoil and urine of man. And since much of the nitrogen,
as well as of the saline matter of the food, is contained in the
urine of the cow, if this urine be allowed to escape, the solid
cow-dung will be still colder and less fertilising. The dry mixed
manure of the cow is richer in nitrogen than the dry food,
weight for weight, but not so much so as if the cow gave off
from her lungs a larger proportion of the carbon contained in
her food.

b. Since the parts of animals—their blood, muscles, tendons,
and the gelatinous portion of their bones—contain much nitro-
gen, young beasts which are growing must appropriate to their
own use, and work up into flesh and bone, a portion of the ni-
trogen contained in the non-respired part of their food. But the
more they thus appropriate, the less will pass off into the fold-
yard; and hence it is natural to suppose that the manure, either
liquid or solid, which is prepared where many growing cattle
are fed, the food being the same, will not be so rich as that which
is yielded by full-grown animals. This deterioration has actually
been observed in practice, and it may with some degree of cer-
tainty be expected in all cases to take place, unless, by giving
a richer food to the young cattle, the difference to the farmyard
is made up.* |

* Though I have dwelt as long upon these interesting, and, I believe,

220 EATING OFF WITH SHEEP.

SECTION IV.—IMPROVEMENT OF THE LAND BY EATING OFF. WITH
SHEEP.

The eating off with sheep is a practice on which some light
is thrown by the considerations presented in the preceding sec-
tion. This practice is adopted in different places with a view
to very different objects.

1. On sandy soils, as in Norfolk, the whole or part of the
turnip crop is eaten off with sheep, for the purpose chiefly of
treading down and consolidating the soil, and thus fitting it
for the better growth of the succeeding crop of barley. The
production of a mechanical effect upon the soil is here the chief
thing sought for.

2. When the soil is not so light, the turnips are often eaten
off with sheep for the sake of the regular and even manuring
which the land is sure to obtain. The effect sought for here is
also chiefly mechanical. The turnips could be drawn, and the
dung collected, but it would afterwards have to be spread—and
it could not by hand be so easily spread, or laid on the land ‘so
completely without loss.

3. Independent of the above considerations, the general be-
nefit to the land of eating off with sheep arises from the con-
version of the vegetable produce into a manure richer, weight
. for weight, in nitrogen and saline matter, and, therefore, having
& more immediate and powerful effect upon the after crops. In
the case of land which is otherwise in good heart or condition,
_ perhaps no better or more profitable husbandry than this, for
rural districts, could readily be recommended.

4. But the manure is richer, as we have seen, because the
respiration of the animal separates a large proportion of the

novel considerations, as the limits of this little work will permit, yet for
fuller details, and for perhaps a clearer exposition of the principles above
advanced, I must refer the reader to my Lectures on Agricultural Chemistry
and Geology, 2d edition.

EATING OFF AGAINST PLOUGHING IN. 221

carbon which the food contains. This fact throws light upon a
question which the improving farmer has frequently asked him-
self in reference.to poor or worn-out arable land, or to land he
wishes to reclaim. If I sowa green crop—rape, or buckwheat,
or rye, or tares=had I better eat it off with sheep, or plough
itin? Iam in doubt about the effect of ploughing in, but
I am sure that by eating off I shall give the land a good ma-
nuring. ;

Now theory answers this question distinctly. If the only
object be to enrich the ground, plough in green. By this means
the carbon is saved which would otherwise be dissipated by the
lungs of the animal,—and this carbonaceous matter is of great
value in improving poor, thin, or sandy soils, in which organic
matter is deficient.

But if enriching the soil be not the sole object—if some mut-
ton also be desired—then it is good husbandry to eat off, with
full-grown and fattening stock. The land will improve less
rapidly in this way than by ploughing in, and it will be longer
before you can safely crop it with corn, but it wld gradually
improve under such treatment.

Why fattening and not growing stock is to be kept on such
land will appear from the considerations to be presented in the
concluding chapter—on the feeding of animals.

CHAPTER XVII.

Saline and mineral manures.—The salts of ammonia as manures.—Ammo-
niacal liquor, sal-ammoniac, and sulphate of ammonia.—Results of expe-
riments with these salts.—Quantity of nitrogen required by the wheat
crop.—Carbonates, nitrates, and silicates of potash and soda.—Sulphates
of potash and soda.—Common salt.—Sulphate of magnesia.—Sulphate of
iron.—Gypsum.—Use of the phosphate and super-phosphate of lime, and
cause of their beneficial action—Use of kelp, and of the ashes of wood,
straw, the husk of oats, parley, and rye, and of the sugar-cane.—Compo-
sition and use of peat or Dutch ashes.—Coal ashes.

Tuer general nature and mode of operation of such saline and
mineral substances as are capable of acting as manures, will be
in some measure understood from what has already been stated
as to the necessity of nitrogen and of inorganic food to living
plants, and as to the kind of inorganic food which they espe-
cially require. It will be necessary, however, to advert briefly
to the more important of these manures,—their use, their mode
of action, and the theory of their observed effects.

SECTION I.—THE SALTS OF AMMONIA AS MANURES,

The value of ammonia as a manure has been already spoken
of (pages 27 and 52.) It exists in all fermenting animal ma-
nures, and thus is constantly applied to the land even in the
least advanced districts. There are several states, however,
in which it has lately begun to be used, unmixed with other
substances, and with manifest advantages to the crops.

1. Ammoniacal Liquor.—This is water rich in ammonia,
which is distilled from coal during the manufacture of coal gas.
It is of various degrees of strength, and therefore, if applied to
the land alone, it must be diluted with a variable proportion of —

CARBONATE OF AMMONIA. IIS

water. It often contains ammonia enough to yield, when satu-
rated with spirit of salt, as ‘much as a pound and a half of sal-
ammoniac from a single gallon. That of the London gas-
works is said to yield, when saturated with sulphuric acid,
about 14 ounces of sulphate of ammonia from the gallon.

To grass land this ammoniacal liquor may be applied with
great advantage, by means of a water-cart @ previously
diluted with from three to five times its bulk of water. If too
strong it will burn up the grass at first, especially if the wea-
ther be dry; but, on the return of rain, the herbage will again
spring up with increased luxuriance.

On arable land it may be applied with profit to the young
wheat or other corn by the water-cart, or it may be dried up
by any porous material, and thus put into the turnip or potato
drills. A friend in Northamptonshire writes me that the 200
gallons of ammoniacal liquor per imperial acre, drunk up by
sawdust and put into the drills, has alone given him an excel-
lent crop of turnips. This manuring, however, cannot be ex-
pected to keep the land in heart. A certain proportion of
bone-dust should be mixed with this ammoniated sawdust, or
else the corn crops should afterwards be top-dressed with rape-
dust, guano, or bones. If, indeed, the land be already bone-
sick, the saturated sawdust may be used alone, or with a mix-
ture of wood or peat ashes for one rotation.

The ammoniacal liquor may also be used advantageously to
promote the fermentation of peat, sawdust, and other com-
posts,—or it may be added to the ordinary dunghill, or to the
liquid manure of the farmyard, and applied along with it to
the land.

It is said to extirpate moss from old grass land more perma-
nently than lime.

2. Carbonate of ammonia is the common smelling salts of the
shops. It exists in the ammoniacal liquor above described, and
is very useful, in a diluted state, in promoting vegetation. It
is: too expensive, however, in the form in which it is at present

224 STEEPING SEEDS IN SALTS OF AMMONIA.

sold, to be of much use to the practical farmer. An ounce of
it, dissolved in a gallon of water, gives a solution which
destroys insects on rose-trees and other plants, and adds to their
luxuriance at the same time. <A few pieces laid on a plate and
allowed to evaporate slowly into the atmosphere of a conserva-
tory, are said to add greatly to the green and healthy appear-
ance of the plants. .

3.- Sal-ammoniac_—The same may be said of muriate of ammo-
nia, the sal-ammoniac of the shops. Though experiment has
shown that this substance exercises a very beneficial influence
on the growth of our cultivated crops, yet the pure salt is too
high in price to admit of its being economically used in ordinary
husbandry. An impure variety, however, is prepared from gas
liquor, which is sold at about 15s. a cwt.

4. Sulphate of ammoma is now manufactured at a compara-
tively cheap rate, and is sold at £16 a ton. This salt may be
applied with advantage, especially to soils which are locally
called deaf—which contain, that is, much inert vegetable matter,
and to such as are naturally rich in phosphates. It may also
be mixed with bones, rape-dust or wood-ashes, and put into the
turnip or potato drills, or it may be used as a top-dressing in
spring to sickly crops of corn. .

A case is mentioned of a field being manured for wheat, in
part with ordinary farmyard manure, and in part with 13 ewt.
per imperial acre (cost £1°2s.) of sulphate of ammonia—when
the produce of the former was 24, and of the latter 33 bushels
per imperial acre. In other cases, also, it has been found a
profitable application, both to young corn and to meadow hay.

Faded flowers, when introduced into a solution of sulphate of
ammonia, are said to be perfectly restored and revivified.

5. Steeping of seeds in the salts of ammonia.—The salts of
ammonia, especially sal-ammoniac and the sulphate of ammonia,
have been strongly recommended as steeps for seed-corn.. They
have in many cases been found very advantageous in hastening
germination, and in increasing the after luxuriance of the crop.

EXPERIMENTS UPON WHEAT. 225

Thus, in one experiment, seeds of wheat, steeped in the sulphate
of ammonia on the Sth of July, had by the 10th of August
tillered into nine, ten, and eleven stems of nearly equal vigor,
while unprepared seed had not tillered into more than two,
three, or four stems. — |
Sal-ammoniac has a similar effect. In Upper India it is pre-
pared by heating together cmel’s dung and sea salt, and is used
in the plains, among other purposes, for the steeping of seeds.
It is to be observed, however, that neither when applied
directly as a manure to the growing crops, nor when used as a
steep for the seed, can the salts of ammonia alone bring a plant
to maturity. They tend to hasten its growth, ¢f all its other
wants can be readily supplied by the soil; but if this is not the
case, a quick decay will succeed to a short-lived luxuriance.

SECTION II.—RESULTS OF EXPERIMENTS WITH THE SALTS OF AMMONIA.
NITROGEN NECESSARY TO THE WHEAT CROP.

The last mentioned fact, as well as the general value of the
salts of ammonia, is illustrated by the results of some experi-
ments made by Mr. Lawes at Rothampstead in Hertfordshire.
He sowed wheat for three successive years on the same piece of
ground, applying only mineral manures the first year, and only
ammoniacal manures the second and third years. The following
were the results :-—

Application per imperial acre. rae ae Si sind
1844, Superphosphate of lime 560 Ib. )
Silicate of potash, x ph laa oe a
1845. ‘Sulphate of ammonia P, 4 5
Manaiaor age each Ji cwt. 315 .. 4266 ..

1846. Sulphate of ammonia, ae ae rif AE 2244 ,.

Thus upon a soil already rich in mineral manure, the applica-
cation of salts of ammonia nearly doubled the crop of grain in
1845, and quadrupled that of straw ; and, in 1846, added

10*

226 NITRATES OF POTASH AND SODA.

again one-half to the grain above 1844, and doubled the straw.
In each case, however, some allowance must probably be made
for the influence-of natural varieties in the seasons.

As to the necessity of nitrogen to the wheat crop, Mr,
Lawes concludes, from numerous experiments, that, upon his
soul and in has locality, five pounds of ammonia—or four of ni-
trogen, in some other available fofm—are “‘ required for the
production of every bushel of wheat beyond the natural yield
of the soil and the season.”* But as a bushel of wheat con-
tains only about 1 Ib..of nitrogen, (equal to 14 Ib. of ammonia, )
it is obvious that, if this estimate be correct, the greater part
of the nitrogen is lost to the farmer. The subject, therefore,
is open to further investigation.

SECTION III,—SALTS OF POTASH, SODA, MAGNESIA, AND IRON,

1°. Carbonate of potash and soda.—The common pearl-ash,
and the common soda of the shops, have not in this state been
much employed in agriculture. Both, however, greatly pro-
mote the growth of strawberries in the garden,—and the latter
is now cheap enough (10s. a ewt.) to admit of its being tried
as a top-dressing on clovers and grass lands, on such as are old
and mossy especially, with every prospect of advantage. It
should be dissolved in much water, and put on with a water-
cart, or thoroughly mixed with earth, and applied as a top-
dressing. Mixed at the rate of one cwt. an acre, with bone or
rape dust, or eyen with guano, it may be expected to improve
both the turnip and the potato crops.

Carbonate of soda, in the form of soda ash, has been applied
with success to kill or to remove the effects of the wire-worm.
It may either be sown with the wheat in winter, or applied as
a top-dressing in the spring, to the affected wheat or oats.
2°, Nitrates of potash and soda.—Saltpetre and nitrate of

* Journal of Royal Agricultural Society of England, viii. 246.

COMMON SALT. 23't

soda have been deservedly commended for their beneficial ac-
tion, especially upon young vegetation. They are distinguished,
like the salts of ammonia, for imparting to the leaves a beautiful
dark green color, and are applied with advantage to grass and
young corn of any kind, at the rate of 1 ewt. to 1) ewt. per
acre. They are said even to benefit young fir-trees. Applied
to young sugar-canes they have been found largely to increase
the crop, and éven, in the second year after their application,
to add much to the luxuriance of the cane fields. The nitric
acid they contain yields nitrogen to the plant, while potash and
soda are also put within reach of its roots, and no doubt serve
many beneficial purposes. Upon land rich in phosphates, ni-
trate of soda is a profitable application to wheat, being found,
in Norfolk, to return an {ncrease of from 4 to 7 bushels of grain
for every cwt. applied to the corn in spring.* It is especially
recommended for wheat, on light, gravelly, and sandy soils, and
on cold undrained clays.

3°. Sulphate of potash is likely to be useful, especially to
root and leguminous crops. Its price, however, is usually high,
varying from £12 to £20 a ton.

4°, Common salt has, in many districts, a fertilising influence
upon the soil. It destroys small weeds; improves the quality
of pastures, and renders them more palatable; strengthens and
brightens the straw, and makes the grain heavier per bushel,
both of wheat and oats. It has been observed, also, to pro-
duce specially good effects upon mangold-wurtzel.

A small quantity of salt is absolutely necessary to the healthy
growth of all our cultivated crops, but it is in inland and shel-
tered situations, and on high lands often washed by the rains,
that its effect is likely to be most appreciable. The spray of
the sea, borne to great distances by the winds, is in many dis-
tricts, where prevailing sea winds are known, sufficient to sup-
ply an ample annual dressing of common salt to the land.

* See the Author’s Lectures on Agricultural Chemistry, 2d edition.

+ At Penicuik, near Edinburgh, the rain that falls contains so much com-
mon salt as alone to convey 640 Ib. to every acre in a year—(Dr. MappEy.)

298 SULPHATES OF MAGNESIA AND IRON.

It has sometimes been found to be of still more advantage,
in strengthening the straw, to apply a mixture of quicklime
with a fourth or a fifth part of its weight of dry salt; or the
salt may be dissolved in water, and the lime heap slaked with
the solution—or sea water may be at once employed to slake
the lime:

5°. Sulphate of soda, or Glauber’s salt, has lately been re-
commended in this country for clovers, grasses, and green crops,
Mixed with nitrate of soda it produces on some soils remarka-
ble crops of potatoes, and in some localities, when used alone,
it has greatly benefited the turnip crop. Mr. Girdwood found
that 14 cwt. of this sulphate per acre, sprinkled upon the other
manure in the drills, added 16 bushels an acre to his crop of
beans. It is on rich land only, however, that the addition of a
single saline substance can be expected to produce results so
favorable as this.

6°. Selicates of potash and soda.—When potash and soda are
melted together with silicious sand, they form a kind of glass
which is soluble in water. This has produced remarkable
effects upon the potato crop, and, like other silicates, is recom-
mended as a strengthener of the straw of our corn crops.

1°. Sulphate of magnesia, or Kpsom salts, is also beneficially
applied in agriculture to clovers and corn crops. It can be had
in pure crystals at 10s. a cwt., and in an impure state at from
3s. to 6s. a cwt. It has been found of advantage as a top-
dressing for the young wheat, and as an application to the ©
potato. Where the soil is deficient in magnesia, it may always
be expected to improve the crops of corn.

8°. Sulphate of zron—Common green vitriol, applied in the
form of a weak solution, has been observed to strengthen feeble
plants, and to give them a brighter green. It has also been
used as a top-dressing for grass, and as an application to dis-
eased fruit trees. It deserves a further trial.

GYPSUM AND OTHER SULPHATES. | 229

SECTION IV.—USE OF THE SULPHATE AND PHOSPHATES OF LIME, AND
CAUSE OF THEIR BENEFICIAL ACTION.

1°. Sulphate of hme, or gypsum, is in Germany applied to
grass land with great success, and over large tracts of country.
In the south of England it has been applied to some grass lands
with benefit for thirty-five years in succession, at the rate of 24
ewt. per acre. It supplies the lime and sulphuric acid annually,
which are annually removed by the crop. In the United States
it is used for every kind of crop ; and I have there seen it pro-
duce very striking effects on Indian corn. It is especially
adapted to the pea, the bean, and the clover crops. It is more
sensibly efficacious when applied in the natural state than after
it is burned.

The sulphates all afford sulphur to the growing plant, while
the lime, soda, magnesia, &c., which they contain, are themselves
in part directly appropriated by it, and in part employed in pre-
paring other kinds of food, and in conveying them into the
ascending sap.

Though there can be no question that these sulphates, and
other similar substances, are really useful to vegetation, yet the
intelligent reader will not be surprised to find, or to hear, that
this or that mineral substance has not succeeded in benefiting
the land in this or that district. If the builder has already
bricks enough at hand, he needs mortar only, to enable him to
go on with his work : so, if the soil contain gypsum or sulphate
of magnesia in sufficient natural abundance, it is at once a need-
less and a foolish waste to attempt to improve the land by add-
ing more ; it is still more foolish to conclude, because of their
failure in one spot, that these same saline compounds are unlikely
to reward the patient experimenter in other localities.

2°. Phosphates of lime—a. Burned bone-—When bones are
burned in an open fire, they diminish in weight about one-half,
and leave behind a white earthy matter long known by the name

‘

930 ACID OR SULPHATE OF LIME.

of Donte earth. This bone earth consists chiefly of phosphate of
lime (page 193.)

Bones are know n to be an excellent manure, and as our cul-
tivated crops, and especially our corn crops, contain much phos-
phorie acid, it has been justly concluded that part of their effect
is due to the bone earth they contain. Hence the use of burned
bones as a manure has been warmly recommended.

In soils which are poor in phosphate of lime, there is no doubt
but burned bones will be likely to benefit the crops of corn ;
but there are few soils, I think, in which a ton of bone-dust
would not produce a better effect than the ash left by an equal
weight of bones.

b. Native phosphate of lime-——Phosphate of lime is found as
a native mineral in many countries, and has been applied with
advantage to the soil. It has lately been met with in the States
of New York and New Jersey in sufficient quantity to make it
likely to prove a profitable article of import into this country.
It has also been discovered in considerable quantity in the marls
of the crag and green-sand formations (see p. 94,) of England,
and is now dug up in large quantities for agricultural purposes.*
In our ordinary limestones it also exists in variable quantity.
Jn a burned lime from Carluke, which is full of fossils, I have
found it to the extent of 24 per cent ; so that every ton of such
lime conveys to the land as much phosphate of lime as two
bushels of bones. This must modify in a favorable manner the
effect of such lime when applied to the land.

c. Acid or swper-phosphate of lime-—When burned bones are
digested with sulphuric acid diluted with three times its bulk of
water, gypsum (sulphate of lime) is produced, and falls to the
bottom of the solution, while the phosphoric acid, and a portion
of the lime, remain in the sour liquid above it. When this
liquid is boiled down or evaporated to dryness, it leaves a white
powder, which is known by the name of acid or super-phosphate

* Journal of the Royal Agricultural Society, vol. ix. p. 56, and vol. xii. p. 93.

ASHES OF SEA-WEED, WOOD AND STRAW. 231

of lime. Under the latter name it has been introduced into the
manure market. It is extensively manufactured in this country,
by grinding the mineral phosphate obtained from the crag of
Norfolk and Suffolk, (p. 93,) mixing it with about an equal
weight of strong sulphuric acid, and then drying the whole.
Some manufacturers mix a portion of bone dust with the mine-
ral powder, and thus produce a manure containing some animal
matter, and therefore of more general utility.

As the ordinary burned bones are difficult to dissolve in the
soil, and as the acid phosphate is more easy of solution, it is
likely to be taken up more readily by the roots, and thus more
rapidly to aid the growth of plants. These super-phosphates
are sold at present at about £7 a ton.

Numerous experiments have been made with the super-phos-
phate, and very remarkable results have been obtained by its
use, chiefly as a manure for the turnip crop, but also as a top-
dressing for grass, and for wheat, and other kinds of corn.
What is sold as super-phosphate by the manufacturers, is very
variable in its composition, and is often largely adulterated.

SECTION V.—OF THE ASHES OF SEA-WEED, WOOD, STRAW, THE HUSK
Or OATS, BARLEY, AND RICE, AND OF THE SUGAR@ANE.

1. Kelp is the ash left by the burning of sea-weed. It con-
tains potash, soda, lime, silica, sulphur, chlorine, iodine, and
several other of the inorganic constituents of plants which are
required by them for food. It is nearly the same also—with
the exception of the organic matter which is burned away—
with the sea-weed which produces such remarkably beneficial
effects upon the soil. In the Western Isles a method is prac-
tised of half-burning or charring sea-weed, by which it is pre-
vented from melting together, and is readily obtained in the
form of a fine black powder. The use of this variety ought to
combine the beneficial action of the ordinary saline constituents
of kelp, in feeding or preparing food for the plant, with the

932 LIXIVIATED WOOD AND STRAW ASHES.

remarkable properties observed in animal and vegetable char-
coal. In Jersey, the sea-weed is dried and burned in the
kitchen grates, and the ash is considered to be efficacious in
- destroying grubs. In the Orkneys, potatoes are _raised by
means of a mixture of peat ashes and kelp, applied at the rate
of fifty bushels to the Scotch acre.

2. Wood ash contains, among other substances, a portion of
common pearl ash in an impure form, mixed with sulphate and
silicate of potash. These substances are all valuable in feeding
and in preparing the food of plants, and hence the extensive
use of wood ash as a manure in every country where it can
readily be procured. Wood ash, applied alone, is especially
beneficial to clovers, beans, and other leguminous plants. Mixed
with bones in nearly equal bulk, it is extensively employed in
this country as a manure for turnips. In some soils it has been
found, without any admixture, to raise large crops of potatoes.
In Persia, seed wheat and melon seeds are always steeped, for
24 hours before sowing, in a ley of wood ashes. In Lower
Canada, 40 bushels of wood ashes applied alone, give a crop of
200 to 250 bushels of potatoes.

3. Lizxiviated wood ash—When the common wood ash is
washed with water as long as any thing dissolves, and the solu-
tion is then boiled to dryness, the common potash of commerce
is obtained. Buta large portion of the ash remains behind un-
dissolved, and in countries where much wood is burned for the
manufacture of potash, this /izzvzated or washed refuse accumu-
lates. It consists of silicate of potash mixed with silicate,
phosphate, and carbonate of lime, and when applied to the
land is remarkably favorable to oats. It suits better for clay
lands, and when laid on in considerable quantity, (1 or 2 tons
to the acre,) its effects have been observed to continue for 15
or 20 years. (SpRENGEL.)

4. Straw ashes—In this country straw is seldom burned for
the ash. In Germany, rye-straw is not unfrequently burned,
and the ash employed as a top-dressing. The dry straw is

ASHES OF OATS, BARLEY, RICE AND CANE HUSKS. 233

strewed over the field, then burned, and the ash ploughed in on
the spot. In many countries—among others, in some parts of the
United States—the straw is often burned, and the ash scattered
to the wind. When it is too much trouble to ferment the
straw in the farmyard, labor might surely be spared to strew
the ash upon the fields from which the crop was taken. The
soil would not fail to give a grateful return.

5. Ash of the husk of oats, barley, and rice—The husk, seeds,
or shellings of oats or barley, being supposed to contain no
nourishment, are often burned for the purpose of heating the
kiln on which the grain is dried. When thus burned, these
husks leave a considerable quantity of a white or. grey ash.
The oat husk I find to leave about 53 per cent of its weight.
This ash has hitherto been neglected by the millers, being ge-
nerally thrown into the stream by which their mills are worked.
It should, however, be carefully preserved. It may be ex-
pected to prove a valuable top-dressing to meadow land, to
young corn crops, and especially to bog oats. One miller in
the north of Scotland informs me that he makes about two
bushels a day of ash from the husk of the oats he grinds. The
waste of this ash, long persevered in, can scarcely have failed
slowly to impoverish the adjoining land.

In China, India, and other countries where rice is grown,
the husk of this grain also is burned; but the ash is rarely
afterwards returned to the soil. In China, it is said to be em-
ployed in the making of certain articles of manufacture.

6. Cane ash.—The sugar-cane when brought from the mill in
the state of trash, is burned for the purpose of boiling down
the syrup. The ash left by it is rich in those saline substances,
without which the cane cannot thrive. Without having per-
sonally examined any of our West India plantations, I may
safely hazard the opinion that some, at least, of the exhaustion
complained of by the planters is owing to the neglect of this
valuable ash—and that the large importation of foreign_ma-
nures, now~had recourse to, might by and by be in some mea-

¢

934 PEAT ASHES FROM PAISLEY.

sure dispensed with, by carefully collecting, grinding, and
returning it to the soil.

SECTION VI.—COMPOSITION AND USE OF PEAT OR DUTCH ASHES.—
COAL ASHES.

Peat or Dutch ashes are the ashes of peat burned for the
purpose of being applied to the land. They vary in composi-
tion with the kind of peat from which they have been prepared.
They often contain traces of potask and soda, and generally a
quantity of gypsum and carbonate of lime, a trace of phos-
phate of lime, and much silicious matter. In almost every
country where peat abounds, the value of peat ashes as a ma-
nure has been more or less generally recognised. The following
analyses of two samples of such ashes from the Paisley moss,
and of two from the island of Lewis, all examined in my labo-
ratory, show how valuable, and, at the same time, how very
different in quality, such ashes may be, even when they are ob-
tained from the same locality.

a. Ashes from the Paisley moss.

White Peat Black Peat

Ashes. Ashes.
Charcoal, - - - 54.12 3.02
Sulphates and carponares of potash,
soda, and magnesia, - - - 6.57 ; 5.16
Alumina, - - - - - 2.99 2.48
Oxide of iron, - - - - 4.61 18.66
Sulphate of lime, - - - - 10.49 21.23
Carbonate of ditto, - - - 8.54 3.50
Phosphate of ditto, - - - 0.90 0.40
Silicious matter, - - - 10.88 43.91
99.10 98.36

Tt will be observed that the first of these contained more
than half its weight of unburned charcoal, and still was richer
than the other, weight for weight, both in soluble salts and in
phosphate of lime—two of their most valuable mgredients.

PEAT ASHES FROM LEWIS. 235

The reason of this is, that the white peat, being nearer the
surface, consists of vegetable matter less decomposed. The
ashes of the upper layers of peat, therefore, will generally be
more valuable than those of the under layers.

b. Ashes from the island of Lewis.

Chloride of sodium, (common salt,) 0.41 0.29
Phosphate of lime, - - - 2.46 6.51
Sulphate of lime, (gypsum,) — - - 28.66 16.85
Sulphate of magnesia, - . 1.68 2.01
Magnesia. ' oa 6.32 5.86
Potash and soda, a - ete 5.32 3.59
Alumina, pod garbonate, it 94.63 7.54
Oxide of iron, - - - 9.18 6.58
Silica, soluble in caustic potash, - 15.55 28.58
Insoluble silicious matter and sand, - 7.94 14.20
Carbonic acid, charcoal, and loss, - 10.85 1.393
100. 100.

These samples, again, present other differences. They con-
tain, in addition to the alkaline matter and the gypsum, a more
considerable proportion of phosphate of lime than the others.
In the one, the phosphate amounts to 63 per cent, and must
contribute materially to its fertilising value. The soluble silica
is also deserving of notice, as likely to be useful—especially to
grass land and to crops of corn.

Peat ashes are not unfrequently used alone, and with
success, for the raising of turnips. Much of their success,
however, will depend on the peculiar composition of the ashes
employed. .

In Lancashire, peat only half burned is considered preferable
to double the quantity burned to a perfect ash.

Coal ashes consist in general of alumina and silica mixed
with a variable proportion of gypsum, carbonate of lime, phos-
phate of lime, and oxide of iron, mixed with half-burned coal.
They vary, however, with almost every different kind of coal
that is burned.

CHAPTER XVIII.

Why saline manures are required by the soil—Mode of determining their
local value.—Circumstances necessary to insure the successful application
of saline manures.—Of saline manures which exercise a special or specific
action upon plants.—Results of experiments with mixed saline manures,
made with the view of increasing the crop or of affecting its quality. —
Artificial mixtures in imitation of valuable natural manures.—Recipe for
artificial guano.

‘

SECTION I.—WHY SALINE MANURES ARE REQUIRED BY THE SOIL.

Tue use of saline substances as manures is of comparatively
recent introduction. In many districts, however, they are indis-
pensable, if we wish to maintain the present condition, or to
restore the ancient fertility of the land. This will appear from
the following considerations :

1. These saline substances exist in all plants, and must there-
fore abound, to a certain extent, in all soils in which plants can
be made to grow.

2. The rains gradually wash out from the surface—especially
of undrained arable soils, and in inland districts—a portion of
the saline matter they contain. If the surface soil is to be
retained in its present condition, this natural waste must, by
some means or other, be supplied.

3. The crops we carry off the land remove also a portion of
this saline matter from the soil, and thus gradually impoverish
it, if the saline substances be not again brought back.

4. And though we return to the soil, in the form of farmyard
manure, all the straw of our corn crops and the dung of our
cattle, land still loses all that we carry to market, ‘and all that
escapes from our farmyards and dung-heaps in the form of liquid

LOCAL VALUE OF SALINE MANURES. 237

manure. Even where tanks for liquid manure are erected, the
farmer can never return to the land a// the saline substances
contained naturally even in his straw. The rains that fall, were
there no other cause of waste, would wash away some portion
of what he would desire to carry back into his field.

The necessary waste of saline matter, arising from the above
causes, must be supplied from some source or other. When, for
a long period of time, the land has maintained its fertility with-
out receiving any artificial supply, it must contain within itself
naturally a very large proportion of these substances—must
derive from springs a continued accession of such matter, or
from waters that flow down from a higher level and bring with
them the washings of the upper soils—or it must obtain from
abundant sea-spray a sufficiency to supply the wants of the
plants that grow upon it.

The practical man will readily acknowledge that, when a suffi-
ciency of saline matter is not conveyed to his land from these
or similar sources, he must necessarily supply it by art. He
will understand, also, that the saline manures he adds to the soil
operate by yielding to the plant what it could not otherwise so
readily obtain; and that a saline substance which has been
found to benefit his neighbor’s land, may happen, when applied,
to do no good to his own—because his own may already con-
tain a sufficient supply of that substance.

SECTION II.—MODE OF DETERMINING THE LOCAL VALUE OF SALINE
MANURES.

In order, therefore, to determine whether fzs land will rea-
dily be benefited by the application of those saline substances ~
from which, in other districts, or upon other soils, much benefit
has been derived, the intelligent farmer will commence a series
of preliminary trials or small experiments.

That many of the saline substances described in the preced-
ing Sections may be profitably applied to most soils by the prac-

238 VALUE OF SALINE MANURES.

tical farmer, can no longer be doubted. At the same time, no
prudent man will at once expend any large sum upon them,
until either he himself, or some of his immediate neighbors who
cultivate a similar soil, have previously proved their efficacy on
a smaller scale. It is no doubt the duty of every practical
farmer—a duty he owes not only to his country but to himself
—to be alive to the benefits which are to be derived from every
improved method of culture that may be introduced ; but it is
no less his duty to avoid every reasonable risk of pecuniary
loss which might be injurious to himself. - ?

Suppose, therefore, I were to enter upon a farm which I was
desirous of rendering as productive as possible, by the applica-
tion of every new manure, or every new method of culture that
might prove to be suited to the kind of soil I possessed, I
would begin by trying the effect of each manure or method
upon a single acre, and I would extend my trials or alter my
methods according to the success I met with.

Among saline manures, for example, I would try nitrate of
soda, or carbonate of soda, or wood ashes, or sulphate of soda, or
common salt, or silicate of soda, or gypsum, or sulphated urine, or
guano, or the ammoniacal salts, or the soluble phosphates, or a
mixture of two or more of these substances, on a single acre or
half acre of my various crops—never expending in this way, during
any one year, more than I could easily afford to lose if my trials
should fai ; and I would not begin to use any of these sub-
stances largely till I was satisfied that there was a reasonable
prospect of remuneration. And having once begun upon this
assurance, I would cease applying them for a while as soon as
the crops no longer gave me a fair return for my outlay—the
probability then being, that the soil for the present had ob-
tained enough of the peculiar substance I had been employing,
and stood more in need of some other. |

Thus if, as happened to a friend of mine, a dressing of salt
was followed by a produce of 35 bushels from the first wheat
crop, and yet, when applied to the next crop of the same grain

~

CIRCUMSTANCES NECESSARY TO SUCCESS. 239

on the same field, the yield was only 20 bushels, I should con-
clude that, for the present, my land was sufficiently salted, and
that I had better apply something else. I would therefore
begin my experiments anew upon my salted land. I would try
some of the other substances above named, employing always
the same caution and economy as before, and carefully keeping
an account of my procedure, and of my profit and loss from
each experiment.

Such facts, also, as that in the State of New York, after a
long-continued use of gypsum, the employment of leached or ex-
hausted wood ashes (p. 233) was found to be more beneficial,
wotild incline me to make many trials of such variations or ro-
tations of manures.

