Scientific agriculture; or, The elements of chemistry, geology, botany and meterology, applied to practical agriculture

LIBRARY

UNIVERSITY OF CALIFORNIA.

GIFT OK"

Mrs. SARAH P. WALS WORTH.

Received October, 1894.
Accessions Afo.LftT Cfes M).

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SCIENTIFIC AGRICULTURE,

OR THE ELEMENTS OF

CHEMISTRY, GEOLOGY,

BOTANY AND METEOROLOGY,

™.;ot

PRACTICAL AGRICULTURE

BY M. M. RODGERS, M. D.,
AUTHOR OF "AGRICULTURAL CHEMISTRY," "PHYSICAL EDUCATION

AND MEDICAL MANAGEMENT OF CHILDREN," &C.

ILLUSTRATED BY NUMEROUS ENGRAVINGS, & A COPIOUS GLOSSARY.

Nature maintains uniformity in the operation of all her laws, and produces nothing
by chance : whenever, th- refore, we observe an apparent exception to this prin-
ciple, it is due to deficiency of knowledge or error in conclusion. And who-
tver pi'actically disregards this truth, and rests his hopes upon contingent
events, will be compelled to correct his error at his own cost.

ROCHESTER:

PUBLISHED BY ERASTUS DARROW,

CORNER OF MAIN & ST. PAUL STREETS.

1848.

;l/J^

JOEHUC:

Entered according to Act of Congress, in the year of our Lord
one thousand eight hundred and forty-eight,

BY ERASTUS D ARROW,

in the Clerk's Office of the District Court of the Northern District
of New York.

BESTON & FISHER, PRINTERS,
Reynolds' Arcade, Rochester.

TO

HON. ZADOC PRATT,

THIS VOLUME IS RESPECTFULLY DEDICATED BY

THE AUTHOR.

PREFACE

No apology ought to be required for the appearance of a work like
this : the importance of the subjects discussed should secure at least an
impartial examination.

But from the humiliating consciousness which the author feels of his
own inability to do justice to so difficult a task, he is induced to say
something by way of explanation, in order if possible, to put himself
upon friendly terms with his readers. The importance of an enter-
prise, however, furnishes no reason to an incompetent person for at-
tempting its prosecution.

If, after the book has passed the trial of the public prosecutors in be-
half of science, the critics,— they shall decide against it, the author has
no alternative, but must plead guilty: neither will he claim indulgence
on the ground of its being the first offence, or plead, in extenuation of
his fault, his ignorance of the law in relation to the case.

But a sincere desire, (augmented by personal considerations,) to aid in
the diffusion and cultivation of science, has induced him to make au
effort, which may not be regarded by liberal minds as altogether in-
excusable.

The practice of issuing crude and imperfect books, is a fault quite
too prevalent at the present day : there are already too many mere
alphabets of science, abridgements, and books of learning made easy ;
their tendency is to make conceited and superficial scholars, without
the labor of personal observation and patient study.

But the elements of any science may be so explained and arranged,
as to give a synopsis which may be of much service to the student ;
and when these elements are learned, he has laid the foundation for
future advancement by his own observation. Plainness and brevity have
been studied, and technical language avoided as much as possible ; a
glossary has been appended which explains such technical terms as

1*

VI PREFACE.

.were indispeusible. It is needless to say, that a treatise on science
cannot be entirely divested of all difficulties, and couched in language
which is at once simple and expressive.

It was deemed better to give the rudiments of each sciencej in a
separate systematic treatise, than to intersperse them through the whole
book without order or method. A reader will profit more to have the
principles given in this way, that he may apply them himself, — than he
will to have a perfect system of agriculture made up of them all, with-
out systematic arrangement.

Another advantage of such a book is that the general reader may ob-
tain the first principles of Chemistry, Geology, Botany or Meteorology,
without reading a large amount of agricultural science, which, to him,
may be of little use.

The author is aware that an amount of matter is embodied in thi.s
book sufficient to make, when extended and amplified, several such
volumes: but nearly all books contain much by way of explanation
and speculation, that could well be omitted. Some things may be found
in the book which do not appear to have any direct connection with
practical agriculture; but a little observation shows that the science*
discussed all have such a connection and relation, that to omit any prin-
ciple would destroy the harmony of the whole system.

The best authorities have been consulted, — so that whatever may be
open to criticism must be judged by their testimony. It is desirable
that the agricultural community, for whose more special use the book
is designed, may be disposed to favor the enterprise: with all its faults,
therefore, it is respectfully committed to them — and the public; — with
no claims except to their forbearance, and no means of propitiating
their favor, beyond its own merits.

M. M. RODGERS

Rochester. August. 1848.

AUTHORITIES CONSULTED,

KANE'S CHEMISTRY,

FOWNE'S

SILLIMAN'S "

TURNER'S "

LIEBIG'S AGRICULTURAL "

LYELL'S GEOLOGY,

HITCHCOCK'S "

COMSTOCK'S "

GRAY'S BOTANY,

WOOD'S "

EATON'S "

MULLER'S ELEMENTS OF PHYSICS AND METEOROLOGY,.

BOUSSINGAULT'S METEOROLOGY,

BRANDE'S ENCYCLOPEDIA,

LARDNER'S LECTURES ON SCIENCE,

ENCYCLOPEDIA BRITTANICA,

JOHNSTON'S AGRICULTURAL CHEMISTRY,

BOUSSINGAULT'S RURAL ECONOMY,

THAER'S PRINCIPLES OF AGRICULTURE,

PETZHOLDT'S LECTURES ON AGRICULTURE,

COLMAN'S EUROPEAN AGRICULTURE,

GARDNER'S FARMER'S DICTIONARY,

REPORT OF THE REGENTS OF THE UNIVERSITY OF N. YORK,

TRANSACTIONS OF THE N, Y, STATE AGRICULTURAL SOCIETY,

ACKNOWLEDGEMENTS.

THE Author acknowledges with pleasure, the valuable assist-
ance of several scientific and practical gentlemen, to whose
names he is permitted to refer — viz:

CHESTER DEWEY, M. D., Professor Chemistry, Geology, &c-
JOHN J. THOMAS, Esq.

L. WlTHEREL, A. M.

P. BARRY, Esq.
L. B. LANGWORTHY, Esq.
AARON ERICKSON, Esq.
D. D. T. MOORE, Esq.

1C., GOODSELL, Esq.

Several of the above named gentlemen have examined por-
tions of the manuscript of this book, and made such sugges-
tions and corrections as they thought necessary.

They should not, however, be held responsible for any state-
ment which may appear to be erroneous, or for the selection*
and arrangement of the topics discussed. M.. M. E.

INTRODUCTION.

AGRICULTURE is doubtless one of the oldest, most honorable
and important pursuits among civilized nations. Without it
the food of man must have been limited to the flesh of wild
animals and the spontaneous productions of the earth : Com-
merce could not exist to any extent; the arts and sciences
would be almost unknown ; and society could not advance in
improvement beyond a refined state of barbarism. But the
culture of the soil enables men to produce more of the neces-
sary food than they require, so that a part only are required
in this pursuit, while the remainder are enabled to turn their
talents and ingenuity to some other useful calling, the products
or services of which are given to the agriculturist in exchange
for food.

This is the origin of the division of labor, which is at the
foundation of all political economy and true governmental
policy : this division and subdivision of labor is adopted more
extensively the more a nation becomes enlightened and pros-
perous. Without such distribution of pursuits, • little wealth
could be accumulated by nations or individuals. In order
that every man should be independent of the services of all

12 INTRODUCTION.

others, he must manufacture and produce every thing with
his own hands which in the social and civilized state of society,
he receives from them : this would so occupy his time and
talents that he could only produce the bare necessities of a
primitive life: his food must be obtained by hunting, fishing
and digging roots, — his clothing, the skins of animals, — his
shelter, a rude hut, and his only beverage" water.

From this mode of living, also, the earth must soon contain
more inhabitants than could subsist on its spontaneous food,
and part must die of starvation.

The art of agriculture has been known and successfully
practiced by some of the oriental nations from remote ages.

The Chinese appear to have a good practical knowledge of
soils, and have, by industry and skill in agriculture, sustained
a population of an almost incredible number: and, although
they are supposed to be but little removed from barbarism,
they are said to excel all other nations in the amount of food
which they produce from a given space of soil.

That the ancient Romans had an amount of practical know-
ledge equal to most nations of the present day, is evident from
the following passages from Virgil's Georgics. Thus in his
first Georgic he alludes to the rotation of crops, the art of
manuring and burning land.

" Yet shall thy lands through easier labor rear
Fresh crops by changeful produce year by year,
If rich manure new life and nurture yield,
And ashes renovate the exhausted field.
Thus interchanging harvests, earth repair;
Nor lands unplowed, meantime no profit bear.
Much it avails to burn the sterile lands,
And stubble, crackling as the flame expands;
Whether earth gain fresh strength or richer food,
Or noxious moisture, forced by fire exude;
Whether it draw through many an opening vein,
Juice to fresh plants that clothe anew the plain,
Or brace the pores, that pervious to the day,
Felt the prone sun's intolerable ray,
To piercing showers the expanded fissure close,
And the chill north that blisters as it blows."

INTRODUCTION. 13

Again in the second Georgic we have evidence that they
studied the nature of, and adapted various crops to different
qualities of soils.

" Now learn the soils, the nature of each field,

What fruits their varying strength and virtue yield;
Know first, the ungenial hill and barren land,
Where sterile beds of hungry clay expand,
And thorns and flints deface the rugged earth,
Demand the long lived plants palladian birth."

In the other three Georgics we learn that the Romans
understood horticulture, gardening, the management of do-
mestic animals and bees, — and the extermination of noxious
weeds and insects. Limited as were their mechanical means,
and their knowledge of chemistry, geology and botany, — still
their skill and success would seem to exceed that of agricultu-
rists of the present day ; and in fact we may almost believe
that the practical knowledge of farming has retrograded since
that time. If this is the case, it cannot be because science
has been detrimental to modern practice, — but is rather owing
to their close observation of nature, and their attentive indus-
try. It is no argument against the art of culture being
conducted on scientific principles : the success of practical men
is due to the discovery and carrying out of these principles,
although they may be ignorant of them, and may not recog-
nize them as such. The idea that the farmer requires nothing
but practice and experience to ensure success, is as erroneous
as to suppose the school teacher requires no knowledge of
arithmetic or grammar. Not a blade of grass can be made to
grow without perfect conformity to the laws of nature, — and
still the farmer arrogates to himself the credit of success in an
operation, the philosophy of which he neither does, nor desires
to understand.

The failures of practical men in attempting to apply some
new principle, are owing to want of knowledge and skill in
combining science with practice, — and not to any discrepancy

2

14 INTRODUCTION.

in facts. It must be admitted that many of the processes of
successful farming are not yet explained, — and many things,
true in theory, are not, as yet, demonstrated in practice, but
this does not justify the conclusion that nature is not entirely
consistent with herself. Men have been too much disposed to
consider certain phenomena as " mysterious and past finding
out," and thus have ended their investigations.

But the time has arrived when the application of science is
the only means of any great success in agriculture ; and those
who reject this light must be content to plod their way
through life like one groping in darkness, — be considered as
wanting in intelligence and enterprize, — to accomplish but
little and barely subsist, — while the scientific farmer reaps
abundant harvests. However strong the prejudice may be
against what is absurdly called "book farming," — the old
empyrical system cannot, in a country where the population is
dense, the soil becoming exhausted, and manures scarce,
maintain a successful competition with one which is conducted
upon scientific principles.

No art or profession presents more points of contact with the
various branches of natural science than that of agriculture ;
and in no pursuit is education regarded as of less importance.
While in all the learned professions and many mechanical
arts, education is considered indispensible, — the farmer whose
knowledge consists of reading, writing, and a few empyrical
dogmas of his ancestors, is supposed to be abundantly quali-
fied for his calling. Trained and educated in all the old and
established practices of his fathers, he is sceptical upon all
that is written, and slow to adopt any new improvement in
practice.

An ancient philosopher being asked what things were most
propei for boys to learn, replied, — " Those things which they
intend to practice when they become men." Now inasmuch
as agriculture involves the same branches of knowledge as

INTRODUCTION. 15

most other arts and professions, it follows of necessity that the
farmer requires the same education and discipline of mind as
those do who practice law, medicine, engineering, and the
mechanical arts.

Agriculture should not be looked upon as the end of life, —
but only as a means of securing the necessary food for subsis-
tence: this, as well as all other pursuits, should be adopted
with the view of enabling men not only to improve and
beautify the earth, but to cultivate the moral, intellectual and
social powers, and to fulfil according to their capacity, their
proper station among their fellow men. It should not tend to
make men mere machines, who toil for the sole purpose of
gratifying grovelling and depraved appetites ; but it should
elevate and refine to the highest degree of perfection, all the
better faculties of our nature.

A large part of the farming community already recognize
the utility of the natural sciences in the cultivation of the soil.

Some elementary books have been written which have
been favorably received by the farming public. Among
the natural sciences, Geology has received more attention than
any other among this class of men. The connection of this
science with agriculture is so apparent to every one who
learns but the rudiments of it, that it needs only to be intro-
duced, (in treatises which are plain and well arranged,) to be
studied and applied in practice. It teaches the origin and
nature of all the various soils and rocks, and all great physical
changes which are taking place from natural causes on the
earth, and beneath its surface.

Botany is also of much importance: and indeed the agricul-
turist and horticulturist are the only persons to whom the
study and practical application of its principles are indispen-
fitble. It teaches the characters, habits and localities of nearly
one hundred thousand different species of plants; it treats

T.6 INTRODUCTION.

also of their physiology, and explains many of the most
interesting processes of vegetation.

Chemistry is the key which unlocks the great laboratory of
nature, and shows us how she performs her complicated
processes, and produces all her wonderful phenomena.

Meteorology investigates all the facts and phenomena per-
taining to weather, climate, seasons, temperature, storms, lati-
tude, altitude, winds, &c.

Zoology treats of the habits, localities, depredations and
uses of all the objects of the animal kingdom. Comparative
anatomy and physiology constitute a branch of zoology which
treats of the form, structure, functions, differences and pecu-
liarities of all the organs of animal bodies. It is the -basis of
all knowledge relative to breeding, rearing, feeding, and
curing the diseases of animals.

Natural Philosophy treats of the properties and dynamic
forces of light, air, water, and the mechanical powers, and
their application to machinery and other practical purposes of
life. Besides these, many other branches of knowledge are
indispensible to the education of the accomplished agricultu-
rist. The study of astronomy, geography, architecture, politi-
cal economy, algebra, geometry, — a knowledge of the lan-
guages, general literature, and the fine arts to some extent, —
and in fact we might say, a complete collegiate course, belongs
as much to the farmer as to the professional man.

But the means by which this amount of preparatory educa-
tion is to be attained by farmers' sons, are not yet provided.
Various plans for agricultural schools have been proposed,
none of which have been successful in this country. Where
such schools have been established and endowed with compe-
tent instructors, library and apparatus, the number of pupils
have been a mere fraction of the young men who were
destined for agricultural pursuits. While a few are ambitious
of high attainments, the great mass are indifferent, or preju-

INTRODUCTION. 17

diced against what they suppose to be only an innovation. In
this way the schools fail for want of patronage, and young
are deprived of their education for want of schools.

But if we are not yet prepared to sustain agricultural
schools, some other plan may be available. The teachers of
common schools may be educated in scientific agriculture, so
as to be able to instruct all such pupils as are designed for
this pursuit, in at least the elements of the most necessary
branches. In this way the germs of science will be planted
and a taste excited, which will lead ultimately to a thorough
and systematic course of study.

This plan, though limited and imperfect in its operation, has
the ad/antage of giving to boys, early impressions, and a
preference for those studies, which, if proper books are acces-
sible, may be pursued in connection with practice in after life.
A plan has been proposed for securing the agricultural educa-
tion of teachers, which is to establish a professorship of agri-
cultural science in the State Normal School. By this means
teachers could be educated, who would be competent to teach
the science to the extent required in the schools of farming
communities.

Every farm should be considered a chemical laboratory,
and every farmer a practical chemist and philosopher : farming
would then be honorable and lucrative. Education would
give to the cultivator of the soil that dignified confidence and
polish which he has a right to possess, — and which he now "
too often ridicules or envies in men in other pursuits. No-
reason exists why rural pursuits should alienate their votaries
from the rest of mankind, and give rise to those jealousies and
suspicions with which they look upon men of other occupa-
tions, or fill the mind with that dogged arrogance which is

always the offspring of ignorance.

'

The profits of productive farming would, when conducted
2*

IO INTRODUCTION.

scientifically, enable the farmer to accumulate wealth, and
enjoy all the comforts and luxuries of refined life. Every
community could be made up of the best society, — every
family could have its fine library and its accomplished sons
and daughters: farmers' sons need not leave the favorite
pursuit of their fathers, and go into the learned professions,
from the erroneous conclusion that they were more honorable
or profitable. Farmers' daughters need not despise the
delightful and healthful employments of the dairy, the
kitchen, or the loom, — and seek elevation in the miserable
pursuits and fashions of the city.

Nothing conduces more to the elevation and refinement of
the mind than the study of nature ; the man who holds fre-
quent communion with nature, and studies and obeys her
laws, is always made a better and happier man.

The more we explore the mysteries of nature, the more are
we humbled with the reflection, that to our finite view, only a
small part of her works are comprehensible. And when, after
years of patient toil, we fancy we have learned most of her
laws, we still find the great Author has only opened to our
view new vistas to more extensive and unexplored fields of
knowledge.

" Nature is always perfect and unvarying, but man's
knowledge is progressive ; consequently in every advance he
arrives nearer the truth, yet as far from knowing all nature
and her laws as he is from infinity. Exact knowledge consists
in those things which can be seen and demonstrated, — while
in all knowledge of inference there is progression. Opinions,
which are often the result of imperfect knowledge, are liable
to change, and the mind is never advanced by adopting the
opinions of others; for by that means man is never made a
thinking being, but rests upon authority In all sciences, the
acquisition of new truths exhibits in a new light, the beautiful
and harmonious operation of the laws of nature."

INTRODUCTION. 19

Besides the benefit of mental discipline derived from the
study of nature, for which agriculture opens as wide a field
as any other pursuit, the charms of rural life are unalloyed
by the reflection of ill-gotten gain, and uncontaminated by
immoral influences. The farmer has no occasion to review
with remorse, a life of injustice to his fellow men, or mourn
the loss of fortunes accumulated by an occupation almost
necessarily dishonest. — The lawyer looks upon his briefs pre-
pared for unjust causes, the physician upon the emaciated
forms of his patients, and the speculator upon the wealth
amassed from the ruined fortunes of others, with the humilia-
ting consciousness that they have not, in all cases, returned an
equivalent for what they have received. But the cultivator
of the soil may pursue his calling with the cheering reflection,
that an all bounteous Providence has rewarded his efforts, and
through him bestowed means of happiness upon his fellow
men.

The reminiscenses of rural life and scenes are always
pleasant: who would not wish to return to the bounding and
joyous days of youth, which were spent among woodland
scenes, green fields, along the river's shore, on the sunny hill's
side, or in the silence of the cool ravine, where every object
lent enchantment to the scene, afforded pleasure without
alloy, and prepared the mind for the admiration of nature and
study of her laws in maturer years. What haunts so sacred,
what objects so linked to our affections, as those associated
with rural life in childhood. Who that appreciates the
quietude and smiling plenty, the balmy air and variegated
landscape of the country, — would not prefer it to the crowded
noisy streets, the pestiferous atmosphere and demoralizing
influences of the city. It is in the country alone that man
enjoys the beauties of nature, as she spreads them out before
him in all their wild luxuriance, or as she patiently smiles
beneath the improving hand of cultivation.

20 INTRODUCTION.

Agriculture is an honorable, a delightful and a glorious
pursuit: the first man who lived on earth was an agriculturist,
—-and agriculture must exist till the last man leaves it.