I should thus have always several experimental patches upon
my farm; and I should not only avoid the risk of serious disap-
pointment and pecuniary loss, but I should enliven my ordinary
farm routine by the interest I should necessarily feel in watch-
ing the results of my different experiments—I should gradually
acquire habits of reflection, and of careful observation also,
which would be of the greatest possible service to me in all my
future operations.*

SECTION III.—OF THE CIRCUMSTANCES WHICH ARE NECESSARY TO
INSURE THE SUCCESSFUL APPLICATION OF SALINE MANURES,

The application of saline substances to the soil is not always
attended with sensible benefit to the crop. ‘The same substance
which, in one district, or in one season, has produced an increased
return, may fail in another district or in a different season. The
circumstances which are necessary to insure success in the appli-
cation of saline manures are chiefly the following :-—

1°. They must contain one or more of those substances which

* For numerous suggestions as to such experiments, I would refer the
reader to my published Eaperimental Agriculture—a work entirely devoted
to the subject of rural experiments.

240 SUBSTANCES EXERCISE A SPECIAL ACTION

are necessary to the growth of the plant, and in a condition or
state of combination in which the plant can take them up.

2°. The soil must be more or less deficient in these substances.

83°. The weather and soil must be moist enough to admit of
their being readily dissolved and conveyed to the roots, or the
land must be artificially irrigated.

4°, They must not be applied in too large a quantity, or
allowed to come in contact with the young shoots in too con-
centrated a form. The water that reaches the roots or young
leaves must never be too strongly impregnated with the salt, or,
if the weather be dry, the plant will be blighted or burned up.

5°. The soil must be sufficiently light to permit the salt easily
to penetrate to the roots, and yet not so open as to allow it to
be readily washed away by the rains. In reference to this
point the nature of the subsoil is of much importance. A re-
tentive subsoil will prevent the total escape of that which
readily passes through a sandy or gravelly soil ; while a very
open subsoil, again, may retain little or nothing of what has
once made its way through the surface.

6°. I may add, lastly, that it is in poor or worn-out soils that
all such applications may be expected to produce the most
marked and characteristic effects.

SECTION IV.—OF SALINE MANURES WHICH EXERCISE A SPECIAL OR
SPECIFIC ACTION UPON PLANTS.

An interesting branch of the present part of our subject is
the use of what are called special manures. Certain substances
have been observed to exercise a special action.

1. Upon all plants—Thus, the salts of ammonia promote
the growth, or prolong the green and growing state of most
plants. Nitrate of soda has a similar effect—while the addition
of lime to the soil, especially in well-drained and high lands,
almost uniformly hastens the ripening of the seed, and produces
an earlier harvest. |

ON DIFFERENT KINDS AND PARTS OF PLANTS. 241

2. On particular parts of plants ;—as when the gardener
improves his roses by mixing manganese with the soil, reddens
his ornamental hyacinths by putting carbonate of soda into the
water in which they grow—or by other substances, as by the
acd or swper-phosphate of soda, attempts to vary the hue or
bloom of his cultivated flowers. This principle is attended to
in practical agriculture, when substances are mixed with the
manure, which are believed to be specially required by the stalk
of corn, where a field produces a defective straw—or by the
ear, Where the grain refuses to fill. The application of silicate
of potash, of soda, or of lime, to the soil may add strength to
the straw, while the phosphates fill the ear, or bring it to ear-
lier maturity—as carbonate of potash, according to Wolff, pro-
motes the growth of the leaves and stems of the vine, while the
phosphates develop the fruit.

3. On particular kinds of plants—Farmyard manure rarely

comes amiss to any soil or any crop; but gypsum exercises a
peculiar action upon red clover; while wood-ashes, lime, and
other alkaline manures, cause white clover to spring up sponta-
neously, where it had before refused to grow even when sown.
So lixiviated wood ashes are favorable to oats; ammonia, or
the nitrates, are by some regarded as the peculiar manures for
wheat; phosphate of magnesia has been extolled as a specific
for potatoes ; and superphosphate of lime for our British turnip
crops.
All such facts as these are exceedingly valuable. Many of
the alleged specifics, however, are only locally so. Thus bones,
which produce such wonderful effects in Great Britain, espe-
cially upon turnips and upon some old grass lands, as those of
Cheshire, are much less conspicuously effective in some parts of
Germany, and even of our own island;* while gypsum, so
much and so generally prized by the German and American
farmer, is more rarely found to answer the expectations of the
English agriculturist.

* On some of the soils of the green-sand, for example.

949 RESULTS OF EXPERIMENTS

The truth is, that if the crop we wish to raise specially re-
quires any one substance which is not present in sufficient quan-
tity in the soil, that substance will there prove a specific for
that crop ; while, in another soil in which it is already abun-
dantly present, this substance will produce little beneficial ef-
fect. Failures, therefore, may every now and then be expect-
ed in the use of so-called specific manures, the evil of which is
not limited to THE IMMEDIATE Loss experienced by the incau-
tious experimenter. ‘They serve also to dishearten those who,
through their much faith, have been disappointed in their ex-
pectations, and thus to retard the progress of a truly rational
experimental agriculture.

SECTION V.—RESULTS OF EXPERIMENTS WITH MIXED SALINE MA-
NURES, MADE WITH THE VIEW OF INCREASING THE QUANTITY OF
THE CROP.

The same remark applies also to artificial mzxed manures,
when held forth as specifics for any or for all crops on every
soil. The animal and vegetable manures which occur in na-
ture, are all mixtures of a considerable number of different
substances, organic and inorganic. We are imitating na-
ture therefore, and are in reality so far on the right road,
when we compound our artificial mixtures. The soil may be
deficient in two, three or more substances ; and to render it
fertile, it may be necessary to add all these ; while, if it be de-
fective in one only, we are more likely to administer the right
one, if we add a mixture of several at the same time. It is
safer and swrer, therefore, to add a mixture of several saline
substances to our soils.

There are only two ways, however, in which we can safely
make up mixtures that are likely to be useful—either by actual
experiment upon the kind of land we wish to improve, or by an
exact imitation of the procedure, and by attention to the re-
quirements, of nature.

WITH MIXED SALINE MANURES. 243

1. Mixture of nitrate with sulphate of soda.—In 1840 I re-
commended the trial of sulphate of soda (Glauber’s salts) as a
manure, and in 1841, Mr. Fleming of Barochan, besides mak-
ing an experiment with the sulphate alone, tried a mixture of it
with nitrate of soda in equal weights—adding 14 ewt. of the
mixture to the acre. The effect of this mixture as a top-dress-
ang upon potatoes was extraordinary. The stems were six and
seven feet in length, and the produce upward of 30 tons per impe-
rial acre. In 1842, tried on a larger scale, the produce was
not so extraordinary ; but, though a very dry season, the pro-
duce was 18 tons per acre of early American potatoes ; while
the dung alone, 40 cubic yards per acre, gave less than 13 tons.
These results are sufficiently striking to justify the reader in
trying this mixture on any soil. If his fields be like the land
of Mr. Fleming, the trial may prove eminently successful ; if
different in physical character or chemical composition, or if
the season be unpropitious, the result may be less favorable.
A mixture, though it succeed in the hands of fifty experiment-
ers, will still not be entitled to be considered as a specific. It
must first be found never to fal.

The cost of this mixture, as applied per acre, was at that
time as follows :— oe.

75 lb. nitrate of soda, at 22s. percwt. . £0
75 lb. dry (uncrystallised) sulphate of soda, at 9s., 0

[about $5 25] TH? sg

The increased produce from this application—strewed about
the young plants when they came above ground—was 8 tons
per acre in 1841, and 5 tons per acre in 1842.

2. The superior effect of mixtures above that of the substances
they contain when employed singly, is shown in an interesting
manuer by the following results, obtained by the same experi-
menter :—

An entire field was manured for potatoes with 40 cubic yards

244 MIXED SULPHATES AND NITRATES.

of dung, and when the potatoes—early Americans—were a few
inches above the ground, different measured portions of the
field were top-dressed with different saline substances, with the
following results per imperial acre :—

Tons.
Dung alone gave “ : 122. -
with 2 cwt. sulphate of soda, : é 133
13 cwt. nitrate of soda, ‘ 3 16
14 ewt. sulphate, t eee 18
4 cwt. nitrate, y .

Here, though the sulphate alone produced no increase, it
materially augmented the effect of the nitrate when the two
were applied together.

3. Sulphate of soda with sulphate of ammonia.—Again, on
the same field on which sulphate of soda, applied alone, gave
no increase,

Tons.

14 ewt. sulphate of ammonia alone gave only . 143

While 15 cwt. sulphate of soda, and :
% ewt. sulphate of ammonia, { mixed, Sm

Being an increase of 6 tons an acre above sulphate of soda,
and 4 tons above sulphate of ammonia applied alone.

4. Nitrate of soda with sulphate of magnesta.—Also on the
same field, while

Tons

13 cwt. of nitrate of soda gave, as above, only . 16
And 13 cwt. of sulphate of magnesia, only . > ee
1 cwt. of each, mixed together, gave . Ree 2

Thus experiment, as well as theory, indicates that the appli-
cation of several saline substances mixed together, 1s more likely to
encrease the produce of the sow than a larger addition of either
applied alone. ;

5. Phosphate of magnesia with phosphate of ammonia.—I have
said that attention to the requirements of nature will indicate

EXPERIMENTS WITH MIXED PHOSPHATES. 245

what mixtures may be tried with the hope of success, and even
what mixtures may be likely to prove specific manures. Thus
it is known from analysis that the seeds of plants—the grain of
our corn crops for example—contain much nitrogen in their
gluten, and that the ash of grain is rich in phosphoric acid and
magnesia. It was natural to suppose, therefore, that the appli-
cation to growing corn of a mixture capable of specially sup-
plying these three substances would specially act in filling the
ear. A saline compound known by the name of phosphate of
magnesia and ammonia, containing the two phosphates united,*
is fitted for this purpose, and was consequently recommended
for trial.
Experiments, recently made, show that it exercises a power-
ful influence, especially upon Indian corn. Applied at the rate
of 130 to 260 lb. per acre, it had also a very favorable, though
less marked, influence upon wheat. Upon Indian corn, at the
rate of 3 cwt. per acre, it increased the crop of grain six times,
and of straw three times. A constant effect is to increase the
~weight of the grain per bushel as common salt does; and, like
‘many other substances, it produces most marked effects upon
poor and worn-out soils.
This compound, therefore, is deserving of further trial ; and
it is desirable that attempts should be made to manufacture it
for the manure-market at a moderate price.

SECTION VI.—RESULTS OF EXPERIMENTS WITH MIXED SALINE MaA-
NURES MADE WITH THE VIEW OF AFFECTING THE CHARACTER OR
QUALITY OF THE CROP.

The above are illustrations of the kind of mixtures which, on

* It is prepared by pouring mixed solutions of sulphate of magnesia and
sulphate of ammonia into a solution of the common phosphate of soda of
the shops.

+ See the Author's Experimental Chemistry, p. 216. Also the Annales
de Chemie for September 1852, p. 46.

246 MIXTURES PROMOTING GROWTH

the faith of results obtained by actual trial, may be recom-
mended to the practical man as likely to increase the quantity
of the crop. But mixtures may, by the reflecting farmer, be
applied for other purposes.

1. As when he mixes together

Nitrate of Soda, ; 4 2 ; . 3 ewt.
Gypsum, ‘ : 2 . : eas at 28 cwt.
Wood ashes, . : : ° : 5 EO Soe

and applies this mixture at the rate of 5 or 6 cwt. an imperial
acre as a cure for clover-sick land—as recommended by Mr.
Prideaux.

2. Or when two good effects on the growth are sought for
at the same time by the simultaneous application of two sub-
stances to the crop, Or when an evil effect, considered likely
to follow from the use of one substance alone, is to be pre-
vented or counteracted by the use of another substance along
with it.

Thus, nitrate of soda applied to corn crops gives increased
luxuriance, and greatly promotes the growth of straw, while it
also increases the size of the ear. But this rapid growth makes
wheat, in some localities, liable to mildew. It is apt also to
give a feebleness to the straw, which makes the crop more
liable to be laid by the wind and rains ; so that if stormy wea-
ther come when harvest approaches, the corn may be seriously
damaged. On the other hand, common salt, while it usually
strengthens and brightens the straw, makes mildew more rare,
and adds, besides, to the weight of the grain per bushel. By
using the two substances together, therefore, the increased
growth caused by the nitrate will be secured, and mildew pro-
bably prevented ; while the common salt will give the straw
strength to stand. With this view experiments have been made
with such a mixture by various persons, with the best results,
I quote only two results, obtained at Holkham by Mr. Keary, |
from applications to his wheat crops in 1850 and 1851.

AND PREVENTING MILDEW. 247

Application Produce.
per imperial acre. Grain. Straw.
1850. No application, : : ‘ 37 bush. 26 cwt.
Nitrate of soda, 1 cwt. . - 400 Cp aaa
Nitrate of soda, 1 ..
Common salt, 2 t " : piven Beith

In this case the addition of salt produced no increase above
the nitrate alone, except in augmenting by 2 ewt. the weight of
the straw.

1851. No application, ; ; : 37z bush. 27 ewt.
Nitrate of soda, 1 ewt. . : 43% .. ST AS.
Nitrate of soda, 1 .. 1 x
Common salt, sp t ; . rie tee eer

In this experiment the grain was increased nearly 2 bushels
by the salt, while the straw was lessened by 1 cwt. These
differences are of little pecuniary consequence. The chief ad-
vantage to be looked for from the use of the salt is, as I have
said, in its making more sure the gain which nitrate of soda, on
all poor soils, and especially upon sickly crops, may be expected
to produce.

SECTION VII.—USE OF ARTIFICIAL MIXED MANURES, COMPOUNDED
IN IMITATION OF NATURAL MANURES—ARTIFICIAL GUANOS.

The above experiments illustrate how saline mixtures may
be made and used for a definite and known purpose, other than
that of simply adding to the natural produce of the land. But
mixtures may also be made, with the view of imitating nature,
and of compounding by art those valuable manures which she
furnishes in such variety, where we can do it effectually, and at
a reasonable cost.

Thus guano is a highly fertilising substance; and as the sup-
ply brought to this country is limited, and the price at which it
was sold, when first introduced into this country, was a great

* Journal of the Royal Agricultural Society, vol. xiii. p. 210. See also
for similar experiments by Mr. Pusey, vol. xii. p. 202.

248 ARTIFICIAL GUANOS.

bar to its extensive employment, I was induced at the time to
recommend the following, or some similar mixture—as likely to
resemble it in fertilising virtue, because it contains the same in-
gredients, as determined by analysis—to be inexhaustible in
supply, because prepared chiefly from the. produce of our own
manufactories—and to be at least as cheap ai as the best import-
ed guano.

S15 Ib. (7 bushels) of bone dust at 2s. 9d. a bushel, £0 19 0, [$4 75
100 “ sulphate of ammonia, : 0 14 6 3 63
20 “ of pearl ash, or 80 Ib. of wood ashes, 0 40 1 00
80 ‘ of common salt, : 4 2 6. 136 0 37
20 “ of dry sulphate of soda, 020 0 50
25 “ of nitrate of soda, 0 50 1 25
50 “ of crude sulphate of magnesia, . : 0. 1 Ge ..0°S8
610 £2 76 $11 88

This quantity should be equal in efficacy to 4 or 5 ewt. of
guano, and may by many be made at a cheaper rate.

This recipe has formed the basis of numerous varieties of ar-
tificial guano which have been manufactured in different parts
of the country, and sold under different names, and at various
prices—some of them sufficiently low to indicate that either the
mixtures are not good, or that they are not made of valuable
materials. They have, therefore, been applied to the land with,
as might be expected, very discordant results.

Though we should never be able to manufacture an artificial
guano equal to the native, this good effect to the practical man
arose at once from the publication of the above reczpe, and from
the manufacture and sale of artificial guano—that natural guano
fell remarkably in price, and with it rape-dust, bone-dust, and
other costly manures of a similar kind. Thus chemistry pos-
sesses an intelligible money value even to the working farmer.

This question of cheapness is second only to that of efficiency
ina manure. To make these manures cheap is the next point
after making them well. With many manufacturers—and un-
fortunately with many purchasers too—cheapness is made the

-

CHEAPNESS SECOND ONLY TO EFFICIENCY. 249

first consideration; and hence mixtures are brought into the
market at a low price, which are of comparatively little value,
and can produce a sensibly profitable result in a few cases only,
and upon peculiar soils.

To make the manure cheap, the ingredients employed must
be so. ‘The refuse of manufactories has been looked to as a
source of such cheap materials, and not without the prospect of
ultimate advantage to the country. The use of such refuse,
however, has, in the first instance, led to much imposition. The
exact nature of the refuse must be known, and its uniformity
and constancy of composition ascertained, before it can be safe-
ly employed in the manufacture of any mixed manure.

It is a great objection to the numerous artificial guanos and
mixed manures now offered for sale, that the public have no
guarantee, either of the competency of the parties who make
them to devise a mixture which shall be universally advanta-
geous—of their ability to select materials which shall render
it of that uniform composition which is essential to its success
—or of their good faith in endeavoring to secure such a compo-
sition.*

* For numerous recipes for particular crops, the reader is referred to the
author’s Lectures, 2d edition, p. 639-646.

CHAPTER XIX.

Use of lime in Agriculture—Composition of limestones, chalks, corals,
shell-sands, and marls.—Burning and slaking of lime, hydrate of lime,
spontaneously slaked lime.—Effects of exposure to the air upon quick-
lime.—Advantages of burning lime partly mechanical and partly chemi-
cal.—Silicate of lime produced by burning.—Quantity of lime usually
applied to the land —Visibie improvements produced by lime.—Why
liming must be repeated.--How lime is gradually removed from the land.
—Circumstances which modify the effects of lime upon the land.—Che-
mical effects of caustic and of mild lime upon the soil—What is meant
by overliming.—Proportion of lime in overlimed land.—How overliming
is to be remedied.—Exhausting effects of lime.—Is lime necessarily ex-
hausting.

Tue use of lime is of the greatest importance in practical
agriculture. It has been employed in the forms of marl, shell,
shell-sand, coral, chalk, limestone, limestone gravel, quick-lime,
&c., in almost every country, and from the most remote period.

SECTION I.—COMPOSITION OF LIMESTONES AND CHALKS.

When diluted muriatic acid, or strong
vinegar, is poured upon pieces of lime-
stone, chalk, common soda, or common . )

> fie =<
pearl ash, effervescence takes place, and wie) al!

itr

carbonic acid gas is given off, (p. 18.)
If a current of this gas be made to pass
through lime water, (see figure,) the
liquid becomes milky, and a white pow- =
der falls, which is pure carbonate of lime.
It consists of

COMPOSITION OF LIMESTONES. 951

Per cent.
Carbonic acid, . : ‘ L : : 43°%
Lime. ;: _ > ; ; ‘ 56°3
100

One ton of pure dry carbonate of lime contains, of

Cwts,
Carbonic acid,.. . : vere ; 8%
Lime, : - ° . ; . : 113

20

Limestone and chalk consist, for the most part, of carbonate
of lime. In soft chalk, the particles are held more loosely to-
gether; in the hard chalks and in limestones, the minute grains
have been pressed or otherwise brought more closely together,
so as to form a more solid and compact mass.

In regard to limestones and chalks, there are several circum-
stances which it is of importance for the practical man to know.
For example—

a. That they are not composed entirely of mineral or inor-
ganic particles, such as are formed by the passage of a current
of carbonic acid through lime-water. They consist in great
part, sometimes almost entirely, of minute microscopic shells,
of the fragments of shells of larger size, or of solidified masses
of corals, which formed coral reefs in ancient seas which once
covered the surface where the limestones are now met with.
The blue mountain limestones contain many of these coral reefs,
while in our chalk rocks vast quantities of microscopic shells
and fragments of shells appear.

b. Being thus formed at the bottom of masses of moving wa-
ter, the chalks and limestones are seldom free from a sensible
admixture of sand and earthy matter. Hence, when they are
treated with diluted acid, though the greater part dissolves
and disappears, yet a variable proportion of earthy matter al-
ways remains behind in an insoluble state. This earthy matter

252, PHOSPHATE OF LIME IN LIMESTONE.

is sometimes less than half a per cent of the whole weight,
though sometimes it amounts to as much as 30 or 40 per cent.

c. Ad] animals hitherto examined contain in the parts of their
bodies traces more or less distinct of phosphoric acid, generally
in combination with lime, forming phosphate of lime. This phos-
phate of lime their remains, when dead, retain in whole or in
part. It thus happens that limestones almost invariably con-
tain phosphoric acid, and that the proportion of it usually in-
creases with that of the visible remains of animals, shells, co-
rals, &c., which occur init. In the magnesian Himestonee of the
county a Durham, I have found the proportion of phosphate of
lime to be as small as 0.07 to 0.15 per cent ; while in a lime-
stone from Lanarkshire (Carluke,) analysed in my laboratory,
it amounted to 14 per cent ; or one hundred pounds of the
burned lime contained as oe as 23 pounds of phosphate of
lime.

d. The parts of animals also contain sulphur, and this has
given rise to the presence of sulphuric acid in chalks and lime-
stones. This acid exists in them in combination with lime—in
the state of gypsum. The proportion of this gypsum which I
have hitherto found in native chalks and limestones is small,
varying from one-third to four-fifths of a per cent.

e. Carbonate of magnesia, the common magnesia of the shops,
is also present, almost invariably, in all our limestone and chalk
rocks. In the purest it forms 1 or 2 per cent, in the most im-
pure from 40 to 45 per cent of the whole weight. The rocks
called dolomites or magnesian limestones, (p. 97,) are charac-
_terised by the presence of a large proportion of carbonate of
“magnesia. In the old red sandstone formation also, beds of
limestone occur which are rich in magnesia. Such limestones
are usually considered less valuable for agricultural purposes.
They can be applied less freely and abundantly to the land, and
possess what practical men call a burning or a scorching quali-
ty. They are, however, preferred to purer limesin some dis

CORALS, SHELL SANDS, AND MARLS. 253

tricts, as in the high lands of Galloway, for application to hill
pastures. .

SECTION II.—COMPOSITION OF CORALS, SHELL-SANDS, AND MARLS.

1°. Corals, as they are gathered fresh from the sea on the
Trish (Bantry Bay) and other coasts, contain, besides carbonate
of lime, a small percentage of phosphate of lime, and sometimes
not less than 14 per cent of animal matter—(Jacxson.) This
animal matter adds considerably to the fertilising value of coral
sand, when laid upon the land in a recent state, or when made
into compost.

2°. Shell-sand consists of the fragments of broken shells of
various sizes, mixed with a variable proportion of sea sand. It
contains less animal matter than the recent corals, and its value
is diminshed by the admixture of sand, which varies from 20 to
79 per cent of the whole weight. On the shores of many of
the Western Islands, shell-sand is found in large quantities, and
is extensively and beneficially applied, especially to the hill-side
pastures, and to peaty soils.

3°. Marls consist of carbonate of lime—generally the frag-
ments of shells—mixed with sand, clay or peat in various pro-
portions. ‘They contain from 5 to as much as 80 or 90 per cent
of carbonate of lime, and are considered more or less rich and
valuable for agricultural purposes as the proportion of lime in-
creases. They are formed, for the most part, from accumula-
tions of shells at the bottom of fresh-water lakes which have
gradually been filled up by clay or sand, or by the growth of
peat.

SECTION III.—OF THE BURNING AND SLAKING OF LIME.

1°. Burning.—Limestones, when of a pure variety, consist
almost entirely of carbonate of lime. This carbonate of lime,
as we have seen, contains about 56 per cent of lime, or 114
cwt. to the ton.

254 BURNING AND SLAKING OF LIME.

When this limestone is put into a kiln, with so much coal as,
when set on fire, will raise it to a sufficiently high temperature,
the carbonic acid is driven off in the form of gas, leaving the
pure lime behind.

In this state it is known as burned lime, lime-shells, caustic
lime, and quick lime, and possesses properties very different
from those of the unburned limestone. It has a hot alkaline
taste, absorbs water with great rapidity, falls to powder or
slakes, and finally dissolves in 732 times its weight of cold water.
This solution is known by the name of lime-water.

2°. Slaking.—Its tendency to combine chemically with water
is shown in the process of slaking. Almost every one is fami-
liar with the fact that, when water is poured upon quick-lime,
it heats, emits steam, swells, cracks, and at last falls to a fine,
usually white, powder, which is two or three times as bulky as
the lime in its unslaked state. When thus fully slaked and
cool, the fine powder consists of—

Lime, . , . ; ‘ 76 per cent.
Water, . F < 24.
100

Or 20 cwt. of pure burned lime absorb and retain in the solid
state 63 cwt. of water, forming 264 ewt. of slaked lime, called
hydrate of lime by chemists.

When quick-lime is left exposed to the air, even in dry
weather, it gradually absorbs moisture from the atmosphere,
and falls to powder without the artificial addition of water.
In this case, however, it does not become sensibly hot as it does
when it is slaked rapidly by immersion, or by pouring water
upon it.

SPONTANEOUS SLAKING. 255

7

SECTION IV.—OF THE CHANGES WHICH SLAKED LIME UNDERGOES
BY EXPOSURE TO THE AIR, AND OF THE BENEFITS OF BURNING
LIMESTONES.

1°. Effects of exposure to the atr—When lime from the kiln
is slaked by means of water, it still retains its quick or caustic
quality. But if, after it has fallen to powder, it be left un-
covered in the open air, it gradually absorbs carbonic acid from
the atmosphere, gives off its water, and becomes reconverted
into dry carbonate of lime.

When lime is allowed to slake spontaneously in the air, it
first absorbs water, and slakes, and falls to powder, and then
absorbs carbonic acid and is changed into carbonate.

But as soon as a portion of the lime slakes, it begins to absorb
carbonic acid, probably long before the whole is slaked. Thus the
two processes go on together, so that, in lime left to slake sponta-
neously, as it is often on our fields and headlands, the powder
into which it falls consists in part of caustic hydrate and in
part of mild carbonate of lime. Its composition is nearly as
follows :—

Per cent.
Carbonate of lime, : : = ‘ 7 : 517.4
; lime, . 32.4
Hydrate of lime, j water, ” 10.2 t 42.6
100

When it reaches this stage or composition, the remainder of
the hydrate absorbs carbonic acid much more ,slowly, so that
when spread upon or mixed with the soil, it takes a much longer
time to convert it into carbonate. At last, however, after a
longer or shorter period of time, the whole of the lime becomes
saturated with carbonic acid, and is brought back to the same
state of mild wn-caustic carbonate in which it existed in the na-
tive chalk or limestone before it was put into the kiln.

256 ADVANTAGES OF BURNING.

2°, Advantages of burning lime.—If the lime return to the
same chemical state of carbonate in which it existed in the state
of chalk or limestone,—what is the benefit of burning it ?

The benefits are partly mechanical and partly chemical.

a. We have seen that, on slaking, the burned lime falls to an
exceedingly fine bulky powder. When it afterwards becomes
converted into carbonate, it still retains this exceedingly mi-
nute state of division ; and thus, whether as caustic hydrate or
as mild carbonate, can be spread over a large surface, and be
intimately mixed with the soil. No available mechanical means
could be economically employed to reduce our limestones, or
even our softer chalks, to a powder of equal fineness.

b. By burning, the lime is brought into a caustic state, which
it retains, as we have seen, for a longer or shorter period, till
it again absorbs carbonic acid from the air or from the soil.
In this caustic state, its action upon the soil and upon organic
matter is more energetic than in the state of mild lime ; and
thus it is fitted to produce effects which mere powdered lime-
stone or chalk could not bring about at all, or to produce them
more effectually, and in a shorter period of time.

c. Limestones often contain sulphur in combination with iron,
(iron pyrites.) The coal or peat, with which it is burned, also
contains sulphur. During the burning, a portion of this sulphur
unites with the lime to form gypsum, by this means adding to
the proportion of this substance, which naturally exists in the
limestone.

d. Karthy and silicious matters are sometimes present in
considerable quantity in our limestone rocks. When burned
in the kiln, the silica of this earthy matter unites with lime to
form szlicate of lime. This silicate of lime, being diffused through
the burned and slaked lime, and afterwards spread, in a mi-
nute state of division, through the soil, is in a condition in which
it may yield silica to the growing plant.

Thus the benefits of burning are, as I have said, partly me-
chanical and partly chemical. ‘They are mechanical, inasmuch

QUANTITY OF LIME REQUIRED. 257

as, by slaking, the burned lime can be reduced to a much finer
and more bulky powder than the limestone could be by any me-
chanical means ; and they are chemical, inasmuch as, by burn-
ing, the lime is brought into a more active and caustic state,
and is, at the same time, mixed with variable proportions of
sulphate and of silicate of lime—which may render it more
useful to the growing crops.

SECTION V.—QUANTITY OF LIME USUALLY APPLIED TO THE LAND.

The quantity of quick-lime laid on at a single dressing, and the
frequency with which it may be repeated, depend upon the
kind of land, upon the depth of the soil, upon the quantity
and kind of vegetable matter which the soil contains, and upon
the species of culture to which it is subjected. If the land be
wet, or badly drained, a larger application is necessary to pro-
duce the same effect, and it must be more frequently repeated.
But when the soil is thin, a smaller addition will thoroughly
impregnate the whole, than where the plough usually descends
to the depth of 8 or 10 inches. On old pasture lands, where
the tender grasses live in 2 or 3 inches of soil only, a feeble
dressing, more frequently repeated, appears to be the more rea-
sonable practice ; though in reclaiming and in laying down
land to grass, a heavy first liming is often indispensable.

In arable culture, larger and less frequent doses are admissi-
ble, both because the soil through which the roots penetrate
must necessarily be deeper, and because the tendency to sink
beyond the reach of the roots is generally counteracted by the
frequent turning up of the earth by the plough. Where vege-
table matter abounds, much lime may be usefully added ; and
on stiff clay lands, after draining, its good effects are very re-
markable. On light land, chiefly because there is neither moist-
ure nor vegetable matter present in sufficient quantity; very
large applications of lime are not so usual, and it is generally
preferable to add it to such land in the state of compost only.

258 WHY LIME MUST BE REPEATED.

The largest doses, however, which are applied in practice,
alter in a very immaterial degree the chemical composition of
the soil. The best soils generally contain a natural proportion
of lime, not fixed in quantity, yet scarcely ever wholly wanting.
But an ordinary liming; when well mixed up with a deep soil,
will rarely amount to one per cent of its entire weight. It re-
quires about 400 bushels (12 to 15 tons) of burned lime per acre
to add one per cent of lime to a soil of twelve inches in depth.
If only mixed to a depth of six inches, this quantity would add
about two per cent to the soil.

Though the form in which lime is applied, the dose laid on, and
the interval between the doses varies, yet in Great Britain, at
least in those places where lime can be obtained at a reasonable
rate, the quantity applied amounts, on an average, to from 7 to
10 bushels a-year.

SECTION VI.—VISIBLE IMPROVEMENTS PRODUCED BY LIME, AND
WHY LIMING MUST BE REPEATED.

The most remarkable visible alterations produced by lime are
—upon pastures, a greater fineness, sweetness, closeness, and
nutritive character of the grasses—on arable lands, the im-
provement in the texture and mellowness of stiff clays, the more
productive crops, their better quality, and the earlier period at
which they ripen, compdred with those grown upon soils to
which no lime has ever been added.

This influence of lime is well seen when limed is compared
with unlimed land, or when soils, which are naturally rich in
lime, are compared with such as contain but little. Barley
grown on the former is of better malting quality. The turnips
of well-limed land are more feeding for both cattle and sheep.
And the hill pastures on limestone soils, like those of Derby-
shire, continue longer green in autumn, and yield a greater year-
ly return of milk and cheese, than the soils which are produced
from sandstone rocks.

CROPS AND RAINS CARRY AWAY LIME. 259

But this superiority gradually diminishes year by year, in land
artificially limed, till it returns again nearly to its original con-
dition. On analysing the soil when it has reached this state, the
lime which had been added is found to be in a great measure
gone. In this condition the land must either be limed again,
or must be left to produce sickly and unremunerating crops.

This removal of the lime arises from several causes.

1. The lime naturally sinks,—ore slowly perhaps in arable
than in pasture or meadow land, because the plough is continu-
ally bringing it to the surface again. But even in arable land,
it gets at last beyond the reach of the plough, so that either a
new dose must be added to the upper soil, or a deeper plough-
ing must bring it again to the surface.

2. The crops carry away a portion of lime from the soul.—Thus
the following crops, including grain and straw, or tops and
bulbs, carry off respectively—

Of lime.

25 bushels, wheat, about : 13 lb.
40... barley, : : jt
7 oe oats, : : 21
20 tons of turnips, about 3 1s ™
a.4= potatoes, : 4.9
Dit ad red clover, . : eis
ise rye grass, : : a0

The above quantities are not constant, and much of the lime
is no doubt returned to the land in the straw, the tops, and the
manure ; yet still the land cannot fail to suffer a certain annual
loss of lime from this cause.

3. The rains wash out lime from the land—The rain-water
that descends upon the land holds in solution carbonic acid
which it has absorbed from the air. But water charged with
carbonic acid is capable of dissolving carbonate of lime ; and
thus year after year the rains, as they sink to the drains, or
run over the surface, slowly remove a portion of the lime which
the soil contains. Acid substances are also formed naturally by
the decay of vegetable matter in the land, by which another

260 CHEMICAL EFFECTS OF LIME UPON THE SOIL.

portion of the lime is rendered easily soluble in water, and
therefore readily removable by every shower that falls. It is a
necessary consequence of this action of the rains, that lime
must be added more frequently, or in larger doses,where much
rain falls than where the climate is comparatively dry.

SECTION VII.—CIRCUMSTANCES WHICH MODIFY THE EFFECTS OF
LIME UPON THE SOIL.

There are four circumstances of great practical importance
in regard to the action of lime, which cannot be too carefully
borne in mind. These are—

1. That lime has little or no marked effect upon soils in which
organic—that is animal or vegetable—matter is greatly de-
ficient.

2. That its apparent effect is inconsiderable during the first
year after its application, compared with that which it produces
in the second and third years.

3. That its effect is most sensible when it is kept near the
surface of the soil, and gradually becomes less as it sinks
towards the subsoil. And, |

4. That under the influence of lime the organic matter of the
soil disappears more rapidly than it otherwise would do, and
that, as this organic matter becomes less in quantity, fresh ad-

ditions of lime produce a less sensible effect. .
+
SECTION VIII.—CHEMICAL EFFECTS OF CAUSTIC LIME UPON THE
SOIL.

The chemical effects of lime upon the soil in the caustic and
mild states are chiefly the following :—

a. When laid upon the land in the caustic state, the first ac-
tion of lime is to combine immediately with every portion of free
acid matter it may contain, and thus to sweeten the soil.
Some of the compounds it thus forms being soluble in water,
enter into the roots and feed the plant, or are washed out by

CHEMICAL EFFECTS OF CAUSTIC LIME. 261

the springs and rains ; while other compounds which are insol-
uble remain more permanently in the soil.

b. Another portion decomposes certain saline compounds
of iron, manganese, and alumina which naturally form them-
selves in the soil, and thus renders them unhurtful to vegetation.
A similar action is exerted upon some of the compounds of
potash, soda, and ammonia—if any such are present—by which
these substances are set at liberty, and placed within the reach
of the plant.

c. Its presence in the caustic state further disposes the organ-
ic matter of the soil to undergo more rapid decomposition—it
being observed that, where lime is present in readiness to com-
bine with the substances produced during the decay of organic
matter, this decay, if other circumstances be favourable, will
proceed with much greater rapidity. The reader will not fail to
recollect that, during the decomposition of organic substances
in the soil, many compounds are formed which are of importance
in promoting vegetation.

d. It is known that a portion at least of the nitrogen which
naturally exists in the decaying vegetable matter of the soil is
in a state in which it is very sparingly soluble, and therefore
becomes directly available to plants with extreme slownéss.
But when heated with slaked lime in our laboratories, such
compounds readily give off their nitrogen in the form of ammo-
nia. It is not unlikely, therefore, that hot lime produces a
similar change in the soil, though more slowly—hastening, as
above stated, the general decomposition of the whole organic
matter, but specially separating the nitrogen, and causing or en-
abling it to assume the form, first of ammonia, and afterwards
of nitric acid, both of which compounds the roots of plants can
readily absorb. ‘

e. Further, quick-lime has the advantage of being soluble toa
considerable extent in cold water, forming lime-water. Thus
the complete diffusion of lime through the soil is aided by the
power of water to carry it in solution in every direction.

262 CHEMICAL EFFECTS. OF MILD LIME.

SECTION IX.—CHEMICAL EFFECTS OF MILD LIME WHEN APPLIED TO
THE SOIL.

When it has absorbed carbonic acid, and become reconverted
into carbonate, the original caustic lime has no chemical virtue
over chalk or crushed limestone, rich shell-sand, or marl. It
has, however, the important mechanical advantage of being in
the form of a far finer powder than any to which we can reduce
the limestone by art—in consequence of which it can be more
uniformly diffused through the soil, and placed within the reach
of every root, and of almost every particle of vegetable matter
that is undergoing decay. I shall mention only three of the
important purposes which, in this state of carbonate, lime serves
upon the land,

a. It directly affords food to the plant, which, as we have
seen, languishes where lime is not attainable. It serves also to
convey other food to the roots in a state in which it can be
made available to vegetable growth.

b. It neutralises (removes the sowrness) of all acid substances
as they are formed in the soil, and thus keeps the land in a
condition to nourish the tenderest plants. This is one of the
important agencies of shell-sand, when laid on undrained grass
or boggy lands ; and this effect it produces in common with
wood ashes and many similar substances.

c. During the decay of organic matter in the soil, it aids and
promotes the slow natural production of nitric acid. With this
acid it combines and forms nztrate of ame—a substance very sol-
uble in water—entering readily, therefore, into the roots of
plants, and producing effects upon their growth which are very
similar to those of the now well-known nitrate of soda. The success
of frequent ploughings, harrowings, hoeings and other modes of
stirring the land, is partly owing to the facilities which these
operations afford for the production of this and other natural
nitrates.

OVER-LIMED SOILS. 263

SECTION X.—WHAT IS MEANT BY OVER-LIMING ?—-PROPORTION OF
LIME IN OVER-LIMED LAND.—HOW OVER-LIMING IS TO BE REM-
EDIED.

It is known that the frequent addition of lime, even to com-
paratively stiff soils long kept in arable culture, will at length
so open them that the wheat crop becomes uncertain, and is
especially liable to be thrown out in winter.

To lighter soils, again, and especially to such as are reclaim-
ed from a state of heath, and contain much vegetable matter,
the addition of a large dose of lime opens and loosens them, ©
often to such a degree that they sound hollow, and sink under
the foot. This effect is usually ascribed to an over-dose of lime,
and the land is commonly said to be over-limed. In this state it
refuses to grow oats and clover, though turnips and barley
thrive well upon it.

Being desirous of ascertaining the proportion of lime re-
ally present in land which has been brought by lime into such a
condition, I obtained from Sir George Macpherson Grant a
number of soils from different fields upon his estate of Ballin-
dalloch, and caused them to be analysed in my laboratory. The
results of the analyses were as follows :—

¢ | rs 3 : Pee :

8|./Silalaen | 2led lees
aes |2a8 | ens | SHS | eek

ba | Eke ere | Sas 2 vers

Organic matter, : : -| 10.29) 9.547| 5.65 | Ra || o.2e
Salts soiuble in water, . of) ber, O51 M50 0.15 | 0.44
Oxide of iron, : : -| 2.49] 3.68] 0.50 0.96 | 2.04
Alumina, : : a ee 2 oa | EE 1.48 1.15
Carbonate of lime, . : Set AC | -/O69)), 710 9.98 0.67
Oxide of manganese, ; .| trace. | 0.72] trace. | trace. | 0.22
Carbonate of-magnesia, . -| 400... | trace, |< do. do. trace.
Insoluble matter, chiefly sand, .| 81.77 | 82.79| 91.20} 90.34 | 89.60
98.11 100.11 |100.06 | 99.64 | 99.35

264 HOW TO TREAT SUCH SOILS.

In all these soils the quantity of carbonate of lime was
much less than is usually found in fertile soils. I inferred,
therefore, that the effects ascribed to the lime were not due to
its presence in too large a proportion, compared with other
soils. |

Two other facts aided me in arriving at a correct conclusion
upon the subject.

1. That these same soils were known to produce good oats
when they had been some years in pasture, or when turnips
had been eaten off them with sheep, and the ground thus
trodden and consolidated by their feet.

2. That oats and clover prefer a stiffer, stronger soil in
which to fix their roots, while turnips and barley delight in a
light and open soil.

It was therefore the mechanical, and not the chemical con-
dition of the soils, which caused the failure of the turnip and
clover crops. Consolidate them by any means and these
crops would become more certain. The remedies, therefore,
were— F

a. To eat off the turnips always with sheep ;—or

b. To consolidate the loose and open soil by the use of a
heavy roller, a clod-crusher or peg-roller, or other similar me-
chanical means ;—or

c. To use the cultivator as much as possivle instead of the
plough, and thus to avoid the artificial loosening of the soil
which is caused by frequent ploughing.

Still the questions were unsolved,—In what way does the
lime produce, or aid the plough in producing, this opening of
the soil?—-and how are these effects to be prevented in fu-
ture ?

I offer the following considerations, as affording a conjectu-
ral explanation of this matter :—

1. The lime, in whatever state it is added to the land, as-
sumes in a short time the state of carbonate.

2. In soils which are rich in decaying vegetables much acid

EXHAUSTING EFFECTS OF LIME. 265

matter is gradually produced by the action of the air. The
acids thus produced decompose the carbonate of lime, and libe-
rate its carbonic acid more or less copiously.

3. The effect of this liberation of the carbonic acid gas may
be to heave up the land, to loosen it and lighten it under the
foot. In heavy lands this may be less perceived, both because
they are naturally denser and more difficult to heave up, and
because they contain less vegetable matter, and consequently
produce less of these acid substances in the soil. In light
peaty or thin moorish soils, however, which are rich in decay-
ing plants, the particles of soil are more readily lifted up and
separated from one another. }

Will this supposed action never cease? It is doubtful if it
wil], until the nature of the soil is altered—by the gradual re-
moval of the lime—by a diminution of the quantity, and a
change in the nature of the decaying vegetable matter—or by
a permanent solidifying of the land.

Thislast change may be effected either by a top-dressing of clay,
sand, limestone-gravel, or other heavy matter, or by bringing up
a heavier subsoil from below. Where the temporary solidifica-
tion produced by eating off with sheep and the use of a roller is
not approved of, the improvement of over-limed land is to be
sought for in draining, subsoiling so as to admit the air into the
under-soil, and, after a time, in bringing up and mixing with the
surface a sufficient portion of this under-soil.

SECTION XI.—EXHAUSTING EFFECTS OF LIME.—IS LIME NECESSARILY
EXHAUSTING ?

The exhausting effects of lime have been remarked from the
earliest times. It causes larger crops to grow for a certain
number of years, after which the produce diminishes, till at length
it becomes less than before lime was applied to it. Hence the
origin of the proverb that ‘ Lime enriches the fathers and im-

poverishes the sons.”
12

266 ORGANIC MATTER DIMINISHES IN THE SOIL.

Two interesting questions, therefore, suggest themselves in
connection with this circumstance. How is this exhaustion pro-
duced? Is it a necessary consequence of the addition of lime,
or can it be prevented ?

It has already been stated that lime promotes those chemical
changes of the organic part of the soil by which it is rendered
more serviceable to the growth of plants. But in consequence
of this action, the proportion of organic matter in the soil grad-
ually diminishes under the prolonged action of lime, and thus
the soil becomes less rich in those substances of organic origin
on which its fertility in some degree depends.

Again, lime acts also on the mineral matter of the soil, and
prepares it for more abundantly feeding the plant.

Now, as the crops we reap carry off not only organic but min-
eral matter also from the soil, anything which prepares that
mineral matter more abundantly for the use of the plant must
cause also a more rapid diminution of those mineral substances
on which, as well as upon its organic matter, the fr uitfulness of
the soil is dependent.

By this mode of action, therefore, arises the exhaustion which
universal experience has ascribed to the use of lime.

But without reference to the chemical processes by which it
is brought about, a common-sense view of the question sufficient-
ly explains how the exhaustion arises.

It is conceded that the crops we grow rob the soil both of
organic and inorganic matter. A double crop will take twice
as much, a triple crop three times as much, and so on. And the
more we take out in one year, the more rapidly will the land be
exhausted. Now, if lime, by its mode of action, enables us in
the same time to extract three or four times as much matter
from the soil in the form of increased crops, it must so much
the more rapidly exhaust the soil, in the same way as we
should drain a well sooner by taking out fifty than by removy-
ing only five gallons a-day.

But we can restore to the soil what crops carry off. By

THE SOIL CAN BE RESTORED BY MANURE, Wc. 267

farmyard manure, and by saline applications, we can return
everything which the lime enables us thus to extract, and we
can thus preserve its fertility unimpaired. Manure, therefore,
in proportion to the crops taken off, and lime, will cease to be
exhausting. There is much wisdom in the rhyme,

“Time and lime without manwre
Will make both land and farmer poor.”

CHAPTER XxX.

Improvement of the soil by paring and burning.—Use ‘and properties of
burned earth and burned clay as improvers.—Effects of burning upon
clay.—Smother-burning and over-burning.—How they improve the soil.
—Improvement by means of irrigation.—Irrigation a kind of manuring.—
How waters manure the land.—Composition of the water of the Hamp-
stead water-works.— Different virtues of natural streams.

TuHerE remain still a few important modes of improving the
soil by forms of mineral and organic manuring, which it is ne-
cessary briefly to notice.

SECTION I.—IMPROVEMENT OF THE SOIL BY PARING AND BURNING.

A mode of improvement often resorted to on poor lands
is the paring and burning of the surface. The effect of this
treatment is easily understood. The matted sods consist of
a mixture of much vegetable with a comparatively small
quantity of earthy matter. When these are burned, the ash
only of the plants is left, intimately mixed with the calcined
earth. To strew this mixture over the soil is much the same as
to dress it with peat or wood ashes, the beneficial effects of
which are almost universally recognised. And the beneficial
influence of the ash itself is chiefly due to the ready supply of
inorganic food it yields to the seed, and to the effect which the
potash and soda, &c., which it contains exercise either in prepar-
ing organic food in the soil, or in assisting its assimilation in the
interior of the plant. |

Another part of this process is, that the roots of the weeds
and poorer grasses are materially injured by the paring, and
that the subsequent dressing of ashes is unfavorable to their
further growth.

BURNED EARTH AND CLAY. 269

It is besides alleged, and I believe with truth, that poor old
grass land, when ploughed up, is sometimes so full of insects
that the success of any corn or green crop put into it becomes
very doubtful. When pared, these insects collect in the sod,
and are destroyed by the subsequent burning.

Paring and burning is a quick method of bringing land into
tillage, and will secure one or two good crops. But it is
exhausting, and the prudent man will rarely have recourse
to it for the purpose of reclaiming land which is to be kept in
constant tillage. It is very much less practised now than it
was twenty or thirty years ago.

Another evil also follows the practice of paring and burning.
Where the land has little fall for drainage—is raised, that is,
only a few feet above the level of the nearest brook—this
paring and burning gradually lowers the level, and makes it
impossible at last to drain it. In Northamptonshire I have
been told of pieces of land, a few years ago two feet above
the water level, which are now brought down to that level by
the repetition of this hurtful practice. This is certainly enriching
the farmers and impoverishing the sons.

SECTION II.—ON THE USE AND PROPERTIES OF BURNED EARTH
AND CLAY AS IMPROVERS.

1°. Burned earth and clay have long been recognised by the
farmer as useful applications, in certain circumstances, to his
land. Mixed with much vegetable matter of any kind, and
burned slowly and without free access of air, stiff soils of all
sorts will give blackened heaps, which may be spread with ad-
vantage as a top-dressing, or employed, as in China, to cover the
seed after it has been committed to the earth.

To the light porosity of the earth, and to the action of the
vegetable ashes which are mixed with it, the beneficial influence
of such burned mixtures is distinctly to be ascribed.

2°. Burned clay, in which little organic matter exists, and

270 CAUSE OF THEIR USEFUL ACTION.

with which little is mixed during the burning, must owe any
fertilising properties it possesses to a different cause. Such
clay, properly prepared, has in numerous instances been found
beneficial when applied to the land. It is usually laid on in
large doses, and acts both mechanically and chemically.

a. Mechanically, in rendering the soil more friable, so that it
can be worked with less labor, and in especially aiding the cul-
ture of green crops.

b. Chemically, in considerably increasing the produce. Thus
Mr. Pusey found a dressing of burned Oxford clay to increase
his wheat crop from 37? to 454 bushels per imperial acre.
And Mr. Danger, who farms on the new red sandstone, near
Bridgewater, says, that a soil which he found ‘ quite sterile,
has, by the application of burned clay, become totally
changed.”’*

It is equally true, however, that burned clay has often failed
to do any good—that the practice of burning clay, which is
common in some districts, is for this reason never adopted in
others—and that clay from the same locality may or may not
do good according to the method of burning.

All this is easily explained when the true cause of the
chemical action of burned clay is understood.

3°. Cause of its useful chemical action—All clays contain
sensible quantities of most of the mineral substances—potash,
soda, lime, magnesia, phosphoric acid, &c.—which plants re-
quire for their healthy growth. They are, however, in a com-
paratively insoluble condition, which circumstance, united to
the stiffness of the clay, prevents the roots of plants from
readily taking them up. When the clays are burned by a gen-
tle heat, however, the chemical condition of the constituents of
the clay is altered, and the substances which plants require are
rendered more soluble. After the burning, both water and
acids will dissolve out more from the same weight of dry clay,

* Royal Agricultural Journal, vi. 477, and xii. 509.

OVER-BURNED CLAY. a |

and the matter thus dissolved contains a large proportion of
those mineral ingredients which all plants contain. In one ex-
periment, I found that a ton of clay which, in the natural
state, gave to water only 11 lb. of mineral matter, yielded
readily 36 lb. after being burned. Besides, the clay is rendered
more porous by the burning, so that water and the roots of
plants can penetrate more easily to take up the soluble matter.

Again, of burned clay, 50 to 100 tons an acre is not an, un-
usual application. Now, at 36 lb. to the ton, the largest dose
would yield to water not less than 3600* Ib. of soluble mine-
ral matter ; while the whole quantity of such matter carried off
in a four years’ rotation, from our best farms, (p. 69,) is only
1300 lb. It is not surprising, therefore, knowing, as we do,
how applications of saline matter increase the crops, that so
great and ready a supply of such matter in the burned clay
should produce a marked effect upon the fertility of the land
upon which it is spread.

But, further, all clays have not the same composition. Some
zontain more lime, others more magnesia, others more potash or
soda, and others more phosphoric acid ; while some, again, con-
tain so little of any of these substances as to produce no sensible
effeet when burned and laid upon the land. Thus the chemical
composition ofa clay determines whether or not it can be burned
and applied to advantage.

Those clays aré likely to suit well which contain most alkaline
matter, (potash and soda ;) next those which contain a consid-
erable percentage of lime or magnesia, or phosphoric acid ; and,
best of all, those which with the alkaline contain also the cal-
careous matter. Hence it is that to clays which contain little
lime it is a judicious recommendation that a quantity of slaked
lime should be sprinkled upon the clay during its preparation for
burning.

In the fourth place, it is remarkable that, by too complete
and prolonged a burning, the clay is again rendered less solu-

* Experimental Agriculture, p. 261.

272, IMPROVEMENT OF

ble in water and in acids than before. Hence the evil of over-
burning,.as it is called, and the reason why the same clay pre-
pared in different ways does not produce the same good effects.
The method of slow smother-burning—the heat being kept low,
and free access of air prevented—is that which gives the most
constant good results.

Lastly, I notice, as a beneficial consequence of burning, that
the burned clay, being generally porous, absorbs ammoniacal
and other vapors from the air and from the soil more readily
and abundantly than before, and fixes them for the use of plants.
In the black smother-burned clay, which contains much iron,
this metal, in absorbing oxygen from the air, may even give
rise to the formation of ammonia, and thus, in another chemical
manner, act favorably upon the soil.

Advantage is taken of this porous quality of burned clay by
some English farmers—as by Mr. Randall, of Chadbury, near
Evesham—to absorb and preserve the droppings of sheep.
Under house-fed sheep, kept upon boards or otherwise, a layer
of burned clay is spread, upon which the droppings fall : from
time to time fresh layers are added to the surface, till it be-
comes necessary to remove the whole. In this way, the smell
of the dung never becomes excessive, and the clay is rendered so
rich that 10 tons of it are found equal, in the raising of turnips,
to 4 cwt. of guano.

SECTION III.-—ON THE IMPROVEMENT OF THE LAND BY IRRIGATION.

The irrigation of the land is, in general, only a more refined
method of manuring it. The nature of the process itself, how-
ever, is different in different countries, as are also the kind and
degree of effect it produces, and the theory by which these
effects are to be explained.

1. In dry and arid climates, where rain rarely falls, the soil
may contain all the elements of fertility, and require only water
to call them into operation. In such cases—as in the irriga-

>

THE LAND BY IRRIGATION. 213

tions practised so extensively in Eastern countries, and without
which whole provinces in Africa and Southern America would
lie waste—it is unnecessary to suppose any other virtue in
irrigation than the mere supply of water it affords to the parch-
ed and cracking soil.

But in climates such as our own, there are several other be-
neficial purposes in reference to the soil, which irrigation may,
and some of which, at least, it always does serve—thus,

2. The occasional flow of pure water over the surface, as in
our irrigated meadows, and its descent into the drains, where
the drainage is perfect, washes out acid and other noxious sub-
stances naturally generated in the soil, and thus purifies and
sweetens it. The beneficial effect of such washing will be rea-
dily understood in the case of peat-lands laid down to water-
meadow, since, as every one knows, peaty soils abound in
matters unfavorable to general vegetation. These substances
are usually in part drawn off by drainage, and in part destroy-
ed by lime and by exposure to the air, before boggy lands can
be brought into profitable cultivation.

3. But it seldom happens that perfectly pwre water is employ-
ed for the purposes of irrigation. The waters of rivers, as they
are diverted from their course for this purpose, are more or less
loaded with mud and other fine particles of matter, which are
either gradually filtered from them as they pass over and through
the soil, or, in the case of floods, subside naturally when the
waters come to rest. Or, in less frequent cases, the drainings of
towns and the water from-common sewers, or from the little
streams enriched by them, are turned with benefit upon the fa-
voured fields. These are evidently cases of gradual and uniform
manuring.

4. Even where the water employed is clear and apparently
undisturbed by mud, it almost always contains ammonia, nitric
acid, and other organic and saline substances grateful to the
plant in its search for food, and which plants always contrive to

extract, more or less copiously, as the water passes over their
ie

274 COMPOSITION OF THE HAMPSTEAD WATER.

leaves or along their roots. The purest spring waters and
mountain streams are never entirely free from impregnations of
mineral and vegetable or animal matter. Every fresh access
of water, therefore, affords the grass in reality another ——
manuring.

5. In Milustiation of this, I insert the following analyses of the
water supplied by the Hampstead Water-works, for the use of
the city of London, as given by Mr. Mitchell. It contains in all
40 grains of dry matter to the imperial gallon, which consists
of—

Carbonate of lime, - : 3.83 ioe
Carbonate of magnesia, . 3 . : 3.41
Phosphate of lime, - - ’ . 0.28
Sulphate of lime, ; . . . 4.42
Sulphate of potash, E . ° 4 3.28
Sulphate of soda, . ‘ . 4.81
Chloride of sodium (common salt,) : ‘ 17.76
Silica (soluble,) : ; ° ° 0.28
Crenic acid, . : : : 0.17
Aprocrenic acid, : a * : 0.08
Other organic matters, . § ; : 1.72
Oxides of iron and manganese, “ : traces
40.04

In this list of substances, we recognise nearly every mineral
ingredient which is found in the ash of plants. But, in addition
to these ingredients, nearly all river and spring waters contain
appreciable quantities of ammonia and of nitric acid, which are
not mentioned, and were probably not sought for by Mr. Mitchell.
It is not surprising, therefore, that waters containing such sub-
stances, in an available form, should promote vegetation when
used for the purpose of irrigation.

6. The kind of saline substances which spring water or that
of brooks contains, depends upon the nature of the rocks or soils
from which it issues or over which it runs. In countries where
granite or mica-slate abounds, potash and soda, and even mag-
nesia, may be expected in notable quantities, while in limestone
districts the waters are generally charged with lime. When

WATERS DIFFER IN NATURAL VIRTUE. 275

spread over the fields, these latter waters supply lime to the
growing plants, and so affect the general fertility of the soil as
to render almost unnecessary the direct application of lime
to the land. The value of the mountain streams for the purpose
of irrigation in limestone districts is so well known, that some
have been inclined to undervalue all the constituents of natural
waters, and to ascribe little worth as irrigators to the clear
waters of brooks and springs which are not rich in lime. This
opinion, however, is not in accordance with the. results of the an-
alyses made in my laboratory, of waters which have been pro-
fitably employed for irrigation.

T. Flowing water also drinks in from the air, as it passes
along, a portion of the oxygen and carbonic acid of which the
atmosphere in part consists. These gaseous substances it
brings in contact with the leaves at every moment, or it carries
them down to the roots in a form in which they can be readily
absorbed by the parts of the plant. It is not unlikely that, in
consequence of this mode of action, even absolutely pure water
would act beneficially if employed in irrigating the soil.

8. Further, the constant presence of water keeps all the
parts of the plant in a moist state, allows the pores of the
leaves and stems to remain open, retards the formation of hard
woody fibre, and thus enables the growing vegetable, in the
same space of time, to extract a larger supply of food, espe-
cially from the air. In other words, it promotes and enlarges
its growth.

In the refreshment continually afforded to the plant by a
plentiful supply of water—in the removal of noxious substances
from the soil—in the frequent additions of enriching food,
saline, organic, or gaseous, to the land—in the soft and porous
state in which it retains the parts of the plant, the efficiency
of irrigation seems almost entirely to consist.

9. To one other interesting point I must advert. It is
known that waters which have passed over the surface of a
field become sensibly less fertilismg. This is easily explained,

276 SPRING WATERS IN THE VOSGES.

by the reasonable supposition that the plants among which
they have flowed have deprived them of a portion of their en-
riching matter.

But, in the same neighborhood, it has been often observed
that waters from natural springs which are perfectly alike in
appearance, yet differ remarkably in their value for irrigation,
Such is the case among the mountains of the Vosges, where ir-
rigation is much attended to. The same quantity of water,
from two neighboring springs, for example, employed on two
adjoining meadows of similar quality, in 1248, gave of hay per
acre—

1st Cutting. 2d Cutting, Total.
Good spring, . : 58 cwt. 24 cwt. 82 ewt.
Bad spring, . : ee (ne 214% ..

Or the good spring produced nearly four times as much hay as
the bad one.

A chemical examination of the waters of the two springs
satisfied the experimenters (Chevandier and Salvetat) that this
difference was not due, either,

a. To the quantity or kind of the gases which the two waters
held in solution ; nor

b. To the quantity or kind of the mineral matters in which
both were nearly equally rich ; nor

c. To the quantity of organic matter, of which the bad
water in reality contained the most ; nor

d. To the absolute quantity of nitrogen contained in this or-
ganic matter—for the bad water actually spread the larger
quantity over the soil ; but

e. To the circumstance that the organic matter, though
smaller in quantity, was richer in nitrogen. It contained six
per cent of this constituent, while that of the poor water con-
tained only two per cent.

This result is in entire consistency with all I have stated on
the subject of manures—of the necessity of nitrogen to the
growth of plants (p. 51,)—of the tendency of such as are

ENGLISH AND INDIAN RIVERS. 217

rich in nitrogen especially to promote growth—and of the in-
fluence of organic matters, rich in nitrogen, in enabling plants
to work up the mineral and other ingredients in a mixed ma-
nure*or in the soil, (p. 129,‘ which may happen to be within
their reach.* |

* The following extracts in connection with waters good and bad for irri-
gating, will interest the reader :—

“There are two brooks on this estate, Delamere, (the property of G.
Wilbraham, Ksq.,)—one a clear white water, the other brown—both of
which abound in trout, and on each there are irrigated meadows. In the
former stream the trout are large; in the latter small, and never grow be-
yond a certain size. The meadows watered by the former are green, lux-
uriant, and productive; those of the latter comparatively barren. It is
supposed that the pernicious effects of the brown stream are occasioned by
passing through peat or some mineral substance; but the cause has never
been satisfactorily demonstrated.’—Mr. Patty, “On the Agriculture of
Cheshire,” in Royal Agricultural Journai, of the Royal Agricultural Soci-
ety, vol. v. p. 105.

“On the property of the Earl of Caernarvon, near Exmoor, there are
four streams:—the Hudson, containing excellent trout, and making su-
perior water-meadows; the Exe, inferior in the quality of the fish, and less
beneficial to grass; the Barle, worse again in each respect; and lastly, the
Danes’ brook, containing no fish at all, and itself; as I am informed, poison-
ous to grass land. The variation of their color confirms Mr. Palin’s opinion
that these differences are owing to the presence of peat.”—PH. PUSEY,
ibid. Note. .

As a pendent to these home cases, I add the following regarding a
foreign river in different parts of its course :—

‘““Y ought to mention of the Tochee, that so long as it remains in Bunnoo,
its waters are used both for irrigatior: and household purposes, and I never
heard any complaint of it in either of these departments. But, changing
its qualities with its name, in Merwut, the Goombeeluh, as it is now called,’
is deemed useless for agricuiture; and though habit enables the natives to
drink it with impunity, it is very injurious to strangers, producing, after a
few days, and sometimes hours, great pain and inflammation.”——d Year on
the Punjab Frontier in 1848-49, by Major HERsERT B. Epwarps. Voi. i,
p- 68.

CHAPTER XXI.

The products of vegetation.—Influence of different manures on the quan-
tity of a corn crop.—Average composition of the grain of wheat, and
influence of climate upon that composition.—Influence of manure on the
proportion of gluten and yield of flour.—Experiments of Mr. Burnet.—
Composition of the oat, and influence of variety on its composition and
nutritive quality.—Composition of barley, and influence of circumstances
on its sprouting, melting, and feeding properties —Composition of rice,
maize (Indian corn), and buckwheat.—Composition of the bean, the pea,
and other leguminous seeds.—Composition of oily seeds, and nuts, and of
the acorn.—Relation of the quality of the soil to the quality of our corn
crops.

Tue first object of the practical farmer is, to reap from his
land the largest possible return of the most valuable crops,
without permanently injuring or exhausting the soil. With.
this view he adopts one or other of the methods of treatment
above adverted to, by which either the physical condition or
the chemical composition of the soil is altered for the better

It may be useful to show how very much both the quantity
aud the quality of a crop is dependent upon the mode in which
it is cultivated and reaped, and how much control, therefore,
the skilful agriculturist really possesses over the ordinary pro-
ductions of nature.

SECTION I.—-OF THE INFLUENCE OF MANURE ON THE QUANTITY OF
THE WHEAT AND OTHER CORN CROPS.

Every one knows that some soils naturally produce much
larger returns of wheat, oats, and barley than others do, and
that the same soil will produce more or less according to the
mode in which the land has been prepared—by manure or

INFLUENCE OF MANURE. - 279

otherwise—for the reception of the seed. The following table
shows the effect produced upon the quantity of the crop by
equal quantities of different manures applied to the same sort,
sown with an equal quantity of the same seed :—

Return in bushels from each bushel of seed.

Manure applied. Wheat. Barley. Oats. Rye.
Blood, . ; : 14 16 123 14
Nightsoil, ~~. ; — 13 143 133
Sheep's dung, : iba 7 te 14 13
Horses’ dung, : 10: 13 14 ES
Pigeons’ dung, : _ 10 12 ! a
Cows’ dung, : 7 Bo! 16 9
Vegetable manure, . 3 7 13 6
Without manure, — ao 5 4

It is probable that on different soils the returns obtained by the
use of these several manures may not be uniformly in the same
order, yet it will always be found that blood, nightsoil, and
sheep, horse, and pigeons’ dung, are among the most enriching
manures that can be employed. (See table in pp. 213, 214.)

It is a practical fact, bearing upon this point, that in some
parts of Bedfordshire, high-farming causes barley to run to straw,
to the injury of the corn ; while, on the contrary, the wheat in-
creases in yield with higher cultivation.*

Two facts will particularly strike the practical man on look-
ing at the above table.

1. That exclusive of blood, sheep’s dung, in these experiments,
gave the greatest increase in the barley crop. The favorite
Norfolk system of eating off turnips with sheep previous to
barley, besides other benefits which are known to attend the
practice, may possibly owe part of its acknowledged utility to
this powerful] action of sheep’s dung upon the barley crop. Still,
too much reliance is not to be placed on such special results till
the experiments have been carefully repeated.

2. The action of cows’ dung upon oats is equally striking, and
the large return of this crop (thirteen-fold) obtained by the use

* CartRrD’s English Agriculture, p. 451.

280 AVERAGE COMPOSITION OF THE GRAIN OF WHEAT.

of vegetable manure alone, may perhaps explain why, in poorly
farmed districts, oats should be a favorite and comparatively
profitable crop, and why they may be cultivated with a certain
decree of success on land to which rich manure is rarely added.

It is possible, I repeat, that results different from those re-
corded in the above table may be obtained by a careful repeti-
tion of the same experiments on soils of different kinds and in
different circumstances. It is very desirable, therefore, that such
experiments should be undertaken, accurately conducted, and
carefully recorded.

SECTION II.—AVERAGE COMPOSITION OF THE GRAIN OF WHEAT,
AND INFLUENCE OF CLIMATE ON THAT COMPOSITION.

The grain of wheat consists, on an average, of

Water, ; : : : “ 4 14.0
Fatty matter, . : : 4 "3 1.2
Protein compounds, © 14.6
Gluten and albumen, ;
Starch and dextrin, : 3 : 66.9
Cellular fibre, 2 : ¢ a
Mineral matter, Delis ie ae tae 1.6
100

This average composition does not truly represent the composi-
tion of our British and European varieties of wheat. It makes
the proportion of protein compounds rather too large. Climate
and season are believed to influence the proportion of gluten, so
that the grain of warm climates and hot seasons is generally
richer in this ingredient. Thus four varieties gave to Peligot :—

PECULIAR QUALITIES OF IMPORTED WHEAT. 281

Flemish. French. Polish. Egyptian
Grown in France.

Water, 4 . : 14.6 14.6 13.2 13.5
Fat, ea Sra 1.0 1.3 - 15 Ll
Protein compounds, . 10.7 9.9 21.5 20.6
Starehy ke... Mel 74,2 61.9 64.8
Cellulose, : 1.8 ? 7 2
Mineral Maitter, 2 ? Lo ?

{ 100 100 100 100

The increased proportion of protein compounds in the samples
of Polish and Egyptian wheat is very remarkable ; and it is not
less interesting that they had been grown in France from the
foreign seed. This latter fact illustrates—what every practical
farmer is familiar with-—that imported seed always retains for
some seasons the peculiar qualities which distinguish it in the
country from which it is brought. It is not to be supposed that
all varieties of wheat from Poland or Egypt contain the large
proportion of gluten found by Peligot in the above varieties,
which must, I believe, be regarded as very rare and extreme
cases. An increase of 2 or 3 per cent in the protein compounds
is the most that can reasonably be expected in Hastern com-
pared with British wheat ; and even this is by no means con-
stant, as it is modified by season, by modes of culture, and by
other causes.