But all labor is honorable: the GREAT FIRST CAUSE
works, — nature works, — and every man who enjoys her
fruits, ought to hold it honorable to work. When shall the
glorious time dawn, that intelligence and true philanthropy
shall annihilate the selfish distinction which pride has made
between labour and idleness? May that auspicious day soon
arrive when the worthless distinctions between mental and
physical labour shall cease to exist, which separates man from
his fellow man, — and all the tenants of earth meet as equal
sovreigns of our common inheritance.

NATURAL SCIENCE.

NATURAL SCIENCE embraces all the objects of the material
creation, from the minutest insect, plant or particle of dust, to
the most vast of the celestial spheres. This great field of
knowledge is divided into Natural Philosophy and Natural
History. Natural Philosophy elucidates the laws which gov-
ern the phenomena of the material world, — and is divided
into Chemistry and Physics. Chemistry treats of phenomena
which depend upon a change in the constitution of bodies:
Physics treats of the dynamical properties and phenomena of
bodies, which do not depend on a change in constitution or
elements.

Natural History treats of the character and properties of
individual objects : these are divided into three great natural
groups called kingdoms, — viz. the animal, the vegetable and
the mineral kingdom. Natural objects are distinguished also
into two great classes termed animate- organic and inanimate-
inorganic. All the individuals of each of the primary divi-
sions, are again divided or grouped into Classes, Orders, Ge-
nera and Species.

The dividing line between organic life and inanimate mat-
ter, is not well defined; between the lowest form of organic
life and the most perfect and symmetrical crystal of the mine-

22 NATURAL SCIENCE.

ral kingdom, however, the distance must be almost immeasura-
bly great. Passive motion or change, is the peculiar attribute
of inorganic matter: it can neither enjoy life, nor be subject
to death : but life and organization are inseparable, — to this
combination, birth and death, are the necessary and invaria-
ble terms of existence.

PART I.

CHEMISTRY

CHAPTER I.

THE science of Chemistry has for its object the investigation
of the properties of all elementary and compound substances,
their relations and combinations, the agencies by which their
changes are effected, and the laws which govern them. The
basis on which this science rests, is facts and experiment; and
as it is purely a demonstrative physical science, no hypotheti-
cal or speculative views can be practically made of any ser-
vice to its advancement and application.

Every change which takes place in the elementary consti-
tution of matter in the universe, whether effected by natural
causes or by the operations of art, involves a fixed chemical
law, and is due to chemical action.

Chemistry consists of two distinct branches, viz. Analysis
and Synthesis. Analysis consists in decomposing a compound
body and separating its elements. Synthesis consists in uni-
ting simple bodies so as to form a compound substance. The
forces which preside over and cause all chemical changes, are,
attraction, light, caloric, electricity and magnetism. The rela-
tive importance of these several forces cannot be exactly esti-
mated in the present state of the science : the question as to

24 SCIENTIFIC AGRICULTURE.

their individual nature, or identity with electricity, remains
unsettled.

The science of chemistry, which has achieved greater tri-
umphs over matter, and conferred more practical knowledge
of nature upon civilized man than all other sciences com-
bined,— has gradually grown out of the superstitious art of
Alchemy.

Modern chemistry, instead of alluring its votaries into a
fruitless search after the "philosopher's stone," crowns their
investigations with results which tend to the advancement of
civilization and the increase of human comforts and happi-
ness. Its objects are not limited to the study of abstract laws
alone ; — but also to the improvement of the useful arts, the
cure of disease, the production and preparation of food, the
study of the laws of organic life, and finally to every thing-
affecting our physical relations to the material universe.

PROPERTIES OF BODIES.

CAPILLARITY.

Capillarity is the force by which small tubes and porous
substances absorb and raise fluids above the surface of that in
which they are immersed. This force depends upon the cohe-
sion of the molecules, or ultimate atoms of the fluid for each
other, and the attraction of the solid body for those of the
fluid. If we dip the end of a small tube open at both ex-
tremities, into a fluid, it will be observed to rise slowly above
the surface of the surrounding mass : if one corner of a sponge
be dipped into water and allowed to remain, it will by virtue
of its capillarity in a little time be saturated ; the water hav-
ing been raised by this force against the antagonizing force of
gravity.

CHEMISTRY. 25

COHESION.

Cohesion is the force by which the particles of a homogene-
ous body are held together and resist separation. Caloric is
the opposing or antagonizing force of cohesion. " The three
different forms which matter assumes, — viz. solid, liquid and
gaseous, — are determined by the degree of the cohesive force
existing among the elementary particles." This force is great-
est in solids, less in fluids, and least in gases. In gases this
force is negative or absent, the particles having a tendency to
repel each other. The globular form of the drops of liquids
depends upon this force.

It is easy to conceive that if cohesion were to be suspended,
all solids as well as fluids would assume the gaseous form ;
the repulsive tendency beingt henu ncontrolled. This can be
effected to a certain extent by means of heat : heat overcomes
the cohesive power of solids and changes them to liquids : but
when the heat is removed, they are again changed to solids by
cohesion, — as in the case of melted iron : bodies naturally
liquid, as water and mercury, are volatilized by heat, and as-
sume the gaseous form. The cohesive force acts at insensible
distances.

DIVISIBILITY.

Matter is capable of being divided into inconceivably small
particles. We have, however, no means of determining the
question of its infinite divisibility. We can easily imagine that
the minutest particle which can be produced by mechanical
means, must still have extension, form and weight, and would
be divisible, (had we instruments sufficiently delicate,) into
other particles, and these again into others, and so on until
they totally disappeared from the limit of our conceptions.
But we cannot by any process whatever annihilate or destroy
the least particle of matter.

The particles of hydrogen gas, which is itself fourteen times
lighter than common air, would, individually present an idea

3

26 SCIENTIFIC AGRICULTURE.

almost inconceivable. And still this gas is material, and must
be made up of an aggregate of particles. A single grain of
gold used in gilding silver wire, is made to cover a surface of
1400 square inches, and still the gold upon the millionth of a
square inch when examined by the microscope, is distinctly
visible. A square inch of gold leaf may be divided into one
billion and four hundred millions of particles, and still retain
all the characters and color of a large mass.

Chemical action may be supposed to carry the process of
division to a much higher attenuation than mechanical means.
A single drop of solution of indigo colors 1000 cubic inches of
water, and yet this coloring matter is an aggregate of distinct
particles. The fineness of particles has an important effect
on the chemical action of one body upon another. Perhaps a
more definite idea may be given by the following example.
The author had the pleasure of examining with Professor
Dewey's improved microscope, some fossil infusoria, which
were so small that they appeared like perfectly impalpable
powder, and not the least gritty between the teeth. These
minute particles of dust when subject to the greatest magni-
fying power of the instrument, proved to be the shells of in-
fusoria resembling in shape the sow-lug and trilobite, and ap-
parently from three to four inches in length and one inch in
width. And still, minute as they were, they must have had
when living, all the organs and machinery of animals of large
size.

GRAVITY.

The term gravity, in natural philosophy, signifies weight : it
is that force or attraction in nature which causes all bodies to
move towards the earth when not prevented by some other
force. The gravitating force of a body is in proportion to the
quantity of matter which it contains. The force of gravity in-
creases in falling bodies, in proportion as they approach the
earth. Bodies of the same bulk, do not always possess the

CHEMISTRY. 27

same gravity or weight, owing to difference in density : thus
lead weighs about twelve times as much as cork, bulk for
bulk, — that is, it contains twelve times as much matter, — and
hence it has twelve times the gravitating force.

What this gravitating force is, has not been determined ; all
we know in relation to it is, its effects. Specific gravity, de-
notes the weight of any body, compared with some other body
of equal bulk, which is taken as a standard and is reckoned at
unity. Water is taken as the standard of specific gravity for
solids and fluids, while atmospheric ah- is the standard from
which the weight of the gases is estimated.

DENSITY.

By density, is understood, the compactness of bodies, or the
number of ultimate particles contained in a given bulk : bodies
which contain the most particles are most dense, — that is, their
particles are in the closest proximity to each other. Rarity, or
porosity is opposed to density. Density does not depend upon
the peculiar kind of matter of which a body is composed, but
only upon the proximity of its particles. This is apparent,
from the fact that the lava ejected from volcanoes, if cooled
on the surface of the earth, produces a stone sufficiently light
and porous to float upon water, — while if cooled under great
pressure at a distance below the surface, it forms a dense
heavy rock like granite.

ELASTICITY.

Elasticity is the property in bodies, which causes them to
resume their original form and bulk, after being bent, com-
pressed or condensed. Most solid and hard bodies possess
this quality in some degree : glass, ice, ivory, <fec. are elastic
solids : india-rubber is an exceedingly elastic body, — while wet
clay is entirely destitute of this property. The gases are far
the most elastic of all bodies.

23 SCIENTIFIC AGRICULTURE.

TENACITY.

By tenacity, we understand the degree of force or cohesion
with which the particles of a body are held together, — in other
words tenacity means toughness. Some substances, as some
of the metals, are extremely tenacious, while others want this
quality almost totally. The tenacity of the metals varies great-
ly,— cast steel being the most tenacious of them all, while lead
is the least so. The tenacity of the woods varies as does also
that of soils : clay soil is tenacious, while sand soil is destitute
of this property.

CHEMICAL ATTRACTION, OR AFFINITY.

This is a peculiar power in bodies, which disposes them to
unite with other bodies and form compounds. It is the power
by which chemical phenomena are produced: it is different
from cohesion and all other forces in nature: it acts with
various degrees of energy in different elementary bodies, —
showing a preference for some, and refusing to act on others
at all. Chemical affinity is influenced by many other agents,
as heat, electricity, gravity, cohesion, moisture, elasticity and
light. An affinity originally weak, may by some of these
agencies be made strong, while an affinity originally strong
may be rendered weak or, destroyed altogether.

When common salt is thrown in water, it unites with it,
(dissolves,) by means of a weak affinity or chemical attraction,
— but if oil be thrown into water, it does not unite with it,
because it has no affinity for it Some substances unite in all
proportions, as, for example, vinegar and water; while others
unite only in definite and fixed proportions, as sulphuric acid
and lime, &c. When two substances of opposite natures are
brought together, as, vinegar and pearlash, they readily unite,
by means of simple affinity, and form a third substance dif-
ferent from either of the other two. If now a third substance
be added, which has a stronger affinity for one of these two
than they have for each other, the two first separate, or are

CHEMISTRY. 29

decomposed, and one of them goes to unite with the new
substance, and form a compound, by means of elective affinity.
Two bodies which have no affinity for each other, may
sometimes be made to unite by means of a third : thus, oil and
water will not unite alone, — but by the medium of the alkali
potash, which has an affinity for both, they unite and form the
well known compound, soap.* Chemical union is usually
attended with the evolution of heat. Some substances unite
without any apparent action, while others have an affinity so
strong that union takes place with an explosion. Chemical
affinity manifests itself iu a more complex form under the
name of double elective affinity.

When nitrate of ammonia and carbonate of potash are
mixed together in solution, a double decomposition and reunion,
take place : the potash leaves the carbonic acid to go to the
nitric acid, and the nitric acid leaves the ammonia to go to
the potash, — the carbonic acid and ammonia, finding them-
selves deserted and alone, unite and form carbonate of ammo-
nia. Thus nitrate of ammonia and carbonate of potash are
decomposed, and nitrate of potash and carbonate of ammonia
formed. This may be more clearly shown by arranging the
four elements thus :

Nitrate of ( 1. Nitric Acid. 3. Potash. ) Carbonate

Ammonia. ( 2? Ammonia. 4. Carbonic Acid. ) of Potash.

This change of elements took place because a stronger
affinity existed between 1 and 3, than between 1 and 2, — and
a stronger affinity existed between 2 and 4, than between 3
and 4. These compounds might again be decomposed by
others, having affinities sufficiently powerful to overcome that
which holds them together. In order that bodies may be

* This example is taken from Comstock's Chemistry on account of
its plainness; but is nevertheless not strictly true, as the idea of an
intermediate substance is now abandoned by chemists. The truth is,
that the alkali and oil unite and form soap, which it itself dissolved in
the water.

30 SCIENTIFIC AGRICULTURE.

united by affinity, they must possess different chemical proper-
ties: thus acids and alkalies are chemically opposed, and are
consequently drawn together, while they rarely, if ever, unite
with each other. "We might [says Dr. Fownes] define
chemical affinity to be a force by which new substances are
generated."

LAWS OF COMBINATION.

The elements of chemical compounds are -generally limited
to fixed and invariable proportions on both sides. It is this
constancy of proportions alone, which gives to chemistry its
title to the character of an exact science ; for had all bodies
the property of combining in every possible proportion under
every variety of circumstances, no definite or certain knowledge
could be obtained in relation to the constitution, properties or
chemical uses of bodies: experiments would give results so
different and variable, at different times, and under various
circumstances, that the votaries of this sublime and useful
science would long since have abandoned it in despair.

The elements of a given chemical compound are always in
the same proportions : thus, green oxide of iron is composed
of 27 parts, by weight, of iron, and 8 parts of oxygen: com-
mon salt is a compound of 23 parts sodium and 35 parts
chlorine; and these are the smallest proportions in which
those elements can be made to unite. When two elements
unite in more than one proportion on either side, the additional
proportions are just double, triple, quadruple, &c., or 1 to $ —
that is 2 to 3, — 3 to 5, — the amount of the first : that is, they
increase in exact multiple proportions. To illustrate this
principle we may allude to the five compounds of oxygen and
nitrogen.

Protoxide of nitrogen consists of —

Nitrogen, 14.06 Oxygen, 8

Deutoxide " 14.06 " 16

Hyponitrous acid " 14.06 " 24

Nitrous add « 14.06 « 32

Nitric acid « 14.06 « 40

CHEMISTRY. 31

It will be seen that while the nitrogen remains the same, the
oxygen increases by multiples of 8, which is its equivalent
number. The nitrogen, although willing to unite with several
whole proportions of oxygen, would reject a quarter or half
of an equivalent, and not unite with it : so, in the preparation
of any compound, if an excess of either element be used, it is
not combined, but left alone in its original state.

The equivalent or combining number of a body is that which
represents the smallest in which it is known to combine with
other bodies. The representative number of a compound, is
the sum of the combining equivalents of its components. Com-
bining proportions are reckoned by weight and by volume ; in
these two estimations of course different equivalent numbers
are used.

CHAPTER II.

LIGHT.

IN order to understand the relations of light to vegetation, a
short description of its properties is necessary. There are two
theories respecting the nature of light : one supposes it to be
particles of luminous matter emitted, or thrown off by luminous
bodies. The other supposes the existence of a substance
called ether, which pervades all nature, and is put into a
vibrating or wave-like motion by all luminous bodies.

Rays of light proceed in straight lines from luminous bodies,
unless interrupted by some intervening medium. Light moves
with the astonishing velocity of 200,000 miles in a second of
time. When a ray of light falls on a plane surface, it is
disposed of in one of three ways : when the plane is black, the
ray is all absorbed: when it is polished, the ray is partly
absorbed and partly reflected : when the plane is transparent,
as glass or water, it may be partly absorbed, partly transmitted
and partly reflected. The law of reflection of light is the same
as that of sound: when a ray of light falls obliquely on a
reflecting surface, it is reflected in the same angle as the one
in which it approached the surface ; thus the angles of reflec-
tion and incidence are equal.

"When a ray of light passes from a rarer to a denser medium,
it is refracted, or turned out of its course : when it passes from
a rare to a denser medium, as from the air into water, it is

CHEM-J6TRY.

33

bent towards the perpendicular: when it passes from a dense
to a rarer medium, it is turned from the perpendicular.

Light is a compound of seven colors, viz : violet, indigo, blue,
green, yellow, orange and red. The colors can be separated
by a triangular piece of glass, called a prism : they possess
different degrees of refrangibility, as will be seen by the

Fig. 1. Solar Spectrum.

figure.

Violet

Indigo

Blue

Green

Yellow

Orange

Red

[This cut shows the solar spectrum in the order of its seven colors :
the violet appears most, and the red least refracted.]

There are also heating rays, which attend the luminous
ones: the calorific, or heating powers of the red rays, are the
greatest : these powers diminish in the order of the spectrum,
from the red to the violet, which possesses the least of all.
Light is a powerful decomposing agent : many chemical com-
pounds, as the salts of silver, are decomposed by the agency
of light alone. The influence of light on vegetation is very
important, and will be noticed hereafter. The process of
taking phtographic and Daguerreotype pictures, depends upon
the action of light on a sensitive metallic surface.

There are several sources of light : the great source of light
which produces the day to our earth, is the sun, — the moon's
light is only a reflected light which it receives from the sun.
The combustion of bodies is another source of light : another
form of light is called phosphoresence, which is emitted by
certain bodies, as phosphorus, decayed wood, putrid flesh,

34 SCIENTIFIC AGRICULTURE.

certain gases, &c. : this is a feeble light, and is only visible in
darkness.

CALORIC.

Caloric is the substance or agent which is thrown off by
heated or burning bodies, and which produces the sensation
of heat : in common language it is the word used to express
both the cause and the effect. This agent possesses no appre-
ciable weight. Although it must be substance^ or material
in its nature, — still a body when highly heated or charged
with caloric, is not sensibly heavier raan when cold.

Caloric appears to exist in all bodies. Heat and cold are
only relative terms ; when a body is so cold as to produce the
sensation of coldness to our touch, we call it cold; on the
contrary, when it produces the sensation of warmth, we call it
warm, — although the absolute temperature may be the same
in both cases. Caloric always tends to seek an equilibrium:
that is, it constantly passes from the hotter to the colder
bodies: if a piece of ice at 32° be carried into an atmosphere
where the temperature is 60° below 32°, it will, in changing
its temperature to that of the surrounding air, give off 60° of
heat : this illustration is sufficient to prove that the ice really
contains heat.

The expansive power of heat is another property which
involves many important facts : when caloric enters a body, it
is supposed that a mutual repulsion of its particles takes place,
so as to partially overcome their cohesive power, and render
the body less dense. All bodies expand by heat, — the degree
of this expansion, however, differs widely in different bodies.
The expansibility of fluids is greater than that of solids, with
equal degrees of heat.

All gases expand nearly equally with the same degrees of
heat : this is not the case, however, with the solids and liquids.
Some bodies are much better conductors of caloric than others :

CHEMISTRT.

35

dense bodies are generally the best conductors of caloric:
the metals are better conductors than wood or glass ; porous
bodies conduct with less facility than dense ones. Snow is
porous, and therefore a poor conductor of caloric, — this is why
the ground freezes less when covered with snow, than when it
is naked.

The 'different conducting power of bodies is illustrated by a
familiar example: on a cold winter morning we find the
hearthstone intensely cold to the feet, while the woolen carpet
is warm : now as as they are both exposed to the same tem-
perature, the different sensation produced must depend on the
different conducting power of the two bodies, the one con-
ducting off the heat of the body so rapidly as to produce
the feeling of coldness, and the other conducting but very
slightly.

By specific caloric is understood, that quantity which is
peculiar to each body : when one body is found to possess a
greater amount of caloric than another of equal weight, it is
said to possess a greater capacity for caloric. The reason
why different substances possess different capacities for caloric,
is not precisely known. Bodies least dense appear generally
to possess the greatest capacity for caloric, — while those more
dense possess the least. Hydrogen gas, the lightest of all
known bodies, is said to possess this capacity in the greatest
degree.

When a piece of cold iron is hammered for a few minutes,
it becomes hot: when sulphuric acid is mixed with a liquid
less heavy and dense, as water or alcohol, the mixture becomes
hot; when ice melts and becomes water, it absorbs heat, or
becomes colder, as is shown by a thermometer. The heat
which is developed in the last case, and which was before
inappreciable to the senses, is called latent heat.

All heated bodies are constantly emitting or throwing off
caloric; this is called radiant caloric, — because it is radiated

36 SCIENTIFIC AGRICULTURE.

in all directions like the rays of light. This effect is not
produced by the gradual conduction of caloric by the ain
because the same effect takes place in a vacuum, and in a
direction opposite to the wind. When rays of heat fall upon
any body, they are, like the rays of light, either absorbed,
reflected, or transmitted. Highly .polished substances reflect
the heat, — while rough surfaces absorb it The angles of
incidence and reflection are equal in radiant caloric, as well as
in light and sound. The color of bodies has an important
influence on their radiating power: dark colors radiate better
than light ones.

The transmission of heat through the air takes place
without any obstruction, as is the case with light; but with
respect to other transparent media it is different " If a para-
bolic or concave mirror be taken, and its axis directed towards
the sun, the rays of both heat and light will be reflected to
the focus, which will exhibit a temperature sufficiently high to
fuse a piece of metal, or fire a combustible body. If a plate
of glass be now placed between the mirror and the sun, the
effect will be but little diminished. Now let the same experi-
ment be made with the heat and light of a common fire ; both
will be concentrated by reflection as before, — but on inter-
posing the glass the heating effect of the focus will be reduced
to almost nothing, while the light will not" have undergone
perceptible diminution.

" Thus the rays of heat coming from the sun traverse glass
with great facility, which is not the case with those emanating
from an ordinary red hot body." Rays of heat are not
transmitted equally through different bodies of equal trans-
parency: for example, of 100 rays falling on a crystal of rock
salt, 8 were intercepted: of the same number, glass inter-
cepted 61, and alum 91. Color also varies the power of
bodies to transmit heating rays. Black and opake bodies stop
the rays completely. Rays of heat from different sources

CHEMISTRY. 37

differ in their properties: those proceeding from red hot
copper and fluor spar, differ from those from an oil lamp or
the sun. Cold is merely a negative condition depending on
the absence of heat.

There are several sources of caloric, of which the sun is the
principal, and compared with which all others are insignificant.
The sun radiates heating as well as luminous rays, which
reach the earth, and are partly absorbed and partly reflected.
The combustion of bodies is another source, — electricity, gal-
vanism, friction, condensation, animal vital action, and chemical
action, are all sources of caloric. The earth is supposed to
contain in its interior a vast amount of heat. The relations
of heat to the growth of vegetation are important, and will be
noticed in another place.

ELECTRICITY.

Electricity is a fluid or principle pervading all nature, so far
as we kno\v. The first full investigation of this extensive and
interesting branch of science was made by Dr. Franklin ; and
although it is only a few years since, yet it has become iden-
tified with almost every branch of physical science, and has
already had an immense influence on the moral and social,
as well as commercial condition of the civilized world. We
still know little of the nature of electricity ; although many of
its properties and effects are somewhat well understood, still
all investigation and discovery has only tended to render its
true nature and phenomena more mysterious, and its origin
more questionable. We see its effects, but what it is, or
whence it originates, we know not

But for the sake of convenience, philosophers have applied
certain terms to its peculiar properties : these terms in some
cases indicate particular effects and conditions, and in others
they may be said to be little more than names for our
ignorance. Electricity is supposed to be a fluid which exists

4

38 SCIENTIFIC AGRICULTURE,

in two opposite states, viz : positive and negative. The terms
vitreous and resinous have also been used to designate these
t\vo states.

The simplest manner of exciting or producing electricity is
by rubbing a piece of amber or sealing wax on dry cloth*
when it will be found capable of attracting light bodies, such
as feathers, bits of thread, paper, &c. The body so affected is
called an electric, and is said to be in a state of, .electrical
excitation. The sealing wax or amb^r in this case is in the
positive state, or is positively electrified, while the feather or
other substance attracted to it is in the negative state, or is
negatively electrified. It is impossible to develop one of these
states or phenomena without at the same time developing the
other also. After adhering to the electrical body for a few
seconds it will fall off, it being charged with electricity and in
the positive state like the electric : if the electric be excited
again, and the feather presented to it, it will be strongly
repelled and tend to fly off — this is called electrical repulsion.

The passage of the electric spark is instantaneous: it appears
also to be confined to the surface of bodies in its passage.
Bodies which allow electricity to pass over them are called
conductors: these are non-electrics, — that is, they cannot be
excited by friction so as to produce electricity: on the con-
trary, those bodies which can be electrically excited will not
conduct the fluid; so that non-conductors are electrics, and
non-electrics are conductors.

The electric spark fires gaseous mixtures, and is capable of
producing intense heat: electricity also decomposes solutions
of metallic oxides and salts. Some fishes, as the torpedo and
electrical eel, possess an electrical apparatus within their
bodies, which is capable of producing severe shocks upon
other animals ; and this is done, too, at the will of the fish. It
has been satisfactorily settled by Prof. Matteitcci, that electri-
city has nothing to do with the action of the nervous system

CHEMISTRY. 39

of animals, and that life and all the vital functions are not
dependent upon it for their existence and action. Electricity
gives polarity to iron, and is supposed to be the cause of, or
identical with magnetism.

The polarity of the earth is supposed to depend upon the
passage of electrical currents around it. Electricity is desig-
nated according to its different states, by the terms statical
and dynamical. Statical electricity treats of the properties of
the fluid at rest or in a state of equilibrium. Dynamical
electricity treats of the fluid in motion, or as it displays its
phenomena while under experiment. The upper regions of
the atmosphere are generally in a positive state; in cloudy
weather, the distribution of the fluid is disturbed, and this
gives rise to the phenomena of thunder and lightning. Gal-
vanism, as well as magnetism, is supposed to be identical
with, or a modification of, electricity.

Electricity is developed in various ways, by different kinds
of apparatus which cannot be described in this place. All the
forms of electricity are applied to useful purposes, to con-
siderable extent, in the arts and sciences. It remains an
unsettled problem as yet, whether electricity in any form can
be made available to the growth of. vegetation : its efficacy,
also, in the healing art, is not as much relied upon as in
former years ; this, like all newly discovered remedial agents,
has had its day of glory, and has, probably, by means of
correct observation and careful experiment, fallen to about its
proper standard.

NOTE. — The term PVROGEX has been proposed instead of
Electricity : the term signifies generator of heat or fire.

CHAPTER III.

GENERAL PROPERTIES OF GASES.

GA& is an elastic fluid or air, formerly, but not now, supposed
to be produced by the union of some body with caloric: most
gases are inappreciable by the senses, except that of feeling, —
having neither taste, color nor odor. Some have a specific
gravity greater, and others less than common or atmospheric
air. Several gases have been liquified by the conjoined action
of cold and pressure : several have also been solidified by the
conjoined action of intense cold and the pressure of from two
to fifty atmospheres. The product of this experiment is in
most cases an exceedingly transparent crystaline substance.
Gases, like, liquids, have but a slight power of conducting
caloric: their conducting power is so slight as to be imper-
ceptible, and they are therefore called non-conductors of
caloric.

AH gases possess a certain amount of specific caloric, — the
precise quantity which they respectively contain has not been
determined. Gases exist throughout nature, and may be
produced by artificial means. Some of them are capable of
being respired, without injury to health, while others cannot,
without producing deleterious or fatal effects. Some are, in
common language, supporters of combustion, while others are
not. Those gases only which are necessary to be known in
their relations to agriculture, will bo described in this work,

CHEMISTRY. 41

OXYGEN ITS PROPERTIES AND RELATIONS.

• Oxygen is an invisible, transparent fluid, without taste or
odor ; respirable and necessary to organic life, with a specific
gravity of 1.2G, air being 1. It has the most extensive
affinity of all known substances. It combines with metals,
forming oxides and acids : it combines also with other gases,
and is an important element in water and the atmosphere: it
js usually called a supporter of combustion, — it exists in great
abundance in nature, and may be obtained by chemical process
from several substances, — most easily, perhaps, from black
oxide of manganese. It is said that nearly one-third of the
weight of all the solid matter of the globe consists of this
gas. The combustion of all fires depends on the presence of
oxygen, — a lighted taper burns with greatly increased bril-
liancy in pure oxygen gas.

No plant can vegetate without it, although no plant will
long survive after being placed in this gas alone. No animal
can respire for a single minute without oxygen, but when
immersed in a jar of it, the vital processes are all increased
until fever succeeds, and the animal dies. "According to
Dr. Henry, 100 volumes of water absord only 3j of oxygen.''
The combining number of oxygen is 8.

HYDROGEN ITS PROPERTIES AND RELATIONS.

Hydrogen gas is the lightest of all known substances, being
fourteen times lighter than common air, — destitute of taste,
color or odor : it is combustible, but not a supporter of com-
bustion; it is incapable of sustaining animal life, though it
is destitute of poisonous properties, — an animal dies when
immersed in it from want of oxygen, — the death results from
its negative condition, rather than from any positive injury
which is sustained by breathing the gas. It exists in nature
in less abundance than carbon or oxygen, and is not known to
occur in a free or uncombined state. It forms a small part of
all animal and vegetable substances, and constitutes one-ninth

*4

42 SCIENTIFIC AGRICULTURE.

part of the weight of water : it does not occur in combination
witli any of the mineral masses of the globe, except coal, — and
this is itself of vegetable origin. This gas burns with a pale
yellow flame, — its combustion is attended by the formation of
water.

Plants do not grow in this gas, but gradually wither and
die. Its specific gravity is 0.0687: 100 gallons of water
absorb 1-i- gallons of this gas. It is the gas used' for inflating
balloons. Hydrogen is readily obtained by the action of sul-
phuric acid on zinc or iron. It is necessary to the growth of
vegetation, but not in a free or uncombined state. The com-
bining number of hydrogen is 1.

CARBON ITS PROPERTIES AND RELATIONS.

Carbon exists in a pure and crystaline form in the diamond ;
graphite, or black lead, and common charcoal, are examples of
carbon of impure varieties. It constitutes a large proportion
of all animal and vegetable substances: nearly all plants in a
dried state, contain from 40 to 50 per cent, by weight, of
carbon. This substance is of great importance in the art of
culture, on account of its power of absorbing large quantities
of the gases and vapors of the atmosphere, — this is especially
true of charcoal, or carbon in a light and porous form. Char-
coal is used for filtering impure water, which it cleanses f om
decayed animal or vegetable substances, and coloring matters
which are held in solution: it is used also in clarifying syrups
and oils: it has the power of absorbing noxious vapors and
gases, which result from the decomposition of animal and
vegetable matters, and of preventing or retarding the decay
of all organic substances.

The gases and moisture which are arrested and retained by
carbon in the soil, are again readily yielded up to the roots of
plants, during the process of growth. Several important ends
are subserved by carbon in the soil : it purifies impure air and

CHEMISTRY. 43

water, which would not nourish plants, but on the contrary
prove destructive to their tender germs and roots : it absorbs
gases from the air as before stated ; prevents putrefaction (and
acidity to some extent,) in the soil, and is itself an indispen-
sable element in vegetation.

Carbonic acid is a gas or air, which results from the com-
bustion of charcoal, — when charcoal is burned, it nearly all
disappears in the form of gas, leaving only a small residue of
ash behind. Carbonic-acid-gas is heavier than common air,
colorless, invisible, having an agreeable pungent taste and
odor, but cannot be respired without poisonous effects resulting
from it. Carbonic acid may be obtained for experiment from
white marble, which is a carbonate of lime, or from common
limestone. The combining number of carbon is 6.

It is neither combustible nor a supporter of combustion, — a
lighted taper dipt into a jar this gas is instantly extinguished ;
— it often exists in deep wells, mines, caverns and pits, and
proves fatal to those who enter them, — the precaution should
therefore always be taken to let down a lighted candle, which
will determine the presence or absence of the gas. It is this
gas also which proves so deleterious in ill ventilated rooms
heated by coal fires. It is formed during the combustion of
all wood, coal and oil fires, — it is generated by the respiration
of animals and the growth and decay of vegetation: it is
produced also, together with alcohol, during the fermentation
of sugar. It is evolved in vast quantities from the ground in
volcanic countries, and exists in combination with metallic
oxides in the earth : these compounds are called carbonates,
the most important of which is carbonate of lime. This gas
has an acid reaction : water dissolves its own volume of it, and
forms an agreeable sparkling solution: it is this gas which
escapes during the effervesence of soda water and various
kinds of beer.

It is apparent that the excessive accumulation of so poi-

...

SCIENTIFIC AGRICULTURE.

ra gas must prove destructive to all animal and vegeta-
e, if some means were not provided by which it could be
removed as fast as it is generated by natural causes : growing-
vegetables, although they could not live in this gas alone,
require a constant supply of it as an element of food, — and
this is just sufficient to preserve a wonderful balance in this
respect throughout all nature.

According to Liebig, a healthy man expires from his lungs
5 ounces a day, or 100 pounds a year, of carbon: a horse, or
cow, expires six times this amount, — or 600 pounds a year.
ISTow if the crops of an acre of land require 2 tons of carbon in
a year, (which is Johnston's estimate,) a farm of 25 acres
would require, if all cultivated, 50 tons of carbon. If the
family of the farm be reckoned at 5 adults, and the stock at 2
horses, 5 cattle, 40 sheep, 5 hogs, including the poultry, the
amount of carbon they would all expire would be not far from
10 tons in a year. They would then supply from this source
alone one-fifth of all the carbon requisite to grow the crops of
the farm.

Coal which is dug from the earth and burned as fuel, adds
to the carbon of the atmosphere a new portion, which had
been buried in the earth, and consequently lost to vegetation
for many centuries. The coal consumed annually in Great
Britain, contains 14 millions of tons of carbon, which would
supply this element to the crops of twenty-eight millions of
acres. — [Johnston.] Decay of vegetation, when extensive, as
in the peat bogs of Europe, the jungles of India, and the
tropical forests of Africa and South America, furnishes im-
measurable quantities of carbon.

The final result of this eremacausis, (slow combustion,) or
slow decay, is the same as that of ordinary combustion: the
immediate result, however, is different: decay furnishes much
less carbon in proportion to the matter consumed than com-
bustion; decay produces, also, light carburetted hydrogen,

CHEMISTRY. 45

which combustion does not. The latter gas is changed by the
electricity of the air to carbonic acid and water.

The evolution of carbon from volcanoes, and fissures in the
earth in volcanic regions, is immense. In the ancient volcanic
region Eifel, on the bank of the Rhine, an annual evolution
takes place, according to Bischoff, of 27,000 tons of carbon.
Some carbon is absorbed by the waters of seas and oceans,
which is not, as far as we know, restored to the atmosphere.
Vegetable matters carried away by water, deposited and em-
bedded in beds of sand and clay, are thus prevented from
decaying, and their carbon is consequently lost. These are
two sources of loss of carbon: and although the balance
between its production and consumption is nearly equal, "still,
according to Prof. Johnston, there is supposed to be a slight,
permanent loss to the entire mass of our atmosphere.

NITROGEN ITS PROPERTIES AND RELATIONS.

Nitrogen is widely diffused through nature, constituting
nearly four-fifths of the atmosphere, and existing in many
vegetable, and most animal substances. It is destitute of
color, taste or odor, and is a little lighter than common atr ; it
is incapable of supporting combustion or animal life, — but, like
hydrogen, it has no positively poisonous properties. Water
absorbs it in very small quantity: it is in fact distinguished for
negative properties, — the reason why it does not sustain com-
bustion and animal life, appears to be merely the Absence of
oxygen. Its use in the atmosphere seems to be only to dilute
the oxygen sufficiently to render it fit for respiration.

Nitrogen combines with oxygen and forms acids and oxides.
Its combining number is 14. Nitrogen may be obtained by
burning phosphorus under a bell glass over water. It does
not enter into the composition of any of the mineral con-
stituents of the earth's crust, except coal, which is of vegetable
origin. Nitrogen forms an important part in the growth of
both animals and plants.

46 SCIENTIFIC AGRICULTURE,

GASEOUS COMPOUNDS.

WATER ITS PROPERTIES AXD RELATIONS.

Pure water is transparent, colorless, tasteless, and inodor-
ous: it is a compound of the gases oxygen and hydrogen, in
the proportion of 8 parts of the former to 1 of the latter, by
weight, — or by volume, 1 of oxygen to 2 of hydrogen. It
boils, under ordinary circumstances, at 212° and freezes at
82o, Fall. : its greatest density is at about 40°, — at 212°, it
takes the form of vapor or steam, and is thus increased to
1700 times its former bulk, and is about two-fifths lighter than
common air, — it consequently rises and becomes diffused
through the air.

Water evaporates at all temperatures above freezing: it is
780 times heavier than common air, — a cubic foot weighs six-
ty-two and a half pounds. It is the standard of specific gravity
for all bodies, — its number in this respect is unity or 1.

The purest water, except that which has been distilled, falls
from the clouds in the form of rain and snow at the close of a
shower: all other natural waters contain various soluble and
insoluble gaseous, mineral and organic matters, — among which
are, carbonic acid, carbonate of lime, ammonia, salts of iron,
soda, iodine, bromine, magnesia, silica, sulphur and others.
"Water possesses the most extensive solvent power of all known
liquids : it absorbs gases from the air to a considerable amount :
these are again expelled by boiling, and are altered in their
proportions from those which constitute the atmosphere.

Water mixes with, or dissolves all liquids except those of an
oily nature : it dissolves also most salts, many gums, coloring
matters, and slowly dissolves many rocks and earths: water
has a wide range of affinities for animal, vegetable and mine-
ral elements, which it exercises without being itself decom-
posed, It is the most universally diffused through the three

CHEMISTRY 47

kingdoms of nature, of any substance: it enters largely into
the composition of living animal bodies, and constitutes, ac-
cording to Johnston, half the weight of all green or newly
gathered vegetables which are cultivated for the use of man.

Without water, neither animals nor plants could exist, (with
their present organization,) the earth would become a scorched
and sterile waste : many compounds resulting from chemical
affinities which require the presence of water, would be un-
known : the varieties of climate which now exist would also
to a great extent be unknown. Water in its relations to vege-
table life, and also its meteorological influences, will be more
particularly discussed in a subsequent part of this book.

THE ATMOSPHERE ITS PROPERTIES AXD RELATIONS.

The atmosphere which we breathe is an immense ocean of
gaseous fluid : the depth of this ocean is about 45 miles, at
the bottom of which we live, — or rather, it extends about 45
miles above the surface of the earth, which it entirely sur-
rounds. It is composed of the two gases oxygen and nitro-
gen, in volume in the proportions of about 21 of the former
to T9 of the latter in 100. It contains also, according to
Sausseur, ^ jV ^ °f ^s bulk of carbonic acid.

The quantity of this gas is greater in cities than in the coun-
try, slightly less in the air over the seas and great lakes, — it
is less over a wet than a diy soil, and by day than by night.
The air is imbued with watery vapor which varies in different
climates : it holds in suspension, traces of various animal and
vegetable matters and ammonia. Heat and electricity also
exist more or less at all times in the atmosphere. Air diffuses
itself everywhere, penetrates the minutest recesses of every
porous body, and presses with the almost incredible weight of
15 pounds to every square inch of the earth's surface: it is
transparent, colorless, invisible, elastic, tasteless and inodorous.
The two essential elements of the atmosphere, viz. oxygen and

48 SCIENTIFIC AGRICULTURE.

nitrogen, arc not, according to Dr. Kane and others, in a state
of chemical union, but only a mixture.

The specific gravity of air is about 7 SO times less than that
of water; 100 cubic inches weigh about 31 grains. A column
of air 45 miles high just balances a column of water of the
same diameter, 33 feet high, or a column of mercury 29
inches high : hence water cannot be raised in a pump on the
principle of atmospheric pressure, more than about 33 feet, —
hence also the mercury in the barometer tube is about 29
inches high. The air expands and becomes less dense by
heat ; hence warm air always rises, and cold air descends : the
composition of the air is everywhere nearly uniform, — its com-
plete and beautiful adaptation to the wants of animal and
vegetable life will be more apparent the more we become
acquainted with its nature and laws : without it no animal or
plant could exist for a single day. Its relations to vegetation
more especially, will be described hereafter.

CARBONIC OXIDE.

Carbonic oxide is a colorless, inodorous gas, composed of
one equivalent of carbon, united to one of oxygen : it extin-
guishes a lighted taper, takes fire at the same time itself, and
burns with a pale blue flame, forming carbonic acid. It is
lighter than common air, nearly insoluble in water, and does
not support animal life. It is produced, together with car-
bonic acid, by the combustion of coal fires. " It is not known
to occur in nature, or to minister directly to the growth of
plants."