SECTION III.—INFLUENCE OF THE KIND OF MANURE ON THE
PROPORTION OF GLUTEN IN WHEAT, AND ON THE YIELD OF FLOUR.

Among these other modifying causes may be mentioned the kind
ofmanure by which its growth is assisted. That this is really ca-
' pable of altering the proportion of gluten contained in the grain
is very probable ; though it has not as yet been experimentally
established that it is capable of doing so in a very great degree.
. Another influence of manure upon the grain of wheat appears
less uncertain—that is, the proportion of fine flour which the

282 COMPOSITION OF THE OAT.

grain will yield when sent to the mill. This issomewhat striking-
ly illustrated by the following experiment :—

The same variety of wheat, top-dressed with the same rich
manure—sulphated urine, (p. 201,) mixed with different saline,
substances—and grown in the same season on the same fields,
gave Mr. Burnett of Gadgirth—

Manure. Produce Fine Flour Gluten in
per acre. from the grain. the flour.
In bush. Per cent. Per cent.
No manure, : : : : 31% 76 93
Sulphated urine and wood-ashes, _ 40 66 : 104
Do. and sulphate of soda, . : 49 63 94
Do. and common salt, : 2 49 65 95
Do. and nitrate of soda, . ‘ 48 54 10

In these results we see, first, that the produce of fine flour
from the grain is very different in the different samples ; and
second, that the rich top-dressings did not very largely increase
the proportion of gluten in the flour.

The whole produce of gluten in ‘the crop was increased, be-
cause the crop was increased in quantity ; but in none of the ex-
periments was the percentage of gluten largely augmented. A
flour peculiarly rich in gluten is required—such at least is the
prevailing opinion—for the manufacture of macaroni and vermi-
celli : and such is said to be the quality of the grain naturally
produced in southern Italy. Further experiments are required
to show how far, by what means, and in what circumstances, the
percentage of protein compounds can in this country be econo-
nically increased by the management of the cultivator.*

SECTION IV.—COMPOSITION OF THE OAT, AND INFLUENCE OF VARI-
ETY ON ITS COMPOSITION AND NUTRITIVE QUALITIES.

The following analyses of two samples of Scotch oats, made

* In the neighborhood of Kirkcaldy wheat is said to be poorer after early-
lifted than after ripe potatoes. Is this the case ?—and if.so, how is it to
be explained ?

COMPOSITION OF OATS. 283

in my laboratory by Professor Norton, will show the relative
proportions in which the several constituents exist in this kind
of grain, and the amount of variation which these relative pro-
portions are liable to undergo in this country in different vari-
eties :—

Composition of Oats, dried at 212 Fah.°

Potato Hopetoun
Oats. Oats.
Starch, Ec ° : : : 65.60 64.80
Gum, z : . ‘ 3 2.28 2.41
Sugar, 3 S : . : 0.80 2.58
Oi, : : : ‘ 7.38 6.97
Avenin,* . : ° - : 16.29 16.26
Albumen,* . : : : ; 2.17 1,29
Gluten, ! : . , . 1.45 1.46
Husk, A - ; i : 2.28 2.39
Ash, PL Ste i Me EG 2.32
100.85 100.4

The united percentage of the three varieties of protemm compounds
(within the bracket) in the oat’is very large ; and hence the
very nutritive quality of this grain. But the quality of the oat,
like that of wheat, varies with the soil, the climate, the manure,
and the variety. As an instance of the latter, I may mention
that the hinds in many parts of Scotland live only on oatmeal,
of which they are allowed two pecks each a-week. If made from
potato oats, the two pecks are often insufficient ; but when made
from the common Angus oat, this quantity is frequently more
than the hind can consume.

SECTION V.—INFLUENCE OF VARIETY ON THE QUANTITY OF PRODUCE,
AND ON THE PROPORTION OF MEAL YIELDED BY THE OAT.

The quantity, as well as the quality, of the grain of the oat
yielded by the same soil is much affected by the variety of oat
which is sown. The proportion of meal yielded by an equal

* See page 47.

284 COMPOSITION OF BARLEY.

weight of the grain is also materially affected by the variety.
This is shown by the following table of the results obtained by
Mr. Hay from eight different varieties of oats well known in
Scotland. The experiment was made in the year 1850, upon a
thorough drained field of stiff cold clay with a relentive subsoil.
All the varieties were sown on the 26th and 27th of March, all
reaped between the 20th and 26th August, and the extent of
each experimental plot was three quarters of an imperial acre.

|

Produce. Meal yielded
Variety. itise tet i ee
Grain. Straw. of pa
bush | cwt. Ib
Potato dake of td See, 69 4S Views 604
Sheriff ped Voamuee beirad 654 554 525
Berlie SESS ESSE Sane ihe 55% 554 58
Hopetoun iM Sea ad ae 563. 564 605
Blainslie <%. aoe. wee 524 603 513
Sandy Si TL dase: AT A83 60
Barly Mtge es 5 whe sh 48} 454 553
Barbachla sp i tack 45 49 605

The differences in each of these three columns are very
striking, and will suggest to the reader many interesting con-
siderations, to which space does not permit me to advert.

I only add, that in all the different grains we cultivate vari-
ety is found to affect in a similar manner the quantities of pro-
duce reaped.

SECTION VI.—OF THE AVERAGE COMPOSITION OF BARLEY.

The Scotch oat is the most nutritious of our homegrown
grains. Among the ancients, barley was highly esteemed for
its feeding qualities The Greeks, Egyptians, and Hebrews
made much use of it, and the wrestlers and gladiators ate only
barley bread ; hence they were called hordearii.* It is still re-
cognised in this country as possessed of great feeding power,

* PLiny, Book xviii.

MALTING QUALITIES OF BARLEY. 285

though the higher price obtained for samples which malt well
has thrown somewhat into the shade its purely nutritive qual-
ities.

The average composition of fine barley meal is nearly as
follows :—

Water, . : : : 4 14
Protein compounds, * . . é 14
Starch, &c., ; : : 5 P 68
Fatty matter, : é - “ : 2
Mineral matter, : . ° . 2

100

The above is exclusive of the bran separated by the miller,
which forms from 10 to 18 per cent of the weight of the grain.
It shows the flour to be very nutritious, containing 14 per cent
of the protein or flesh-forming constituent, while fine wheaten
flour rarely contains more than 10 per cent.

SECTION VIII.—INFLUENCE OF CIRCUMSTANCES ON THE SPROUTING,
MALTING, AND FEEDING QUALITIES OF BARLEY.

‘1°. Malting qualities—The malting of barley is known to be
affected by various circumstances. Unless the grain be dry, it
does not sprout readily, and hence it is customary for maltsters
to sweat their barley on the kiln before malting it. The grain
should also be so uniform in ripeness as to sprout uniformly, so
that no part of it may be beginning to shoot when the rest has
already germinated sufficiently for the maltster’s purpose. On
this perfect and uniform sprouting of the whole depends in some
degree the swelling of the malt, which is of considerable conse-
quence to the manufacturer.

The uniformity of sprouting depends sometimes on the mode
of husbandry practised where it is grown. Thus when barley is
taken after turnips, if the land be merely cross-ploughed, the ma-
nure which had been laid in the turnip drills will remain in lines
along the field where the turnips had grown, and the barley along

286 FEEDING QUALITIES OF BARLEY.

those lines will ripen first. But if the land be ploughed diagon-
ally, the manure will be equally spread and the barley nourished
and ripened equally, and thus it will be likely to sprout uniform-
ly also. ‘

But the malting quality of the grain, which is of more con-
sequence to the brewer and distiller, is understood to be modi-
fied chiefly by the proportion of gluten which the barley contains.
That which contains the least gluten, and, therefore, the. most
starch, is supposed to malt the most easily and the most completely
and to yield the strongest beer or spirit from the same quantity
of grain. Hence the preference given by the brewer to the malt
of particular districts, even where the sample appears otherwise
inferior. Thus the brewers on the sea-coast of the county of
Durham will not purchase the barley of their own neighbor-
hood, if Norfolk grain can be had at a moderate increase of price.
But that which refuses to malt well inthe hands of the brewer,
will cause pigs and other stock to thrive well in the hands of the
feeder, and this is the chief outlet for the barley which the brew-
er and distiller reject.

2°. Feeding qualities—So far as a practical deduction can be
drawn from the experiments hitherto made in regard to the
effects of different manures upon the proportion of gluten in
barley, it would appear that the larger the quantity of cows’
dung contained in the manure applied to barley land—in other
words, the greater the number of stock folded about the farmyard,
the more likely is the barley to be such as will bring a hgh price
From the brewer.

The folding of sheep appears to produce a larger return from
the barley crop, and the folding of cattle to give grain of a better
quality. These points also, however, require to be elucidated
by more careful experiment. Such statements stand in our
books at present rather as guesses at the truth, than as deduc-
tions from rigorously made observations.

COMPOSITION OF BEAN, PEA, &Xc. 287

SECTION VIII.—COMPOSITION OF RYE, RICE, MAIZE (INDIAN CORN),
AND BUCKWHEAT.

These four species of grain contain respectively, when dried at
212° Fahr., of—

Rye Rice. Maize. | Buckwheat.
|
|
baron Mos Sy 78.0 87.4 71.6 60.6
Protein compounds, . . 12.5 7.5 12.3 10.7
Fatty matter, : 3.5 0.8 9.0 0.4
MS se ee Se) x 6.0 3.4 5.9 26.0
Mineral matter, : 0.9 1.2 2.3
100 | 100 | 100 100

These numbers, it will be understood, are liable to variation in
different samples ; especially the quantity of protein compounds
inrye varies, and that of the fatty matter or oil contained in
Indian corn. In some varieties of the latter grain this oil is
only 2 to 3, in others as much as 9, per cent of the dry cone.

In their natural undried state they alf contain 14 to 15 per
cent of water. It will be seen that, in so far as that the protein
or muscle-forming ingredients are concerned, rice is the least,
and rye and maize the most nutritious of these four varieties of
grain.

SECTION IX.—COMPOSITION .OF THE BEAN, THE PEA, AND OTHER
LEGUMINOUS SEEDS.

The bean, pea, lentil, vetch, &c., are distinguished from whzte
corn by the large proportion of protein compounds they contain,
and their consequently greater nutritive power# They resemble
each other very much in composition ; and in the state of dry-
ness in which they are generally brought to market, as field
crops, they consist of about

288 COMPOSITION OF OILY SEEDS AND NUTS.

Water, : : : : - 14
Starch and sugar, f : 48
Protein compounds, (egumin,) . : 24.
Fatty eS : : : 2
Husk, : ; ‘ : : 10
Mineral matter . - - = - 2
100

The proportion of husk varies ; the pea, which contains 10 per
cent, having generally a thinner, and the bean a thicker skin.
The proportion of protein compounds varies from 20 to as high
as 30 per cent ; and according to experiment, the kind of ma-
nure employed materially influences this proportion. Manures
rich in nitrogen cause it to increase. It is also an interesting
fact that the young legumes, when just beginning to form in the
shell, are exeedingly rich in protein compounds. The very
young pea, for example, contains as much as 48 per cent ; while,
as the above table shows, the ripe pea rarely contains more
than 24 per cent (p. 51.)

The kind of protein compound which exists in these grains
possesses peculiar chemical properties, and has been called le-
gumin, (p. 47 ;) but its nutritive qualities are believed to be
very much the same as those of gluten and albumen.

SECTION X.—COMPOSITION OF THE OILY SEEDS AND NUTS, AND
. OF THE ACORN.

Many seeds, like those of flax and rape, contain a much larger
quantity of oil than the kinds of corn which are usually em- —
ployed as food for man. ‘The same is the case with nuts. From
the kernels of the walnut, for example, and from those of the sweet
almond, upwards of half their weight of oil can often be extracted.

1. Linseed and linseed cake-—Linseed contains from 20 to 30
per cent of oil. “A large proportion of this is squeezed out in
the oil mills, and sold under the name of linseed oil. The cake
or residue which remains, still contains a considerable proportfon
of oil; and, as it is very nutritive, is extensively employed in

COMPOSITION OF THE ACORN. 289

the feeding of cattle. The relative values of the seed and the
cake for feeding purposes, and the value of both compared with
other kinds of food, is shown very nearly by the following
table :—

Composition of
Linseed. Linseed cake.

Water, : : ; 9 10
Protein compounds, . : 19 22
Starch, &c., 4 Pe ae 34 39
Oil, RIE 25 12
Husk, : é : 8 9
Saline mineral matter, ; 5 8

100 100

Both seed and cake, therefore, are very nutritious ; and even
the pressed cake still contains more fatty matter than Indian
corn, some varieties of which contain as much as 9 per cent.

What is called starch in the above analyses is, in reality, a
kind of mucilage or gum, which dissolves readily in water, but
serves the same purposes as starch in the feeding of animals.

2. Rape cake is about of equal nutritive value with linseed
cake, but is often refused by cattle on account of its hot and
acrid taste : this repugnance, however, may be overcome by
mixing the crushed cake with a small quantity of molasses, or,
by boiling it into a jelly with one-third of bean-meal, and making
this into a mess with cut straw or hay. Sheep eat it readily
when fed upon cabbage, and if kept upon other green food they
soon become accustomed to it, if copiously supplied with water.
The lower market price of rape cake makes a knowledge of
these circumstances of money value to the practical feeder.

3. Nuts resemble the oily seeds in their composition ; and
hence nwut-cakes approach linseed cake in value as a food for
cattle. _

4. The acorn is also very nutritious, though it does not con-
tain much fatty matter. As it falls ripe from the tree it consists
of—

13

290 INFLUENCE OF THE SOIL ON OUR CORN CROPS

Water, :

Protein compounds, :
Starch and sugar, ; : .
Fatty matter, : * ° .
Cellular fibre,

Mineral maiter,

ie et OO

eb & -“T on bo
’

100

Were the acorn made as dry as the bean is usually sold,
it would, weight for weight, be nearly as nutritive. Hence the
fattening of pigs when turned into oak forests, the use of the
common acorn in periods of famine in many countries, and the
constant use of the sweet acorn, (that of the Quercus gramuntia
of Linnzus,) in parts of Spain and Sardinia, as a common food
of the people. A sweet acorn is also regularly found in the
North African markets of Constantine, Bona, and Algiers.

The acorn is remarkable for containing as much as 7 per cent
of sugar, of which a small portion is sugar of milk. Could the
bitter astringent substance, which gives our common acorns their
unpleasant taste, be readily extracted, it might become an ac-
ceptable article of food in every country.

SECTION XI.—INFLUENCE OF THE CONDITION AND QUALITY OF THE
SOIL ON THE QUALITY OF OUR CORN CROPS.

We have already shown that the quantity of the crop is ma-
terially affected by the character of the soil, but the quality of
the produce is no less affected by the same cause. Thus—-

1. Barley.—The varying quality of this grain raised in different
localities is familiar to every farmer. On stiff clays, barley may
yield a greater produce, (North Hampshire,) but it is of a
coarser quality. On light chalky soils it is thin-skinned, rich in
color, and, though light in weight, well adapted for malting ;
while on loamy lands and on sandy marls it assumes a greater —
plumpness, yet still retains its malting quality.*

* See p. 95, on the growth of the Ware malt.

PECULIARITIES OF THE PEA AND BEAN. 291

2. Wheat.—Similar differences affect the same variety of wheat
when grown upon different soils. In a previous section it was
stated that the quantity of gluten contained in wheat is believed
to vary with the climate, and in some degree also with the ma-
nure applied to the land ; but a similar variation occurs on unlike
soils, when manured, or otherwise treated in every respect alike.
The miller knows by experience the relative qualities of the wheat
grown on the several farms in the neighborhood of his mill, so
that even when his eye can detect no difference of quality be-
tween two samples, a knowledge of the places where they were
grown enables him to decide which of the two it will be most for
his interest to buy.

3. The oat varies in quality likewise with the soil on which
it is grown. ‘The meal made from oats grown upon clay land is
the best in quality, is the thriftiest, keeps the longest, and gen-
erally brings the highest price.

I lately visited a farm in Forfarshire, part of which consisted
of a sharp gravelly soil on a slope, and part of flat boggy land,
resting on marl. Oats were usually grown on both soils, and I
asked what difference the tenant observed in the quality of the
grain he obtained from each. ‘‘ In appearance,” he answered,
“there is no difference ; I could take the samples to market, and
get the same price for each. If I wanted them for seed, I would
buy either of them indifferently at the same price ; but for meal
for my own eating, I would give two shillings a boll more for
the oats of the sharp land. The sharp land meal,” he added,
“ wives a dry knotty brose anda short oat cake; that from the bog
land may do for porridge, but it makes bad soft brose and a tough
cake.”

4, Rye also flourishes upon light and sandy soils in general,
but when grown upon sandy marls it is found (in Germany) to
yield much brandy.

5. The pea and the bean are distinguished by similar peculiarities,
when grown in light and in heavy soils. There are certain spots
in the neighborhood of all large towns, which are known to

292 BOILING AND PIG PEAS.

produce the best boiling peas,—such as boil soft and mealy.
Thus the gravelly slope of Hopwas Hill, near Tamworth, on the
Lichfield road, grows the best szdder or boiling green peas for
the Birmingham market ; the Vale of Tamworth in general
growing only pg peas—hard boilers used only for feeding. Lime
and gypsum are said by some to impart the boiling quality, while
by others exactly the reverse is stated. No doubt the different
results are owing to differences in the soils upon which the seve-
ral experiments were made. :

It is a remarkable circumstance, that on the London corn
exchange, the dealers seldom buy British peas without first
sending a sample to be boiled,—while foreign peas are gene-
rally bought without any trial. They are almost invariably
boilers. For split peas, used in making soups and pease-meal,
it is obvious that this boiling quality is of great importance.

The explanation of all these differences is, to a certain extent,
simple. The relative proportions of gluten and starch in all
vegetable juices, and seeds, is variable. The plant is fitted to
flourish, to live in a comparatively healthy manner, and to per-
form all its natural functions, although thesupply of those
kinds of food out of which its gluten is formed be greater or
less within certain limits ; but the boiling, feeding, malting, or
distilling qualities of its stems, seeds, or roots will be materially
affected by variations in this supply.

Again, the proportion of gluten seems to be dependent upon
the quality of the soil, not only because the nitrogen it con-
tains is chiefly imbibed by the roots of the plant, but because
this gluten is always associated with a certain small quantity
of sulphur, phosphorus, and earthy matter, which can only be
derived from the soil. Where these elements abound in the
neighborhood of the roots, the plant may produce much glu-
ten; where they are absent, it may not ; so that the feeding.
and other important qualities of the plant depend no less upon
the presence of sulphur and phosphorus in the soil, than upcn

CAUSE OF THESE DIFFERENCES. 293

that of any of the so-called organic elements of which its se-
veral parts are principally made up.

Still it must be borne in mind, that these explanations of the
differences observed on the corn exchange, and by the miller,
are as yet hypothetical. The causes stated may produce the
effects actually observed, but it has not been proved, by ana-
lytical and other experiments, that they really do produce them.
Mere age induces changes in the qualities of grain, such as I
have described, which the miller values and is willing to pay for.

CHAPTER XXII.

Average composition of the potato, turnip, mangold-wurtzel, and carrot.—
Influence of soil, variety, manure, &¢., on the quality of the potato and
the quantity of starch it contains.—Influence of soil, season, variety, and
manure on the composition and feeding properties of the turnip.—Com-
position of the cabbage, cauliflower, mushroom, turnip-top, and of hay,
straw, and the leaves of trees—Composition of fruits, and the effect of soil
upon their quality and flavor.—Relative quantities of starch and gluten
contained in our usually cultivated crops.—Quantity of oil or fat in grain,
root, and hay crops.—Absolute quantity of food yielded by an acre of
land under different crops.

SECTION I—AVERAGE COMPOSITION OF THE POTATO, TURNIP, MAN-
GOLD-WURTZEL, AND CARROT.

1. Tue turnip tribe differs from the potato in two principal

points.
a. In the quantity of water they respectively contain. In

the potato this forms three-fourths, but in the turnip nine-tenths,
of the whole weight, when taken from the ground: or they
consist of—

Potato. Turnip.

Water, : p 75 91
Dry nutritive matter, ° - 25 a
100 100

b. In the presence of starch in the potato, while the turnip
contains inits stead a substance—pectose or pectic acid—which
contains more oxygen than starch, but serves the same pur-
poses in the nutrition of animals, (p. 44.)

2. The dry nutritive matter of the potato and ped con-
tains, on an average, about—

IMPORTANCE OF THE POTATO. 295

Starch or pectose, * ;

Sugar and gum, ‘ . 15 56

Protein compounds, - ; a) 15

Fatty matter, : : - db 2

Cellular fibre, . 7 9 i!

Mineral matter, . : : 4 5
100 100

This table shows also that the turnip contains more sugar
than the potato, and is richer also in protein compounds. Hence
the advantage derived from, and the preference generally given
to it, in the feeding of stock.

3. The dry matter of the mangold-wurtzel and the carrot
resembles in composition that of the turnip. Some varieties of
these roots contain still more sugar. They likewise surpass the
turnip in their per-centage of dry nutritive matter. This, in
the three roots, is nearly as follows :-—

Turnip. Mangold. Carrot.
Dry nutritive matter, 8 to 12 15 14 to 20
Water, : . 92 to 88 &5 86 to 80
100 100 100

Hence the generally more nutritive quality of the two latter
roots, weight for weight.

SECTION II.—INFLUENCE OF SOIL, VARIETY, DEGREE OF RIPENESS,
KIND-OF MANURE, AND OTHER CIRCUMSTANCES, ON THE QUALITY
OF THE POTATO, AND THE QUANTITY OF STARCH IT CONTAINS.

The potato is a crop of so much importance in this country,
that it may be interesting to introduce a few more detailed re-
marks in regard to the variations which the quality, and especiz
ally the proportion of stareh contained in it, has been found to
undergo.

1. Influence of soil.—It is familiarly known to the potato grow-
er, that clay soils produce waxy, and sandy soils mealy potatoes.

296 INFLUENCE OF VARIETY

But the condition of the land also exercises a material in-
fluence both upon their growth and quality. When, for example,
potatoes are planted in rich newly broken-up land, they run up
greatly to shaws or tops, produce generally few or small tubers,
and of bad eating quality, because they seldom ripen before the
frost sets in. Thus in one case it was remarked by Mr. Thompson,
of Kirby Hall, York, that black kidneys planted on such a soil
seemed quite to have changed their character. Instead of the
fine mealiness for which they are usually remarkable, they bore
much more resemblance to a piece of yellow soap. They, how:
ever, proved excellent seed, and in the wet summer of 1843
showed no failures, and gave a capital crop. They were certain-
ly not ripe, and to this circumstance Mr. Thompson ascribed their
badness for eating and their goodness for seed.

Again, it has been observed that the quantity of starch is
larger in potatoes which are grown upon land long in arable
culture than upon sach as is newly brought into cultivation or
broken up from grass. Thus Mr. Stirrat states, that from one
peck of potatoes grown upon land near Paisley, which had been
almost constantly under crop for the last thirty years, he obtain-
ed 7 lb. of starch, while another peck grown on his bleach-green,
newly broken up, gave him only 4 lb.*

2. Influence of variety—On the same soil, different varieties
produce different proportions of starch. Thus, in 1842, Mr. Flem-
ing, of Barochan, obtained from four yarieties of potato grown
on his farm, the following percentage of starch :—

Connaught Cups, H : ; 21 per cent.
Trish blacks, : : “ iW abe 8
White Dons, . ‘ : 5 13

Red Dons, : 5 = ; 10z

These differences in the per-centage of starch become very
striking when we calculate the relative quantities per acre yielded

* See the Author’s Lectures on Agricultural Chemistry and Geology, 2a
edit. p. 901. '

EFFECT OF MANURES. 297
by these varieties. Thus under similar treatment they gave re-
spectively—

Produce per acre.
Of potatoes. Of starch.

Cups, A 4 ; 135 tons. 2.9 tons.
Red Dons, 3 . 144 1.5
White Dons, : : 185 2.4

So that the lightest crop gave the most starch. Though five ton
an acre heavier, the crop of white Dons gave half a ton less starch
than the Connaught Cups.

3. Effect of manures.—I have already mentioned the alleged
influence of sea-weed, (p. 169,) and of skin parings, (p. 162,) in
making potatoes waxy. It is not so surprising, therefore, that
the kind of manure employed should affect in a sensible degree
the proportion of starch yielded by the potato. Thus Mr. Flem-
ing found his potatoes, raised with different manures in 1843, to
give the following per-centage of starch :—

Per cent.
1. Cups with dung alone, gave - 14.5 of starch.
and guano, - 14°4 ar
2. White Dons with guano alone, - 9.0 ts
and dung, - 10.2 ee
3. Rough reds with guano alone, - 15.7
——————_—_ and dung, - Li.1
4, Perth reds with guano alone, - 15.3 oi
————_—_——_—_——_—————- and dung - 15.5

These experiments show, first, that in so far as the proportion
of starch is concerned, either dung alone, or half guano and half
dung, may be used with equal advantage. The experiment upon
the Cups shows this. Second, that a mixture of dung and guano
is in this respect better than guano alone.* All the other trials _

* This arises from the tendency of the potato to rush up to stalk when
manured with guano alone,—the effect of the guano being more or less
exhausted before the plant reaches maturity, or has time to form its tubers.
When mixed with dung, the latter carries on the growth which the former
may have left unfinished.

13*

298 INFLUENCE OF SOIL.

show this,—while they show further, also, how much the propor-
tion of starch depends upon the variety of potato we grow.

These varying proportions of starch are of much moment to
the practical farmer at the present time, when potato failures
are so common,—inasmuch as the certaunty of the growth of the
potato, when used as seed, appears to be the greater, the smaller the
per-centage of starch.

4. Effect of other circwmstances.—I advert briefly to three
other circumstances which affect the quantity of starch con-
tained in the potato.

a. The effect of keepong is to diminish the quantity of starch.
Potatoes which in October yielded readily 17 per cent of starch,
gave in the following April only 143 per cent.

In connection with the keeping of the potato, it is‘a very
interesting fact, that the epidermis or outer covering of the
skin consists of.a thin layer of cork, without visible pores, and
through which-water passes with extreme slowness. Hence
the potato can be kept for months at a temperature of 86°
Fahrenheit, without losing more than three per cent of its
weight.

b. The effect of frost is also to lessen the starch. It acts chiefly
upon the vascular and albuminous part, but it also converts a
portion of the starch into sugar, hence the sweetish taste of
frosted potatoes. 5

c. The heel end of the potato contains more starch than the
rose end, and both more than the central part. Thus, a variety
of red potato which yielded 21 per cent of starch from the heel
end, gave me only 164 from the rose end, and 14 per cent
from the central part.

SECTION IJI.—INFLUENCE OF SOIL, SEASON, VARIETY, AND MANURE,
ON THE COMPOSITION AND FEEDING PROPERTIES OF THE TURNIP.

1. Sow.—That the soil has an influence on the composition
of the turnip crop, has long been believed by the practical man,

INFLUENCE OF MANURE. 299

because of the difference in the taste and feeding properties of
the same kinds of turnip grown on different fields and farms.

The chemical nature of this difference has lately been inves-
tigated by Dr. Anderson. His analyses of turnips, grown in
the same season and circumstances, upon

a. The heavy alluvial clay of the Carse of Gowrie ;

b. The black land which separates the clay from the hill,
and there, as in- Lincolnshire, skirts the slopes ;

c. The hill land, which is a light loam—
showed that the proportion of nitrogen or of protein compounds
was almost always greater on the hill land than on either of
the other soils—sometimes ¢zezce as great. The turnips of the
black land were also slightly superior in this respect to those
of the clay. This result of analyses fully supports that of prac-
tical experience in the feeding of stock.

2. Season.—The same analyses have confirmed another opin-
ion of practical men, that the turnips of different seasons differ
in their nutritive properties. Thus, in 1850, the turnips, from
all the varieties of soil above mentioned, contained a smaller
per-centage of protein compounds than in 1849, and the dif-
ferences among them were less. ‘The proportion of phosphates
was also considerably less in the turnips of 1850.

3. Variety.—The influence of variety is more striking, per-
haps, on the turnip than upon any other of our more largely
cultivated crops. The swede not only keeps better and longer,
but is also sweeter and more nourishing than the white globe
or yellow turnip. Hence in our large towns, when swedes, as
they sometimes do, sell for 30s. a ton, the yellow will bring
only 25s., and the globe turnip 18s.

4. Manure—The kind of manure affects the quality and
feeding properties of the turnip. According to the experiments
of Mr. Lawes,* it appears that where a field is in a condition
to produce an average crop of turnips, the proportion of ni-

* Journal of the Royal Agricultural Society of England, viii. 494.

300 COMPOSITION OF THE CABBAGE.

trogen in the crop—that is of albumen and other protein com-
pounds, which are very nutritive—may be increased by the ap-
plication of animal or other manures containing nitrogen—such
as pigeons’ dung, guano, woolen rags, rape cake, the salts of
ammonia, nitrate of soda, &e. Mr. Lawes states, that by the
use of such manures the proportion of this valuable ingredient,
compared with what is contained in turnips raised by farm-
yard manure, may be doubled. This result has, to a certain
extent, been confirmed by the more recent analyses of Scotch
turnips published by Dr. Anderson.*

It is desirable, however, that the results of experiments in
the laboratory, as to the composition of the crop, should be
tested by after experiments with the same turnips in the actual
feeding of cattle. Such experiments are difficult of execution,
and require much care, but they are necessary to the attain-
ment of results on which the practical man can be requested
confidently to rely.

SECTION IV.—COMPOSITION OF THE CABBAGE, CAULIFLOWER, MUSH-
ROOM, TURNIP-TOP, HAY, STRAW, AND THE LEAVES OF TREES.

1. The Cabbage is one of the most nutritious crops we grow.
Like the turnip, it contains a large proportion of water—about
89 per cent ; but the dry matter of the cabbage is much more
rich in protein or tissue-forming compounds than that of the
turnip. It consists very nearly of—

Starch, sugar, &c., i . 5 46

Protein compounds {albumen, te) : - 30 to 35

Oil or fat, . d 3

Cellular fibre, : i ‘ ; 4 9

Saline or mineral matter, : j ; ‘ 12 to 18
100

The value of the cabbage in feeding—especially for milch

* Quarterly Journal of Agriculture for January 1852, pp. 221-233.

HAY, STRAW, AND LEAVES OF TREES. 301

cows—and its exhausting effect upon the soil, are not therefore
to be wondered at.

2. The Cauliflower is still more nutritious than the cabbage
leaf. It contains about 64 per cent of protein compounds. In
this respect it approaches nearer to animal food than any ve-
getable we grow, of which the composition has yet been ex-
amined.

3. The Mushroom comes nearest to the cauliflower in this
respect. It contains about 56 per cent of protein compounds ;
and though by some found to be indigestible, its nutritive qua-
lities are very generally admitted.

4. The Turnip-top, though apt to scour cattle if given too
freely, is generally as nutritive as the bulb. It contains as
large a per-centage both of protein compounds and of phos-
phates, especially when young. The young sprouts which tur-
nips, left in the field, throw out in spring, resemble cabbage
very much, and are very nutritious. Hence the reason why
turnips which have thrown out large leaves in spring are gene-
rally found less valuable in feeding.

The composition of the turnip-top indicates the cause both of
its great value as a manure when left upon the land, and why
it forms a very appropriate food for the milch cow and the
growing calf.

5. Hay and Straw are distinguished by the large proportion
of cellular or woody fibre, in an indigestible state, which they
contain. Good hay, however, contains also from 6 to 9 per
cent of protein compounds, and clover hay even as much as 12
per cent; so that, in muscle-forming matter, hay is nearly as
stich as our English wheat. The straw of our white-corn plants
contains only 3 or 4 per cent of these compounds. Pea and
bean straw are more nutritious—good pea straw approaching
in this respect to the best clover hay.

6. The Leaves of Trees are often very nutritious; and did
they not frequently contain substances which render them un-
palatable or unwholesome when eaten, they might be very ex-

302 COMPOSITION OF FRUITS.

tensively employed as food for cattle. The dry tea-leaf con-
tains about 25 per cent of protein compounds, chiefly albumen,
and would prove as nutritious in this respect as an equal weight
of beans or peas, were it the fashion in Kurope to eat it. The
tobacco leaf contains about 23 per cent. The elephant—the
largest of existing quadrupeds—lives much upon leaves in its
native forests ; and in some Alpine countries, the annual har-
vest of dried leaves forms an important part of the winter’s
provision for the domesticated cattle.* (See p. 316.)

It is not surprising, therefore, that leaves should form a valu-
able manure, or that poor land should be permanently improved
by planting it with trees. (P. 158.)

SECTION V.—OF THE COMPOSITION OF FRUITS, AND THE EFFECT
OF SOIL UPON THEIR QUALITY AND FLAVOR.

To fruits it is necessary to do little more than allude in the
present work.t They contain from 70 to 90 per cent of water
—the quantity diminishing as the fruit ripens. In the fleshy
fruits—plums, peaches, &c.—when ripe, the water forms about
75 per cent ; in apples, pears, and gooseberries, a little more
than 80 per cent of the whole weight. The dry matter con-
tains chiefly sugar and pectic acid, with a considerable propor-
tion of protein compounds and of soluble phosphates. Fruits
are therefore fitted to nourish as well as to refresh. The dried
gooseberry contains about 9 per cent of protein compounds.
The acidity of our usually cultivated fruits is due to the pre-
sence of variable quantities of malic and citric acids.