OXALIC ACID.

This is another compound of carbon and oxygen, in the
proportions of two of the former to three of the latter. It is
found in the interior of many plants, as the sorrel, rhubarb,
bistort, gentian, chick pea, and several lichens : it is not known
to contribute to their growth, but appears to be the result of a

CHEMISTRY 49

gaseous combustion consequent upon their growth. It is
found combined with potash and lime in the form of salts
called oxalate of potash and lime : it is one of the most impor-
tant of the organic bodies.

Crystalized oxalic acid is, in transparent bodies, intensely-
sour, and very poisonous. This acid is not found in the soil,
nor in the waters which reach the roots of plants : the simple
process by which it is elaborated in the interior of plants will
be described hereafter. Oxalic acid neutralizes alkalies per-
fectly, and forms several important salts. There exists a rela-
tion between carbonic acid, carbonic oxide and oxalic acid,
which will be described under the head of vegetable physi-
ology,

LIGHT CARBURETTED HYDROGEN.

This is a light, inflammable gas, which is formed by the
decomposition of organic substances at high temperature : in
warm weather it may be seen rising in bubbles from marshy
places and stagnant pools, when vegetables are in process of
decomposition. This gas is colorless, destitute of taste or odor,
about half the weight of common air: a lighted taper is
extinguished by it, while the gas ignites and burns with a pale
yellow flame : animals immersed in this gas cease to breathe
almost instantly. This is the gas which exists in marshes
under the name of marsh (fas, — and also in coal mines under
the name of fire damp: violent explosions sometimes took
place in coal mines by the ignition of this gas mixed with
oxygen, from the miners' lamps, previous to the invention of
the safety lamp by Dr. Davy. It consists of one equivalent
of carbon and two of hydrogen.

This gas, together with carbonic acid, is given off during
the fermentation of compost, and all large collections of vege-
table matter. " It is supposed, [says Johnston,] by many, to
minister to the nourishment of plants: it is, however, very

o

50 SCIENTIFIC AGRICULTURE.

sparingly soluble in water, so that in a state of solution, it
cannot enter largely into the pores of the roots, even though it
be abundantly present in the soil:" it probably exists in all
well manured soils; "but the extent to which it really acts as
food to living vegetables is entirely unknown."

NITRIC ACID ITS PROPERTIES AND RELATIONS.

Nitric acid is a compound of one part nitrogen and five of
oxygen: liquid nitric acid, when pure, is colorless, intensely
sour and corrosive, heavier than water, and boils at 187° Fah-
renheit. If exposed to the air, it gives off white fumes with
the disengagement of part of its oxygen, becomes yellow, and
is converted into nitrous acid.

" True nitric acid [says Dr. Kane] has never been isolated ;
that substance generally spoken of as nitric acid, is a compound
of it with water ; it is a nitrate of water, or, as it is popularly
termed, liquid nitric acid, or aquafortis." This acid decom-
poses all organic substances rapidly, neutralizes the alkalies,
and oxidizes the metals, for which it has a strong affinity.

This acid is not found in nature in an uncombined state; but
it occurs in combination with soda, lime and potash, in the
form of nitrates, in many tropical countries. In the West
Indies, vast quantities of nitrate of potash (salt petre) are
formed by nature : in Chili and Peru, immense beds of nitrate
of soda are also found. The origin of these salts is as follows :
rain water, particularly that which falls during a thunder
shower, contains nitrate of ammonia, when the water comes in
contact with the potash, soda and lime of the soil, — having a
stronger affinity for them than for the ammonia, it unites with
them and forms the salts, while the ammonia is again set free
and escapes into the air. These salts are soluble in water, and
are important agents in promoting the growth of cultivated
plants.

CHEMISTRY. 51

AMMONIA ITS PROPERTIES AND RELATIONS.

Ammonia is a colorless gas, having a strong, pungent odor
and alkaline taste: it is composed of one proportion of nitro-
gen and three of hydrogen: its equivalent number then is 17.
It is slightly combustible, but does not support combustion.
" Ammunia is rapidly absorbed by water, which takes up 780
times its volume at 32°:" this is called water of ammonia, or
spirits of hartshorn, — it has a specific gravity about one-tenth
less than water, and boils at 120°. In its power of neutrali-
zing acids, it ranks next to lime, being a powerful base: it
forms, with the metallic salts and with acids, many compounds.
Ammoniacal gas does not support respiration, — animals are
speedily suffocated by it, and living plants confined in it soon
wither and die. It is absorbed largely by porous bodies, such
as charcoal, burnt brick, burnt clay, &c., — charcoal is said to
absorb 95 times its own bulk.

Ammonia is sufficiently caustic to destroy both animal and
vegetable substances. It is remarkable that the two gases
which form ammonia, having neither taste nor odor when
separate, produce, when united in certain proportions, a gas so
intensely strong, pungent, and acrid. Ammonia being only
about three-fifths the weight of common air, it rises and
mingles with the air when it is set free, unless it is retained
by some substance with which it will unite and form a solid
substance not volatile. The salts of ammonia are easily soluble
in water.

Ammonia exists in considerable abundance in nature, — it is
almost universally diffused, but does not enter as a constituent
into any of the mineral masses of the earth's crust. It is found
mostly in a state of combination with acids, in the form of
nitrate, muriate and carbonate of ammonia. It is evolved
largely by the decay of animal and vegetable matters, and
does not remain long in a free state in the air, but combines

52 SCIENTIFIC AGRICULTURE.

with acid vapors which it meets in the atmosphere, and forms
other compounds.

The salts of ammonia are decomposed by lime, magnesia,
potash and soda, and the ammonia is set free in the gaseous
state : the ease with which compounds of ammonia are decom-
posed, constitutes one of its most valuable properties, and
renders it peculiarly adapted to the various offices it performs
in the processes of vegetation. In the air, the, soil, or the
interior of plants, it is easily decomposed by electricity and the
alkaline bases before named.

" The hydrogen it contains in so large quantity, [says Prof.
Johnston,] is ready to separate itself from the nitrogen in the
interior of the plant, and, in concert with the other organic
elements introduced by the roots or the leaves, to aid in pro-
ducing the different solid bodies of which the several parts of
plants are made up. The nitrogen also becomes fixed in the
colored petals of the flowers, in the seeds, and in other parts,
of which it appears to constitute a necessary ingredient, passes
off in the form of new compounds, in the insensible perspira-
tion or odoriferous exhalations of the plant, — or returning with
the downward circulation, is thrown off by the root into the
soil from which it was originally derived." The transforma-
tions which actually take place in the interior of plants, is not
yet perfectly understood, although many of them can be
clearly explained. The agency of ammonia and its various
compounds, in the promotion of vegetation, is both powerful
and important, — and will be explained more fully in a subse-
quent chapter, as will also its formation and sources.

CHAPTER IV.

ELEMENTARY BODIES.

ELEMENTARY or simple bodies, are those which consist of a
single substance, and cannot be decomposed, or reduced to a
more simple form. They are such as have hitherto resisted
all attempts at decomposing them; but still, new methods of
analysis may yet enable the chemist to prove them to be of a
compound nature, — and indeed this has already been the case
with some which were formerly considered elementary. These
simple bodies are about sixty in number, so far as yet known ;
but chemical analysis will doubtless make us acquainted with
others. Several attempts at classification of these bodies have
been made ; but none, as yet, has been on all accounts unob-
jectionable.

One division is, into metallic and non-metallic substances:
this division, although entirely arbitrary and less philosophical
than some others, is still the most convenient, and sufficiently
explicit for our present purpose. It is the one adopted by
Doct. Fownes.

Non-Metallic Elements.

Oxygen, Chlorine, Silicon,

Hydrogen, Iodine, Boron,

Nitrogen, Bromine, Sulphur,

Carbon, ' Fluorine, Selenium.

*5

04 SCIENTIFIC AGRICULTURE.

Elements of Intermediate Characters.
Phosphorus, Arsenic, Tellurium.

Metals.

Antimony, Uranium,

Chromium, Cerium,

Vanadium, Lantanum,

Tungsten, Platinum,

Rhodium, Palladium,

Iridium, Yttrium,

Osmium, Bismuth,

Gold, Tin,

Alumnium, Mercury,

Glucinum, Silver,

Zirconium, Lead,

Thorium, Barium,

Cadmium, Strontium,

Copper, Calcium,

Iron, Magnesium,

Manganese, Zinc,

Lithium, Nickel,

Sodium, Cobalt,

Pelopium, Potassium,

Niobium. Ruthenium,

Molybdenum, Erbium,

Columbium, Terbium.

Titanium,

These sixty simple elements combine with each other in
such manner as to form the innumerable compounds which
make up the whole animal, vegetable and mineral kingdoms.
So far as we know, all ponderable bodies in the universe are
only the varied compounds of these few substances. The
imponderable agents, light, caloric, electricity, galvanism, and
magnetism, and the vital principle, are not well understood in
their natures and composition ; so that nothing can be predi-

CHEMISTRY. 5o

catcd as to their relation in composition to the simple bodies.
Such, only, of these bodies will be described, as are necessary
to be known in their relations to Agricultural Science.

ACIDS.

Acids are chemical compounds whioh are capable of uniting
in different proportions with alkalies, to form a third class
called salts : by this union the properties of both the acids and
alkalies are destroyed, or neutralized. Most acids have a sour
taste, — there are, however, some exceptions: they change
vegetable blues to red ; they are electro-negative, and there-
fore have a strong affinity for the electro-positive compounds,
such as alkalies, alkaline earths and oxides. Nearly all of
them contain oxygen; when the oxygen is not present, it is
replaced by hydrogen: they are therefore called by some
writers, oxacids and hydracids.

Acids are divided again into mineral and vegetable; the
mineral are, nitric, sulphuric, muriatic, &c. : the vegetable acids
are very numerous, — acetic, citric and tartaric are examples.
Most vegetable acids contain both oxygen and hydrogen. The
mineral acids are heavier than water, exceedingly caustic and
corrosive, — destroying both animal and vegetable textures.
Some acids are in a fluid, and others in a dry, solid or crys-
taline form. They unite with water in all proportions. They
absorb water from the atmosphere, if exposed, and become
weaker in strength, diminished in weight, and increased in
bulk.

ALKALIES.

Alkalies are a class of bodies possessing properties opposite
to those of acids, having a strong affinity for, and uniting with
them in different proportions, to form salts, as before stated.
They are incombustible, caustic and acrid, very soluble in
water, and change vegetable blues and red to green, and yellow
to brown, — in fact they destroy or change the vegetable colors

50 SCIENTIFIC AGRICULTURE.

generally. They are divided into fixed and volatile, — the
fixed alkalies are potash and soda: these do not evaporate, like
ammonia, which is therefore called a volatile alkali. They
have a sharp, pungent taste, destitute of acidity, and, with the
exception of ammonia, have but little odor. They unite with
the oils and fats, and form the well known compound, soap.
There is also a class of compounds called alkaline earths, as
lime, barytes, magnesia and strontium. The alkalies and alka-
line earths are electro-positive in their affinities.

SALTS.

Salts constitute a numerous class of compounds, which
result from the chemical union of acids and alkalies. They
are of three kinds, viz : acid, basic and neutral.

Acid salts contain an excess of acid ; most of them are not
really acid salts, but double salts, of which one base is water ;
bi-carbonate of potash is an example. — [Kane.] The sub-
stance which unites with an acid to form a salt, is called a
lase,

Basic salts are those in whicli there is more than one
equivalent of base for one of acid, as in sulphate and nitrate
of copper.

Neutral salts do not manifest either acid or alkaline proper-
ties on vegetable colors, — they have neither an acid nor an
alkaline taste, and generally consist of one equivalent of acid
and one of base.

Double salts are formed by the union of two simple salts;
in general both salts contain the same acid, but different bases.
Salts usually crystalize in regular determinate forms; some
being in prisms or crystals, having three, four, five, six,
&c., sides, and as many angles. Most salts contain some
water in a loose state of combination : this is called their water
of crystalization. This water evaporates from some salts, and
they become a dry powder, — such are called effervescent salts:

CHEMISTRY. 57

others absorb more water from the atmosphere, and are dis-
solved in it, — these are called deliquescent salts.

Salts may effervesce or deliquesce without destroying their
peculiar qualities or the chemical union between the acid and
base. Salts dissolved by water again crystalize when the
water is evaporated. The crystals of some salts are very
small, as in epsom salts, — in others they are large, as in chro-
mate of potash.

ORGANIC ELEMENTS OF PLANTS.

Organic bodies possess a much greater complexity of com-
position, than substances of mineral origin. The organic
bodies are distinguished from the inorganic by the nature of
their elements : the products of the vegetable kingdom surpass
in number and variety those of the mineral, — but still those of
the former consist almost exclusively of six elements, viz : car-
bon, oxygen, hydrogen, nitrogen, sulphur, and pkospkortt?: of
these six, carbon alone exists in all bodies of both animal and
vegetable origin. Sulphur and phosphorus are met with but
seldom : iodine and bromine exist in marine plants and
sponges; besides these, plants contain in most cases, iron,
silicon, calcium, potassium, magnesium, manganese, and some-
times fluorine. These are called the ultimate elements of
plants, — because they are the final result of analysis, and
cannot themselves be reduced to a more simple form, or sepa-
rated into other elements.

These combine in such a manner as to form the various
substances, such as starch, gum, sugar, and an almost endless
variety of others found in plants. These latter are called
organic products, or immediate or proximate elements, because
they are more easily separated and obtained without a rigid
analysis. As a general rule, bodies most complex in their
number of elements and simplicity of equivalent relations, are
the weakest, and least capable of resisting those disturbing

58 SCIENTIFIC AGRICULTURE.

forces which tend to produce decomposition, or transformation
of their elements. Substances of different properties, but
identical in composition, are called isomeric bodies.

These bodies, although containing the same ultimate ele-
ments, may be as widely different in their chemical relations
as bodies which have no elements in common. Oil of turpen-
tine and oil of citron are isomeric compounds, — each being
composed of carbon 5 — hydrogen 4.

LIGNINE.

The proper wood of plants, when separated by chemical
means from all soluble substances, is called lignine. It is
composed of carbon, hydrogen and oxygen, — these are its
constant elements, whether it be obtained from the porous
willow, dense boxwood, or the fibres of linen and cotton. The
hydrogen and oxygen exist in the same proportions as in
water; so that lignine is apparently only carbon and water:
but distillation does not prove this to be the case.

Pure lignine is white: it undergoes no decomposition in dry
air, or under water which contains no air; but by the joint
action of heat and air it undergoes changes which produce
another series of compounds, very different from itself. Woody
fibre is arranged in cells and tubes : the walls of these cells
and tubes are composed of cellular woody fibre, and covered
by a solid substance called incrusting matter. It is difficult to
separate the two, so as to determine by analysis the precise
difference in their composition. It is evident that woody fibre
constitutes the great mass of all forest trees, and also of the
dried stalks and roots of most plants.

STARCH.

Starch is probably the most abundant product of vegeta-
tion, with the exception of woody fibre. It is obtained from
the flower of all the grains, many roots, the .pith and seeds of
many other plants. Starch is obtained in the form of a fine

CHEMISTRY. oU

powder, consisting of rounded, shining white particles. They
are tasteless and inodorous, and when kept dry undergo no
change in any length of time. Starch is insoluble in cold
water or alcohol, but dissolves readily in hot water, and forms
a jelly. Starch, like lignine, is composed of carbon, hydrogen
and oxygen. Starch is a delicate test for the presence of
iodine.

Arroiv root, sago, tapioca, inulme and lichenine are varieties
of starch. It is frequently deposited among the woody fibres
and in the inner bark of trees, as the willow, beech and pine.
This is the reason, [says Prof. Johnston,] that the branch of a
willow takes root so readily, and also, that the bark of trees is
used in some countries as food.

GUM.

Gum arabic is a familiar example of this class of substances ;
the gum from peach and plumb trees is similar in constitution.
Pure gum is light colored, having a sweetish taste, destitute of
odor, insoluble in alcohol, soluble in water, with which it forms
an adhesive mucilage. Gum is composed of carbon, hydrogen
and oxygen : it exists in the seeds and other parts of many
plants. Arabine, carasine, bassorine, dextrine, and traga-
canthine are all varieties of gum: this, as well as starch, is
highly nutricious as food.

SUGAR.

Sugar exists in many plants, — but is obtained principally
from sugar cane, sugar maple, and beet root. Pure sugar is
in large transparent crystals, having a pure sweet taste, desti-
tute of odor, soluble in water, highly nutricious. Its constit-
uent elements are carbon, hydrogen and oxygen. Grape
sugar, sugar of milk, and sugar of mushrooms, are all va-
rieties.

60 SCIENTIFIC AGRICULTURE.

MUTUAL RELATIONS OF LIGNINE, STARCH, GUM AND SUGAR.

It is a remarkable fact, that these four substances, though
possessing properties so entirely different, are composed of the
same elements in the same proportions. This fact, so evident
to the analytical chemist, is still little more comprehensible to
him, after his most profound investigations, than to the most
unlearned. And, although we can readily separate the ele-
ments of these bodies, we cannot combine the same elements
so as to form any one of them. The formulae below show
their constitution.

Woody fibre is composed of C. 12, H. 10, 0. 10.

Starch " " « C. 12, H. 10, 0. 10.

Gum " •' " C. 12, H. 10, 0. 10.

Cane sugar « " « C. 12, H. 10, 0. 10.
These four substances are capable of being transformed ono
into another, as woody fibre into starch, starch into sugar, gum
into sugar, &c., as will be hereafter described.

GLUTEN.

Gluten exists in the flour of wheat, rye, barley and oats,
from which it may be obtained by washing the paste or dough
for a long time in water. It is a soft, tenacious, elastic, grayish
substance, with very little taste or odor. It is nearly insoluble
in water, but easily dissolved by alcohol, acids and alkalies :
when moist gluten is dried at 212°; it becomes a semi-trans-
parent, yellowish, brittle mass, resembling glue. Wheat con-
tains more gluten than any of the other grains: it contains,
according to its quality, from 8 to 35 per cent. Gluten is
highly nutricious: it is composed of carbon, hydrogen, oxygen
and nitrogen.

ALBUMEN.

Albumen is a gelantinous, colorless substance, without taste
or smell, dissolved by acids and alkalies, but insoluble in

CHEMISTRY. 61

alcohol and water. Albumen resembles the white of eggs,
which is animal albumen; it abounds in the juices of many
plants, as cabbage, turnips, <fec. : its composition is identical
with that of gluten, which is as follows:

Carbon, 54.76
Hydrogen, 7.06
Oxygen, 20.06
Nitrogen, 18.12

100

When exposed to air and moisture it undergoes decomposi-
tion, which is attended by the formation of vinegar and ammo-
nia. It possesses highly nutrient properties.

WAX.

Wax is found in many plants : beeswax may be taken as
the type of this class of bodies. It is insoluble in water or
cold alcohol, but dissolved by boiling alcohol, which separates
it into two proximate principles, viz: cerine and myridne.
Beeswax melts at 144°, and when freed from its yellow
coloring matter, has a white crystaline appearance, Cerine,
boiled with a solution of potash, forms soap. Wax is supposed
to be derived from the oils of plants.

RESIN.

Resin is obtained from the pitch of various of the coniferous
family, such as the pine, hemlock, fir, &c. Resin is highly
inflammable, insoluble in water, but readily dissolved by
alcohol and essential oils: the principal resins are, common
rosin, copal, mastic and elemi. Common rosin is what remains
after the distillation of pitch to obtain spirits of turpentine.

CAMPHOR.

Camphor is a gum-like, white, brittle, semi-transparent sub-
stance, having a strong peculiar odor and an acrid bitter taste.

6

62 SCIENTIFIC AGRICULTURE.

It exists in several plants, but is found in most abundance in
the camphor tree. It is highly inflammable, and resembles in
some respects the resins : it is nearly insoluble in water, but
dissolved by alcohol and oils.

CAOUTCHOUC.

Caoutchouc, or India Rubber, is the product of several
trees in tropical countries, from which it exudes in tlie form of
a milky juice which hardens by contact with the air. It is
insoluble in water or alcohol, and dissolves but imperfectly in
ether; its proper solvent is volatile oils: oil of turpentine dis-
solves it, but it dries imperfectly afterwards. At a tempera-
ture a little above that of boiling water it melts and never
resumes its elasticity : in its properties, it possesses considera-
ble resemblance to the resins: it may be^converted into a
volatile oil by distillation.

FIXED OILS.

Oils are divided into two classes, viz: fixed and volatile:
the former are capable of being distilled without decomposi-
tion,— the latter are not. The animal and vegetable oils agree
in their properties very nearly in every respect. The fixed
oils are obtained by pressure, from the seeds of various plants,
as the castor bean, flax seed, <fcc.

They have little taste or odor, are lighter than water, con-
geal at a lower temperature, and require a higher heat than
that of boih'ng water to evaporate them. They are highly
nutricious, and combine with soda to form soap: by contact
with air they become rancid and gummy : they are all inso-
luble in water, and, with the exception of castor oil, but
slightly so in alcohol: they dissolve easily in ether and the
volatile oils.

VOLATILE OILS.

Volatile or essential oils are numerous in the vegetable
kingdom, and give to plants their peculiar odors: they are

CHEMISTRY. 63

obtained by distillation. Most of them are lighter than water,
highly combustible, and dissolve in alcohol to form essences:
when pure, they are colorless, and evaporate from paper
without leaving a greasy stain, as fixed oils do: they do not
form soap with alkalies,

VEGETABLE ACIDS.

Acids are numerous in the vegetable kingdom, and possess
much interest and importance ; but the limits of this book will
not admit of a detailed account of them : they constitute but a
small part of the plants from which they are derived. The
most important are the acetic, oxalic, tartaric, citric and malic
acids. The general properties of acids have already been
described.

VEGETABLE ALKALIES.

Alkalies exist in all plants, and always in the form of salts,
or in combination with an acid. Potash, lime and soda,
although found in plants in greater abundance than the
others, are not vegetable alkalies : the true vegetable alkalies
are, morphia, quinia, strychnia, <fec.

METALLIC OXIDES AND EARTHS found in plants have already
been named, and their properties will be described in another
chapter. The few organic proximate elements of plants which
have been briefly described, are but a comparatively small
part of the whole number: only such as possess most interest,
and are most common and necessary to be understood, have
been selected.

DIASTASE.

Diastase is a white, tasteless powder, formed during the
process of malting barley, and also during the germination of
plants. The properties of diastase are not well understood, —
it is supposed to be the first product of the putrefactive fer-
mentation of vegetable gluten and albumen.

64 SCIENTIFIC AGRICULTURE.

EXTRACTIVE MATTER.

Extractive matter (apotheme) exists in vegetables, and may
be obtained by steeping them in hot water, and then evapo-
rating the water, when a brown powder will remain, which is
but slightly soluble in water or alcohol, but soluble in alkalies.
Its nature is not well understood ; Dr. Kane, however, supposes
it may be identical with ulmic or hamic acid. It is not nutri-
cious.

TANNIN.

Tannin exists in the bark of most trees, but most abun-
dantly in the bark of the oak, horse chestnut and hemlock. It
is an astringent brownish powder, soluble in alcohol and water.
It has an astringent taste and is destitute of odor : it combines
with animal gelatine and forms an insoluble precipitate ; hence
by soaking the skins of animals in a solution containing tannin,
it is converted into leather, which is no longer subject to
putrefaction. It is composed of carbon, hydrogen and oxygen :
it is not nutricious : it precipitates most metallic solutions, and
is hence used in practical chemistry as a re-agent.

COLORING MATTER.

The matter which constitutes the basis of vegetable colors
is found in most plants. "The organic coloring principles,
[says Dr. Fownes,] with the exception of one red dye, cochi-
neal, are all of vegetable origin." The art of coloring is based
upon the affinity which exists between the coloring matter and
the fibres of the different fabrics to be colored. This is
stronger in woolen than in cotton and linen ; hence in dyeing
the two latter a third substance, called a, mordant, is used,
which strengthens their affinity: for this purpose, salts of
alumina, iron and tin are used.

The coloring principle of vegetable blues is indigo: that of
madder red is alizarine: of madder yellow, xanthine: the
green color of plants depends upon a substance called chloro-

CHEMISTRY. 65

phylle. The coloring principle of logwood is hcematoxyline :
carmine is a beautiful pink color derived from the cochineal
insect: several substances produce yellow and brown.

Nearly all vegetable colors are destroyed by the action of
solar light, — and all of them, without exception, by the action
of chlorine gas : acids and alkalies destroy or change them.
No coloring principle has yet been found in plants, capable of
being transferred to other bodies so as to produce a green:
greens are therefore produced by the action of blues upon a
base of yellow. Substantive colors are those which combine
directly with the fibres of cloth without the intervention of a
mordant : adjective colors require the assistance of a mordant
to make them permanent,

INORGANIC ELEMENTS OF PLANTS.

Besides the organic elements which enter into the compo-
sition of plants, and which, as before stated, are themselves in
most cases composed of the four principal elements, carbon,
oxygen, hydrogen and nitrogen, — there are several inorganic
substances, which are constantly present in all plants, and in
about the same relative proportions in the same plant in all
cases. These are in combination with the gases and with one
another. Chlorine, iodine, sulphur, phosphorus, potassium,
sodium, calcium, magnesium, aluminum, silicon, iron and man-
ganese,

CHLORINE.

Chlorine is a yellowish green gas, having a pungent, suffo-
cating odor ; it is soluble in water, extinguishes a lighted taper,
has a specific gravity of 2.47, and when submitted to the
pressure of four atmospheres, is condensed into a limpid,
yellow liquid. This gas is a supporter of combustion, but not
of animal life : a piece of phosphorus, gold leaf, potassium or
sodium, introduced into it, inflame and burn spontaneously.
Chlorine has but little affinity for oxygen, its chemical pre-

e*

66 SCIENTIFIC AGRICULTURE.

ferences being principally hydrogen and the metals : it is not
found in an uncombined state in nature. The most charac-
teristic property of this gas is its bleaching power ; it decom-
poses readily the most permanent organic coloring principles ;
the presence of water is necessary to develop the bleaching
properties of chlorine. 'This gas is a highly disinfecting agent.
Common salt is a compound of chlorine and sodium.

IODINE.

Iodine is a solid substance, in shining lead-colored scales.
It is volatilized or converted into vapor by a moderate haat, —
the vapor has a beautiful violet color, and an odor resembling
chlorine. It is soluble in water, and more perfectly so in
alcohol. It is obtained from the ashes of marine plants, but
has not as yet been detected in any of the plants cultivated
for food. Both plants and animals confined in the vapor of
iodine soon perish.

SULPHUR.

Sulphur exists in considerable abundance in nature; the
most common source of the sulphur of commerce is volcanic
action : it is sublimed and thrown out in large quantities from
the earth, — it exists also in natural waters. It is a yellowish
green powder, having little taste or smell, — it is but slightly
soluble in water. When heated it exhales white fumes of an
intensely suffocating odor, — these fumes are called sulphurous
add. This gas is destructive to both animal and vegetable
life: it possesses bleaching properties. There are several
compounds of sulphur which are essential to the growth of
vegetation.

PHOSPHORUS.

Phosphorus is a solid substance, having the consistence of
wax, and of a pale yellow color: when exposed to the air, it
takes fire spontaneously and burns with a pale blue flame,
scarcely visible except in the dark. When heated, however,

CHEMISTRY.

67

it takes fire and burns with a brilliant flame and intense light,
with the evolution of dense white fumes.

It is not found in nature in an uncombined state, "and is
not known [says Johnston,] to be susceptible of any useful
application in practical agriculture." Phosphoric acid results
from the combination of 'the fumes of burning phosphorus
with the oxygen of the atmosphere. It has the characteristic
properties of acids, and unites with lime, soda and potash, to
form phosphates. This acid is not found in nature in a free
state, — but the compounds of phosphorus are extensively dif-
fused throughout nature, and are essential to the growth of
all cultivated plants.

CATALOGUE OF THE COMPOUNDS DERIVED FROM THE INORGANIC
ELEMENTS OF PLANTS.

Sulphurous acid,

Sulphuric "

Phosphoric "

Potash,

Soda,

Lime,

Magnesia,

Chloride of Potassium,
" Sodium,

" Calcium,

" Magnesium,

First Chloride of Iron,

Second " " "

Carbonate of Soda,

Bi-carbonate "

Nitrate "

Sulphate «

Phosphate "

Bi-phosphate "

Alumina,
Silica,

Protoxide of Iron,
Peroxide "
Protoxide of Magnesia,
Sesquioxide "

Peroxide "

Sulphuret of Potassium,
Sodium,
Calcium,
Iron,

Bi-sulphuret "
Carbonate of Potash,
Bi-carbonate "
Sulphate "

Nitrate "

Binoxalate "

Bitartrate "

Phosphate «

SCIENTIFIC AGRICULTURE.

Carbonate of Lime, Bi-p'uospliate of Potash,

Sulphate " Carbonate of Magnesia,

Nitrate " Bi-carbonate "

Phosphate " Sulphate

Bi-phosphate " Nitrate *'

Silicate of Potash, Phosphate "

Bi-silicate " Sulphate of Alumina,

Silicate of Soda, Phosphate "

Bi-silicate " Silicate "

Silicate of Lime, Carbonate of Iron,

" Magnesia, Sulphate "

Carbonate of Magnesia,
Sulphate

These are not all the compounds found in plants; but they
are those which exist in most plants, and which are more or
less essential, in some quantity, to the healthy growth and
maturity of the various parts of the vegetable organization.

CHAPTER V.

FERMENTATION.

Fermentation is a peculiar decomposition or transformation of the ele-
ments of a complex organic substance, by the agency of some
external disturbing force different from ordinary chemical attraction,
as heat, air, or contact with some other body similarly affected.

Liebig.

THE compounds which are capable of fermentation, or any
similar change, are those in which a weak affinity or equilib-
rium exists, and is consequently easily disturbed and overcome,
by several different agencies, such as heat, acids, oxygen,
chlorine, &c. If we add to a solution of sugar and water a
small quantity of any organic substance which is itself in the
act of slow decomposition, the sugar becomes affected in the
same way, and is changed to carbonic acid and alcohol

This is called vinous fermentation: another form of vinous
fermentation is that which takes place in the transformation of
must into wine: when the expressed juice of the grape is
exposed to a temperature of about 70° F., its own temperature
is raised, carbonic acid is given off, a scum rises to the surface*
and a sediment subsides to the bottom, and the must is changed
to wine. This is the simplest case of fermentation : yeast is
peculiarly effective in producing this kind of fermation. Yeast
is the product of the vegetable gluten or albumen in fermen-

0 SCIENTIFIC AGRICULTURE.

tation. Tiie fermenting power of yeast is destroyed by boiling,
by alcohol, by many salts and acids, and generally by all those
agencies which render albimnn and gluten insoluble.

Besides yeast, there are several vegetable substances, as
gluten, albumen, caseine and fibrine, which, when in a state of
decomposition, act as ferments on a solution of sugar. The
same effect is produced, also, by animal gluten, albumen, flesh
and blood, after putrefaction has commenced. When wine
and cider are exposed to the air at a certain temperature, a
second fermentation, called the acetous, takes place, and they
are changed to vinegar: during this change oxygen is absorbed
from the air, and carbonic acid is evolved : " but the apparent
cause of the formation of vinegar is the abstraction of hydrogen
from the alcohol, so as to leave the remaining elements in such
proportions as to constitute acetic acid. The presence of nitro-
gen seems to be necessary to the composition of all ferments.
The precise nature of the changes which take place during
fermentation are not yet precisely understood or explained.

" We can offer no other explanation of these facts of fermen-
tation than this, that when a body in a state of progressive
change, the particles of which are in a state of motion, is
placed in contact with another body, the particles of which
are in a state of unstable equilibirum, the amount of motion
mechanically communicated to the particles of the latter from
those of the former is sufficient to overturn the existing equi-
librium, and by the formation of a new compound, establish a
new equiblirum more stable under the given circumstances."

[Turner.

METAMORPHOSIS OF ORGANIC ELEMENTS.

There are certain organic compounds which, from the com-
plexity of their constitution and consequent weakness of affinity,
are peculiarly disposed to decomposition and change of elemen-
tary form. Among these are starch, gum, sugar and lignine,
the first three of which are composed of the same elements in
the same proportions.

CHEMISTRY. 71

These are disposed to change of elementary form whenever
the balance of opposing forces is destroyed: that is, whenever
by the agency of some external disturbing force, as heat, air or
water, the affinity which holds these elements together is over-
come, the elements are separated entirely, or one element is
replaced by another ; and thus lignine is changed into starch,
starch into sugar, &c.

This intimate relation of composition among these substances
renders it plain that they may all occur together in the same
plant, and that when one occasionally disappears from the
plant, it may be replaced entirely or in part by another; and
this is really the case. Lignine or woody fibre may be changed
to starch by boiling sawdust in water so as to separate all
soluble matters, then drying it in an oven and fermenting with
yeast. In this way the author has made bread of beech wood,
which was but little inferior to that made from unbolted wheat
flour.

Woody fibre may be transformed to starch, also, by the
action of sulphuric acid or caustic potash.

Starch, when gradually heated to a temperature not ex-
ceeding 300° F., acquires a brownish tint, and is changed to
gum. Starch may be changed to gum by dissolving it in hot
water, and allowing it to remain in a cold place for a few
months ; or it may be changed more rapidly by boiling it in
water for a length of time. By the action of sulphuric acid,
also, starch may be changed to gum, and this gum again into
grape sugar.

Gum arable may be changed to sugar by the agency of
chalk and sulphuric acid. — [Berzelius.

Cane sugar which is crystalized, if heated to a temperature
of 360° F., gives off two atoms of water and is changed to
caramel: this is an uncrystallizable sugar, containing one pro-
portion of oxygen and one of hydrogen less than cane sugar.
Cane sugar may be changed to grape sugar by digesting it in

V2 SCIENTIFIC AGRICULTURE.

dilute sulphuric acid at a gentle heat. The formula for these
two varieties of sugar is as follows :

Cane Sugar. Dry Grape Sugar.

Carbon, 12, Carbon, 12,

Hydrogen, 10, Hydrogen, 12,

Oxygen, 10. Oxygen, 12.

From the fact that we can produce these metamorphoses at
pleasure, it is easy to conceive that they may take place even
more readily and perfectly in the vegetable organization, than
by the comparatively clumsy operations of the chemical labor-
atory. This is one of an infinite number of the beautiful
processes of nature which modern chemistry has discovered.

PART II,

GEOLOGY.

CHAPTER I.

GEOLOGY investigates the nature, composition, origin, struc-
ture, and arrangement of the materials of which the earth
is composed. Geology may be divided into three parts, viz:
1. Chemical Geology, which investigates the chemical nature
and composition of the various materials of which the earth
is made up. 2. Mechanical Geology, which treats of the
arrangement, structure and relative position of these various
materials. 3. Historical Geology, which treats of then: relative
ages and origin, and the changes which they are undergoing.*

Every part of the earth, including air and water, except
undecomposed animal or vegetable matters, is regarded as
mineral.

The term rock, in geological language, includes besides the
solid parts of the globe, the loose materials, such as sand,

* This division is proposed by the author, and is, like all the othe rs
which have been proposed, imperfect, and, in some respects, objec-
tionable. It has the advantage of being plain and convenient: such a
division, however, whether perfect or imperfect, is not indispensable to
the successful study of Geology.

74 SCIENTIFIC AGRICULTURE.

gravel, clay, soils, <fec., which constitue a part of its crust
" Taken as a whole, the earth is about five times heavier than
water, and two and a half times heavier than common rocks."
The density of the earth increases from the surface towards
the centre. The surface of the earth beneath the ocean, as
well as the dry land, is elevated into hills, with plains and
Tallies intervening. The mean depth of the ocean is estimated
at between two and three miles; from the phenomena of tides,
the Atlantic, in its middle part, is supposed to be over nine
miles deep.

DEFINITION OF TERMS.

Rocks are divided into two great classes, viz: stratified and
unstratified.

Stratification consists of the division of a rock into regular
parallel planes or leaves, varying in thickness from that of thin
paper, to several yards. Strata are often tortuous and variable
in thickness in different parts of the same lamina or layer;
"nevertheless, the fundamental idea of stratification, is that of
parallelism in the layers." "The term stratum is sometimes
employed to designate the whole mass of a rock, while its
parallel subdivisions are called beds, or layers." So, also, of
sand, clay, gravel, &c.

The term bed is used to designate a layer or mass of rock
more or less irregular, lenticular or wedge shaped, lying
between the layers of another rock, — such as beds of coal,
gypsum or iron.

Fig. 1.

- - - - "Without lamina.

- With waved lamina.

• Finely laminated.

- Coarsely laminated.

- - - Obliquely laminated

- - - - Parallel lamina.

GEOLOGY.

" A seam is a thin layer of rock that separates the beds or
strata of another rock, as a seam of coal, limestone, <fec."

A joint is a separation of rocks, both stratified and unstrati-
fied, into masses of some determinate shape : joints are more
or less parallel, and usually cross the beds obliquely.

Cleavage planes are divisions in rocks, which do not coincide
with those of stratification, lamination or joints. They are
supposed to result from a crystaline arrangement of the par-
ticles of the rock.

Fig 2 Cleavage Planes.

d A A

A A a B

[Fig. 2 exhibits the planes of stratification, B, B, — the joints, A, A, A,
A, and the slaty cleavage, d, d.]

Horizontal strata are those which have little or no inclina -
tion,— but lie parallel Fig" 3' Horizontal *™**

with the horizon: this
position, however,
rare, almost all strata being more or less inclined.

The Dip of strata signifies the angle which they form with

the horizon. Fig. 4. Dip and Outcrop.

0 utcrop. — When
strata are uncovered
above the surface, or
protrude from the side of a hill so as to be visible, they are
said to crop out.

An Escarpment is formed when strata terminate abruptly,
so as to form a precipice.

76 SCIENTIFIC AGRICULTURE.

A Fault in a rock is the dislocation of strata, so that their
continuity is destroyed, and a series of strata on one or both
sides of the fracture are forced from their original position,
and raised one above another, or moved laterally. Faults are
generally filled with clay, sand and fragments of other rocks.

A Gorge is a wide and open fissure or fault: when still
wider, with sloping sides and rounded at the bottom, it is
called a valley.

Fig. 5. Dyke.

A Dyke is a mass or wall of
rock interposed between the
ends of a dislocation, so as to
break their continutity: dykes
rarely send off branches.

Veins are portions of rocks smaller than dykes, proceeding
from some large mass, and ramifying through a rock of a
different kind. Metallic veins were originally melted metals,
which were injected into the fissures and crevices of rocks by
some subterranean force.

Fossil. — This term includes those petrified remains of plants
and animals which are found in alluvium, or imbedded in solid
rock, and constituting part of its structure.

Formations. — The term formation is used to designate a
group of rocks having some character in common, — either in
relation to age, origin or composition. JSvery formation con-
sists of several varieties of rock, all agreeing in certain qualities,
and occupying such relative situations as to indicate that they
were formed during the same period and under similar circum-
stances. Thus we speak of graywacke formation, gneiss for-
mation, coal formation, &c.

CLASSIFICATION OF ROCKS.

Many different classifications of rocks have been proposed,
none of which is entirely unexceptionable : the present state of
Geological science will admit of our adopting any one of them*

GEOLOGY.

77

without the risk of incurring much inaccuracy. It is not
designed in this treatise to give a full classification of all the
rocks, with a detailed description of their characters, but only
the outlines of classification, and a brief description of such as
are deemed most important to our present purpose.