In cider, perry, and wine countries, the nutritive qualities of

* “ For several miles, when crossing the high Alps of Savoy, we ob-
served the peasants stripping the mountain ash trees of all their ieaves, for
their cattle during the winter.’—WELD’s Tour in Auvergne and Piedmont.—
[ Were these leaves gathered for food or for litter ?]

+ For fuller information, see the Author’s published Lectures.

INFLUENCE OF TIME OF CUTTING. 303

the apple, pear, and grape are seen in the use of the refuse of
the mills in feeding pigs or other animals; or where it is not
used up in this way, these qualities are equally shown by the
profitable employment of the refuse as a manure.

Fruits of all kinds, like our corn and root crops, are affected
in flavor and quality by the soil on which they grow. In the
Norman orchard, the gout de terrain is a recognised quality
both in the apple and in the cider. The extended apple and
peach culture of North America has led to similar observations ;
and the peculiar qualities possessed by the wines of neighboring
vineyards are familiar everywhere. There are only three farms
situated on the side of a hill which produce the famous Con-
stantia wine. The same grape has been tried in various parts
of the Cape colony without success. Even a mile from the hill
the wine is of a very inferior description. In Europe, cn the
banks of the Rhine, the Johannisberg is equally well known for
the unique qualities of its celebrated wine.

SECTION VI.—INFLUENCE OF THE TIME OF CUTTING ON THE QUANTITY
AND QUALITY OF THE PRODUCE OF HAY AND CORN.

1. Hay.—The period at which hay is cut, or corn reaped,
materially affects the quantity (by weight) and the quality of
the produce. It is commonly known that when radishes are.
left too long in the ground they become hard and woody—that
the soft turnipy stem of the young cabbage undergoes a similar
change as the plant grows old—and that the artichoke becomes
tough and uneatable if left too long uncut, The same natural
change goes on in the grasses which are cut for hay.

In the blades and stems of the young grasses there is much
sugar and starch, which, as they grow up, are gradually
changed into woody or cellular fibre, (p. 42.) The more com-
pletely the latter change is effected—that is, the riper the
stem of the plant becomes—the less sugar and starch, both
readily soluble substances, its various parts contain. And

304 CUTTING STRAW AND GRAIN.

though it has been ascertained that cellular fibre is not wholly
indigestible, but that the cow, for example, can appropriate a
portion of it for food as it passes through her stomach—yet the
reader will readily imagine that those parts of the food which
dissolve most easily, are also likely, other things being equal,
to be most nourishing to the animal.

It is ascertained, also, that the weight of the hay or of the
straw we reap, is actually less when it is allowed to become
fully ripe; and therefore, by cutting soon after the plant has
attained its greatest height, a larger quantity, as well as a bet-
ter quality of hay, will be obtained, while the land also will be
less exhausted.

2. Straw.—The same remarks apply to crops of corn—both
to the straw and to the grain they yield. The rawer the crop
is cut, the heavier and more nourishing the straw. Within
three weeks of being fully ripe, the straw begins to diminish in
weight ; and the longer it remains uncut after that time, the
lighter it becomes, and the Jess nourishing.

3. Grain.—On the other hand, the ear, which is sweet and
milky a month before it is ripe, gradually consolidates—the
sugar changing into starch, and the milk thickening into the
gluten and albumen of the flour. As soon as this change is
nearly completed, or about a fortnight before it is ripe, the
grain of wheat contains the largest proportion of starch and
gluten. If reaped at this time, the bushel will weigh most,
and will yield the largest quantity of fine flour and the least
bran.

At this period the grain has a thin skin, and hence the small
quantity of bran. But if the crop be still left uncut, the next
natural step in the ripening process is, to cover the grain with
a better protection—a thicker skin. A portion of the starch of
the grain is changed into woody fibre—precisely as in the
ripening of hay, of the soft shoots of the dog-rose, and of the
roots of the common radish. By this change, therefore, the
quantity of starch is lessened and the weight of husk increased ;

WHEN OATS SHOULD BE CUT. 305

hence the diminished yield of flour, and the increased produce
of bran.

Theory and experience, therefore, indicate about a fortnight
before it is fully ripe as the most proper time for. cutting wheat.
The skin is then thinner and whiter, the grain fuller, the bushel
heavier, the yield of flour greater, its color fairer, and the
quantity of bran less; while, at the same time, the straw is
heavier, and contains more soluble matter than when it is left
uncut until it is considered to be fully ripe.

In regard to oats, it is said that the superiority of Ayrshire
oatmeal is partly owing to the grain being cut rather glazy,
(that is, with a shade of green upon it,) and the straw is con-
fessedly less nourishing for cattle when the crop is allowed
to stand till it is dead ripe. arly cut oats, also, are heavier
per bushel, fairer to the eye, and usually sell for more money.
A week before full ripeness, however, is the utmost that is re-
commended in the case of oats, the distance of the top and
bottom grains upon the stalk preventing the whole from becom-
ing so uniformly ripe as in the ear of wheat.

Barley cut in the streped state is also thinner in the skin,
sprouts quicker and more vigorously, and is therefore preferred
by the maltsters. It is also fairer to the eye, and generally
brings a higher price in the market.

SECTION VII.—OF THE RELATIVE QUANTITIES OF STARCH AND GLUTEN
IN OUR USUALLY CULTIVATED CROPS.

In addition to the details already given in regard to the
composition of the several kinds of grain and roots usually cul-
tivated in this country, it may be useful to exhibit, in a tabular
form, the relative proportions of starch and gluten contained in
each. The following numbers cannot be considered as precisely
accurate, yet they represent pretty nearly the average quanti-
ties of these two substances contained in 100 lb. of our common

306 PROPORTIONS OF STARCH, GLUTEN,

crops in the state of dryness, &c., in which they are usually
sent to market :—

Starch, gum, Gluten, albu-

and sugar. men, &c.
Wheat, (flour,) : a : “ 55 10 to 19
Bran of wheat, ; : : A — 16
Barley, . 2 : : : ° 60 12 to 15
Oats, (without husk,) ; : , 60 14 to 19
Rye, , : ‘ a‘ ‘ : 60 10 to 15
Indian corn (maize,) - , : 70 12
Bran of do. . d d : : — 13
Rice, ‘ ‘ ‘ ; ; : 75 7
Beans, peas, vetches, and lentils, . 40 to 50 24 to 28
Linseed, . , ¢ ; 3 : 40 24
Potatoes, : 2 : : é 18 2
Do. _ sliced and dried, , : 72 8
Turnips, carrots, and mangold-wurtzel, oto LE He te ve
Do. sliced and dried, . ‘ 90 12 to 16
Cabbage, ‘ ‘ , ; — 30 to 35

These numbers are somewhat open to correction. Indeed, if
the reader recollects what has been stated in the previous sec-
tions, in regard to the variable quality of the different crops we
raise, he will understand that the numbers contained in all
tables such as this are to be regarded only as approximations
to the truth.

SECTION VIII.—OF THE QUANTITY OF OIL OR FAT IN GRAIN, ROOT,
AND HAY CROPS.

It is generally known that linseed, rape-seed, turnip-seed,
hemp-seed, poppy-seed, and the seeds of many other plants,
abound so much in oil, that it can be squeezed out by strong
pressure, as is done in the mills of the oil manufacturers. The
kernels of some nuts also, as those of the walnut, the hazel, and
the beech, contain much oil; and even some trees, as certain
species of the palm, yield it in large quantities.

It has only recently been discovered, however, that all our
cultivated grains contain an appreciable quantity of oil or fatty

AND OIL IN DIFFERENT CROPS. 307

matter—that it is present also in our root crops, and that even
in straw and hay it exists in sensible proportion.

Soil, climate, mode of culture, manure, and the variety of
_ the plant we grow, all affect the proportion of oil which its
seeds, stems, or roots contain. To extract this oil we have
only to reduce the part of the plant into minute fragments, to
boil these in ether, filter the solution, and afterwards distil off
the ether, when the oil or fat will remain behind. It is usually
more or less of a yellow color, and when heated, not unfre-
quently emits an odor peculiar to the plant. Thus the oil from
the oat emits, when heated, the well-known odor of burned
oatmeal.

The proportion of oil contained in 100 lb. of some of our
more commonly cultivated plants is as follows :—

Wheat flour (fine), : : : 2to 4\)b.
Bran of wheat, . : : : 3 to 5b.
Barley, °. : 5 : : 2to 3 Ib.
Oats, : ; A : : 5 to 8 lb.
Indian corn, : d t é 5 to 9 Ib.
Linseed, ‘ - ; 30 to 35 lb.
Rape and turnip seeds, . - : 40 lb.

Potatoes, turnips, and cabbage, . 4 1-5 lb.

Wheat straw, : ; : : 2 to 33 lb.
Oat straw, : F : : 4 lb.

Meadow hay, A - : ; 2to 5_]b.
Clover hay, : - ‘ : 3to 5 |b.

The quantity of fat varies, as this table shows, in the same
kind of food. These variations are caused by differences in
the soil, manure, climate, season, &c. In most seeds, however,
the largest proportion of fat resides in the exterior part, near
to or actually in the husk or bran. Hence the bran of wheat
generally contains much more oily matter than the fine flour.
Thus in two varieties of wheat, the fine flour from which con-
tained only 14, the bran contained from 8$ to 5 per cent of fat.

To this large quantity of oil, bran owes part of its value in
feeding pigs, as we shall see more clearly when, in a subsequent
chapter, we come to consider the important part which this

308 FOOD YIELDED BY AN ACRE

fatty matter performs in the artificial rearing and fattening of
stock.

SECTION 1X.—ON THE ABSOLUTE QUANTITY OF FOOD YIELDED BY AN
ACRE OF LAND UNDER DIFFERENT CROPS.

The quantity of food capable of yielding nourishment to
man, which can be obtained from an acre of land of average
quality, depends very much upon the kind of crop we raise.

In the seeds of corn, when fully ripe, little sugar or gum is
generally present ; and it is chiefly by the amount of starch
and gluten* they contain, that their nutritive power is to be
estimated. In bulbs, such as the turnip and potato, sugar and
gum are almost always present in considerable quantity in the
state in which these roots are consumed, and this is especially
the case with the turnip. ‘These substances, therefore, must be
included among the nutritive ingredients of such kinds of
food.

If we suppose an acre of land to yield the following quan-
tities of the usually cultivated crops, namely—

Of wheat, 5 ‘ 25 bushels, or 1,500 Ib.
Of barley, : 5 35». ds; op) Oke, BBO.
Of oats, ° ; ; 50... OP anger
Of pease, : : 20 or OUR es
Of beans, : 5 2B pixayeer “OR ESRB. oe
Of Indian corn, ‘ A 30 joes) ) OD TBOR as
Of potatoes, - : 12 tons, or 27,000 ..
Of turnips, . : 30° 5) 3.) Sor 6100S.
Of wheat straw, . P IS... ie) sens S0GRLe 4
Of meadow hay, . 2 BA aw (GR. eee eas
Of clover hay, - : Be iar! Te ss
Of cabbage, ‘ ‘ 20 .. or 45,000 ..

The weight of dry starch, sugar, and gum—of gluten, albumen,
casein, &c.—of oil or fat—and of saline matter, reaped in each

* Including under gluten the albumen, avenin, legumin, and casein—all
the varieties of the protein compounds, in short, which are contained in
grain. (See page 47.)

OF DIFFERENT CROPS. 309

crop, will be represented very nearly by the following num-
hers :-—

Husk or Starch, Gluten, al- Oil or Saline

woody fibre. sugar, &c. bumen, &c. fat. matter.
Wheat, : 225 825 lb. 180 lb. 45 30
Barley, Soe AO 1080 230 50 50
Oats, : 420 1050 300 100 75
Pease, “eee 3 800 380 34 48
Beans, F 160 _ 640 420 40 50
Indian corn, . 100 1260 220 130 30
Potatoes, . 1080 4800 540 45 240
Turnips, «1340 6000 1000 200 450
Wheat straw, 1500 900 40 80 150
Meadow hay, 1020 1360 240 120 220
Clover hay, . 1120 1800 420 200 400
Cabbage, . 430 2300 1300 130 600

1. If it be granted that the quantities above stated are fair
average returns of the different kinds of produce from the same
' quality of land—that the acre, for example, which, in our cli-
mate, produces 25 bushels of wheat, or 30 of Indian corn, will
also produce 50 bushels of oats, or 12 tons of potatoes, or 30
of turnips, and so on *—then it appears that the land which,
by cropping with wheat, would yield a given weight of starch,
gum, and sugar,’ would, when cropped with barley or oats,
yield one-fourth more of these substances—with potatoes about
four times as much—and with turnips eight times the same
quantity. In other words, the piece of ground which, when
sown with wheat, will maintain one man, would support one
and a quarter if sown with barley or oats, four with potatoes,
and eight with turnips—in so far as the nutritive power of these
crops depends upon the starch, sugar, and gwm they contawn.

* These are not by any means to be regarded as universally equivalent
crops. Even in our country, local climate modifies very much the relative
quantities of the same crops obtained in different localities. Thus, in the
southern part of Wigtonshire, 30 tons of Swedes, 20 tons of mangold, and
20 tons of white carrots per acre are equivalent crops, while in Berkshire
it is as easy to grow 30 tons of mangold as 20 tons of Swedes per acre.
See Journal of the Royal Agricultural Society, vol. xiii. part 1.

310 . RELATIVE NUTRITIVE VALUES

2. Again, if we compare the relative quantities of gluten,
&c., in the several crops, we see that wheat, barley, and Indian
corn yield, from the same breadth of land, nearly equal quan-
tities of this kind of nourishment—oats one-half more, peas and
beans upwards of twice, potatoes upwards of thrice, turnips
upwards of four times, and cabbage six times as much as wheat or
Indian corn,

On whichever of these two substances, then—the starch or
the gluten—we consider the nutritive property of the above
kinds of food to depend, it appears that the turnip is, on the
whole, the most nutritive crop we can raise. It is by no means
the most nutritive, weight for weight; but the largeness of the
crop—here taken at 30 tons—affords,us from the same field a
much greater weight of food than can be reaped in the form
of any of the other crops above mentioned.

If, again, we look to tht gluten alone, none of our crops can
compete with the cabbage, even supposing the crop not to ex-
ceed 20 tons an acre.

3. Further, the oil or fat they contain is not without its
value in relation to the nutritive, and especially to the fattening
properties of the different crops. In this respect also the tur-
nip would appear to be superior to most of the other usual
forms of vegetable produce. Clover hay and Indian corn can
alone be compared with it.

In these two facts the practical farmer will see the peculiar
adaptation of the turnip husbandry to the rearing and fatten-
ing of stock. Could the turnip be rendered an agreeable
article of general human consumption, the produce of the land
might be made to sustain a much larger population than under
any of the other kinds of cropping above alluded to. At-
tempts have been made to grind them, and convert them into
meal, as is done with the potato; but the cost of manufactur-
ing, and the disagreeable taste of the meal, have hitherto stood
in the way of a successful prosecution of this branch of rural
industry.

OF DIFFERENT VEGETABLE SUBSTANCES. 311
a

The relative nourishing powers of different vegetable sub-
stances, or their value for food, is supposed by some to depend
entirely upon the relative proportions of gluten, &c., they con-
tain. According to this view, the pea and the bean are much
more nourishing, weight for weight, than wheat, or any other
grain, since 100 lb. of beans would afford as much gluten to an
animal as 230 lb. of wheaten flour or Indian corn, or as 130 lb.
of oats or 200 lb. of rye; and, in like manner, an acre of cab-
bage would support both more people and more stock even
than an acre of turnips. This opinion, however, is not alto-
gether correct. -

But we shall be able to form a better judgment in regard to
the relative value of the starch and gluten, as well as to under-
stand the importance of the saline matter of the food, when we
come in a succeeding chapter to consider the several purposes
which the food is destined to serve in the animal economy—
what different substances the animal must derive from its food
in order to nourish its growing body, to maintain its existing
condition when full grown, or to admit of a healthy increase in
its bulk.

CHAPTER XXIII.

Of milk and its products.—The properties and composition of milk.—Tnflu-
ence of breed, constitution, food, soil, &c., on its quantity and quality.—
Adulteration of milk.—Composition of cream.—Churning.—Quality,
composition, preservation, and coloring of butter.—Theory of the action
of rennet.—Manufacture, quality, and varieties of cheese.

Or, the indirect products of agriculture, milk, butter and
cheese are among the most important. They are in reality ne-
cessaries of life in all civilised countries, and are almost the sole
productions of many agricultural districts. The various
branches of dairy husbandry present also many interesting sub-
jects of inquiry, on which modern chemistry throws much
light.

SECTION I.—OF THE PROPERTIES AND COMPOSITION OF MILK.

Milk is a white opaque liquid, possessed of a slight but pecu-
liar odor. It is heavier than water, usually in the proportion
of 103 to 100. When left at rest for a number of hours it se-
parates into two portions—the cream, which rises to the sur-
face, and the thinner creamless milk on which it floats. When
the whole milk or the cream alone is agitated in a churn, the
fatty part of the milk separates in the form of butter, while
the milk itself, butter-milk, becomes slightly sour.

If left to itself for several days, milk sours and curdles; and
if in this state it be placed upon a linen cloth, the liquid part,
or whey, will pass through, while the cwrd or cheesy part will
remain on the cloth. The same effect is produced more rapidly
by adding vinegar tothe milk, lemon juice, muriatic acid (spirit
of salt), or rennet. In Holland the milk is sometimes curdled

COMPOSITION OF MILK. 313

for the manufacture of cheese by the addition of muriatic acid;
_ but in most countries rennet is employed for this purpose. It
- is coagulated also by alcohol or any strong spirit, and hence,

probably, the practice of adding a quantity of. whisky or

brandy to the rennet—as is done in many dairy districts.

When exposed to the air for a length of time, milks begins
to putrefy and to ferment. It becomes disagreeable to the
taste, emits an offensive smell, and ceases to be a wholesome
article of food.

The milk of nearly all animals contains the same ingredients
—cheesy matter or casein, butter, milk-sugar, and saline mat-
ter, but in different proportions. The best known varieties of
milk consist nearly of

Woman. Cow. Ass. Goat. Ewe.
Casein, (or curd,) LOM eR SCA By i AL Ba) 9 BED Oca ny Aa
Butter, CO EERO CNC near: 2) ICE rege | Me Rater ae RR «7
Milk-sugar, - Op eS 7) BB le FBS sk RD
Saline matter, - Wat OO Lat Oscke <=) ae ein na Oe
Water, - ST.9- = ST.0% = SEN oe SE t- SRG

100 100 100 100 100

The milk of the ass appears from the above table to resem-

ble woman’s milk, in containing little cheesy matter and much

_ sugar. It contains also much less butter than any of the other

varieties above mentioned, and hence, probably, its peculiar
fitness for invalids.

¢

SECTION II.—INFLUENCE OF BREED, CONSTITUTION, FOOD, SOIL,
&Cc., ON THE QUANTITY AND QUALITY OF THE MILK.

Both the quantity and the quality of the milk are affected

by a great variety of circumstances. Every dairy farmer

_ knows that his cows give more milk at one season of the year

than at another, and that the quality of the milk also—its

richness in butter or in cheese—depends, among other condi-

tions, upon the kind of food with which his cows are fed. It
14

314 INFLUENCE OF CIRCUMSTANCES

will be proper to advert to these circumstances a little in
detail.

1. The quantity and quality of the milk are affected by the
breed.—Small breeds generally give less milk, but of a richer
quality. Good ordinary cows in this country yield an average
produce of from 8 to 12 quarts a-day. ‘Thus the dairy cows of

Devonshire give 12 quarts a-day,
Lancashire - 8 to 9 quarts a-day,

Cheshire and

Ayrshire, t 8 quarts a day,

during ten months of the year; but crossed breeds are, in
many districts, found more productive of milk than the pure
stock of any of the native races.

The influence of breed both on the quantity and on the qua-
lity of the milk appears from the following comparative pro-
duce of. milk and butter of one cow of each of four different
breeds, in the height of the season, and when fed on the same
pasture. The

Milk. Butter.
Holderness gave 29 quarts and 38% oz.
Alderney, = Ni ee Se 25 oz.
Devon, =i BF OP 28 OZ.
Ayrshire, US 5 aes Sots 34 02.

Not only was the quantity of milk very different in the four
cows, but the produce of butter also—the Holderness, in the
quantity both of milk and of butter, being greatly superior to
all the other breeds.

The milk of the Holderness and of the Alderney breeds
was equally rzch in butter, as was the case also with that of the
Devon and the Ayrshire, since 1 lb. of butter was yielded by

12 quarts of milk from the Holderness cow,
Meh eee Alderney cow,
SZ = sds Devon cow,

94 1, oe Ayrshire cow.

Some stocks of Jersey cows produce 1 lb. of “butter from 8}

ON THE QUANTITY AND QUALITY OF MILK. 315

quarts of new milk, the year round, and at the same time con-
sume less food than others.

The butter of the milk is often in great part derived directly
from the fat of the food. Hence the value of food which, like
Indian corn and linseed cake, is rich in oil. Hence, also, those
animals which lay the smallest proportion of this fat upon their
own bodies will be likely to give the largest proportion in their
milk. Thus the’ Ayrshires and Alderneys, which are good
milkers, are narrow across the shoulders, and wiry and muscu-
lar about the flanks. They give a rich milk, but rarely fatten
well. The short-horns, on the contrary, are celebrated for their
fattening tendency. They deposit more of the fat under their
skin, and impart less of it to their milk. In both breeds, how-
ever, there are striking exceptions, because—

2. The individual form and constitution of the cow causes both
the yield and the richness to vary much among animals of the
same breed. Every dairy farmer knows that some Ayrshire,
or Holderness, or Devon cows are better milkers than others.
And even when they yield nearly the same quantity of milk, the
richness or produce in butter may be very unlike. Thus, four
cows of the Ayrshire breed, fed on the same pasture, gave in
the same week—the

Milk. Butter.
First, : : 84 ce which yielded 33 lb.
Second and third, each, 86 ‘ ae 53 “
Fourth, . : 4 88 oe ie tees

so that the fourth, though it produced only four quarts more
milk, gave twice as much butter as the first.

Individual cases of extraordinary productiveness occur now
and then. Thus a Durham cow belonging to Mr. Hewer of
Charleton, Northampton, gave in the height of the season 8
‘imperial gallons of milk in a day, yielding 3 Ib. of butter. A
‘cow upon ordinary keep has been known also to produce as
much as 350 lb. of butter in a year. The tendency to yield

316 CONSTITUTION AND FOOD.

butter is no doubt constitutional, like the tendency to lay on
fat.

3. The kend of food also exercises, as all cowfeeders know,
much influence upon the quantity and upon the richness of the
milk.* The Swedish turnip and the cabbage give a richer
milk, the white globe turnip a larger quantity, while both vari-
- eties of turnips are said to cause a greater yield of milk when
tops and bulbs are given together. Culpepper recommends the
leaves of the black alder as a fodder for causing cattle to give
much milk. (See p. 302.) Spurry is said to have a similar
effect. When fed on grass and brewers’ grains, the cow vields
a larger quantity of milk; and when fed on malt dust, she
drinks much and milks well.

It is believed also, that cabbage and the leguminous plants,
such as clover, tares, &c.—as well as the cultivated seeds of
such plants, beans, peas, &c.—promote the production of °
cheese ; while oilcake, oats, Indian corn, and other kinds of
food, which contain much oily matter, favor the yield of butter.
The cakes left by oily seeds, linseed, poppy seed, dodder, sesa-
min, give a milk which contains more solid matter, and is richer
both in butter and cheese. If the cake be not old or rancid, it
does not impair when given in moderate quantities, but rather
increases the flavor and pleasantness of the butter.

If the food contain little fat, the animal still produces butter
It has the power of changing the starch and sugar of its food into
fat during the process of digestion. It even robs its own body
of fat, becomes leaner, and thus yields more fat in the form of
butter than it has eaten in its food. Where only part of a
dairy of cows is kept for their butter, and the rest for cheese,
the hutter-milk from the former may be given to the latter, and
thus the produce of cheese increased. In the State of New
York, cows are said: to yield 100 lb. more cheese in a year

* Hence the Ayrshire adage, ‘ The cow gives the milk, by the mou.”

INFLUENCE OF THE SOIL. 31T

when the whey from their own milk is added to their daily
food.

4. The nature of the soil also in which plants grow, and the
manure by which they are raised, affects their influence upon
the milk. It has been known from the most remote times,
that when fed upon one pasture the cow will yield more butter,
upon another more cheese. This difference must depend upon
the soil. Again, it has been found by experiment, that vetches
grown upon well-limed or marled land promote the production
of cheese, while, after a manuring with wood-ashes, they in-
crease the quantity of milk and of cream, (Spreneen.) In
Cheshire the addition of bones has greatly increased the value
of the grass, and the produce of milk and cheese ; while, as to
the quality, it has been found in Leicester that the manuring of
old pasture with good farm-yard manure, rendered the cheese
for three years nearly unsaleable.

On this curious subject numerous experimental researches are
still required.

5. The milk is affected also by @ variety of other circwm-
stances. Its quantity depends very much upon the distance
from the time of calving, diminishing as the calf in the womb
gets older. This is no doubt a natural adaptation to the wants
of the calf, which, in a state of nature, gradually ceases to re-
quire support from its mother. A cow which, during the first
fifty days after calving, yields 24 quarts of milk a-day, may
yield no more than 6 quarts a-day after six months have
elapsed.

The quality of the milk is better from cows that are in good
condition and have already been two or three times in calf—it
is richer in warm climates, in dry seasons, and when the cow is
not too frequently milked. It is said to be richer when cows
are kept constantly in the house and regularly fed—those which
go at large in the pasture yielding more cheese. When a cow
is allowed to go dry for two or three months before calving, it
is believed to give more milk the following season. In autumn

318 ADULTERATION OF MILK.

’ it is richer upon the whole, giving a less proportion of butter,
but a greater of cheese ( Arron, ) while it becomes poorer in both
when the cow is in calf. The first milk which comes from the
udder is also poorer than that which is last drawn, the strap-
pings or stroakings—and, lastly, the quality of the milk is very
much affected by the treatment and moral state of the animal.
Gentle treatment and a state of repose are favorable to the
richness of the milk ; while anything that frets, irritates or ha-
rasses the animal, injures its quality. I need scarcely add that
eleanliness and good ventilation in the cow and milk houses are
essential to the good flavor of milk.

SECTION III.—-OF THE ADULTERATION OF MILK,

Milk is almost everywhere more or less adulterated with wa-
ter. In Paris and the neighborhood, the cream is taken off,
and the skimmed milk thickened with sugar and an emulsion of
sweet almonds and hemp-seed, (Raspam.) Skim milk may
also be thickened with magnesia, and by this means the thick-
ness of cream may be given to new milk, while it will also be
kept longer sweet. Common soda or pearl ash is sometimes
added to milk which has turned, to restore its sweet taste.

But the most singular adulteration of which I have heard is
that of mixing up the skim milk with calf’s and sheep’s brains.
This mixture renders it thick and rich, and causes a coating,
apparently of cream, to rise to the surface, which it requires a
nice chemical examination to distinguish from genuine cream.*

* The method ofexamination is to treat the creamy matter with ether,
and to boil what the ether takes up with water containing a little sulphurie
acid. Ifthe cream is not genuine, the acid solution will then give with
lime or baryta traces of phosphoric acid.

.

THE CHURNING OF CREAM. 319

SECTION IV.——OF THE COMPOSITION OF CREAM AND THE CHURNING
OF BUTTER.

1. Cream.—When milk is left at rest for a length of time,
the fatty matter which floats in it in the form of minute
globules, rises to the surface in the form of cream. The rapi-
dity with which.it thus rises to the surface depends upon the
temperature to which it is exposed—being quicker in warm
than in cold weather. Thus, for example, when milk is set
aside it may be perfectly creamed in

Hours. Degrees, F.

36 when the temperature of the air is 50
24 ate a 55
18 to 20 es = 68
10 to 12 as ve TT

while at the temperature of 34° to 37° F.,—a little higher
than the freezing point of water,—milk may be kept for three
weeks without throwing up any notable quantity of cream.

If the milk when new is placed in a hot basin, and covered
over with another, the cream is thrown up more quickly, and a
larger quantity of butter is obtained. Of course, the skimmed
milk wiil be so much the poorer.

The cream thus thrown up contains the greater part of the
fatty matter of the milk, mixed with a small proportion of the
curd and much water. Cream of good quality in this country,
when skilfully churned, will yield about one-fourth of its weight
of butter; or, one wine gallon of cream weighing 8} lb. will
give nearly 2 lb. of butter.

2. Churning.—When milk or cream is agitated for a length
of time, the fatty matter gradually separates from the milk,
and collects in lumps of butter. There are several circum-
stances in connection with the churning to which it is of inte-
rest to attend. ;

a. In the churning of cream it is usual to allow the cream to

320 TEMPERATURE FOR CREAM.

stand in cool weather for several days, until it becomes dis-
tinctly sour. In this state the butter comes sooner, and more
freely. The butter, when collected in lumps, is well beat and
squeezed from the milk. In some places it is usual also to
wash it in cold water as long asit renders the water milky; in
other places the remaining milk is separated by repeated
Squeezings, and by drying with a clean cloth.

b. Clouted cream may be churned with advantage in the
sweet state—the butter separating from it with great ease.
Colonel le Couteur states that, in Jersey, zt 7s usual to make ten
pounds of butter in five minutes from the clouted cream of the
Jersey or Alderney cow. Clouted cream is obtained_ by gra-
dually heating the milk in deep pans, almost to boiling, but so
as never to break the skin or clout that forms on the surface.
The cream is said to be more completely separated by this pro-
cess than by any other, and a larger quantity of ee to be
obtained from the milk.

c. The whole milk may also be churned, after being allowed
to stand till it has attained the proper degree of sourness, which
is indicated by the formation of a stiff brat on the surface,
which has become wneven. This method is more laborious, re-
quiring more time than when the cream only is used; but it has
the advantage, as many practical men have found, of yielding
five per cent more butter from the same quantity of milk, and
of a quality which never varies in winter or insummer. It also
requires no greater precautions or more trouble to be taken in
warm than in cold weather.

d. Temperatwre.—This latter advantage is derived from the
circumstance, that the temperature at which the whole milk ©
ought to be churned is higher than that of the air in our cli-
mate, throughout nearly the whole course of the year. The
temperature at which milk can be churned most economi-
cally is about 65° F., a degree of heat which the air seldom
attains in our warmest summer mornings. The dairy-maid has
simply to add hot water enough to the milk to raise it to 65°

TIME REQUIRED FOR CHURNING. 321

F., and to repeat this every morning of the year, if she churns
so often. On the other hand, the temperature of cream, when
churned, should not be higher than from 53° to 55° F., a tem-
perature beyond which the air often rises. It becomes neces-
sary, therefore, in summer, to cool the milk-room in which the
cream is churned, and, by churning early in the morning, to en-
deavor to keep the cream down to the proper temperature.

Thus, in churning cream, the task of the dairy-maid is a
more difficult one. In winter, she must add hot water to bring
the temperature up to 55°, and in summer must apply cold, to
keep it down. In this she sometimes fails, and on these occa-
sions the quality of the butter suffers.

e. The tume required for churning the whole milk in the ordi-
nary churn is from three to four hours, while the cream alone
can be churned in about an hour and a half. A churn, how-
ever, has lately been introduced which churns both milk and
cream in a much shorter period of time. It is made of tin, is
of a barrel shape, and is placed in a trough of water, which is
heated to the temperature the milk or cream ought to be
brought to. In this churn the butter was extracted from
cream, at the temperature of

Nb age Butter was harder, but no
e ?
ee ep ene 44: better than the following.
58° F. in 10 to 20 minutes, . Butter excellent.

60° F. in 5 to 7 minutes, : Bot at ie. DOk. gh en ae

color and quality.

The whole milk in this churn gave the butter in one hour to
one hour and a half. Mr. Burnett of Gadgirth informs me,
that he obtains in this churn a larger quantity of butter from
the cream than from the whole milk. Thus, from 508 quarts
of milk—the produce of five cows in one week of July (1843)
—he obtained, on churning the whole milk, 36 lb. 11 oz. The
cream, on the other hand, yielded by an equal quantity of milk
drawn from the same cows during another week, gave him 37 lb.
4 oz., being a difference of 9 ounces, or about 3 per cent in

322 SMALL BREEDS GIVE MOST BUTTER.

favor of the cream, which is contrary to general experience
with the ordinary churn, as stated in the previous page.

Other persons who have tried this churn have not been so
successful in the use of it as Mr. Burnett. Where they have
obtained the butter much sooner than usual, they have found
reason to complain of its quality. Perhaps in these cases the
churn has not been skilfully used, or something may depend
upon the quality of the milk—since the cream frum the milk of
some cows is said in the ordinary churn always to come to but-
ter in ten minutes or less. |

The air churn—a still more recent invention—which agitates
the milk, by forcing a current of air through it, is said to bring
the butter in the still shorter period of four minutes.

f. The largest quantity of butter from a given weight of the
same food, and the richest milk, is yielded by the milk of the
smaller races. The small Alderney, or Jersey, West Highland,
and Kerry cows, give a richer milk even than the small Ayr-
shire. But the small Shetlander is said to surpass them all.
These breeds are all hardy, and will pick up a subsistence from
pastures on which other breeds would starve.

The quantity of butter yielded by different cows in the same
yard, and eating the same food, is sometimes very different.
Some will yield only 3 or 4 lb. a week, while more will give
8 or 9 lb., and a few 15 Ib. a-week. Asarare instance, I may
mention that a cow has been known in Lancashire to yield up-
wards of 22 lb. in seven days.

SECTION V.—OF THE QUALITY, COMPOSITION, PRESERVATION, AND
COLORING OF BUTTER.