Notwithstanding the apparent discrepancies among the
systems of classification, " in all the essential principles, geolo-
gists are nearly agreed : they all admit one class to be stratified
and another unstratified: — one portion of the stratified rocks
to be fossiliferous and another portion not fossiliferous : and
they generally agree also as to the extent of the different
distinct formations. Now these three principles are all that
are essential for classification ; and some of the best geologists
limit themselves to these." — [Hitchcock.]

One very common and natural classification of rocks is, into
two great families, viz : stratified and unstratified. We shall
give the outlines of two others, viz : the improved Wernerian
and that of Mr. Lyell.

IMPROVED WERNERIAN CLASSIFICATION.

( Alluvium,
ALLUVIAL.

TERTIARY. <J Tertiary strata.

ChalTc,

Green sand,

Wealden,

Oolitic system,

Lias,

New red sandstone,

Coal formation,

Carboniferous limestone,

Old red sandstone.

SECONDARY.

TEANSIT.ON.

Silurian system,
ywt

*7

PRIMARY.

78 . SCIENTIFIC AGRICULTURE.

f Clay slate,

Quartz rock,

Hornblende slate,

Talcose slate,
j Primary limestone,

Serpentine,

Mica slate,

Gneiss.

Alluvium. — If we commence at the surface of a soil which
has been formed by the successive deposits of annual floods, or
the freshets of rivers, and descend to the lowest class of rocks,
viZj — the primary, — we shall pass through the different classes
of rocks in the following order. The first few feet, usually
less than one hundred, is composed of vegetable and earthy
matters, loam, sand and fine gravel, deposited in horizontal
beds.

Drift. — The second formation is made up of coarse and fine
sand, gravel, and. sometimes clay, containing rounded masses
of rock called boulders. This mixture is often horizontally
stratified.

Tertiary. — The third series is composed of clay, sand, gravel
and marl, with occasional beds of quartzose and calcareous
rock, which have been deposited from water in a quiet state.
This series also contains many organic remains : the strata are
usually horizontal, but sometimes they have a small dip.

Secondary. — The next series below the tertiary is composed
mostly of solid rocks : these rocks are made up mainly of sand,
clay and pebbles cemented together : these are interstratified
by organic remains and several varieties of limestone, — they
usually dip at various angles. The older fossiliferous rocks
included in this series are sometimes called transition rocks.

Primary — Transition. — This class includes both stratified
and unstratified crystaline rocks, which are destitute of organic
remains. The unstratified rocks lie below the stratified ones
wherever they have been found : hence it is inferred that the
interior of the globe consists of unstratified crystaline rocks.

80 SCIENTIFIC AGRICULTURE.

L YELL'S CLASSIFICATION.

Mr. Lyell comprehends all the various rocks which compose
the crust of the earth in four great classes, depending for their
distinctive characters on their origin and age. These are
named as follows.

f AQUEOUS,
J VOLCANIC,
j PLUTONIC,
^ METAMORPHIC.

Aqueous Rocks. — This class, called also, the sedimentary
rocks, covers a larger portion of the earth's surface than any
of the other three classes. They are stratified, and supposed
to have been deposited by water, both running and quiescent:
they contain fossils, shells and coals.

Volcanic Roclcs. — This class of rocks has been produced,
both in ancient and modern times, by the action of volcanic
fires or subterranean heat. "They are for the most part
unstratified, and devoid of fossils:" they are more partially
distributed than aqueous formations, at least in respect to
horizontal extension.

Plutonic Rocks. — This class of rocks has been formed, " at
great depths in the earth, and they have cooled and crystalized
slowly, under enormous pressure, where the contained gases
could not expand." They are more crystaline than the others,
have no cavities, and contain no organic remains. They lie
below, and are older than all others.

Metamorphic Rocks* — These rocks, according to Mr. Lyell,
were originally deposited from water in regular strata, and
afterwards metamorphosed or changed by subterranean heat,
so as to assume a new and different texture. They contain no
pebbles, pieces of imbedded rock, nor organic remains, and are
often crystaline, as granite. They vary in color and compo-

* This class is considered as merely a hypothetical division by many
of the best Geologists.

GEOLOOT. 81

sition. The degree of heat which produced the change in
those rocks was less intense than that which produced the
plutonic class, and was doubtless assisted by gaseous agency.

We have thus given a brief outline of two systems of classi-
fication, without, however, giving the reasons in favor of the
propriety of any theory or classification. Our limits will not
admit of a subdivision of the classes into orders, genera and
species, — much other useful matter must also be excluded.
A few of the most important rocks and the metalloids have
been described, being thought indispensable to a proper under-
standing of the principles of geology and the constitution of
soils.

CHAPTER II.

GRANITE.

GRANITE is a compound of three minerals, viz: quartz,
feldspar and mica : the different ingredients are sometimes in
coarse crystaline fragments, and in other cases so fine as to
be scarcely distinguishable by the naked eye. Granite is
most usually of a whitish or flesh color, — it has, however, other
tints. Feldspar predominates in the composition of granite,
while the mica is in the smallest quantity. "These three
minerals are united in what is termed confused crystallization:
that is, there is no regular arrangement of the crystals in
granite as in gneiss." The coarse grained granites contain
the most interesting specimens of simple minerals, while the
finer kinds are best for architectural purposes.

Granite often preserves a uniform character through a great
extent of country, forming rounded hills: it is sometimes,
though not generally, subdivided by fissures into masses of a
cuboidal and columnar form. Where it is naked at the
surface, and exposed to atmospheric changes and action, it is
in a crumbling state, and covered with a scanty vegetation. It
is remarked by Lyell, that all granitic rocks are frequently
observed to contain metals, at or near their junction with
stratified rocks.

Granite is supposed to be the oldest, most abundant and
important of all the unstratified rocks. There are several

GEOLOGY. 83

varieties of granite, viz: graphic granite, syenitic granite,
talcose granite, porphyritic granite, eurite and pegmatite:
these varieties have various proportions of each element, and
also various colors and crystaline arrangement.

SYENITE.

Syenite is composed of quartz, feldspar and hornblende : it
is sometimes called syenitic granite, — it has received this name
from the ancient quarries at Syene in Egypt. It has the
appearance of granite, but its composition is different, horn-
blende being substituted for the mica in granite. Syenite,
according to Lyell, frequently loses its quartz and passes insen-
sibly into syenitic greenstone.

PORPHYRY.

Rocks of a homogeneous, compact structure, containing some
other crystaline mineral, of the same age with the base, are
called porphyry. The base, or principal mass of the rock, may
be greenstone, claystone, basalt, or other rock containing crys-
tals of feldspar, augite, olivine, <fec.

" True classical porphyry, [says Dr. Hitchcock,] such as was
most commonly employed by the ancients, has a base of com-
pact feldspar, with embedded crystals of feldspar." The term
porphyry is indefinite, and does not belong to any particular
rock. The term is of Greek origin, and signifies purple, — but
this rock is of a variety of colors, and is the hardest and most
durable of all rocks.

GREENSTOXE.

This is a granular rock composed of feldspar and hornblende ;
the felsdpar is imperfectly crystalized : greenstone sometimes
contains augite and iron also. The hornblende predominates
in quantity over the other ingredients.

TRACHYTE.

Trachyte is a porphyritic rock of a grayish or whitish color,

84 SCIENTIFIC AGRICULTURE*

composed principally of glassy feldspar, containing also crystals
of feldspar, mica, hornblende, and sometimes iron. It is rough
and harsh to the touch, — hence its name from the Greek word
trachus, (rough:) it occurs in vast quantities in Europe and
South America, in volcanic regions, but is not found in the
United States.

BASALT.

" Basalt consists of an intimate mixture of augite, felspar
and iron, to which a mineral of an olive green color called
olivinc, is often superadded in distinct grains or nondular
masses." The iron is usually magnetic, and is sometimes
accompanied by the metal titanium, hence the name, "titani-
ferous iron." Augite is the predominant element in this rock:
basatt presses insensibly into most other varieties of trap rock.
True basalt does not occur in the United States.

AMYGDALOID.

Any rock containing almond shaped pieces of some other
mineral, as quartz, chalcedony, agate, calcareous spar, or zeo-
lite, may be denominated amygdaloid: the base may be wacke,
basalt, greenstone, or any other trap rock. Some amygdaloid
rocks have the almond shaped cells or cavities, which are
empty, and glazed on their sides by a glassy coating, showing
their igneous origin.

SERPENTINE.

This is a greenish colored rock, containing, according to Dr.
Hitchcock, 40 per cent, of magnesia, — it is a hydrated silicate
of magnesia. Serpentine sometimes contains diallage, steatite,
talc, and some iron. It is classed by most authors among
unstratified rocks. Comparatively it is not a rock of great
extent: it is often associated with talcose slate.

LAVA.

Under the term lava, are embraced all the varieties of

GEOLOGY. 85

melted matter thrown out by volcanoes: these are composed
almos't entirely of feldspar and augite. Some lavas are por-
phrytic, and contain imperfect crystals, "derived from some
older rocks, in which the crystals pre-existed, but were not
melted, as being more infusible in their nature."

When lava is cooled in the open air, it is light, porous and
spongy, and floats on water, as is the case with pumice stone ;
but when cooled under great pressure, at considerable depths
below the surface, solid rock is the result

There are several varieties of lava, varying in composition,
and also of different colors, as gray, whitish, greenish and dark:
fragments of granite and other rocks, — several metals and
gases, water, sulphur, mud, glass, and various salts and acids,
are ejected from the craters of active volcanoes.
GNEISS.

Gneiss is composed of quartz, feldspar and mica, and some
specimens contain hornblende. This rock is essentially the
same as granite, except it is stratified. The laminated struc-
ture becomes obscure where the gneiss passes into granite:
its stratification is remarkably regular in some specimens, and
in others tortuous and irregular. This rock is said to be very
extensive in the United States, particularly in New England.
QUARTZ.

This rock is composed either of an aggregate of fine grains
or crystals compacted together, or of a solid homogeneous
mass of quartz, sometimes containing feldspar, mica, horn-
blende, talc or clay slate. " In these compound varieties, [says
Hitchcock,] the stratification is remarkably regular; but in
pure granular quartz, it is often difficult to discover the planes
of stratification."

It is alternated or interstratified with all the primary rocks,
in which case its structure is regular. Some quartz is capable
of sustaining a powerful heat without cracking or other
change, — hence it makes an excellent fire stone.

8

86 SCIENTIFIC AGRICULTURE.

HORNBLENDE SLATE.

Hornblende predominates in this rock, over the various
quantities of quartz, feldspar and mica which it sometimes
contains. ' When it contains much feldspar, it is not slaty, but
resembles greenstone. It is of a dark color, commonly asso-
ciated with, and passes insensibly into clay slate, mica slate
and gneiss.

CLAY SLATE.

This rock is composed mostly of fine clay, and is usually
more or less dark and shining from the mixture of chlorite and
black lead which it contains. " It may [says Lyell,] consist of
the ingredients of gneiss, or of an extremely fine mixture of
mica and quartz, or talc and quartz." It passes insensibly
into mica slate, talcose slate, or hornblende slate : on the other
hand it passes into unconsolidated clay.

Clay slate is the kind used for roofing: it varies in color
according to its composition, from greenish or bluish gray to
lead color. This rock, as well as the following, is used for
whetstones: the best hones are compact feldspar, and are
erroneously supposed to be petrified wood.

MICA SLATE.

This rock is a compound of quartz and mica, the mica being
in the greatest quantity. This is one of the most common
and abundant of the stratified rocks. It sometimes contains
beautiful twelve-sided crystals of garnet in considerable abun-
dance : beds of pure quartz also occur in this rock.

PRIMARY LIMESTONE.

This rock is sometimes in thick beds of white, bluish,
greenish or gray granular marble, such as is used in sculpture :
it sometimes contains, mica, quartz, hornblende, feldspar and
talc. It is both stratified and unstratified; sometimes being in
thick beds without any marks of mechanical arrangement, and

GEOLOGY.

87

at others it is in laminated leaves or scales like slate, of various
thickness.

TALCOSE SLATE.

Talc is the principal ingredient in this variety of slate, — it
is sometimes in a pure state and sometimes mixed with quartz,
feldspar, mica, hornblende or limestone : it is a softish stone,
valuable for building purposes. There are several varieties.

Composition of Feldspar.
Silica, - - 65.21

Alumina, - - 18.13

Potash, 16.66

100.00

Composition of Basaltic Hornblende.
Silica, - 42.24

Alumina, - - 13.92

Lime, - 12.24

Magnesia, - 13.74

Protoxide of Iron, - 14.59

Oxide of Manganese, - - - p. 3 3

Composition of Mica.
Silica, -

Alumina, - -

Protoxide of Iron, -
Potash, -
Oxide of Magnesia,
Fluoric Aeid, -
Water, -

CHALK.

97.06

46.10
31.60
8.65
8.39
1.40
1.12
1.00

98.26

Chalk is similar in composition to carbonate of lime, viz:

88 SCIENTIFIC AGRICULTURE.

carbonic acid, 44, — lime, 56, — 100. It is a pulverizable rock,
of several varieties, which have resulted from the impurities
which were deposited with it. The chalk beds contain great
quantities of flint, which is dispersed through them in small
masses. Chalk also contains organic remains: it is a durable
building stone, and is used for docks, &c. ; some ancient
buildings are of chalk : no chalk has been found in America.

ROCK SALT.

This cannot be considered a rock, but yet it occurs in vast
beds, and in connection with rocks, at great depths in the
earth. In its pure form it is a transparent crystaline salt,
having the appearance of flint glass : the impure specimens are
reddish or bluish, and mixed with sulphate of soda and muriate
of magnesia. Its origin is not exactly known ; it is supposed,
however, to have resulted from the evaporation of sea water.
It is found in Spain, Poland, Hungaiy, Germany, and in some
parts of Asia and America.

COAL

Mineral or fossil coal is of several varieties, differing in
density and weight, and of a dark color, varying from brown to
jet black. It is composed of carbon and bitumen, and usually
contains some other matters. Coal is undoubtedly of vegetable
origin : as evidence of this, the organic structure of coal can be
seen in some specimens so distinctly that about three hundred
species of plants have been discovered in the various kinds. It
contains also many species of fossil animals.

Coal beds vary in thickness, from a few feet to three thou-
sand or more, — and are often several miles in length. The
manner in which such immense masses of vegetable matter
have accumulated during the lapse of ages, may be conceived
by reference to a single example.

"According to Bringier, the quantity of timber which
drifted into the Atchafalaya, an arm of the Mississippi, during

GEOLOGY.

89

an overflow in 1812, amounted to 8,000 cubic feet per minute.
The raft thus collected at the mouth of the Red River, is sixty
miles long*, and in some parts fifteen miles wide." The quan-
tity which descends the Mississippi in a few years might
furnish sufficient matter for the largest coal bed known.

The varieties of coal are brown coal, or lignite, — bituminous
coal, — anthracite coal, and graphite, or black lead : this consists
of carbon and iron, — and, according to Dr. Hitchcock, "appears
to be anthracite which has undergone a still further minerali-
zation." All these varieties of coal occur in seams or beds,
interstratified by sandstone and shales: brown coal is found
mostly in the tertiary, bituminous in the secondary series, and
also with new red sandstone and clay.

Anthracite is found in graywacke, mica slate, limestone,
gneiss, plastic clay, and almost all stratified rocks.

[Fig. 7 is a sketch of the great coal basin of South Wales, in Great
Britain, — which contains seventy-three beds of coal, whose united
thickness is ninety-three feet.] — Hitchcock.

*8

PART III.

BOTANY.

CHAPTER I.

BOTANY is that branch of natural science which investigates
the nature and character of, and includes all knowledge in
relation to the vegetable kingdom. It treats of the structure,
habits, locality, uses, classification and nomenclature of every
species of plant known on the globe.

Botany is divided, for the sake of convenience and method,
into PHYSIOLOGICAL and SYSTEMATIC: Physiological Botany
resolves itself into Anatomy, Morphology and Vegetable Phy-
siology.

Anatomy treats of the organic structure and relations of all
the various parts of plants.

Morphology treats of their form, symmetry, and arrange-
ment.

Vegetable physiology treats of all the phenomena of the
vital functions, as absorption, exhalation, digestion, respiration,
circulation, germination, &c.

Systematic botany is divided into botanical classification,
special descriptive botany, glossology, and geographical botany.

92 SCIENTIFIC AGRICULTURE.

Classification treats of the proper grouping and arrangement
of plants according to their natural affinities and characters.

Special descriptive botany consists in applying correctly the
generic and specific botanical names to parts.

Glossology consists in the explanation and application of
names to all the various organs of plants.

Geographical botany treats of the climate, country, zone
and locality to which the various species belong.

Finally, botany comprehends, in its most extended sense, a
knowledge of the relations of the vegetable kingdom to other
departments of natural objects, and the development of the
limitless resources of this part of the CREATOR'S vast plan for
the sustenance and happiness of his creatures. «

PRIMARY DIVISIONS OF PLANTS.

The vegetable kingdom is divided into two great natural
families, viz : PHENOGAMIA, or that division which includes all
flowering plants, and CRYPTOGAMIA, or that which includes all
floioerless plants.

These two divisions are further distinguished by the dif-
ference in their elementary structure. The phenogamous, or
flowering plants, abound with the woody and vascular tissues ;
while the cryptogamous, or flowerless plants, consist almost
entirely of the cellular tissue. The phenogamia produce seeds
having the cotyledon and embryo, — while the cryptogamia
produce minute organs called spores, having no such distinc-
tion of organs. The phenogamia are therefore called cotyle-
donous, and the cryptogamia, acotyledonous. In the former,
also, we find a system of compound organs, regularly and suc-
cessively developed, in the order of root, stem, leaf, flower and
seed, — while the latter appear to be "simple expansions of
cellular tissue, without order, symmetry or proportion."

CLASSIFICATION OF PLANTS.

All natural sciences classify their respective objects under

BOTANY. 93

certain fundamental divisions. The first of these divisions is
into CLASSES, — the second divides classes into ORDERS, — the
third divides orders into GENERA, — the fourth divides genera
into SPECIES, and these are again divided into varieties.

The number now known on the whole earth, is between
80,000 and 100,000 distinct species of plants. The classifica-
tion of plants, and all other natural objects, is founded on the
resemblance and differences, in some one or more points, of the
individuals of each class, order, <fec.

A CLASS, in natural history, comprises an assemblage of
objects or individuals, having one or more common charac-
teristics. Thus the whale, the hog and the cow all belong to
the class mammalia, — because they all have red blood, breathe
by means of lungs, and nourish their young by means of milk :
the whitewood, rose and locust all belong to the division phe-
nogainia and class angeiosperma, — because they all produce
flowers and woody stems, and bear fruit in capsular vessels.

An ORDER is a subdivision of a class, and divides objects
into groups, which are distinguished by more minute and
peculiar points of resemblance than those on which a class is
based, but still possessing all the peculiar characteristics of
that class. The lion, tiger, dog and cat, all belong to the class
mammalia and order carnivora, because they live, in their
native state, on flesh: the water-cress, turnip and mustard all
belong to the order cruel/era, because they all produce flowers
having four petals, arranged in the form of a cross.

" A GENUS is an assemblage of species with more points of
agreement than difference, and more closely resembling each
other than they resemble any species of other groups." This
is a subdivision of an order. The dog, wolf, lion and cat, all
belong to the same order, — but, on account of certain dif-
ferences, the lion and cat belong to one genus, and the dog
and wolf to another: the apple, cherry, rose and almond, all

94 SCIENTIFIC AGRICULTURE.

belong to the order rosacea, but they belong to different
genera, according to some peculiarity in the organs of each.

A SPECIES "embraces all such individuals as may have
originated from a common stock: such individuals bear an
essential resemblance to each other, as well as to their common
parent, in all their parts." This is a subdivision of a genus.
The white and red clover both belong to the genus trifolium;
but they differ in some minor points sufficiently to place them
in different species.

A variety is a subdivision of a species, and is the last
distinction made in any system of classification : varieties in the
vegetable kingdom occur principally in the cultivated species;
they depend only upon slight differences, as, for instance, the
same apple tree, rose bush, or potato vine, may produce fruit,
tubers and flowers of different colors, but still alike in all essen-
tial characteristics.

We see through the whole vegetable kingdom, a most
marked analogy and connection, from the minutest organized
microscopic plant, to the largest forest tree: there are also
differences so obvious that there can be no doubt of the pro-
priety of arranging them into different groups according to
their peculiar characters.

ELEMENTARY ORGANS OF PLANTS.

The most simple and elementary form of a plant is that of
the embryo, which is produced by, and contained in the seed.
This consists of two parts, viz : the plumula and radicle. The
plumula is the part which is afterwards developed into the
ascending part of the plant, the stem, branches and leaves-
The radicle is that which becomes the root, and descends into
the earth in search of food and moisture. The ascending part
of the young plant is at first merely a minute growing point,
enveloped in delicate rudimental leaves, which constitute a
lud.

95

fed c

[Fig. 1, — Forms of tissue; a, cutting of elder pith, cellular; b, cells
from the gritty centre of the pear; c, from the stone of the plum — both
strengthened by solid matter; d, woody fibre; e, spiral vessel with a
single fibre partly drawn out; f, vessel with a quadruple fibre. — Wood.~\

The several elementary structures of which the various
parts of plants are made up, are called elementary tissues:
they are five in number, viz: the cellular, woody, vasiform,
vascular, and laticiferous. The chemical elements of which
these tissues are composed, are enumerated and described in
works on chemistry.

Cellular tissue is composed of a series of minute cells
attached together, and having a more or less regular form.
Fig. 1, a.

Woody tissue consists of minute tubes, tapering to a point
at both ends, and adhering by their sides, the end of one tube
overlapping that of another so as to" form continuous threads.
Fig. 1, d.

The vasiform tissue consists of tubes, large enough to be
seen by the naked eye in some plants, — as, for example, in a
transverse section of the oak. In some plants these tubes are
jointed, or divided by partitions, and in others they arc con-
tinuous. It is through these that the sap rises, and they are
the largest vessels in the vegetable organization. Fig. 2, a.
Vascular tissue consists of spiral vessels, resembling some-

96

SCIENTIFIC AGRICULTURE.

what the woody fibre; they contain air, and their internal
structure differs in various plants. Fig. 2, b.

The laticiferous tissue is that through which is circulated
the latex, or nutricious sap. It consists of minute, irregular
branching tubes opening into each other, and situated mostly
in the bark and under side of the leaves. Fig. 2, c.

The epidermis, or outside bark, is formed of celluar tissue,
and envelopes the entire plant, except the stigma of the flower,
and the spongioles of the roots. In plants whose bark is rough
and ragged, as in the walnut and oak, it is not distinguishable.

The delicate membrane which may be stripped from the
iris, or house leek, is the epidermis ; this covering of plants is
perforated by minute orifices or mouths, which open and close
by the presence or absence of light The epidermis and leaves
have several appendages, as glands, hairs, prickles, thorns*
receptacles and stings, which it is not necessary to describe in
this treatise.

Fig. 2.

[Fig. 2,— Fornn of tissue, &c.; a, annular ducts; b, spiral and annu-
lar at intervals; c, laticiferous tissues; e, stomata of iris, vertical section;
d, d, green cells at the orifice; f, f, cells of the parenchyma; e, air cham-
ber; g, g, epidermis and stomata of yucca; h. stomata closed; the dots
represent small luminous bodies in the cells. — Wood.~\

CHAPTER II.

ORGANS AND STRUCTURE OF THE FLOWER.

TIIE essential organs of a flower are three, viz : the stamens,
the pistils, and the receptacle. These are all the parts neces-
sary to the perfection of the seed, — they therefore constitute a
perfect flower: to these, however, is added in most flowers,
the perianth, consisting of the calyx and corrolla.

The STAMENS are slender, thread-like organs within the
"flower" or perianth, around the pistils: their most common
number is five : but this varies from one to a hundred. Their
office is said to be the fertilization of the seed.

The PISTILS are usually slender, larger than the stamens,
and occupy the centre of the flower : " they are destined to
bear the seed." They are sometimes numerous, but in many
cases there is only a single one.

The RECEPTACLE is placed at the end of the flower stalk, and
constitutes the basis upon which the organs of fructification are
usually placed, in such manner as to encircle it.
Fig. 3. The CORROLLA is the interior Fi£- ••'

i part of the perianth, consisting
kof one or more circles of colored
leaves of various hues and deli-
cate texture, situated upon the
receptacle : these leaves are called
petals, (Fig. 4, a, a,) — and they may be

98

SCIENTIFIC AGRICULTURE.

united at the edges, constituting a bell-form flower, (Fig. 3,)
or they may be separate, constituting a wheel-form flower.
Fig. e.

Tig. 4.

a

The CALYX is the external part of the
perianth, consisting of a circle of leaves,
the same in number as those of the
corrolla, in some cases distinct, and in
others united: they are usually green:
these leaves are called sepals. Fig. 5, a.

We see now, that a complete flower is
made up of four regular sets of organs,
viz : the stamens, pistils, receptacle and
perianth: these organs are arranged in
concsntric whorls, or rings: some of them may be absent, or
suppressed, some superfluous ones may be developed and some

BOTANY.

09

degenerated into those of a different set, as petals into stamens,
flowers into leafy branches, &c.

The stamen consists of three distinct parts, viz: the filament,
(Fig. 6, a,) the anther, (Fig. 6, b) and the pollen. The filament
Fis> 6- is the thread-like part which sup-

ports the anther at its summit:
the pollen is a fine yellow dust
of various forms contained within
the cells of the anther, until dis-
charged through its pores into
the air.

The pistil consists also of three
parts, viz: the ovary, the style,
and the stigma.

The ovary is the base of the
pistil which contains the young
seeds, and which ultimately be-
comes the fruit Fig. 6, d.
The style is a prolonged column arising from the ovary, and
supporting the stigma at its top. Fig. 6, e.

The stigma is the upper extremity of the style, usually of a
globular form: ii may be either simple or compound, according
to the structure of the ovary and style. Fig 6, f.

The ovules are minute globular bodies in the cells of the
ovary, which become the seeds of the matured fruit

The placenta is a fleshy ridge within the cells of the ovary,
from which the ovules are developed, and to which they are
attached.

There are several other secondary and minute parts, be-
longing to the flower, which it is not necessary or practicable
to describe here, as it would only burthen the memory with
technical terms which would convey but little useful know-
ledge.

100

SCIENTIFIC AGRICULTURE.

Fig. 7.

THE FRUIT.

The ultimate object of the whole vegetable organization
appears to be the production of fruit; which is the agent
through which the reproduction of the species is accomplished.
After the seed is perfected in annual plants, they soon wither
and die : the flower always precedes the fruit, and is neces-
sary to its development and perfection. The fruit consists of
two parts, viz: &e pericarp and the seed, or the seed-covering
and the seed: the pericarp is wanting in some plants, but the
seed is essential in all. In the coniferous plants, as the pine,
spruce, &c., the seed is naked and destitute of the pericarp.

The PERICARP is the part which envelops
the seed, whatever be its substance or struc-
ture. Fig. 7. In the peach and plum, this is
a fleshy, pulpy substance, — in the oak and
FiS' 8- walnut, a dense hard shell : (fig. 8.)
thus the structure and composi-
tion of the pericarp varies in dif-
ferent plants, from a soft watery
pulp to a dense shell. The pro-
cess of the ripening of fruit con-
sists of certain chemical changes produced
by the action of light, heat and air, and
perhaps other agents. Pericarps have
received specific names, according to their

Fig. 9. form and structure: that of the pea and bean
is called a pod, — that of the walnut and but-
ternut is called a nut, — that of the apple and
pear, a pome, — that of the currant and whor-
tleberry, a berry, &c. Fig. 9.

This figure represents the pericarp, or seed
capsule of the cenothera.

BOTANY. 101

THE SEED.

The seed contains the rudiments of a new plant, and is the
final product of all the complicated and beautiful processes of
vegetation. The essential parts of the seed are, the integu-
ment a, the albumen and the embryo.

The integuments are composed of several distinct layers,
which constitute the immediate coverings of the other parts.

The albumen lies next to the integuments, constituting the
principal bulk of some seeds ; it is a whitish substance, com-
posed mainly of starch, which, by the chemical changes which
it undergoes during the process of germination, serves to
nourish the embryo plant.

The embryo comprises all the rudiments of the new plant:
it consists of three parts, viz : the radicle, the plumule, and the
cotyledon.

The radicle is the part which forms the root, — the plumule
Fig. 10. forms the ascending portion of the plant, —

the cotyledon is the bulky part of seeds, and
forms the first leaves of young plants, which
lin the garden bean, cucumber, &c., are
I thick, fleshy and oval, when they first rise
above the surface of the ground: these
! support the plant and perform the function
of leaves until the proper leaves are formed.

[This figure shows an embryo with its plumule
and radicle developed from the cotyledon: a, radi-
cle; b, plumule; c, cotyledon.]

GERMINATION OF SEEDS.

Germination consists of the first chemical changes and vital
action, which take place when a new plant is about to be
produced.

" When the seed is planted in a moist soil, at a moderate
temperature, the integuments gradually absorb water, soften

*9

102

SCIENTIFIC AGRICULTURE.

and expand. The water is decomposed, its oxygen combines
with the carbon of the starch which has been stored up in the
tissues. Thus, losing a part of its carbon, the starch is con-
verted into sugar for the nourishment of the embryo, which now
begins to dilate and develop its parts. Soon the integuments
burst, the radicle descends, seeking the damp and dark bosom
of the earth, and the plumule rises with expanding leaves, to
the air and light. The conditions requisite for the germination
of the seed are, heat, moisture, oxygen, air and darkness."

[Wood.

Fig. A.

[Fig, A. This cut represents a young dicotyledonous plant, with its
radicle, a, developed; its cotyledons, c, c, appear in the form of large
succulent leaves; the plumule is just appearing as a minute point
between the cotyledon*.]

THE ROOT.

The root constitutes the basis of the plant : it serves two
purposes in the vegetable economy, — first to fix the plant

BOTANY.

103

mechanically in the soil and retain it in its position, — secondly
to absorb from the soil those inorganic elements which are
necessary for its food. The general direction of the root is
downwards ; but the roots of various plants grow at all angles
from the horizontal to the perpendicular : the principal perpen-
dicular axis is called the tap root. The number and extent of
the roots must correspond with those of the stalk and leaves
of the plants, in order to supply their demand of food from the
soil.

Roots do not usually extend to great depths, but keep
within the limit of that portion of soil which supplies their
proper nutriment. Roots are distinguished from stems and
branches by the absence of stomata, buds and pith, — and by
the presence of absorbing fibres.

The stock, or main body of the root, sends off i\\Q fibrils, or
minute, slender branches of the root, — the delicate, tender
extremities of the fibrils are called spongioles: these arc the
growing points, and the organs which absorb from the soil the
earthy part of the food of all plants. If some trees, as the
willow or currant, be inverted in the soil, the branches are
changed to roots, while the roots put forth leaves in the air,
and the plant grows.

Roots are of several different forms, which have received
Fis- llt specific names for the sake

of convenience.

Ramose, or branching
roots, are those which send
:off many ramifications in
various directions, like the
branches of a tree: such
are the roots of the oak
and elm. Fig. 1 1 .

104

SCIENTIFIC AGRICULTURE.

Fig. 12. Fusiform, or spindle shaped roots, consist of a
fleshy stock, tapering downwards to its extremity,
sending off fibrils, which are its true roots: such
are the raddish, carrot and parsnep. Fig. 12.

The napiform root is a variety of
the fusiform, in which the neck or,
upper part swells out, so that its'
diameter equals or exceeds its
length. The turnip and turnip-
raddish are examples. Fig. 13.

Fibrous roots are made up
of numerous small thread-like
roots, attached directly to the
stalk, without any neck or main
root : such are the roots of most
grasses. Fig. 14.

Fasciculated roots differ from
the fibrous in having some of their fibres thickened and fleshy,
as in the dahlia and peony.

Tuberous roots consist of fleshy, roundish knobs or tumors,
Fis 15- at or near the extremity of the stalk, as in

the orchis : " the potato was formerly classed
among tubers, — but as it uniformly bears
buds, it is classed among stems." Fig 15.

Granulated roots consist of many small
rounded bulbs connected together by fibres,
as in the common wood sorrel.

Fig 16.

Fig. 16.

BOTANY. 105

Besides these varieties of roots, there are several others
which are peculiar, and distinguished by not being necessa-
rily fixed in the soil.

Aerial roots are those which grow from some part of the
plant above the surface of the soil in the open air. Some
creeping plants, as the ground ivy, send forth these roots from
their joints. The screw-pine also sends off roots which are
several feet in length before they reach the ground. Such
roots are often seen in the common maize.

Floating roots belong to plants which float upon the surface
of water. The water-starwort is said to float upon the surface
until flowering, when it sinks and takes root in the mud till its
seeds ripen.

The epiphytes, or plants fixed upon the branches of other
species, derive their nourishment mostly from the air: such
are some species of moss.

Parasites are those plants which grow upon other plants ;
and some of whose roots are said to penetrate their tissues
and subsist upon their juices; while the roots of others are
aerial, and derive their food from the air : such are the mistle-
toe and dodder.

Roots are divided again into three varieties, viz: annual,
biennial and perennial, according to their duration.

Annual roots are those which live only one year, and must
be raised from the seed, sown every spring, — as beans, peas
and cucumbers.

Biennial roote_are those which live two years and do not
blossom the first season, — but they produce flowers, fruit and
seeds the second year, and then die : such are the beet, cab-
bage and carrot.

Perennial roots live several years, — some of them, as forest
trees, live to a very great age: the grasses, dandelion and
asparagus are other examples.

106 SCIENTIFIC AGRICULTURE.

STRUCTURE AND FUNCTIONS OF THE ROOT.

The internal structure of the root and stem are similar : the
fibrils are composed of vascular tissue, inclosed in a cellular
epidermis, which, however, does not extend to the ends of the
fibrils; — these ends are naked and spongy, — hence they are
called spongioles, and have the power of absorbing large quan-
tities of water.

The growth of the root takes place by layers upon its
surface and the addition of matter at the extremities. The
fact is considered established, [Johnston,] that the spuigioles
absorb gaseous as well as aqueous matters, when in contact
with them. The root absorbs only from its spongioles ;->— from
these it is carried by the vessels of the fibrils to those of the
main roots, and thence into the stem and to all parts of the
plant. 1. Both organic and inorganic substances, in a state of
solution in water, enter the circulation of plants. 2. The roots
have the power of selecting such substances as are necessary
for their food, and of rejecting those that are^njurious to their
healthy growth. 3. Roots possess the power of excreting
certain matters which are in excess, or are unnecessary or
injurious to them. 4. Roots have the power of modifying the
fluids as they pass through them. — [Johnston.]

THE STALK OR STEM.

The part of a plant which rises above the surface of the
soil, which constitutes the principal axis, and is intermediate
between the roots and branches, is called the stem. The
direction of the stem is generally vertical, but in some plants
it is oblique or horizontal. Stems, like roots, may be annual,
biennial or perennial. Plants are divided into kerbs, shrubs,
and trees, according to the size and duration of the stem.

Herbs are plants with annual roots and annual stems, which
do not become woody: such are the grasses, mints, most
flowers, <&e.

Shrubs have perennial, woody stems and roots, divided into

BOTAN1T. 107

numerous branches near the ground, and do not attain the
size of trees : such are the alder, whortlebeny, lilac and haw-
thorn.

Trees have perennial, woody stems and roots, — do not
branch off near the ground, and attain a great size : examples,
elm, oak and pine. The distinguishing property of the stem
is the production and development of luds.

Buds are of two kinds, viz: the leaf -bud and the flower-bud.

The leaf-bud consists of delicate layers of cellular tissue, or
embryo leaves, covered by hardened crusty scales.

The "flower-bud consists of the rudiments of the new flower.

There are several subordinate organs, which are little more
than appendages to the stem, and which it is unnecessary to
describe.

STRUCTURE AND FUNCTIONS OF THE STEM.

Plants are divided into exogenous and endogenous.
The exogenous are those which grow by accumulation, or
layers of matter from the outside. This class includes nearly
all forest trees and most shrubs and herbaceous plants of tem-
perate climates.

The endogenous plants are those which grow from the inside,
or by accretion of matter within that already developed. Most
of the bulbous plants of temperate regions, all the grasses, and
the palms, cane, <fec., of tropical countries, are endogenous.
The exogenous stem consists of bark, wood and pitL
The pith is a light spongy substance, at the centre of the
stem : it is composed of cellular tissue, and seems to exercise
its peculiar functions only during the earlier growth of plants.

[Wood.

The icood is composed of cylindrical or concentric layers, in-
tersected by medullary rays, which are those thin dense plates
of wood dividing the "grains," and are large and easily seen
in a piece of beech or oak wood which has been split. The
pith, together with the first layer which incloses it, are the

108

SCIENTIFIC AGRICULTURE.

Fig. 17.

product of the first year's growth;
one new layer is formed every suc-
ceeding year, — so that the number
of rings or "grains" at the base of
the stem indicate correctly the age
of the tree. Each layer is composed
of woody fibres, vasiform tissue and

ducts.

Fig. 17.

[Fig. 17. 1, represents an erogenous
stem of one year's growth; a, pith; b,
bark; c. medullary rays; d, woody bun-
dles of fibre; 2, laticiferous vessels of the
bark.]

The outside, lighter colored lay-
ers constitute the allurmnn or "sap
wood:" the brownish layers inside are harder than the sap
•wood, and are hence called the duramen.

The bark forms the external covering or integuments of the
stem and root. The bark consists of three distinct layers : the
outside covering is called the epidermis, — this layer is some-
times covered with a coating of gummy, oily or resinous matter.
The middle layer is the cellular integument; and the inner coat
the liber. The two outer layers are of cellular structure, "while
the inner one is both cellular and woody.

The sap is carried by the vessels through the alburnum to
the leaves, with the vessels of which they communicate: while
in the leaves, the sap undergoes some changes, (not well
understood,) by moans of the air and light, by which it is
converted into a fluid called latex. From the vessels of the
under side of the leaf, it descends by the vessels of the inner
bark ; part of it is carried inwards by the pores of the medul-
lary rays, and diffused through the stem, while the remainder
descends to the roots, and is distributed through them. Sap
is milky, gummy, saccharine bitter, &c., in various plants.

At the end of spring a portion of the descending sap, which

BOTANY.

100

is now transformed into a viscid glutinous matter called cam-
bium, is deposited between the liber and the wood, becomes
organized into cells, ajid forms a new layer upon each. Soon
afterwards, the new layers are pervaded by woody tubes and
fibres, which commence at the leaves and grow downwards.
" The number of layers in the bark and wood will always be
equal." (Wood.) The outer bark of young twigs seems to
perform the same function as the leaves : in the cactus, sta-
pheliu, and other plants which produce no leaves, the bark must
perform the same office as the leaves do in plants which pro-
duce them. (Johnston.)

^ Fig. is.

4

C C

[Fig. 18. 3, horizontal section of an endogenous stem, exhibiting the
bundles of woody fibre, spiral vessels and ducts, irregularly disposed in
the cellular tissue : 5, a, a, cellular tissue ; b, spiral vessels on inner side
of dotted ducts, c, c; d, woody fibre on the exterior side: 4, stem of
three year's growth; a, pith; e, bark; b, c, d, successive annual layers:
6 a, pith; b, spiral vessels of the medullary sheath; c, dotted ducts; d,
woody fibre; e, bark.]

The endogenous stem exhibits no distinction of bark, wood
and pith, — and no concentric annual layers or grains. It is
composed of cellular tissue, woody fibres, spiral vessels and

10

110

SCIENTIFIC AGRICULTURE.

ducts, the same as that of exogens. The cellular tissue exists
equally in all parts of the plant; the rest are in bundles, im-
bedded in the stem: "each bundle consists of one or more
ducts, with spiral vessels adjoining their inner side next to the
centre of the stem, and woody fibres on the outside, as in the
exogen.