1. The quality of butter varies with numerous circumstances.
The kind of natural pasture, or of artificial food, upon which
the cow is fed, the season of the year, the breed, the individual

constitution and state of health of the animal, the mode of
14*

QUALITY OF BUTTER VARIES. 323

churning, the cleanliness of the cow and milk houses, &c., all
more or less affect the quality of the butter.

But from the same cow, fed on the same food, and in the
same circumstances, a richer butter, and of a finer and higher
flavor, will be obtained by churning the last drawn portions of
the milk. So the first cream that rises gives the finest flavored
butter,—while any cream or milk will give a butter of better
quality if it be- properly soured before it is churned, and be
then churned slowly and at a low temperature.

2. The composition of butter—Butter, as it is usually brought
to the market, contains more or less of all the ingredients of
milk. It consists, however, essentially of the fat of milk, inti-’
mately mixed with about one-eighth of its weight of water,
and a small quantity of casein or curd, of saline_matter, afd of
the sugar of milk. The quantity of casein (cheesy matter or
curd) seldom amounts to one per cent of the whole weight of
the butter.

If the butter be melted in hot water several times, shaken
with renewed portions of water as long as they become milky,
and left then to repose, it will collect on the surface in the
form of a fluid yellow oil, which will concrete or harden as it
cools. If when cold it be put into a linen bag, and be sub-
mitted to strong pressure in a hydraulic or other press, at the
temperature of 60° F., a slightly yellow transparent oil will
flow out, and a solid white fat will remain behind in a linen
cloth. The solid fat is known by the name of margerine, and
is identical with the solid fat of the human body, with that of the
goose, and with that which causes the thickness of olive oil
when exposed to the cold. It is very similar also to the solid
fat of palm oil, The liquid or butter oc is a peculiar kind of
fat not hitherto discovered in any other substance.

The proportion of these two kinds of fat in butter varies con-
siderably, and hence the different degrees of hardness which
different samples of butter present. The solid fat is said to
abound more in winter, the liquid fat in summer, Winter and

324 SOLID AND LIQUID FATS iN BUTTER.

summer samples of butter manufactured in the Vosges were
found to contain per cent respectively of

Summer. Winter.
Solid fat or margerine, é é 40 65
Liquid fat or butteroil, : 60 35
100 100

These proportions, however, will be found to vary more or
less in almost every sample of butter we examine.

In Jersey, the drainings of the curd in rich-cheese making
give a butter which is inferior for eating with bread, but very
superior for pastry. It is peculiarly hard, and fitted for such
use in hot weather. It probably contains more of the solid fat
of butter.

3. The preservation of butter—Fresh butter cannot be kept
for any length of time in our climate without becoming rancid.
The fats themselves undergo a change ; and the same is the
case with the small quantity of milk sugar which the butter
contains. ‘The main cause of this change is the casein or curd
which is usually left in the butter. The proportion of this
cheesy matter I have found in two samples of fresh butter to
vary from one-half to three-fourths of a per cent,—or from half
a pound to three-quarters of a pound in 100 pounds of butter;
and yet this small quantity is sufficient, if the butter be expos-
ed to the air, to induce those chemical decompositions to which
the disagreeable smell and taste of rancid butter are owing.
The butter made in the pure air of the Alpine valleys of Pied-
mont and Switzerland, after a complete expression of the milk,
is said to be ‘ preserved sweet, or at least fit for use, through
the whole season, without any admixture of salt.” By melting
and skimming the butter also, and then pouring it hot into a
jar, it is in Switzerland preserved without salt. In this latter
state it is called boiled butter, (dwerre cuzt,) and is chiefly used —
for cookery.*

* Physician's Holiday, by Dr. ForBzs, p. 336.

HOW BUTTER BECOMES RANCID. 325

I do not enter here into the theory of the action of this
casein, nor into an explanation of the nature of the chemical
changes themselves.* It is sufficient to state, that this evil
action of the cheesy matter may be entirely prevented.

a. By salting immediately after the butter is made, and be-
fore the cheesy matter has had time to become altered by ex-
posure to the air.

b. By taking care that any water which may remain in or
around the butter be always kept perfectly saturated with salt.

c. By carefully excluding the air from the casks or other ves-
sels in which the butter is packed.

So long as the cheesy matter is kept from the air, and in a
saturated solution of salt, it will neither undergo any rapid
alteration itself, nor will it soon induce any offensive alteration
in the butter.

About half a pound of salt is used to 12 or 14 Ib. of butter ;
but when salted for exportation, or for the use of the navy, one
pound of salt is added to 10 or 12 of butter. Though many
wash their butter, it is a rule with others never to wash it or dip
ut into water when intended to be salted, but to work it with cool
hands till the butter milk is thoroughly squeezed out, and then~
to proceed with the salting. ‘Theoretically, I should consider
this latter the better plan, since it exposes the cheesy matter
less to the air, and consequently to less risk of incipient decom-
position.

Some fancy they cure their butter better by dissolving the
salt in the cream before churning, while many consider its pre-
servation and good quality to depend much upon the quality of
the salt that is employed.

Some prefer, instead of salt alone, to make use of a mixture
of one part of sugar, one of nitre, and two of salt ; and some
who use an impure salt, consider the butter to be improved by
washing it in a saturated solution of salt.

* The reader will find these fully explained in the Author’s published
Lectures on Agricultural Chemistry and Geology, 2d edit., p. 976.

326 SOURING OF MILK.

It is said that rancid butter may be rendered sweet by churn-
ing it with fresh sweet milk, in the proportion of six ath te of
butter to the gallon.

4. Citorens butter.—Butter is sometimes colored, and the
juice of scraped carrots is not unfrequently employed for the
purpose.

SECTION VI.—OF THE SOURING OF MILK, OF MILK-SUGAR, AND OF
THE ACID OF MILK.

1. When milk is left to itself for a sufficient length of time,
it becomes sour and curdles. This takes place sooner in warm
weather, and in vessels which have not been cleaned with suffi-
cient care.

Why does milk thus become sour ?

a. Sugar of Malk—_I have already stated that milk contains
a quantity of a peculiar kind of sugar, found only in milk, to
which, therefore, the name of milk-sugar is given. It differs
from common cane sugar in being harder, less sweet, and much
less soluble in water. Of this sugar, milk contains generally a
larger proportion than it does of either fat or curd, (p. 313). A
gallon of milk, therefore, would yield a greater weight of sugar —
than it does of either butter or cheese. In this country, the
sugar is usually neglected. In our cheese districts, it is given
to the pigs, and sometimes to the cows in the whey with which
they are fed. In Switzerland and elsewhere, it is extracted as
a profitable article of commerce.

b. Acid of milk.—When milk becomes sour, a peculiar acid
is formed in it, to which, from its having been first observed in
milk, the name of lactic acid, or acid of milk, has been given.
To this acid the sourness of milk is owing. The same acid is
produced when crushed wheat—as in the manufacture of starch
from wheat—wheaten flour, oat-meal, pease-meal, &c., or when
cabbage and other green vegetables are mixed with water, and

SUGAR AND ACID OF MILK. 327

allowed to become sour. It exists also in small quantity in the
acorn, (p. 289.) |

c. But how is the aad produced ?2—As the acid of milk in-
creases in quantity, the sugar of milk diminishes. The acid,
therefore, is formed from or at the expense of thesugar. There
is no fermentation, and therefore no loss of matter : the sugar
is merely transformed into the acid, and by a process the out-
line of which it is very easy to understand. Like cane sugar,
grape sugar, and gum, (p. 43,) both may be represented by,
or may be supposed to consist of, carbon and water, and in the
same proportions. 'Thus,—

Carbon. Water.
Sugar of milk consists of : : 6 and 6

Acid of milk, (Jactic acid,) : 2 6 and 6

The same particles of matter, therefore, which compose the
sugar, are made to assume a new arrangement, and, instead of
a sweet sugar, to form a sour acid. In the interior of the milk,
nature takes down and builds up its materials at her pleasure,
—using the same molecules to form now this and now that kind
of substance—as the child plays with its wooden bricks, erect-
ing a hut or a temple with the materials of a ruined palace or
a fallen bridge. So nature seems to play with her materials,—
working up all, wasting none,—yet so skilful in all her opera-
tions as to excite our wonder, so secret as not unfrequently to
escape our observation, and so quick as often to show that she
has been working, only by the striking effects she has produced.
To the simple peasant and to the instructed philosopher, it is
equally a matter of wonder, and almost equally unintelligible,
that the same number of material particles arranged in one way
should affect the organs of taste with the sweetness of sugar,
in another with the sourness of lactic acid.

328 WONDERFUL CHANGES OF FORM.

SECTION VII.—OF THE CURDLING OF MILK, OF CASEIN, AND OF THE
ACTION OF RENNET.

As milk becomes sour, it also thickens or curdles. If it be
then slightly heated, the curd runs together more or less, and
separates from the whey. If the whole be now thrown upon
a linen cloth and gently pressed, the clear whey will run through
and the curd will remain on the cloth. This curd, when salted,
pressed, and dried, forms the cheese which we consume so ex-
tensively as an article of food.

In consequence of what chemical change does this separation
of the curd take place ?

1. It is to be borne in mind, that this curdling does not take
place naturally till the milk has become sour. The acid of the
milk, therefore—the lactic acid—has some connection with the
Separation of the curd. It is, in fact, the cause of the curd-
ling.

2. But, in order to understand how this is, we must turn for
a moment. to the properties of the curd itself. Chemically pure
curd or casein is a protein compound, which contains less sul-
phur than albumen does, and no phosphorus, (p. 46.)

a. When the curd of milk is separated carefully from the
whey, it may be washed or even boiled in water, without being
sensibly lessened in quantity. Pure curd is nearly insoluble in
pure water.

6. But if a little soda be added to the water in which the
curd is heated, it will dissolve and disappear. Pure curd ts
soluble in a solution of soda.

c. If to the solution of the curd in soda and water a quanti-
ty of the aced of milk be added, this acid will combine with the
whole of the soda—will take it from the curd, which will thus
be again separated in an insoluble state. The curd is insoluble
an water, rendered sour by the acid of milk.

These facts explain very clearly the curdling of milk. As it

WHY THE CURD SEPARATES. 329

+ comes from the cow, milk contains a quantity of soda not com-
bined with any acid, by which soda the curd is believed to be
held in solution. As the milk becomes sour, this soda combines

with the lactic acid produced, and thus the curd becoming in-
soluble separates from the whey—or the milk thickens and
curdles.

Now, the effect which is thus produced by the natural for-
mation of lactic’acid in the milk, may be brought about by the
addition of any other acid to it—such as vinegar or spirit of
salt. And, in fact, vinegar is used now, in some countries, and
in ancient times was used more extensively, for curdling milk ;
while in some of the cheese districts of Holland, spirit of salt
(muriatic acid) is said to be employed for the same purpose.
Sulphuric acid has been also recommended, but has been found
to give the cheese an unpleasant taste.

3. But in most dairy countries rennet is the substance used
for the curdling of milk. What is rennet? and how does it
act ?

a. The stomach of the calf, of the kid, of the lamb, of the young
pig, and even of the hare,* when covered with salt, or steeped for
some time in water perfectly saturated with salt and then dried,
forms the dried maw-skin or bag which is used for the prepara-
tion of rennet. If the dried skin of nine or ten months old be
steeped in salt and water, a portion of its substance dissolves,
and imparts to the water the property of coagulating milk.
The water thus impregnated forms the rennet or yirning of the
dairy-maid. In some districts it is usual to steep several skins
at once, and to bottle the solution for after use—mixed with
more or less brandy, whisky, or other spirit. In others, a por-
tion of the dry skin, sufficient to make the quantity of rennet
required, is cut off the night before, and steeped in water till
the milk is ready in the morning. To this solution many dairy-

* Three hares’ stomachs are considered equal tc one calt’s.

330 HOW RENNET ACTS.

maids add a quantity of strong spirit before putting it into the |
milk, which probably increases its coagulating power.

b. The rennet thus prepared coagulates more or less readily,
according to its strength. On what principle does it act ?

If a piece of the fresh membrane of the calf’s stomach or
intestine, or even if a piece of fresh bladder, be exposed to the
air for a short time, and be then immersed into a solution of
milk-sugar, it gradually causes the sugar to disappear, and- to
change into lactic acid—the acid of milk. If the salted and
dried membrane be employed instead, it will produce the same
effect, only with greater rapidity.

But, by long exposure to the air in drying the surface, the
salted membrane undergoes such a change, that a portion of it
becomes soluble in water, yet still retains or acquires, even in a
higher degree, the -property of changing milk-sugar into the
acid of milk. It is this soluble portion which exists in the
liquid rennet.

Now, the same effects which the membrane produces upon
the sugar of milk alone, it produces also upon the sugar as itis
contained naturally in the milk—in other words, the rennet,
when added to the warm milk, changes the sugar into the acid of
milk. This it effects more or less rapidly according to circum-
stances, and hence the different leneth of time which elapses in
different dairies before the milk is fully thickened.

c. The addition of rennet, therefore, is only a more rapid way
of making the milk sour, or of converting its sugar into lactic
acid. The acid produced, as in the natural souring of milk,
combines with the free soda, and renders the cheesy matter in-
soluble, which, in consequence, separates ;—in other words, the
milk curdles. The milk, it is true, does not become sensibly
sour, because the production of acid in a great measure ceases
as soon as the soda of the milk is fully saturated with the acid ;
and if any excess of acid be produced, it is taken up and ab-
sorbed or separated in and by the curd, so as to leave the whey
comparatively sweet. Even the rennet that is added is carried

MANUFACTURE OF CHEESE. 331

off by the curd, which is thus often injured in quality if too
much rennet have been added, or if its smell or taste have been
‘unpleasant. The sugar that remains in the whey is thus ena-
bled to retain its sweetness—that is, to remain unchanged into
acid—longer than it could have done had any excess of rennet
remained in it after the separation of the curd.

The chemical change produced by rennet in curdling milk,
therefore, is precisely the same as that which takes place when
milk sours naturally. In both cases the lactic acid which is
formed causes the milk to curdle.

SECTION VIII.—OF THE MANUFACTURE AND THE QUALITY OF
CHEESE.

1. The manufacture of cheese is, generally speaking, con-
ducted in the same manner in all countries. The milk is
curdled by the addition of rennet, vinegar, muriatic acid
(spirit of salt,) lemon juice, tartaric acid, cream of tartar,
salt of sorrel,—by sour milk even, as in some parts of Switzer-
land,* or by the decoction of certain plants or flowers, as of those
of the wild thistle, employed for the ewe cheeses of Tuscany.

The curd is then more or less carefully separated from the
whey, tied up in a cloth, and exposed to gentle pressure. In
general, the curd at this stage is broken small, and mixed with
a due proportion of salt before it is allowed to consolidate and
dry. For the thin cheeses of Gloucester and Somerset, how-
ever, this mode of salting is not adopted, the whole of the
salt that is necessary being afterwards rubbed in and made to
penetrate through the exterior of the cheese.

After it is removed from the press, the cheese is rubbed over

* It is stated by old cheese-makers in Nottinghamshire, that churned
milk added to cheese milk in the usual way, very much improves both the
quality and taste of the cheese, and prevents it from rising after it is
made.

833 THE QUALITY OF THE CHEESE

with salt, or is covered with a layer of it—at a later period is
more or less frequently anointed with butter, is kept for a
week or two in a rather warmish place, and is frequently
turned. There are minute details to be attended to, where
cheese of good quality is desired, with which the skilful and
experienced dairy-maid is familiar, but upon which it is unne-
cessary here to dwell.

2. The quality of the cheese varies with a great variety of
circumstances, partly natural and unavoidable, but partly also
to be controlled by art.

a. Thus there are natural differences in the milk, arising
from the kind of grass or other food on which the cows are
fed, which necessarily occasion corresponding differences in the
quality of the cheese made from it. The milk of different
animals also gives cheese of unlike qualities. The ewe-milk
cheeses of our own country, of Italy, and of France, and those
of goat’s milk made on Mount d’Or and elsewhere, are dis-
tinguished by qualities not possessed by cow’s milk cheeses pre-
pared exactly in the same way. The milk of the buffalo like-
wise gives a cheese of peculiar qualities, arising, as in the cases
of the ewe and the goat, from some natural peculiarity in the
composition of the milk itself.

b. But every dairy farmer knows that, from the same milk,
cheeses of very different flavors, and of very unlike values in
the market, may be made—that the mode of management has
not much less to do with the peculiar quality of his dairy pro-
duce than the breed of cattle he uses, or the pasture on which
his cows are fed. Very slight circumstances, indeed, affect the
richness, flavor, and other valuable properties of his cheese.

Thus if the new milk, when the rennet is added, be warmer
than 95° F., the curd is rendered hard and tough ; if colder, it
is soft, and difficult to free from the whey. If heated on the
naked fire, as is often done, in an iron pot, the milk may, by a
very slight inattention, become fire-fanged, and thus impart an
unpleasant flavor to the cheese. If the curd stand long un-

IS AFFECTED BY MANY CIRCUMSTANCES. 333

broken after the milk is fairly coagulated, it becomes hard and
tough. If the rennet have an unpleasant flavor, or if too much
be added, the flavor and keeping qualities of the cheese are
affected. If acids are used instead of rennet, the properties of
the cheese are altered. It is less rich if the whey be hastily
and with much pressure squeezed out of the curd; or if the
eurd be minutely broken up and thoroughly mixed and stirred
up with the whey: or washed by it, as is the custom in Norfolk
—instead of being cut with a knife, so that the whey may
flow slowly and gently out of it, as is done in Cheshire or Ayr-
shire—or instead of being placed unbroken upon the cloth, as
in making Stilton cheese, so that the whey may drain and
trickle out spontaneously, and may carry little of the fatty mat-
ter along with it. Some of the Cheshire dairy-maids give their
cheese a tendency to green mould, by setting or curdling their
milk at a low temperature ; and the inferiority of Dutch cheese
is ascribed by some to the custom of soiling or feeding in the
house, which affects the flavor of the cheese without injuring
the health of the animal.

c. The kind of salt also which is used,* the way in which the
cheese is salted, the size of the cheese itself, and, above all, the
mode in which it is cured, have very much influence upon its after
qualities. Hence a fair share ofnatural ability, as well as long ex-
perience, are necessary in the superintendent of a large dairy
establishment, when the best quality of cheese which the milk
can yield is to be manufactured wnzformly, and at every season
of the year.

SECTION IX.—OF THE VARIETIES OF CHEESE.
The varieties of cheese which are manufactured are very
* The kind of salt preferred in the dairy districts of the west of Scotland
is an impure variety from Saltcoats, which contains a notable quantity of

the deliquescent salts, (chlorides of lime and magnesium.) These salts seem
to keep the skin of the cheese moist, and to assist its stoning.

334 VARIETIES OF CHEESE.

numerous, but the greater proportion of these varieties owe
their peculiar qualities to the mode of management which is fol-
lowed in the districts or dairies from which they come. Natural
varieties, however, arise under the same general management,
and from the same milk, according to the state in which the
milk is used. Thus we have——

a. Cream cheeses, which are made from cream alone, put into
a cheese-vat, and allowed tc curdle and drain of its own accord,
and without pressure; or as in Italy, by heating the cream,
and curdling with sour whey or with tartaric acid. These
cheeses are too rich to be kept for any length of time.

b. Cream and milk cheeses, when the cream of the previous
night’s milking is mixed with the new milk of the morning, be-
fore the rennet is added. The English Stz/ton cheeses and the
small soft Brie cheeses, so much esteemed in France, are made
in this way.

c. Whole or full malk cheeses, which, like those of Gloucester,
Wiltshire, Cheshire, Cheddar, and Dunlop, are made from the
uncreamed milk. These cheeses, like the preceding, however,
will be more or less rich according to the way in which the
curd is treated, and according as the milk is curdled while
naturally warm, as in the best Ayrshire dairies, and in some
parts of Holland—or is mixed, as in Cheshire and in some Ayr-
shire dairies, with the milk and cream of the previous evening.

The large 60 to 120 lb. cheeses of Cheshire will not stand,
will break and fall asunder, if all the cream is left in the milk.
About one-tenth of the cream, therefore, is skimmed off and
made into butter. About 20 1b. of butter a-week are thus
made in a cheese dairy of 100 cows.

d. Half-milk cheeses, such as the single Gloucester, are made
from the new milk of the morning, mixed with the skimmed
milk of the evening before.

e. Skimmed-milk cheeses—which may either be made from the
milk once skimmed, like the Dutch cheeses of Leyden, twice
skimmed, like those of Friesland and Groningen, or skimmed

WHEY AND BUTTER-MILK CHEESES. 335

for three or four days in succession, like the horny cheeses of
Hssex and Sussex, which often require the axe to break them,
and are sometimes used for certain purposes in the arts.*

f. Whey cheeses made from the curd which is skimmed off the
whey when it is heated over the fire. This is by no means a
poor kind of cheese; and good imitations of Stilton are said to
be sometimes made by mixture of this curd with that of the
whole milk. | :

g. Butter-milk cheeses, made by simply straining the butter-
milk through a cloth, and then either gently heating the butter-
milk, which causes the curd to separate, or, as is sometimes
done, by the addition of rennet. This kind of cheese is not
unworthy of attention, as it is often richer than that made
from milk only once skimmed. Though it cannot, of course,
have the richness, it is said to possess some of the other cha-
racteristic qualities of good Stilton cheese.

h. Vegetable cheeses are made by mixing vegetable substances
with the curd. The green Wiltshire is colored by a decoction
of sage leaves, marigold, and parsley. I do not know if it is
to this practice, or to one of actually mixing the sage leaves
with the curd, that Gay alludes in the line—

‘“‘ Marbled with sage, the hardening cheese she pressed.”

The Schabzieger cheese of Switzerland is a mixture of the curd
obtained from the whey of skimmed milk, with one-twentieth of
its weight of the dried leaves of the mellilot trefoil.

2. The Potato cheeses of Saxony and Savoy consist of dry
boiled potatoes mixed with a half or a third of their weight, or
with any other proportion of the fresh curd, or simply with sour
or with skimmed milk. The mixture is allowed to undergo a

* Suffolk cheese, which is locally known by the name of “Suffolk
Bank,” is so hard that “ pigs grunt at it, dogs bark at it, but neither of
them dare bite it.”

+ Zieger is the curd separated from whey either by a fresh addition of
acid or in some other way.

336 POTATO CHEESE.

species of slight fermentation before it is made up into shapes.
Such cheeses, when well cured, are said to form a very agree-
able article of diet, and to be capable of being kept for a long
period of time.*

* For further details in regard to milk and its products, the reader is re-
ferred to the Author’s Lectures on Agricultural Chemistry and Geology, 2d
edition, pp. 928 to 1008.

CHAPTER XXIV.

On the feeding of animals.—Main visible functions of the living animal.—
The food must supply the wants of respiration.—Nature, wants, and pur-
poses of this function.—The daily waste of the muscular parts and tissues
of the body.—Food necessary to repair it.—Saline and earthy matters
contained in its several parts, and daily rejected by the body.— Waste or

‘increase of fat supplied by the food.—Special waste in the perspiration.
—Forms in which the solid matter of the tissues escapes in the urine of
animals.—General balance of food and excretions.—Kind of food re-
quired, as indicated by the composition of the blood.—Importance of a
mixed food.

Tue food of plants we have seen to consist essentially of two
kinds, the organic and the inorganic, both of which are equally
necessary to the living vegetable—equally indispensable to its
healthy growth. <A glance at the purposes served by plants in
the feeding of animals, not only confirms this view, but throws
also additional light upon the kind of inorganic food which
plants must be able to procure, in order that they may be fitted
to fulfil their assigned purpose in the economy of nature.

SECTION I.——MAIN VISIBLE FUNCTIONS OF LIVING ANIMALS.

Man, and all domestic animals, may be supported, may even
be fattened, upon vegetable food alone. Vegetables, therefore,
‘must contain all the substances which are necessary to build up
the several parts of animal bodies, and to supply the waste at-
tendant upon the performance of the necessary functions of ani-
mal life.

All living animals perform three main or leading functions

necessary to the continuance of healthy life.
15

338 FUNCTIONS OF THE LIVING ANIMAL.

1°. They breathe, alternately inhaling and exhaling air by
means of the lungs.

2°, They digest, dissolving the food in the stomach, and se-
lecting from it the materials necessary to form blood.

3°, They excrete, rejecting in the solid excretions and the
urine, or giving off from the skin and the lungs— :

a. That part of the food which cannot be dissolved and
made use of as it passes through the alimentary canal.

b. The materials derived from the decomposed tissues or
parts of the body which are undergoing a constant waste.

To the wants of an animal performing these visible functions
in a healthy and regular manner, the food must be adapted in
kind and quantity. I shall briefly illustrate what these wants
demand.

To the numerous minor and invisible functions performed
within the several parts of the living body, it is unnecessary to
advert in detail. I may have occasion incidentally to advert
to one or two of the more interesting of these ; but as a
healthy blood contains ali that is necessary to the discharge of
these functions, it would only complicate our present inquiry to
consider their several direct relations to the undigested food as
it is introduced into the stomach.

SECTION II.—THE FOOD MUST SUPPLY THE WANTS OF RESPIRATION.—
NATURE, WANTS, AND PURPOSES OF THIS FUNCTION.

While an animal lives it breathes. It alternately draws in
and throws out atmospheric air by means of its lungs.

1. When this air enters, it contains about two gallons of
carbonic acid in every 5000 ; when it escapes from the lungs it
contains 2 gallons or upwards in every 100. The proportion is
increased from 50 to 100 times. Much carbonic acid, there-
fore, is given off from the lungs of animals during breathing.
In other words, living animals are continually throwing off car-

CARBON GIVEN OFF BY THE LUNGS. 339

bon into the air, since carbonic acid contains about two-sevenths
of its weight of solid carbon, (p. 20.)

A man of sedentary habits, or whose occupation requires lit-
tle bodily exertion, may throw off in this way about five ounces
of carbon in twenty-four hours—one who takes moderate exer-
cise, about 8 ounces—and one who has to undergo violent bodily
exertion, from 12 to 15 ounces, In our climate about one-fifth
more is given off in summer than in winter.

If we take the mean quantity respired at 8 ounces, then, to
supply this carbon alone, a man must eat 18 ounces of starch
and sugar every day.* If he take it in the form of wheaten
bread, he will require 1? lb. of bread ; if in the form of pota-
toes, about 73 Ib. of raw potatoes to supply the carbon which
escapes through his respiratory organs alone.

When the habits are sedentary, 5 lb. of potatoes may be
sufficient ; when violent and continued exercise is taken, 12 to
15 lb. may be too little. At the same time, it must be observed
that when the supply is less, either the quantity of carbon gi-
ven off will be less also, or the deficiency will be supplied at
the expense of the body itself, especially its fatty part. In
either case the strength will be impaired, and increased supplies
of nourishing food will be required to recruit the exhausted
frame.

‘Other animals give off from their lungs quantities of carbon
proportioned to their weights. A cow or a horse, eight or ten
times the weight of a man, will give off 4 to 5 lb. of carbon.
The quantity of food required to supply this carbon will be pro-
portionably greater.

I have in the above calculations supposed that the whole of
the carbon given off from the lungs is derived from the starch,
sugar, or gum of the food. This view is the simplest, and most
easily intellegible. It only requires us to suppose that in the
system the starch is separated into carbon and water, of which,

* Since 12 lb. of starch contain about 5 Ib. of carvon, (see p. 43.)

340 THE BODY FED BY OXYGEN.

“as we have seen, (p. 43,) it may be represented to consist ; and
that the former is given or burned off from the lungs in the
form of carbonic acid. But many physiologists do not regard
the process as being really so very simple. They consider that
the carbon given off is partly derived from the gluten or flesh
of the food, as well as from the starch or fat—in which case
the quantity of starch orsugar in the food, as I have calculated
it, need not be so large ; and it is certain that where animals
live on food which contains no starch or sugar, and but little
fat, the gluten or fleshy fibre it contains must yield the carbon
which is given off by the lungs.

2. But when the air escapes from the mouth of a breathing
animal, it contains much moisture also. It enters comparatively
dry, it comes out so moist as readily to deposit dew upon any
cold surface, or to form a white mist in a wintry atmosphere.
This water is given off by the lungs, along with the carbonic
acid, and, like it, is derived from the food, solid or liquid, which
has been introduced into the stomach. It may either be part
of the water which has been swallowed as such, or the water
which may be supposed to exist in the starch and sugar of the
food. Or it may be water formed by the union of the hydro-
een of the other kinds of food with the oxygen inhaled by the
lungs. It is probably derived in part from each of these sour-
ces, in proportions which must vary with many circumstances?

3. But the lungs actually feed the body. The air which en-
ters contains more oxygen than when it returns again from the
lungs. The oxygen which disappears equals in bulk very near-
ly that of the carbonic acid which is evolved. This oxygen
enters the lungs, through them into the blood, and with the
blood flows on and circulates through the body. It also en-
ters partly into the composition of the tissues, so that it is a
real food, and is as necessary to the construction of the human
body as the other forms of food which are usually introduced
into the stomach. The weight of oxygen taken up by the

DAILY WASTE OF TISSUES. 841

lungs exceeds considerably that of all the dry solid food which
is introduced into the stomach of a healthyman, (See p. 387.)
4. The purposes served by the oxygen thus introduced into
the system are very difficult and complicated. But an inciden-
tal circumstance, which accompanies all its operations in the
system, is the evolution of heat. From the time the solid di-
gestible food enters the blood till it escapes from the lungs, or
in the other excretions, it is continually uniting with oxygen
into new forms of combination, and at each change heat is
produced or given off. Thus the animal heat is kept up, and
thus it is, in a certain sense, correct to say that oxygen is taken
in by the lungs for the purpose of giving warmth to the body,
—or, more poetically, that the body is a lamp fed with oil from
the stomach, and with air from the lungs, which burns with a
slow and invisible flame, but which ever does burn while life
lasts, and maintains a gentle warmth through all its parts.

SECTION III.—THE FOOD MUST REPAIR THE DAILY WASTE OF THE
MUSCULAR PARTS AND TISSUES OF THE BODY.

From every part of the growing as well as of the full-grown
body, a portion is daily abstracted by natural processes, and re-
jected either throngh the lungs and skin, or in the solid and
fluid excretions. ‘This proportion is so great that in summer
the body loses one-fourteenth, and in winter one-twelfth of its
weight daily, when no food is taken. And if food be continu-
ously withheld, the mean duration of life is only fourteen days,
and the weight diminishes two-fifths. But the waste or change
of material proceeds more rapidly when the animal is well fed,
so that the opinion now prevails among physiologists that every
twenty or thirty days the greater part of the matter of the hu-
man body, when adequately fed, is constantly renewed. ‘This
waste of the tissues is more rapid in women than in children, in
men than in women, and most of all in men between the ages.
of 30 and 40. The amount of waste is the measure of life.

342 COMPOSITION OF FIBRIN.

The materials for this change must be supplied by the food
And the quantities required must be adapted to the nature,
age, and sex of the animal.

The muscles of animals, of which lean beef and mutton are ex-
amples, are generally colored by blood ; but when washed with
water for a length of time, they become quite white, and, with
the exception of a little fat, are found to consist of a white fibrous
substance, to which the name of fibrin has been given by chem-
ists. The clot of the blood consists chiefly of the same sub-
stance ; while skin, hair, horn, and the organic part of the
bones, are composed of varieties of gelatine. This latter sub-
stance is familiarly known in the form of glwe, and though it
differs in its sensible properties, it is remarkably similar to fibrin
in its elementary composition, as well as to the white of the
egg, (albumen,) to the curd of milk, (casein,) and to the gluten
of flour. They all contain nitrogen, and the three latter con-
sist of the four organic elementary bodies very nearly in the
following proportions :

Carbon, E 4 : R : ‘ 55
Hydrogen, ; ; ; ah : ; 7
Nitrogen, 6 16
Oxygen, with a little sulphur and phosphorus, i 22

100

Gelatine or dry glue contains about 2 per cent more
nitrogen.

The quantity of one or other of these substances removed
from the body in 24 hours, either in the perspiration, (p. 369,)
or in the excretions, amounts to about five ownces, containing
350 grains of nitrogen ; and this waste at least must be made
up by the gluten, fibrin, or other protein compounds of Bi
food.

In the 12 1b. of wheaten bread, supposed in the previous
section to be eaten to supply the carbon given off by the lungs,
there will be contained also about 3 ounces of gluten—a sub-

FOOD CONSUMED. 343

stance nearly identical with fibrin, and capable of taking its
place in the animal body. Let the other two ounces which are
necessary to supply the daily waste of muscle, &c., be made up
in beef, of which half a pound contains 2 ounces of dry fibrin,
and we have—

For For waste
respiration. of muscle, &c.
13 lb. of bread yielding 18 oz. starch and 3 oz. of gluten.
8 oz. of beef yielding é 2 oz. of fibrin.

Total consumed by tenes oe
respiration and the 18 oz. starch and 5 oz- 3 2%
: fibrin.
ordinary waste,

If, again, the 74 lb. of potatoes be eaten, then in these are
contained about 24 ounces of gluten or albumen, so that there
remain 24 ounces to be supplied by beef, eggs, milk, or cheese.

The reader, therefore, will understand why a diet, which will
keep up the human. strength, is easiest compounded of a mix-
ture of vegetable and animal food. It is not merely that such
a mixture is more agreeable to the palate, or even that it is ab-
solutely necessary—for, as already observed, the strength may
pe fully maintained by vegetable food alone;—it is because,
without animal food in one form or another, so large a bulk of
the more common varieties of vegetable food requires to be
consumed in order to supply the requisite quantity of nitrogen
in the form of gluten, albumen, &c. Of ordinary wheaten
bread alone, about 3 lb. daily must be eaten to supply the ni-
trogen,* and there would then be a considerable waste of car-
bon in the form of starch, by which the stomach would be over-
loaded, and which, not being worked up by respiration, would
pass off in the excretions. The wants of the body would be

* The dry flour being supposed to contain 15 per cent of dry gluten,
(a large proportion,) on which supposition all the above calculations are
made.

344 SALINE MATTER OF FLESH AND BLOOD.

equally supplied, and with more ease, by 17 lb. of bread, and 4
ounces of cheese.

Oatmeal, again, contains at least one-half more nitrogen
than the wheaten flour of our climate (p. 283,) and hence 2 lb.
of it will usually go as far in supplying this portion of the na-
tural waste as 3 lb. of wheaten flour, and the stomach will be
less oppressed. This fact throws much light on the use and
value of what has been called the natural food of Scotland.

The stomach and other digestive apparatus of our domestic
animals are of larger dimensions, and they are able, therefore,
to contain with ease as much vegetable food, of almost any
wholesome variety, as will supply them with the quantity of ni-
trogen they may require. Yet every feeder of stock knows
that the addition of a small portion of oil-cake, or of bean-
meal, substances rich in nitrogen, will not only fatten an ani-
mal more speedily, but will also save a large bulk of other
kinds of food.

SECTION IV.—THE FOOD MUST SUPPLY THE SALINE AND EARTHY
MATTERS CONTAINED IN AND DAILY REJECTED BY THE BODY.

The full-grown animal daily rejects a quantity of saline and
earthy matter withdrawn from its wasting tissues ; while the
growing animal appropriates also every day an additional por-
tion in the formation of its increasing parts. The food must
yield all this, or the functions will be imperfectly performed.

1. The flesh, the blood, and the other fluids of the body con-
tain much salzne matter of various kinds—sulphates, muriates,
phosphates, and other saline compounds of potash, soda, lime,
and magnesia. The dry muscle and blood of the ox leave,
when burned, about 45 per cent of saline matter or ash. The
composition of this saline matter is represented in the follow-
ing table of Enderlin :—

MINERAL MATTERS IN THE BODY. 345

Blood. Flesh.
Phosphate of soda, (tribasic,) . : 16.77 45.10
Chloride of sodium, (common salt,) . 59.34. 45.94
Chloride of potassium, . : : 6.12 ;
Sulphate of soda, " : ; 3.85 trace.
Phosphate of magnesia, : 4.19
Oxide, with a little phosphate of i iron, 8,28 6.84
Sulphate of lime, gypsum, and loss, . 1.45
100 97.88

All these saline substances have their special functions to
perform in the animal economy, and of each of them an unde-
termined quantity daily escapes from the body in the perspira-
tion, in the-urine, or in the solid excretionse This quantity,
therefore, must be daily restored by the food.

2. It is interesting to remark how the mineral matter differs
in kind in the different parts of the body. Thus, blood con-
tains much soda and little potash—the former in the serum,
the latter in the globules—the cartilages much soda and no
potash, and the muscles much potash and little soda. So
phosphate of lime is the earth of bones, and phosphate of
magnesia the earth of the muscles. So also the presence of fluo-
rine characterises the bones and teeth, and that of silica, the
horny parts, hair and feathers of animals—while an abundance
of iron distinguishes the blood and the hair.

The distinction now noticed between the blood and the mus-
cle is not brought clearly out by the analysis above given. of
the comparative composition of the saline matter of each. It
is seen more Clearly in the following comparison :—

The minéral matter or ash

of ox blood of ox flesh

contains, contains,

per cent. per cent.
Common salt, ‘ : 47 to 51 _
Chloride of potassium, 2 : —_- — 10
Potash, ; ‘ ‘ PAs 36
Soda, : ? 3 ; 12 - 14 —
Phosphoric acid, : 3- 7 35
Oxide of iron, 7 - 10 1

15*

346 MINERAL MATTERS IN THE BODY.

From the blood, therefore, as a common storehouse, each -
part obtains, by a kind of selection, the mineral matter which
it specially requires. ,

It has not yet been accurately determined by experiment
how much saline matter must necessarily be excreted every
day from the body of a healthy man, or in what proportions
the different inorganic substances are present in what is ex-
creted ; but it is satisfactorily ascertained, that without a cer-
tain sufficient supply of all of them, the animal will languish
and decay, even though carbon and nitrogen, in the form of
starch and gluten, be abundantly given to it. It is a wise and
beautiful provision of nature, therefore, that plants are so or-
ganised as to refuse to grow in a soil from which they cannot
readily obtain an adequate supply of soluble inorganic food,—
since that saline matter, which ministers first to their own
wants, is afterwards surrendered by them to the animals they
are destined to feed.

Thus, the dead earth and the living’ animal are but parts of
the same system,—links in the same endless chain of natural ex:
istences. ‘The plant is the connecting bond by which they are
tied together on the one hand,—the decaying animal matter,
which returns to the soil, connects them on the other.

3. The bones of the animal are supplied with their mineral
matter from the same original source,—the vegetable food on
which they live. The dried bones of the cow contain 55 per
cent of phosphate of lime with a little phosphate of magnesia,
those of the sheep 70, of the horse 67, of the calf 54, and of the
pig 52 lb. of these phosphates in every hundred of dry bone.
All this must come from the vegetable food. Of this bone-
earth, also, a portion—varying in quantity with the health, the
food, and the age of the animal—is every day rejected. The
food, therefore, must contain a daily supply, or that which
passes off will be taken from the substance of the living bones, -
and the animal will become feeble. .

The importance of this bone-earth will be more apparent if

THE FOOD SUPPLIES THE INCREASE. 347

we consider,—Fvrst, that in animals the bones form not only a
very important but a very large part of their bodies.
The body of a full-grown man contains 9 to 12 lb. of clean dry
bone, yielding from 6 to 8 Ib. of bone-earth. In the horse and
sheep the fresh moist bone has been estimated at one-eighth of
the live, or in the sheep to one-fifth of the dead weight, and
to one-third of the weight of the flesh. Second, that in a
growing sheep the increase of bone-earth amounts to about 3
per cent of the whole increase in the live weight. And—
Third, that every hundred pounds weight of live weight indi-
cates 5 or 6 of phosphate of lime.

It is kindly provided by nature, therefore, that a certain pro-
portion of this ingredient of bones is always associated with
the gluten of plants in its various forms,—with the fibrin of
animal muscle and with the curd of milk. Hence man, from
his mixed food, and animals, from the vegetables on which they
live, are enabled, along with the nitrogen they require, to ex-
tract also a sufficiency of bone-earth to maintain their bodies
in a healthy condition.

SECTION Y.—THE FOOD MUST SUPPLY THE WASTE OR INCREASE OF
FAT IN ANIMALS.

Every one knows that in some animals there is much more
fat than in others, but in all a certain portion exists, more or
less intermingled with the muscular and other parts of the
body.* This fat is subject to waste, as the muscles are, and
therefore must be restored by the food. All the vegetable sub-
stances usually cultivated on our farms contain, as we have
seen, (p. 306,) a notable quantity of fatty matter, which seems
to be intended by nature to replace that which disappears na-
turally from the body.

* At Port Philip, in the boiling-houses, a Merino sheep of 55 lb. gives
20 lb. of tallow, and of all weight above 55 1b. four-fifths are tallow.

348 WASTE OF THE FAT.

A full-grown animal, in which the fat may be regarded as in
a stationary condition, requires no more fat in its food than is
necessary to restore the natural loss. In such an animal the
quantity of fatty matter found in the excretions is sensibly
equal to that which is contained in the food.

But to a growing animal, and especially to one which is fat-
tening, the supply ‘of fatty matter in the food must be greater
than to one in which no increase of fat takes place. It is in-
deed held, that, in the absence of oil in the food, an animal
may convert a portion of the starch of its food into fat,—may
become fat while living upon vegetable food in which no large
proportion of fatty matter is known to exist. And it can
hardly be doubted, I think, that the organs of the living ani-
mal are endowed with this power of forming in a case of emer-
gency—that is, when it does not exist ready formed in the
food—as much fatty matter as is necessary to oil the machinery,
so to speak, of its body. But the natural source of the fat is
the oil contained in the food it eats, and an animal, 2f encloned
to fatten at all, will always do so most readily when it lives
upon food in which oil or fat abounds.

It does not however follow, because fat abounds in the food,
that the animal should become fatter,—since if starch be defi-
cient in the food, the fat containing no nitrogen, may be decom-
posed and worked up for what may be called the purposes of
respiration. ‘This working up of the fat, already existing in
the body, is one cause of the rapid emaciation and falling away
of fat animals when the usual supply of food is lessened, or for a
time altogether withheld. The fat is indeed considered by
some as nothing more than a store laid up by nature in a time
of plenty to meet the wants of respiration when a season
of scarcity arrives,—that a fat animal is like a steam-frigate
heavily laden with fuel, which it burns away during its voyage
for the purpose of keeping up the steam.

It is by reference to this supposed purpose of the fat of the
body, and to the possibility of using it up for the purposes of

PURPOSES SERVED BY THE FAT. 349

respiration, that the benefits of repose, of shelter, of moderate
warmth, of the absence of light, and even of a state of torpor,
in conducing to the more speedy fattening of cattle and sheep,
are explained. Exercise causes more frequent respirations,
and hence a greater waste of that part of the food which should
be laid on in the form of fat. Cold also has the same effect,
since more heat must be produced in the interior of the animal
—in other words, more frequeut respiration must take place, in
order to make up for the greater loss of heat by exposure to
the external air.

Thus, as was stated at the commencement of the present
chapter, a study of the nature and functions of the food of ani-
mals throws additional light upon the nature also and final uses
of the food of plants. It even teaches us what to look for in
the soil—what a fertile soil must contain that it may grow nou-
rishing food—what, we must add to the soil when chemical
analysis fails to deteet its actual presence, or when the food it
produces is unable to supply all that the animal requires.

SECTION VI.—-SPECIAL WASTE IN THE PERSPIRATION OF ANIMALS,
AND IMPORTANCE OF THIS FUNCTION.

Animals perspire that they may live, and this function is as
necessary to a healthy life as either breathing or digestion.
The skin, like the lungs, gives off carbonic acid and absorbs
oxygen. But it differs from the lungs in giving off a much
larger bulk of the former gas than it absorbs of the latter.
The quantity of carbonic acid which escapes varies with cir-
cumstances. It is sometimes equal to a thirtieth, and some-
times amounts only to a ninetieth part of that which is thrown
off from the lungs. But exercise and hard labor increase the
evolution of carbon from the skin, as it does from the lungs.
In motion, the human body gives off nearly three times as
much as when it is at rest; while from a horse, when put to the

350 CARBONIC ACID AND NITROGEN FROM THE SKIN.

trot, the carbonic acid of the skin augments as much as an
hundred and seventy times. (GERLACH.)

Waiter is also given off from the skin as from the lungs, and
every one knows that fat exudes from its pores and lubricates
the surface of the body. ‘The salt taste of the perspiration is
an equally familiar proof that a portion, at least, of the saline
matter derived from the waste and change of materials in the
body escapes through this channel.

Nitrogen also escapes from the skin. The quantity of nitro-
gen in the food is a third or a fourth greater than that contained
in the solid and liquid excretions. (Barrau.) This third or
fourth, therefore, is supposed to be given off by the organs of
perspiration, the lungs and the skin. A cow ora horse is reck-
oned to exhale by the skin and lungs about 400 grains of nitro-
gen daily ; a man, perhaps, 100 ; and a sheep or pig 80 grains.
(Bousstne avr. ) .

The functions of the skin, therefore, are very important ; and
thus, in the practical feeding of animals, a healthy and clean
condition of the skin must contribute not only to healthy growth,
but to a profitable employment of vegetable produce in rearing,
maintaining, and fattening them.*

SECTION VII.—FORMS IN WHICH THE SOLID MATTERS OF THE TISSUES
ESCAPE IN THE URINE. :

The lungs throw off, in the form of gas or vapor, a large pro-
portion of the matters which, after being taken into the stomach,
have already served their purpose in the body. The kidneys
remove the greater part of that which is derived from the
destruction of the tissues. The solid excretions in man amount

* Six pigs were put up together for seven weeks. Three were curry-
combed and cared for—the other three left to themselves; the former
three consumed five bushels of pease less, and had gained 2 stones 4 pounds
more, than the uncurried three. The skins of pigs fed in the forest, in the
season of the acorns, are white and shining.

SALTS AND NITROGEN IN THE URINE. 351

only to a fourteenth or an eighteenth of the whole food con-
sumed.

In a state of health, the saline substances of the food escape
for the most part in the urine. The mineral matter contained
in that part of the solid excretions which has undergone diges-
tion, consists chiefly of earthy salts and of iron.

In man, and in our domestic animals, the nitrogen of the
food and tissues ‘is also separated from the blood by the kidneys,
and is found in the urine. It. is chiefly in the form of a°sub-
stance to which the name of urea is given. In birds, serpents,
and insects, it is separated in the form of uric acid. The urine
voided by a healthy man in 24 hours, averages about 40 ounces,
and contains about 150 grains of solid matter, which has served
its purpose in the system. Of this solid matter, about 270
grains consist of urea, 8 of uric acid, and 170 of mineral or
saline matter. The-urine of the horse is richer in urea than
that of the cow, and that of the cow than the urine of man.
It is this urea which, during the fermentation or ripening of
urine, becomes changed into ammonia.

The urea and uric acid discharged daily in the urine of a
healthy man, contains about half an ounce of nitrogen—to fur-
nish which requires 3 ounces of dry gluten, albumen, or
flesh. If so large a proportion of that which is most valuable
in food, and which has been derived from the decay of the tis-
sues of the body, is contained in the urine, it ought to be an
important object to the farmer to contrive some method of re-
turning it without loss to the soil, that it may aid again in rais-
ing new vegetables as food for other animals.

SECTION VIIIl.—GENERAL BALANCE OF FOOD AND EXCRETIONS IN
MAN.

The general balance of the food taken into the human body
and of the excretions of various kinds, has been thus represent-
ed by M. Barral :

352 BALANCE OF FOOD AND EXCRETIONS.

Every 100 parts taken in, consist of—

Food, solid and liquid, containing in all 75 per cent of water . 74.4
Oxygen taken in by the lungs, 4 ; dl ; 0 ee
100

' And are given off as—
Water perspired by the lungs and skin, . . . 34.8

Carbonic acid, do. do., " s : F . y 30.2
Evacuations, solid and liquid, ; s “ ° 5 A 34.5
Other losses, 3 - ; ; : 2 ; ‘ > 0.5

100

In general, the substances perspired are to the evacuations
as 2 to l.

Of course, in an estimate of this kind, it is impossible accu-
rately to put down the several quantities given off in the form
of hair, nails, surface skin—both of the outer and inner parts
of the body—c., &c., all of which are constantly shed or
cut, and as constantly renewed. It is useful, however, in show-
ing generally the relation which the oxygen inspired bears to
the other food which the stomach receives, and the proportion
of the work of excretion performed respectively by the per-
spiring organs, and by the organs of evacuation.

SECTION IX.—KIND OF FOOD REQUIRED BY ANIMALS AS INDICATED
BY THE COMPOSITION OF THE BLOOD.

A knowledge of the kind of food required by animals may
be gathered, as we have seen, from the composition of the
several parts of the animal body, and a study of the functions
they perform. The muscles must be sustained ; therefore glu-
ten, albumen, &c.—often popularly called muscular matter,
must be eaten. The fat of the body must be renewed, and
hence fat should be present in the food. And, as much carbon
escapes from the lungs and skin, it seems natural, if not abso-
lutely necessary, that starch or sugar should be introduced into
the stomach with the view of supplying it. The mineral mat-

WHAT THE BLOOD TEACHES. 353

ter of the flesh, blood, and bones, must in like manner be pro-
vided. .

The study of the excretions indicates, besides, the quantity of
food of each kind which ought to be consumed. The quantity of
carbon evolved in the form of carbonic acid, of nitrogen in the
forms of urea and uric acid, and of saline matters in the urine
and solid excretions of a healthy man, afford a means of ap-
proximating very nearly to the quantity of each which a suffi-
cient food ought to contain ; but the excretions do not alone
tell us in what forms the carbon, nitrogen, and saline matters
are best suited to the wants of the animal.

An examination of the blood gives us this latter information
very clearly. The blood consists essentially, besides the water,
of albumen, sugar, fat, and saline matter. The main purpose or
object of the process of digestion is to form blood ; for out of
the blood are drawn the materials necessary to the wants of the
bones, and of the various tissues and fluids of the body.
Those forms of vegetable or animal matter, therefore, must be
best adapted for food, which most resemble the ingredients‘ of
the blood which is to be produced from them. ‘These will give
the digestive organs least trouble, or will be most easily
digested. ‘Thus we arrive again at the conclusion that a
healthy, nourishing, and easily digestible food ought to contain
gluten or albumen, sugar or starch—which, in-the stomach,
readily changes into sugar—fat either of animal or vegetable
origin, and saline or mineral matters of various kinds. Of
course, if the stomach of the animal be in an unhealthy condi-
tion, the quality of the food may require to be adapted to its
unnatural condition ; but this does not affect our general con-
clusion.

SECTION X.—IMPORTANCE OF A MIXED FOOD.

All these different modes of examining the question, there-
fore, indicate not only the advantage but the necessity of a

354 IMPORTANCE OF A MIXED FOOD.

mixed food to the healthy sustenance of the animal body.
Hence the value of any vegetable production, considered as
the sole food of an animal, cannot be accurately determined by
the amount it may contain of any one of those substances, all
of which together are necessary to build up the growing body
of the young animal, and to repair the natural waste of such
as have attained to their fullest size:

Hence the failure of the attempts that have been made to
support the lives of animals by feeding them upon pure starch
or sugar alone. These substances would supply the carbon
perspired by the lungs and the skin ; but all the natural waste
of nitrogen, of saline matter, of earthy phosphates, and probably
also of fat, must have been withdrawn from the existing solids
and fluids of their living bodies. The animals, in consequence,
pined away, became meagre, and sooner or later died.

So some have expressed surprise that animals have refused
to thrive—have ultimately died, when fed upon animal jelly or
gelatine alone, nourishing though that substance, as part of the
food, undoubtedly is. When given in sufficient quantity, gela-
tine might indeed supply carbon enough for respiration, with a
great waste of nitrogen, but it is deficient in the saline in-
eredients which a naturally nourishing food contains. |

Even on the natural mixture of starch and gluten which ex-
ists in fine wheaten bread, dogs have been unable to live be-
yond 50 days, though others fed on household bread, contain-
ing a portion of the bran—in which earthy matter more largely
resides—continued to thrive long after. It is immaterial whe-
ther the genera] quantity of the whole food be reduced too low,
or whether one of its necessary ingredients only be too much
diminished or entirely withdrawn. In either case the effect
will be the same—the animal will become weak, will dwindle
away, and will sooner or later die.

The skill of the feeder may often be applied with important
economical effects to the proper selection and mixture of the

VALUE OF OILY FOOD IN FATTENING. 355

-

food he gives his animals generally, and at various stages of
their growth.

It has been found by experiment, for example, that food
which, when given alone, does not fatten, acquires that pro-
perty in ahigh degree when mixed with some fatty substance,
and that those which are the richest in the muscle-forming in-
gredients produce a comparatively small effect, unless they con-
tain also, or are mixed with, a considerable proportion of fatty
matter. Hence the reason why a stone of linseed has been
found by some to go as far as two stones of linseed cake, and
why the Rutlandshire farmers find a sprinkling of linseed oil
upon the hay to be a cheap, wholesome, and fattening addition
to the food of their cattle and horses.

A Merino sheep of 55 Ib. contains about 20 lb. of fat, but
four-fifths of any subsequent addition consists of tallow, (p.
347 note ;) hence we may infer that oily food should be profit-
able in fattening sheep. To pigs the same remark applies ;
and, in practice, fat of any kind, animal or vegetable, is found
_ to be a profitable addition to the food of these animals when
they are to be fattened off.

CHAPTER XXYV.

Feeding of animals continued.—Kind and quantity of food necessary to
maintain a healthy man.—Prison dietaries—Food required by other
animals.—Practical value of the constituents of milk in feeding the
growing calfi—Effect of long-continued dairy husbandry upon the quality
and produce of the soil.—On the growing of wool, and its effect upon
the soil—Of the practical and theoretical values of different kinds of
food.—Relative proportions of food for man yielded by the same herbage
in the forms of beef and milk.—Influence of circumstances in modifying
the practical values of animal and vegetable food.—Concluding observa-
tions.

PRACTICAL experience sustains and confirms all the theoretical
views, and the deductions, chemical and physiological, which
have been advanced in the preceding chapter. To a few of |
these practical confirmations I shall briefly advert.

SECTION I.—KIND AND QUANTITY OF FOOD NECESSARY TO MAINTAIN
A HEALTHY MAN.—PRISON DIETARIES.—FOOD REQUIRED BY SHEEP
AND CATTLE.

The dietaries of prisons, and their effects on the bodily
health and weight of the prisoners, afford one of the simplest
methods of testing the influence of kind and quantity upon the
nourishing power of food. In such establishments—though
open to the objection that the prisoners are in a state of un-
usual restraint—experiments can be performed so much more
accurately, and on so much larger a scale than elsewhere, as
to make them worthy of a very considerable amount of confi-
dence. ;

An inquiry lately made into the comparative health and food

SCOTCH PRISON DIETARIES. 357

of the inmates of the Scotch prisons, has afforded very inter-
esting materials for proving the necessity of a mixed food, and
of a certain minimum proportion of that kind of food which is
supposed especially to sustain the muscular and other tissues.

In the course of the preceding chapter we have stated :

1°. That a healthy man in ordinary circumstances voids daily
about half an ounce of nitrogen in his urine alone, (p. 351.)
To supply this he would require to consume three ounces of dry
gluten, albumen, or flesh.

2°. That altogether he gives off from the lungs, skin, and
kidneys, about 350 grains, or five-sevenths of an ounce, to supply
which he must consume about five ounces of the same materials,
(p. 342.)

But in a state of temporary confinement, when not subjected
to hard labor, this quantity may be safely diminished. Yet
even here there is a limit below which it is unsafe to go. In
the Scotch prisons the weight of food is given to prisoners con-
fined for not more than two months, and not subjected to hard
labor, is uniformly about 17 ounces, and the proportion of glu-
ten or nitrogenous food contained in this is about four ounces.
Where this proportion is maintained, the average general health
and weight of the prisoners improves during their confinement.
Where the contrary is the case, the weight diminishes,-and the
health declines. This is shown in the following tabular view
of the kinds and weight of food given in five of the Scofch
prisons, and its effects upon the weight of the prisoners :—

Food GIVEN. Per-centage of pri-
JAIL. soners who lost
a weight.
Nitrogenous. | Carbonaceous. | Total.
dint.) \Aon. 13.0z. . |17 0z.| 18 lost 1} 1b. each |
Glasgow, 4.06 12.58 16.84 | 32.66 4 9
Aberdeen, 3.98 13.03 17 ba9 Mo i
Stirling, y B2T 13.4 17.67 c

Dundee, 2.75 14 16.75 | 50 4,35 ‘ |

358 THEIR RESULTS.

This table shows that, with the Edinburgh dietary and man-
agement, 72 per cent of the prisoners either maintained or in- -
creased their weight, while only 18 per cent diminished in
weight, and that only to the small extent of 14 lb. each. In
Glasgow the result was less favorable, though even there, out
of nearly 500 prisoners, only one-third diminished in weight.

The same was the case at Aberdeen and Stirling ; so that
in these three places the diet may be regarded as, on the whole,
sufficient. But in Dundee, one-half of the prisoners (50 per
cent) lost weight during their short confinement ; and the cause
is obvious, in the diminished proportion of muscle-forming food,
which in this case was reduced to 23, in place of four ounces.

And it is an interesting fact, as marking the close connection
between science and practice, that this deterioration in the
quality of the diet was caused by the swbstitution of molasses
for the milk, which had been previously distributed to the pri-
soners along with their porridge of oatmeal. Milk is rich in
nitrogenous food, while molasses contains none ; and the sub-
stitution was immediately followed by a perceptible falling off
in the health and weight of the prisoners. So general are the
evils which may arise from ignorance or disregard of scientific
principles ina single director or directing ‘body. The appa-
rently trivial substitution of molasses for milk brought weakness
and want of health on the inmates of an entire prison.

¥n the feeding of other animals, similar results follow from
similar inattention to the requirements of animal nature. Of
dry hay it has been found, in practice, that cattle and sheep
require for their daily food—

An ox at rest, 2 per cent of his live weight.
at work, » 2% .. ae
fatting, 5 at first.

half fat, 4% bie
when fat, 4

Milch cow, 3

Sheep, full grown, 3

FOOD REQUIRED BY ANIMALS. 359

In the case of the ox the daily waste or loss of muscle and
tissue requires that he should consume 20 to 24 ounces of glu-
ten or albumen, which, as may be calculated from the table
given in a subsequent section, (p. 364,) will be supplied by any
of the following weights of vegetable food :—

Meadow hay, . . 20 lb. | Turnips, ‘ ; : 120 Ib.
Clover hay, . ‘ 16 “ | Cabbage, ; : : to *
Oat straw, 5 - 110“ | Wheat or other white grain, 11 “
Pea straw, ; : 12 “ | Beans or pease, : fe
Potatoes, : : 60S") OuCaRe. s 8a. ah ape he 4
Carrots, .. : : TOn

Or instead of any one of these, a mixture of several may be
given, with the best results. But if the due proportion of ni-
trogenous food be not given, the ox will lose his muscular
strength, and will generally fail. So with growing and fatting
stock of every kind, the proportion of each of the kinds of food
required by the animal must in practice be adjusted to the
purpose for which it is fed, as theory indicates, or actual money
loss will ensue to the feeder.

SECTION II.—PRACTICAL VALUE OF SALINE AND OTHER INGREDIENTS
OF MILK IN FEEDING THE GROWING CALF.

In the course of the preceding section I have incidentally
remarked, that the substitution of molasses for milk lowered
the proportion of nitrogenous food in the Dundee prison diet,
and rendered it insufficient for the healthy maintenance of the
prisoners. The reason of this appears in the composition of
milk, already given in a previous chapter. The consideration
of milk as a natural food supplies us with another beautiful
practical illustration of our theoretical principles, to which I
shall briefly advert ; and I do so, not merely because of the
light it throws upon the supply of nitrogen which a milk diet is
fitted to yield, but because it so clearly illustrates another of
the positions laid down in the preceding chapter, that the food

360 MILK A TRUE FOOD.

must supply, in kind and quantity, all the saline and earthy
substances contained in the body.

Milk is a true food. It contains sugar, casein, saline mat-
ter, and fat—a portion of each of those classes of substances
on which the herbivorous races live in the most healthy man
ner. But the provision is very beautiful by which the young
animal—the muscle and bones of which are rapidly growing—
is supplied, not only with a large proportion of nitrogenous
food, but also of bone-earth, than would be necessary to main-
tain the healthy condition of a full-grown animal of equal size.
The milk of the mother is the natural food from which its sup-
plies are drawn. The sugar of the milk supplies the compara-
tively small quantity of carbon necessary for the respiration of
the young animal. As it gets older, the calf or young
lamb crops green food for itself, to supply an additional portion.
The curd of the milk (casein) yields the materials of the grow-
ing muscles and of the organic part of the bones ; while along
with the curd, and dissolved in the liquid milk, is the phosphate
of lime, of which the earthy part of the bones is to be built
up. <A glance at the composition of milk will show how copi-
ous the supply of all these substances is,—how beautifully the
composition of the mother’s milk is adapted to the wants of her
infant offspring. Cow’s milk consists in 1000 parts by weight
of about—

Butter, ; ; ‘ : , : 27
Cheesy matter, (casein,) : - : : ‘ 45
Milk-sugar, : 36
Chloride of potassium, and a ‘little common salt, é 13
Phosphates, chiefly of lime, . ; : . : 24
Other saline substances, : : i . “ 6
Water, . . : : : 2 : : 8825
1000

The quality of the milk, and consequently the proportions of
the several constituents above mentioned, vary, as I have ex-
plained in a preceding chapter, with the breed of the cow—

DAIRY HUSBANDRY AFFECTS THE SOIL 361

with the food on which it is supported—with the time that has
elapsed since the period of calving—with its age, its state of
health, and with the warmth of the weather;* but in all cases
this fluid contains the same substances, though in different
quantities and proportions.

Milk of the quality above analysed contains, in every 10 gal-
lons, 44 lb. of casein, equal to the formation of 18 lb. of ordi-
nary eS —and 31 ounces of phosphate of lime, (bone-
earth, ) equal to the ae Nae of T ounces of dry bone. But
from the casein have to be formed the skin, the hair, the horn,
the hoof, &c., as well as the muscle ; and in all these is con-
tained also a minute quantity of the bone-earth. A portion of
all the ingredients of the milk likewise passes off in the ordi-
nary excretions, and yet every one knows how rapidly young
animals thrive, when allowed to consume the whole of the milk
which nature has provided as their most suitable nourish-
ment. ‘

SECTION III.—EFFECT OF LONG-CONTINUED DAIRY HUSBANDRY UPON
THE QUALITY AND PRODUCE OF THE SOIL.

And whence does the mother derive all this gluten and bone-
earth, by which she can not only repair the natural waste of
her own full-grown body, but from which she can spare enough
also to yield so large a supply of nourishing milk ?

She must extract them from the vegetables on which she
lives, and these again from the soil. -

The quantity of solid matter thus yielded by the cow in her
milk is really very large, if we look at the produce of an entire
year. If the average yield of milk be. 3000 quarts, or 750
gallons, in a year, (every 10 gallons of which contain bone-
earth enough to form about 7 ounces of dry bone,) then by the

* In warm weather the milk contains more butter, in cold weather more
cheese and sugar.

ie BY REMOVING BONE-EARTH.

milking of the cow alone we draw from her the earthy ingre-
dients of 33 Ib. of dry bone ina year. These are equal to 40
Ib. of G6ommon bone-dust, or 34 Ib. in a month. And these ©
she draws necessarily from the soil.

If this milk be consumed on the spot, then all returns again
to the soil on the annual manuring of the land. Let it be
carried for sale to a distance, or let it be converted into cheese
and butter, and in this form exported—there will then be
yearly drawn from the land from this cause alone a quantity of
the materials of bones which can only be restored by the ad-
dition of 40 Ib. of bone-dust to the land. If to this loss from
’ the milk we add only 10 lb. for the bone carried off by the
yearly calf,* the land will lose by the practice of dairy hus-
bandry as much bone-earth as is contained in 50 Ib. of bone-
dust—or in 45 years every imperial acre of land will lose what
is equivalent to a ton of bones.

After the lapse of centuries, therefore, we can easily under-
stand how old pasture lands, in cheese and dairy countries, should
become poor in the materials of bones—and how in such dis-
tricts, as is now found to be the case in Cheshire, the applica-
_ tion of bone-dust should entirely alter the character of the

grasses, and renovate the old pastures. |

SECTION IV.—OF THE GROWING OF WOOL, AND ITS EFFECTS UPON
THE SOIL.

_ The rearing of wool affords another beautiful practical illus-
tration, both of the kind of food which animals require for par-

* Tt has been estimated that the proportion of bone in the—
Horse, .125 of the live weight.
Sheep, old, bee ie u 25 of live, 20 of dead do.
3 nearly, of flesh and fat.
Pig, unfatted, a of live, .20 of dead do. ~
And generally, that 100 live we indicate 2 to 3 of phosphoric acid ; but
these proportions are, no doubt, subject to great variation.

LONG GROWTH OF WOOL ON THE LAND. 363

ticular purposes, and of the effect which a peculiar husbandry
must slowly produce upon the soil.

Wool and hair are distinguished from the fleshy parts of the
animal by the large proportion of sulphur they contain. Per-
fectly clean and dry wool contains about 5 per cent of sulphur,
or every 100 lb. contains 5 lb.

The quantity as well as the quality of the wool yielded by a
single sheep varies much with the breed, the climate, the con-
stitution, the food, and consequently with the soil on which the
food is grown. The Hereford sheep, which are kept lean, and
give the finest wool, yield only 14 lb.; but a Merino often
gives a fleece weighing 10 or 11 lb., and sometimes as much as
12 lb. f

The number of sheep in Great Britain and Ireland amounts
to 30 millions, and their yield of wool to 111 millions of
pounds, or about 4 lb. to the fleece. This quantity of wool
contains 5 millions of pounds of sulphur, which is of course all
extracted from the soil. ©

If we suppose this sulphur to exist in, and to be extracted —
from, the soil in the form of gypsum, then the plants which the
sheep live upon, must take out from the soil, to produce the
wool alone, 30 millions of pounds, or 13,000 tons of gypsum.

Now, though the proportion of this gypsum lost by any one
sheep farm in a year is comparatively small, yet it is reasonable
to believe that, by the long growth of wool. on hilly land, to
which nothing is ever added, either by art or from natural
sources, those grasses must gradually cease to grow in which
sulphur most largely abounds, and which favor, therefore, the
growth of wool. In other words, the produce of wool is
likely to diminish, by lapse of time, where it has for centuries
been yearly carried off the land; and, again, this produce is
likely to be increased in amount when such land is dressed with
gypsum, or with other manure in which sulphur naturally ex-
ists. Of course, this general conclusion will not apply to lo-

364 PRACTICAL AND THEORETICAL VALUES

calities which derive from springs or other natural sources a
supply of sulphur equal to that which is yearly removed.

SECTION V.—OF THE PRACTICAL AND THEORETICAL VALUES OF DIF-
FERENT KINDS OF FOOD.

From what has been stated in the preceding sections, it ap-
pears, as the result both of theory and of practice, that dif-
ferent-kinds of food are not equally nourishing. This fact is of
great importance, not only in the preparation of human food,
but also in the rearing and fattening of stock. It has, there-
fore, been made the subject of experiment by many practical
agriculturists, with the following general results :

1. If common hay be taken as the standard of comparison,
then, to yield the same amount of nourishment as 14 lb. of hay,
experiments on feeding made by different persons, and in dif-
ferent countries, say that a weight of the other kinds of food
must be given, which is represented by the number opposite to
each in the following table :—

Hay, , A 10 Carrots, (white,) . 45
Clover hay, ; 8 to 10 Mangold-wurtzel, . 35...
Green clover, . 45 “ 50 Turnips, ; . 50
Wheat straw, . 40 “ 50 Cabbage, , ool 8 38
Barley straw,- .. 20 “ 40 Pease and beans, . 3“ 5
~ Oat straw, o. » 202% 40 Wheat, . : ot ae
Pea straw, ‘ 10 “ 15 Barley, . ee See:
Potatoes, E 20 Oats, . «52 elected
Old potatoes. 40?-: Indian corn, . 5
Carrots, (red). 25 “ 30 Oil-cake, Qo Oh

It is found in practice, as the above table shows, that
twenty stones of potatoes, or three of oil-cake, will nourish an
animal as much as ten stones of hay will, and 5 stones of oats
as much as either. Something, however, will depend upon the
quality of the sample of each kind of food used—which we
know varies very much, and with numerous circumstances; and
something also upon the age and constitution of the animal,

OF DIFFERENT KINDS OF FOOD. 365

and upon the way and form in which the food is administered.
The skilful rearer, feeder, and fattener of stock knows also the
value of a change of food, or of a mixture of the different
kinds of vegetable food he may have at his command—a sub-
ject we have considered in a previous section.

2. The generally nutritive value of different kinds of food
has also been represented theoretically, by supposing it to be
very nearly in. proportion to the quantity of nitrogen, or of
gluten, which vegetables contain. Though this cannot be con-
sidered as a correct principle, yet as the ordinary kinds of food
on which stock is fed contain in general an ample supply of
carbon for respiration, with a comparatively small proportion
of nitrogen, these theoretical determinations are by no means
without their value, and they approach, in many cases, very
closely to the practical values above given, as deduced from
actual trial. Thus assuming that 10 lb. of hay yield a certain
amount of nourishment, then of the other vegetable substances
it will be necessary, according to theory, to give the following
quantities, in order to produce the same general effect in
feeding :— ;

Hay, . ; : ; 10 Carrots, (red,). . 35
Clover hay,* : : 8 Cabbage, . : 30 to 40
Vetch hay, : : A. Pease and beans, 2to 3
Wheat straw, . : 52 Wheat, : 5
Barley straw, . : 52 Barley, 6

Oat straw, ; ; 55 Oats, 5

Pea straw, . : ‘ 6 Rye, 5
Potatoes, . : . 28 Indian corn, 6

Old potatoes, : ; 40 Bran, 5
Turnips, . : : 60 Oil-cake, 2
Mangold-wurtzel, rier

If the feeder be careful to supply his stock with a mixture or
occasional change of food—and especially, where necessary,
with a proper proportion of fatty matter—he may very safely ~
regulate, by the numbers in the above tables, the quantity of

* Both cut in flower.

3566 ON WHAT THE FATTENING PROPERTY

any one which he ought to substitute for a given weight of any
of the others—since the theoretical and practical results do not
in general very greatly differ.

3. As has been already stated, however, it is not strictly cor-
rect that this or that kind of vegetable is more fitted to sustain
animal life, simply because of the large proportion of nitrogen
or gluten it contains; but it is wisely provided that, along with
this nitrogen, all plants contain a certain proportion of starch
or sugar, and of saline and earthy matter—all of which, as we
have seen, are required in a mixture which will most easily sus-
tain an animal in a healthy condition; so that the proportion
of nitrogen in a substance may be considered as a rough prac
tical index of the proportion of the more important saline and
earthy ingredients also. :

4. It is very doubtful, however, how far this proportion of
nitrogen can be regarded as any index of the fattening pro-
perty of vegetable substances. If the fat in the body be pro-
duced from the oil in the food, it is certain that the proportion
of this oil in vegetable substances is by no means regulated by
that of the gluten or other analogous substances containing ni-
trogen. The stock farmer who wishes to lay on fat only upon
his animals, must therefore be regulated by another principle.
He must select those kinds of food, such as linseed and oil-
cake, in which fatty matters appear to abound, or mix, as I
have already said, (p. 354,) a due proportion of fat or oil with
the other kinds of food he employs.

But large quantities of fat accumulate inthe bodies of most
animals, only when they are in an unnatural, and, perhaps in
some measure, an unhealthy condition. In a state of nature
there are comparatively few animals upon which. large accumu-
lations of fat take place. A certain portion, as we have seen,
is necessary to the healthy animal; but it is an interesting
fact, that as much as is necessary to supply this is present in |
most kinds of vegetable food. In wheaten flour it is asso-
ciated with the gluten, and may be extracted from it after the

OF FOOD DEPENDS. 367

starch of the flour has been separated from the gluten by
washing with water, as already described (pp. 40 and 45.) In
so far, therefore, as this comparatively small necessary quantity
of fatty matter is concerned, the proportion of nitrogen may
aso be taken, without the risk of any serious error, as a prac-
tical indication of the ability of the food to supply the natural
waste of fat in an animal which is either growing in general
size only, or is only to be maintained in its existing condition.

While, therefore, it appears from the study of the principles
upon which the feeding of animals depends, that a mixture of
various principles is necessary in a nutritive food, it is interest-
ing to find that all the kinds of vegetable food which are
raised, either by art or by natural growth, are in reality such
mixtures of these several substances—more or less adapted to
fulfil all the conditions required from a nutritious dict, accord-
ing to the state of health and growth in which the animal to
be fed may happen to be.

An important practical lesson on this subject, therefore, is
taught us by the study of the wise provisions of nature. Not
only does the milk of the mother contain all the elements of a
nutritive food mixed up together—as the egg does also for the
unhatched bird—but in rich natural pastures the same mixture
_ uniformly occurs. Hence, in cropping the mixed herbage, the
animal introduces into its stomach portions of various plants—
some abounding more in starch or sugar, some more in gluten
or albumen—some more in fatty matter—while some are natu-
rally richer in saline, others in earthy constituents ; and out of
these varied materials the digestive organs select a due propor-
tion of each and reject the rest. Wherever a pasture becomes
usurped by one or two grasses—either animals cease to thrive
upon it, or they must crop a much larger quantity of food to
supply from this one grass the natural waste of ail the parts of
their bodies.

It may indeed be assumed as almost a general principle, that
whenever animals are fed on one kind of vegetable only, there ©

S08 COMPARATIVE PRODUCE OF BEEF AND MILK.

is a waste of one or other of the necessary elements of animal
food, and that the great lesson on this subject taught us by na-
ture is, that by a judicoous admixture, not only is food economis-
ed, but the labor imposed upon the digestive organs 1s also materi-
ally diminished. ‘0

SECTION VI.—RELATIVE PROPORTIONS OF FOOD FOR MAN YIELDED BY
THE SAME HERBAGE IN THE FORMS OF BEEF AND MILK,

A curious economical question, in connection with the value
of vegetable produce in feeding cattle, presents itself to us
when we come to compare the proportions of human food which
may be obtained from the same weight of herbage when cattle
are fed with it for different immediate purposes.

A ton of hay may be given to a bullock to be dodeetind
into beef. Another ton of the same hay may be. given to a
cow to be converted into milk. Would the beef or the milk
produced contain the larger supply of food for man? We have
rather imperfect data to rely upon in answering this question,
but they lead us to very interesting results. }

1. According to Sir John Sinclair, the same herbage which
will add 112 Ib. to the weight of an ox, will enable a cow to
yield 450 wine gallons, or 3600 Ib. of milk. This milk will
contain 160 lb. of dry curd, 160 Ib. of butter, 180 lb. of sugar,
and 18 lb. of saline matter, while the 112 lb. of beef will not
contain more than 25 lb. or 30 lb. of dry muscle, fat, and sa-
line matter together ; that is to say, the same weight of herb-
age which will produce less than 30 lb. of dry human food in
the form of beef, will yield 500 Ib. in the form of milk.

2. But this statement of Sir John Sinclair’s is, I fear, not to
be relied upon. We have another, however, something differ-
ent, from Riedesel, a Continental authority. He says that the
same quantity of hay will produce either 100 lh. of beef, or
100 imperial gallons (1000 Ib.) of milk. This quantity of

~

CIRCUMSTANCES MODIFY 369

milk contains only 150 lb. of dry food, but it is still five times
as much as is contained in the beef.

This statement of Riedesel is also to be received with hesita-
tion ; but the subject is interesting and important, as well as
curious, and is deserving of further investigation. Should the
population of the country ever become so dense as to render a
rigorous economy of food a national question, butcher-meat, if
the above data deserve any reliance—will be banished from
our tables, and a milk diet will be the daily sustenance of al-
most all classes of society.

SECTION, VII.INFLUENCE OF. CIRCUMSTANCES IN MODIFYING THE
PRACTICAL VALUES OF ANIMAL AND VEGETABLE FOOD.

The indications of theory, and the results of general prac-
tice, in regard to the nutritive power of different vegetable
substances, are modified by many circumstances which ought to °
be borne in mind. Whether fed for work, or for the produc-
tion of flesh or milk, the effect of the food given to animals will
depend partly on the kind, breed, and ‘constitution of the ani-
mal itself—on the general treatment to which it is subjected,
and the place in which it is kept—on its size and state of health
——and on the form in which the food itself is given.

1. The breed or constitution, every feeder knows, has a great
influence on the apparent value of food. Some breeds, like the
improved short-horn, have a natural tendency to fatten, which
makes them increase in weight more rapidly than other breeds,
when fed upon the same food. And even in the same breed,
the rapidity with which one animal lays on flesh will sometimes
make it two or three times more profitable to the farmer than
others which are fed along with it.

2. Warmth and shelter cause the same amount of food to go
farther, as do also gentle treatment and the absence of glaring
light. Sheep have produced double the weight of mutton
from the same weight of vegetable food, when fed under shel-

370 THE PRACTICAL VALUE OF FOOD.

ter, and kept undisturbed and in the dark. Itis probably from
this beneficial influence of warmth that, in the North American ~
' States, a difference of 25 per cent is observed in favor of the
spring and summer over the winter ans of the pigs upon
similar food.

3. The form in which the food rs given is of no less importance.
Grass newly cut goes farther than after it is made into hay;
and the opinion is now becoming very generally prevalent,
that steamed, boiled, or otherwise prepared food, is more whole-
some for cattle, and more economical to the feeder, than the
same food given in a dry state.

In the case of horses, the difference between the practice of
giving all the food dry and uncut, and that of giving all -the
hay cut with the oats and beans crushed, and an evening meal
of steamed food, is such as to effect a saving of nearly one-
third. Thus, the same waggon horses which consumed 3}
bushels of oats per week, and 14 stones of hay, when given
uncut, uncrushed, and uncooked, were kept in good condition
by 24 bushels of oats, 8 stones of hay, and 7 Ib. of linseed
when the grain was crushed, the hay cut into half-inch chaff,
and the linseed with a little bean-meal and cut hay made into
a steamed meal-feed inthe evening.*

4. The malting and sprouting of barley is by many practical
men considered to increase its nutritive qualities. It is certain
that, when mixed with boiled potatoes to the extent of three
or four per cent, and kept warm for a few hours, bruised malt
produces a prepared food which is much relished by milch
cows, and is profitable to the dairy-man. There is reason to
believe that similar mixtures with other kinds of food would
produce similar beneficial effects.

Mr. Hudson, of Castle Acre, feeds his farm-horses on 12 Ib. of
sprouted barley a-day, besides their fodder ; and this, on his

* The dry feeding being—hay 12 lb., with oats and beans 14 lb.; the

steamed feed—hay 3 Ib., beans 3 Ib., linseed 1 lbh.—Caird’s English Agri-
culture, p. 346.

CONCLUDING REMARKS. 3T1

light land, keeps them in good condition. It is prepared by
steeping the barley for 24 hours, and then putting it into a
heap and turning it over for five days.*

5. The sowring of food of all kinds has, by almost universal
consent, been found to make it more profitable. in the feeding
and fattening of pigs. It makes them fatten faster, and gives
a firmer and whiter flesh.

Many other circumstances also modify “e real practical
value of food, and cause. it to produce results different from
those iiidigaded by its chemical composition. But to those,
want of space does not permit me here to advert.

SECTION VIII.—CONCLUDING REMARKS.

In the little work now brought to a close, I have presented
the reader with a brief, but I hope plain and familiar sketch of
the various topics connected with Practical Agriculture, on
which the sciences of Chemistry, Geology, and Chemical Phy-
siology are fitted to throw the greatest light.

We have studied the general characters of the organic and
inorganic elements of which the parts of plants are made up,
and the several compounds of these elements which are of the
greatest importance in the vegetable kingdom. We have exa-
mined the nature of the seed—seen by what beautiful pro-
vision it is fed during its early germination—in what forms the
elements by which it is nourished are introduced into the cir-
culation of the young plant when the functions of the seed are
discharged—and how earth, air, and water, are all made to
minister to its after-growth. We have considered the various
chemical changes which take place within the growing plant
during the formation of its woody stem, the blossoming of its
flower, and the ripening of its seed or fruit,—and have traced
the further changes it undergoes, when, the functions of its,

* Oaird’s English Agriculture, p. 168.

372 CONCLUDING REMARKS.

short life being discharged, it hastens to serve other purposes,
by mingling with the soil, and supplying food to new races.
The soils themselves in which plants grow, their nature, their
origin, the causes of their diversity in mineral character, and
in natural productiveness, have each occupied a. share of our
attention—while the various means of improving their agricul-
tural value by mechanical means, by manuring or otherwise,
have been practically considered, and theoretically explained.
Lastly, we have glanced at the comparative worth of the va-
rious products of the land as food for man or other animals,
and have briefly illustrated the principles upon which the feed-
ing of animals, andthe relative nutritive powers of the vegeta-
bles on which they live, and of the parts of animal bodies
themselves, are known to depend.

In this short and familiar treatise I have not sought so much
to satisfy the demands of the philosophical agriculturist, as
to awaken the curiosity of my less instructed reader, to show
him how much interesting as well as practically useful informa-
tion Chemistry and Geology are able and willing to impart to
him, and thus to allure him in quest of further knowledge and
more accurate details to my larger work,* of which the present
‘exhibits only a brief outline.

_ * Lectures on Agricultural Chemistry and Geology.

‘THE END.

ALPHABETICAL AND ANALYTICAL

INDEX.

A.

Act, Carbonic, 18, 3

Humic, = : tas:
ae Geie: 21
“ -Crenic, 22

““’ Apo-Crenic, . By
Nitric, : 4 29
“ Sulphuric, . 33
‘** ~ Phosphorie, 34
“* Pectose, pectic, » 44

“of milk, how produced, 32
ACORN, composition of, 289
Agriculture, a chemical art, 133
Albumen, : . 46, 342
Alumina, “BG
Ammonia, its properties, 26
nitrate of, ree
9 salts of, as manures, 222
- carbonate of, 223
ss sulphate of - 224

° salts of, experiments
with, 225
Animals, organic parts of, 14
= main visible furictions

of, 337
respiration of, 338
“ carbon given off by, 339
43 bones of 346

re kind of food required by, 359

ANALYSIS of organic parts of

plants,

bs of barley, wheat, oats,
beans, rye, corn,
linseed, potato, and
turnip,

3 of guano,

of experiments with
salts of ammonia,

of carbon and nitro-
gen taken in food
and respired,

of soils,

of water,

Aquafortis, (nitric acid,)

Ash, of wood and grain,

“" of wheat and oat straw,
wheat leaves, oats, oak
wood, animal substan-
ces, and bones,

‘quantity of left by plants,

ob oe

14

64
208

7

"59
of in different plants, 59
. . 64

“quality of,
“of grains, table of, 64
quantity ‘of depends on the.
soil, 63, 67
= ck straw, table ‘of 68
“ of crab apple tree, 67
‘of wheat, table of, . 68
‘* -of wood and straw, . 232

374

~

Ash, ‘of bushels of oats, barley,
and rice, i
“of peat and coal,
Atmosphere, composition of,

~

D.

Barley, coitipasttions of,
malting qualities of,
feeding qualities of,
varying qualities of
oil in 100 Ibs. of
Bean, composition of,
Beef, ‘and milk, .".
Blood, kind of food required, as
indicated by the, °

‘ what it teaches,

Body, muscular parts of the,

‘‘ mineral matter in the,
Bran, value of,

Bromides,

Bromine,

Bones, dry, 6 per cent. phospho-
rus,

- composition of and value

as manure, :

“to dissclve with acid,

‘* experiments with,
Buckwheat, composition ‘of
Butter, quality of varies,

composition of,

«preservation of

why it becomes rancid,

“coloring of,

C.

Cabbage, composition of,
Carbon,

Carbonate of potash and soda,

4 of magnesia in lime-
stone, :

Casein, . a5 MES,
Cauliflower, qualities of,
Chalk, in Alabama,

INDEX.

284
285
286
290
307

. 288

368

352
353
341
345
176

59

58

14

192
194
195
287
322
323
324
325
326

300
218
226

252
342
301

. 14

Charcoal, uses of, . F

Cheese, manufacture of,
79

“
a3

6c

quality of,

varieties of

.cream, cream and milk,
whole or full milk,
half milk, skimmed
milk, .

whey, ‘putter- milk, veg-
etable and potato,

Chemistry, what it will do for

agriculture, é
Chlorides, how formed,
Chlorine,
Churning,

Clay, influence of air, “frost, and

water on,

sinks in the soil,

and earth burned,

cause of the mechanical
and chemical action of,

Clover, red and white, what soils

74

they like, :
hay, oil in 100 Ibs. of,

Coal dust and coal tar,
Cocoanut cake,

Corals, shell- sand, marls, S 253
Corn, Indian, composition of, 287
“oil in 100 lbs. of p 307
Cream, composition of, 319

Crops, why one may grow well
where another fails, 72
‘rotation of necessary, 72, 132
Curd, why it seperates, ; 329

1.

Dairy husbandry, effects of on
the soil, 2 ¥./ SGL
Digestion, effects of animal, ° 217
Draining, benefits produced by, 137
4 of light soils, ‘ 138

¥ summary of advantages
of, ‘ . 142
= depth of, . 142
Dung, value of, 218
Be 5 OL. full-grown animals, 219

INDEX,

E.
Experiments, importance of, 5
F.
Farmer, object of the practical, 1
Fat, waste of in animals, 347
‘¢ purposes served by, 349
Fermentation, of dry vegetable
matter, 174
+ loss of weight by, 175
Fibrin, composition of, 342
Fluorine, 59
Food, quantity yielded by : an
acre, 308
“must repair daily waste
in animals, 341
*- must supply saline and
earthy matters, 344
“importance of a mixed, 353
“value of oily, in fatting, 355
“ kind and quantity neces-
sary to maintain a heal-
thy man, 356
‘“* given prisoners, 357
“required by sheep and
cattle, 5 358
“ practical and. theoretical
value of, 364
“* on what its fattening prop-
erties depends, 366
“* animal and vegetable, 369
‘¢ practical value of, - 370
*« form in which it is given, 370
‘“« the souring of, ‘ Pst
Fork, use of in loosening subsoil, 150
Fruits, composition of, 302
“effects of soil on their
quality and flaver, 303 |
G.
Gas, Hydrogen, : t ee) ee
“ Oxygen, : ¥ . 11
“ Nitrogen, : RAS aes ih

Geology, what it will do for agri-

culture, 1
“its relations to agricul-
ture, 8, 102
“value of to the farmer, 88
Gelatine, 34, 342
Gluten, 342
Grass, laying down land to, 159
** how land is improved by
laying down to, 160
“roots of remaining in the
soil, ‘ 161
‘* natural changes, . 166
Guano, varieties of, 205
fertilizing | effects of, 206
composition of, . 208
‘‘ permanence of action of, 209
“« adulteration of, 210
‘* how to select good, 211
‘* national value of, 212
“ artificial, how to - pre-
pare, ‘ 248
Gypsum, taken from the soil by
wool-growing, 363
H.
Hay and straw, 309
“time of cuiting affects quan-
_ tity and quality of, 303 >
* clover, oil in100 Ibs. of, 307
‘¢ meadow, oil in 100 Ibs. of, 307

Hemp, poppy and cotton cakes, 178

Horn and hoof parings as ma-
~ nure, : : 2 119
| Hydrogen, . - : 9
ia
ILLUSTRATIONS—
Burning the soil, 3 6
procuring hydrogen gas, 9, 10
‘* oxygen gas, 11
“ earbonic acid, 18, 19, 20
burning hydrogen gas, 24
procuring phosphoric acid, 34
pores on the leaf of garden
balsam, d bs, ah

376 INDEX.
ILLUSTRATIONS— M.
procuring starch, 40
starch, gluten and fat in grain, 41 | Magnesia, ‘ . SB
procuring chlorine, : 57 “nitrate of, : . 30
stratified and unstratified “ earbonate of, in lime-
rocks, 84 stone and chalk, 252
section of coast line, E 91 | Maize, (Indian corn), composi-
of different soils, . 94, 95, 98 tion of, . 287
of drifts, : . 113 | Malt-dust, 177
Inorganic bodies, : 6 | Manure, ‘accurate knowledge
“matter carried off in crops, 69 of, : 3
Insects, as a manure, . 189 “artificial, why necessary, i.
Todine, 58 “ - what is a, : 168
Todides, - 59 # \use‘of vegetable, 168
Tron, oxide or rust of 140 “. relative fertilizing and
Irrigation, : . 272 money values of dif-
ferent vegetable, 184
‘« sea-weed, uses of, asa, 169
I. ‘“« . saw-dust and bran, as a, 176
: “« brewers’ grains, malt
and rape dust, 177
Land, improvement of by feed- 290 “* hemp, poppy, and cotton
ing sheep, : m cakes, . i W738
Leaves, how they fertilize 158 “« peat, peat compost, ‘and
‘* of turnips, potatoes, &., 171 tanners’ bark, 178
“of trees, nutrition of 301 “fermented and charred
Lime, , : 6b, 155 peat, 179, 180°
“ Nitrate of, : 30 ‘“« charcoal, soot, and coal-
‘“¢ sinks in the soil, (150, 259 tar, 181
‘¢ phosphate of, in animals, 252 “immediate and perma-
“ purning and slaking of, 254 nent effects of vege-
“ effeets of exposure of, to table manures, 186
the air, . 255 “ animal, fish, 187
“* effects of burning, 256 “* bloed as a, 189
¢ quantity usually applied, 257 “skin, bone, hair, wool, 190
** visible improvements by, 258 i nitrogen in animal, 191
‘* -why it must be repeated, 258 “t) ICOW; ‘horse, and rig, 204
““ crops and rains carry it ‘* droppings of birds, 205
away, 259 ‘« relative values of dif-
“chemical effects of, 260 ferent animal, 213
“ exhausting effects of, 265 ‘difference in animal and
Limestones and chalks, com posi- vegetable, . “295
tion of, . i 250 ‘* causes of difference be-

3 benefits of burning, 255 tween animal and ve-
Ainseed, and linseed cake, 287 getable, 216
“oil in 100 Ibs. of, 307 ‘« saline, why required by
Lungs, carbon given off by, 339 the ‘soil, 236

_“ the, actually feed the “. how to determine the
body, ; 340 value of saline, — 237

INDEX. 317
Manure, saline, circumstances | ba
under which they
are to be used, 238 | Night-soil, and poudrette, 203
“* saline, specific action of Nitrogen, : 12, 218
on plants, 240 . necessity of, to the plant, 15
‘saline, action of on par 8 “forms in which it enters
ticular parts and kinds the roots, 52
of ‘plants, 241 in animal manures, 191
“sulphates and nitrates, “necessary to the wheat ,
mixed, 243 crop, . 225
“mixed, promote growth, “exhaled by the skin and
and prevent © mil- lungs, 350
dew, 246, 247
“ soil can be restored
by, 267 O.
“ influence of on ‘wheat
and other corn Oats, composition of, 282
crops, vik | Pei sa » }
Manuring, green Lit when ( cut, ; 305
i silt Hee ea 5 ; ‘and straw, oil in 307
with dry vegetable Che. creas
pe rene 174 ; grain, hay and root
Matter, organic diminishes in ger. 306
' Organic bodies, : 6
the soil, 266
MILK, properties and composition Oxyger SPs! 9, 32
Sie 312, 360 “the body fed by, 340
" influence of breed on, 314
“of form and constitution P
on, : - 315 if
“ of kind of food on, 316
“* - of soil on, 317} Paring and burning, , 268
o adulteration of, 318 | Pea, composition of, 288
“ the whole may be churn- * and bean, varying quali-
ed, 320 ties of, : : 291
«time required for churn- Peat, use of, - 178
ing, 321| “ fermented, . ? 179
“why it becomes. sour, 326| “ charred, asan absorbent, 180
“ sugar of, acid of, 326] ‘ ashes, composition of, 235
“acid of, how produced, $27 Perspiration, waste in animal, 349
“ curdling of, and casein, 328) Phosphate, how formed, 34, 57
“rich in nitrogenous food, 358 it ammoniaco-magne-
“value of saline ingredients sian, . 202
im)... : 359 ” of lime (and na-
“a true food, 360 tive,) 229, 230
“removes bone-earth from oF experiments with
the soil, 362. mixed, : 245
eg proportions ‘of food yielded of lime in limestone, 252
by, Bocas : 368 | Phosphorus, . 9
Mushroom, . 301 | Physiology, what it will do for
agriculture, pt:

578 INDEX.
Plants, organic parts of, . 13, 14; Rain, mechanical action of,
‘* structure of stem, root Rape-dust, as manure,
and leaf of, 36 ia cake value of,
‘functions of roots of, 37 | Rennet, action of,
“ i of the leaf of, | 37 | Respiration, effects of,
e re of the stem of, 39] Rice, composition of,

substances.of which they
consist,

structure of their seeds

“fatty substance of

waxes and resins of,

growth of,

woody matter of,

select the soils on which
they prefer to grow,
sicken on some soils,
Plow, subsoil, how it acts in
improving the soil,

“results of experiments

with, 149,
Plowing, deep, how it im-
proves the soil,

- chemical effects of,
Potash,
‘“ nitrate of
Potato, average composition
of, 294,
‘* influence of variety on,
“effect of manures on,

‘effects of keeping, ‘and
frost on,
Poudrette,

R.

Rags, woollen, as manure,
Rain, effects of on the soil,
‘“* “causes the air to be re-
newed,
“warms the under soil,
“ equalizes the temperature,
‘“* carries down soluble sub-
stances, . ;
“ washes out noxious mat-
ters,.... % ; a
“ ‘brings down fertilizing
substances, :

191,

49

source of earthy matter of, 54

130
132

147
150
158
153

5d

30
295
296
297

298
203

214
144

144
144
145
145
145

146

Rivers, English and Indian,
Rocks, crumbling of,

“ constancy in mineral
character among the
stratified,

‘* the crag,

“the plastic clays and
chalks,

“ the green sand,

ae wealden formation,

“‘ the upper, middle, and
lower oolite and the
leas,

“ the new red sand- -stone,
the magnesian lime-
stone, and the coal
measures, .

‘the mill-stone grit, the
mountain limestone,

97

and oldred sandstone, 98, 99

“¢ the upper and lower sil-

urian system, ‘ 100

“* the cambrian, mica slate
and gneiss systems, . 101
‘“‘ granite, composition of, 104

‘* quartz, felspar, trap and

hornblende composi-
tion of, 105, 106
‘“* rotten rock, marl, 107
Rye, composition of, : - 287
“varying quality of, . 291

8.

Sal-ammoniac, ; Fs . 224
Salt, common, . “ A 227
Salts, Glauber’s, . : 228
‘“* Epsom, : 228
Sap, cause and motion of, 39
‘“* changes as it ascends, . 48
Saw-dust, value of,” 176

INDEX.

Science and practice, close con-

nection between, 358
Sea-weed and straw, ashes of, 321
Seeds, structure of, oh Al

“ ~ germination of, . AT

“ steeping of in salts of

ammonia, ‘ 224
Sheep, sulphur in their wool, 363
Silica, . oie. : 5
Silicate of potash and soda, 228
Skin, carbonic acid and nitrogen
from, : : F 350
Soda, : 55 |
“ nitrate of, : : 30
“ and potash, carbonate of, 226.

sulphate of (Glauber’s salts), 328
sulphate and nitrate of,

mixed, ‘ ; . 543

Soils, benefit from analysis
of, 3, 122, 123
“organic part of, 74
“ inorganic part of, 1D
‘© galine or soluble portion of, 76

“earthy or insoluble portion *

OL» : ‘ : 77
“sandy, loamy, and peaty, 78
“ djversities of, and subsoil, 79
“ origin of; : ; rs ee
“ cause of the diversity of, 82

“differences of, on stratified
rocks, aad , es

“ density, and absorbent
power of, : : 117

“ evaporative power and
shrinkage of, . 118

absorption of moisture of
the air by, and tempera-

ture of, . : ‘ 11s
“ chemical composition of © 121
“ fertile and barren com-
pared, . ? : 124
“ causes of the fertility of
black, 2 ‘ . 129
“ connection between and
plants, d : . 129
« general improvement of, 135
“ two classes of, 136
“liable to be burned up, 139

379°

Soils, improvement of by mixing, 154
4“ ch

by planting, 156

£5 YF by laying down
to grass, 152
Soot, uses off . = . 189

Starch and gluten, quantities of
in crops, 305
Straw, ashes of, . 231
“and hay,,.-.- : . 301

“ affected by the time of
| cutting, : 304.
Subsoil, importance of, “ae
effects of bringing it up, 152
Sulphate, how formed, 34, 56
% of ammonia, 224
~ of potash, . : 227

a of soda, (Glauber’s
salts, ) : 228

5) of magnesia, (Epsom
salts, ) : 228
t of iron, (green vitrol,) 228
i of lime, (gypsum,) 229
KS of soda with nitrates, 243
Sulphur, , 9, 56, 363
Sulphuric acid, . : 33

* influence of on crops, 196

Super-phosphate of lime, , 34, 230
T.
TABLE— — -
“ of sugars, . : 43
“of the ash of plants, 59, 60

of hornblende and felspar, 106

of soils, P 125, 128

of experiments with tur-
nips, barley, and po-

tatoes,. 149, 150
“of dry food and farm-yard

dung, : F 175
“ of peat compost, 180
“ of farm-yard manure and

guano, d 180

of wheat dressed with soot, 182

of the relative fertilizing
and money values of
different vegetable ma-
nures, 184, 185

380

Table of horn and bones,
‘* of experiments with gu-

ano, } ‘ ‘ 207
“of comparison of man-
nures, 213, 214
“ of .carbon and nitrogen
taken in the food and |
respired, 217
“of experiments with salts
of ammonia, ; 225
“of composition of peat
ashes, 2 235
“ of mixed sulphates and
nitrates, : 244
“of mixtures promoting
growth, 246
4* and preventing mildew, 247
“of -artificial guano, 248
“of composition of lime-
stone, 251
“of lime carried away by
crops, *). 259
“of the effect of equal quan-
tities of manures, 279

of composition of wheat, 280-1
of composition of the

oat, 282, 283
‘of composition of bar-
ley, ; : 284, 285
ie composition of rye, 287
mF OE rice, a ST
apie, Be and corn, 287
aaplet. 8 es buckwheat 287
oD -vighes oe the bean and
pea, 288
ha ee linseed and
cake, 289
3 is the acorn, 290
eT oa the turnip, 294
iS Sage the potato, 294
= One if the cabbage 300
So ar the cauliflower, 301
hi) satay hay, straw,
leaves, 301
POF : fruits, 302
“ of relative quantities of
starch and gluten in
. cultivated crops, 305
r

INDEX.

192| Table of proportion of oil in

plants, .
of quantity of food yield-
ed by an acre of land,
of composition of that

food,
of composition of milk,
of eg cream,
of butter,
of fibrin, or
muscle,
saline matter
in the body,
mineral mat-
ter,
food given in
Scotch pris-
ong.
of food .required daily by
animals, :
of composition of cow's
mine 4 5
of value of different kinds
of food, . :
Taffo, Chinese, night-soil,
Tanks, for liquids, construction
of,
Tanners’ bark,
Trees, why different kinds suc-
ceed each other,
the peach in New Jersey,
effects of the Scotch fir
and beech on a
land,
action of in improving the
soil,
Trenching, how it improves “the
soil, 150,
Tull, Jethro, experiments of,
Turnip, composition of,

of
of
of

ce

oe
oc

66

'294,

U.

Urine, means of preserving and
applying it,

of man, :

of the pig and cow,

cs
és

307
308
309
313
319
322
342
344.

345

357
358
360

364
204

200
178

131
131

197
199

INDEX. 381°

hg sulphated, ; 201 Weeds sea, uses of, . : 172
“solid matters escape from, ‘¢ special action of, ey fe E
the, . : P » ooo *¢ sea, ashes of and straw, 231

«salts and nitrogen in, 351 | Wells, in Alabama, . : 114
Urate, how to form a, : 201 | Wheat, average composition of, 280

‘¢ influence of climate on, 280
«influence of the kinds of

%. manure on, 281
(varying quality of, 291
Vegetable products, analyses of, 3 ‘¢ when to cut it, : 304
Vitriol, oil of, ae 9 OTE, OUP rn : 2 307
‘“« green, sulphate of iron, 228 | Winds, effects of in oe
the soil, , 164
Wool, growing, its effects on ‘the
W. soil, ; 362
“varied by climate and
Water, composition of, ‘ 25 food, . 2 363
“ itsrelations to vegetable , *.. and bain oper cent: ‘sul-
Ce ha 26 phur, *: 14
“differs in natural virtue, 275 | Worms, earth, effect of as labor-
“ — effects of different springs em, i : 3 163
of, ; : 276 “quantity of, : . 164

Weeds, fire, what soils they like, 130

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Lat,
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