" A new set of these bundles is formed annually, or oftener,
proceeding from the leaves, and passing downwards in the
central parts of the stem, where the cellular tissue is most
abundant and soft After descending awhile in tliis manner,
they turn outwards and interlace themselves with those which
were previously formed."

Oryptogamons or Flowerless Planta.

CHAPTER III.

STRUCTURE AND FUNCTIONS OF THE LSAF.

THE leaf is an extension of the two outer layers of the bark
expanded into a broad thin net work: leaves constitute the
verdure of nearly all plants; their color is almost universally
green, which color they derive from a substance called chloro-
phylle, deposited just beneath the cuticle. Towards the end
of autumn, after the verdure of plants has matured, their color
is changed to various hues, as yellow, orange, red, <fec., by the
action of oxygen on their elements.

Deciduous leaves are those which fade and fall off at the end
of autumn, annually.

Evergreens are those which remain green throughout the
year. . %

Leaves are arranged in various ways upon the stem and
branches of plants : in some, as in the potato, they are scattered
along the stem irregularly: in others, as the pea, they aie
alternate, or one above another on opposite sides of the stem :
when two are against each other at the same joint or node,
they are called opposite: when more than two are arranged
in a circle at the same node, as in the meadow lily, they are
verticillate : in the pepper and some others, they are arranged
spirally around the stem.

The prolongation of the leaf-stalk, through the middle of
the leaf, is called the midrib; the smaller divisions, or ribs,
which radiate or go off from this, are called nerves.

112

SCIENTIFIC AGRICULTURE.

The hair-like lines sent off from the midrib and nerves are
called veins. This distinction is arbitrary, as there is no dif-
ference in the structure or function. The various distributions
of the veins have received distinctive names, and these are all
included under the generic term venation.

FORMS OF LEAVES.

Tlieforjns of leaves have also subjected them to an arrange-
ment under specific heads. The forms of leaves are said by
De Candolle to depend upon the length of the midrib and the
relative length of the veins.

rig. IP. Orbicular leaves are roundish, as in the

pyrola rotundifolia, or round leaf wintergreen,
and nasturtion. Fig. 19.

Elliptical leaves, as their name Fig. 20.
implies, are elliptical or oval in
form, as in the whortleberry and
wintergreen. Fig. 20.

Lanceoate leaves are long and tapering at the<
point like the blade of a lancet, as in the willow and peach.
Fig. 21, a.

BOTANY.

113

Pig. 22

rig. 23.

Cordate leaves are heart-shaped, as in the lilac and aster
cordifolium. Fig. 22.

Sagittate leaves have the form of an arrow-head, as in the
sagittaria. Fig. 23, #.

Reniform leaves are kidney-shaped, as in the wild ginger
and ground ivy. Fig 24.

Linear leaves are narrow, long and straight, as in the grasses
and grains. Fig. 21, c.

Deltoid leaves are in the form of the Greek letter delta,- or
nearly triangular, as in the Lombardy poplar. Fig. 21, e.

Acerose leaves are long, narrow and needle-shaped, and
clustered together, as in the pine. Fig. 23, b.

Piimatified, or feather-cleft leaves, have deep clefts between
all their veins, separating the leaf into parallel segments, as in
the lepidium. Fig 25, d.

*10

114

SCIENTIFIC AGRICULTURE.
Fig. 25. Fig 20.

Lyrate leaves have several deep rounded notches between
their veins, as in the water-cress. Fig. 25, c.

Connate leaves have the bases of opposite leaves united so
As to appear like one entire leaf, as in the boneset and sapo-
naria*. Fig. 26.

Digittate leaves have narrow, deep clefts between the veins,
with long segments radiating from the end of the leaf-stalk, as
in the common hemp. Fig. 27.

Fig 28.

Stellate leaves are arranged around
the stem in such a manner as to form a
star, as in the red lily. Fig. 28.

Loled leaves are deeply indented or
cleft at their margins, so as to divide
them into lobes, as in the liverwort. Fig.
.29, a.

BOTANY.

115

Sinuate leaves have their margins divided by deep roundish
clefts, as in the white oak. Fig. 29, b.

Fig 29.

Emarginate leaves are irregular, having but slight indenta-
tions in the margin. Fig. 29, c.

Tubulate leaves have the sides or margins united so as to
form a cup, as in the side-saddle and pitcher plant. Fig. 30.

Fig 30.

Fig 31.

Compound leaves consist of
several small leaves on separate
leaf-stalks, and arranged along
the opposite sides of the same
stem, as in the hedysarum. Fig. 31 .

Ternate leaves rig. 32.
arise in threes from
the same leaf- stalk.
Fig. 32.

Alternate is a se-
cond division by
threes.

116

SCIENTIFIC AGRICULTURE.

Fig. 33. Leaves are opposite when placed at equal

distances in pairs on opposite sides of the stem.
Fig. 33.

These are the principal forms of leaves;
still, many other names are given by botanists
to the various modifications of these. Specific
terms are employed also in describing the
stem, margin, base, point and surfaces of leaves.
There are also various appendages to the
leaves, which have distinctive names,- in sys-
tematic works on botany. To describe all the
minor points in the organography of plants
would exceed our limits, — and, besides, it would render this
brief outline of botany too complex to be interesting to the
general reader.

MINUTE STRUCTURE OF THE LEAF.

The frame work of the leaf is an extension and expansion of
the medullary sheath, which is composed of woody fibre and
vessels. The integument, or outer covering of the leaf, is
the same as that of the bark, of which it is a continuation.

The cellular tissue peculiar to the leaf is called its paren-
chyma. This parenchyma exists in two layers of cells, which
differ somewhat in structure. Within the cells, and adhering
to their walls, are the minute green particles of cklorophylle,
F*g 34. which give color to the leaf: the empty

•spaces between the cells communicate
with the external air by means of sto~
mata, or mouths, which, in most plants,
are found only on the lower surface.
In all those plants whose leaves are
vertical, as the iris, they are on both

[Fig. 34. Magnified sides equally: in the water lily, they
section of the epidermis . , . ., /. * ,-,

•of the my> showing tte exist only in the upper surface, the

storoata, c, >c.

lower surface being in contact with the

BOTANY.

117

Tlio veins which carry the latex, or nutricious fluid of
the leaf, "having reached the edge of the leaf, double back
upon themselves," spread through the lower surface, and are
again collected, and returned through the leaf-stalk into the
bark.

Fig. 35.

[Fig. 35 shows a magnified section of the leaf of the lily: the upper
surface, a, consists of flattened cells of the epidermis, arranged in a
single layer; beneath this, b, is the more compact part of the paren-
chyma, consisting of a layer of oblong cells placed in such a position
that their longer axis is perpendicular to the leaf's surface. Next
below is the parenchyma of the lower surface, c, composed of oblong
cells arranged longitudinally, and so loosely compacted as to leave
larger spaces between. Lastly, d, is the epidermis of the lower sur-
face, with stomata, e, e, opening into air chambers, f.]

FUNCTIONS OF THE LEAF.

The functions of the leaf are, exhalation, absorption, respi-
ration and digestion. The ultimate end of these functions is
to produce the necessary changes on the crude sap brought
up from the roots, and to convert it into the latex, which is the
proper nutrition of the growing plant : this ftuid is to the plant
what the arterial blood is to the animal system.

Exhalation in plants is the throwing off of the excess of
water in the sap, so as to leave it in a more concentrated form,
and consequently better adapted to nutrition : exhalation takes
place through the stomata, and is different from mere evapo-
ration, which depends upon the state of temperature and air.
Exhalation is supposed to cease during darkness.

Absorption is performed mainly by the roots, in nearly all
plants : when, however, these are defective or wanting, the leaf

118 SCIENTIFIC AGRICULTURE.

assumes the vicarious office of absorption. The invigorating
effect of a shower of rain oil the leaves of parched and wilted
plants, is seen long before the water could have reached the
roots and have been carried up to the leaves : this effect must
be produced, therefore, by the absorption of moisture by the
leaf. This action takes place mostly from the lower surface of
the leaf.

Respiration in plants consists, as in animals, in the absorp-
tion of oxygen from the air, and the giving off of carbonic
acid. It is performed mainly by the leaves, but is performed
to some extent by other parts also : it continues without inter-
mission by day as well as by night, during the life of the plant
Respiration is most active during the processes of germination
and flowering: a constant supply of oxygen, and the daily
presence of light, are indispensable to the growth and vitality
of the plant

Digestion comprises all those changes which the mineral,
aqueous and gaseous matters undergo after entering the plant,
until they are assimilated and become a part of the organism.
" It consists in the decomposition of carbonic acid by the green
tissues of the leaves, under the stimulus of the light, the fixa-
tion of the solid carbon, and the evolution of pure oxygen."

[Wood.

INFLORESCENCE.

Inflorescence is the term used to indicate the peculiar
arrangement of flowers upon the stem and branches of plants ;
also their successive development in different parts of the same
plant Flowers are said to be terminal and axillary, in regard
to their position on the stem.

Terminal flowers are placed at the end or summit of the
branch or flower stalk.

Axillary flowers are placed in the angle formed by the
branch or leaf-stalk, and the primary central stem, or larger
lateral braaches.

BOTANY. 119

The peduncle is the flower-stalk, or that part of the stem
which is attached to and supports the flowers : it may be simple
or branching, and it may be entirely absent,
rig 36

[Fig. 36 shows a papilionaceous flower with its peduncles-3

A scape is a flower-stalk, or peduncle, which springs imme-
diately from the root, in those plants which are called stemless,
as the sarracenia, hyacynthus, &c.

A rachis is the main axis, or stem, of a compound peduncle,
along which are arranged the flowers, as in the currant, grape,
grasses, plantain, &c.

A flower is said to be solitary, when a single terminal or
axillary flower is developed, as in the erythronium and con-
volvulus. The successive evolution of flowers is distinguished
into two varieties, viz : the centripetal and centrifugal.

In centripetal inflorescence, the blooming of the flower com-
mences at the circumference and proceeds towards the centre,
as in the mustard, carrot, &c.

In centrifugal inflorescence, the blossoming commences at
the terminal or central flower, and advances laterally to the
circumference, as in the elder, pink and sweet-william. These
two modes of inflorescence are sometimes combined in the
same plant. — [Gray.]

There are several varieties of centripetal inflorescence, which

120

SCIENTIFIC AGRICUJLTURE.

arc designated by specific terms ; as the spike, raceme, amcnt,
spadix, corymb, umbel, head, panicle and thyrse.

Of centrifugal inflorescence, there are also several varieties,
as the cyme, fascicle, whorl, or verticil, &c.

Fig 37.

[Fig. 37 represents a head of oats showing an example of a panicled
flower.]

Tendrils,

CHAPTER" IV.

GENERAL REMARKS.

THE dissemination of seeds is a subject not unworthy o*
allusion. It is known to botanists, that nearly all plants have
particular localities to which they are indigenous. But, by
various means, they have become more or less distributed over
different and distant parts of the earth. Some seeds, as those
of the thistle and dandelion, are furnished with a little plume
or wing, by means of which they are wafted by winds to great
distances, and thus sown in a soil and locality where the
species was never before known. Some seeds are furnished
with hooks or burs, by means of which they attach themselves
to the clothing of men and animals : seeds are also eaten by
animals and birds, carried to great distances, voided undigested
and without injury to their vitality, germinate wherever they
are deposited.

Many seeds are so protected by a thick dense pericarp, that
they make long voyages, being carried along by the current
of streams, or the ebbing and flowing of tides, until they reach
a distant country, and perhaps even another continent, and
there propagate and establish their species. They are carried
also by ships and other conveyances engaged in commercial
transportations, as well by accident as by design for the
purpose of cultivation. Many seeds retain their vitality after
boiling, digestion in alcohol, and being buried in the earth for

11

122 SCIENTIFIC AGRICULTURE.

centuries. Dr. Lindley mentions a remarkable instance of the
longevity of raspberry seeds, which, as proven by circum-
stances, must have been 1,600 years old, and were found
thirty feet below the surface of the earth. Oily seeds are
more liable to putrify and lose their vitality than others.

The blooming of flowers was thought, during the dark and
middle ages, when the human mind was blinded by the
grossest superstition, to be emblematical of something con-
nected with religion: thus when the time of the blossoming
of a flower fell on the birthday of a saint, or on the day of a
martyrdom, that flower was consecrated or dedicated to such
saint or martyr.

Plants exhibit many phenomena which seem to be connec-
ted with atmospheric conditions and changes : thus it is said
a storm may be predicted by the folding or opening of certain
flowers ; also that a clear sky, thunder, wind, &c, may be fore-
told by the various other phenomena observed to take place
in the different organs of plants. Some plants are capable of
enduring a high degree of heat: those of the tropics sustain
a temperature which would be intolerable to animals for a
great length of time : others are found immersed in the waters
of boiling springs, and in a state of thrifty vegetation.

Every country exhibits a flora, or botanical character, pecu-
liar to itself. The influence of light and heat on the growth
of plants is seen to be powerful and important. In the polar
regions, where almost perpetual winter reigns, the vegetation
is rigid, scanty and stinted : the centre of the frigid zone, in
fact, is totally destitute of vegetable life. After passing the
arctic circle, we find a few species of mosses, lichens and ferns,
and a few shrubs. The only country in this zone where the
grains can be successfully cultivated, is Lapland. The tem-
perate zone produces most species of useful nutrient plants,
such as the grains, berries, fruits and grasses, as well as valu-
able timber trees. The torrid zone produces every variety of

BOTANY. 123

vegetation from the equator to the poles: this variety depends
upon the altitude at which they are found; the low land pro-
duces the most luscious fruits and stately trees, with a vast
variety of flowers and spices.

As vegetation ascends the mountain heights, even under
the equator, it assimilates, according as the climate becomes
less congenial, to that of the colder regions, in the same way
as when receding from the equator towards the poles. Plants,
like animals, are liable to various diseases : no inorganic body
can be said to suffer from disease, — although they are subject
to decomposition and disintegration, they are not capable of
diseased action, because destitute of vitality, which i^ indispen-
sable to such a process. Plants may become diseased from
a deficiency or excess of food, air, light, water, heat, — or from
cold, noxious vapors, external injuries, insects, parasites and
hereditary organic or functional debility. They are also
liable to diseases peculiar to old age and excessive action, in
the same manner as animals. Thus they suffer from anemia,*
or want of fluids, like aged persons: they sometimes labor
under dropsy, from deficiency of light, — and from other causes
they suffer and die from dry mortification*

Lastly, plants are liable to disease and death from poisoning
and contagion. The economical uses of plants are well known,
and require only a passing notice : forest trees, and some parts
of other plants, are indispensable in the arts: cereals, fruits
and roots, are used as food for both man and beast : the grasses,
lichens, mosses and herbs serve as food for animals: various
plants, and the substances derived from them, are also used as
medicines. Plants designed for medicinal purposes should be
collected at a time when the whole vitality and forces are not
engaged in the growth of the plant and maturity of the flower
and seed : herbs should be gathered soon after flowering, or
when the seed is nearly ripened : roots, if annual, should be

* Terms proposed by the author.

124 SCIENTIFIC AGRICULTURE.

gathered after the stem and foliage are withered in autumn,
or before the old root begins to decay in the spring: barks
possess more strength if taken after the descent of the sap has
ceased, and the cambium has become hardened into wood and
bark.

Some remarks on the collection and preparation of plants
for herbariums, and upon botanical analysis, classification and
nomenclature, might be made; but they would be of little
service, as they would anticipate a step in the science which
lies beyond the limits of this treatise.

*

PART IV.

METEOROLOGY.

CHAPTER I.

METEOROLOGY is the science which treats of all the various
phenomena which take place in the atmosphere. " Under the
term meteorology, it is now usual to include, not merely the
accidental phenomena to which the name of meteor is applied,
but every terrestrial as well as atmospherical phenomenon,
whether accidental or permanent, depending on the action of
heat, light, electricity, and magnetism. In this extended
signification, meteorology comprehends climatology and the
greater part of physical geography ; and its object is to deter-
mine the diversified and incessantly changing influences of the
four great agents of nature now named, on land, in the sea,
and in the atmosphere." — [Brande.]

A meteor is any phenomenon of a transitory nature, which
appears in the atmosphere. The various conditions and changes
which take place in the air incessantly, with respect to heat,
cold, moisture, dryness, &c., are called weather. Observations
have been made in all ages of the world upon these phenomena,
in order to explain their causes and foretell the changes of
weather. But there are so many conditions to be considered,
and so many influences which probably can never be under-

126 SCIENTIFIC AGRICULTURE.

4

stood, that there is little certainty in all the theories and
weather tables which have been formed. Although many of
the meteorological phenomena are somewhat well understood
in their individual nature, still, when they are combined, their
operation is exceedingly complex, and the number of their
changes almost infinite.

Records of past changes of weather have long been kept,
but it has been found by observation and comparison of the
results of different seasons and years, that few data are
obtained, on which to ground any prognostications of the
future. Some individuals have, by long and close observation,
attained some apparent accuracy of judgment in relation to the
phases of the weather; but their conclusions were not of a
nature to be systemized and transmitted to posterity ; so that,
if any real attainment has been made in this way, it has
always been lost with the observer.

"The registers which are kept in different observatories,
prove, contrary to popular belief that the changes of weather
are in no way whatever dependent on the phases of the moon."
Although the ever varying and endless changes of weather
are all the necessary results of fixed laws, yet it is doubtful
whether these laws will ever be sufficiently understood to
enable us to reduce our knowledge respecting them to demon-
strative ccertainty.

CLIMATE.

Climate, in its most extended signification, embraces all the
modifications of atmospheric temperature and conditions, and
the principal causes on which they are dependent: besides
temperature, it includes humidity, dryness, winds, barometrical
conditions, purity of air, &c. The principal causes which tend
to modify climate are, latitude, altitude, direction in which the
sun' sprays fall upon the earth, configuration and aspect of the
land, its proximity and relation to the sea, direction of the
wind, density of the atmosphere, number of rays of the sun

METEOROLOGY. 127

which are absorbed, amount of vegetation, character of the
soil, and state of agriculture.

But among all these causes none have so important an
influence on determining the climate of a country as latitude
and altitude. The degrees of heat are not always equal for
the same latitude; thus at Rome, in latitude 63° north, the
mean temperature is the same as that of Raleigh, North
Carolina, in latitude 36° north.

Lines passing through points on the surface of the earth at
which the mean annual temperature is the same, are called
isothermal lines. These lines do not pass round the earth in
a direct course like the parallels of latitude, but they vary so
as to assume a tortuous direction.

The isochimenal lines, or lines of equal cold, or equal
winter, vary much more than the lines of equal summer.
The reason why latitude affects the temperature of a climate,
is because it varies the obliquity of the sun's rays in relation to
the earth. This, however, is not the cause of the difference in
the length of day and night at different places.

The following table from Muller shows the length of the
longest day for the different latitudes.

Polar Elevation. Length of longest day.

0° 12 hours.

16°44/ 13

30°48' 14

49°22' 16

63°23' 20 "

66°32' 24 "

67°23' 1 month.

73°39' 3 «

90° 6 "

Altitude has an important effect on determining the mean
temperature on all places, whatever may be their latitude.
The temperature diminishes from the surface upwards as far

128 SCIENTIFIC AGRICULTURE.

as man has ever ascended, and probably beyond this point to
the very limit of the atmosphere. The interior of the earth is
supposed to be yet in a fluid state from the effects of heat ;
the solid outside crust constituting only y^ part of its whole
diameter: at 50 to 40 feet below the surface, invariable tem-
perature prevails; that is, there is always an equilibrium, so
that the mercury in a thermometer would remain stationary
at this depth, whatever might be the temperature above in
the open air. This point would be at the surface if the tem-
perature of the air was always the same. The increase of
cold upwards from the earth is at the rate of 1° F. for every
100 yards. The snow line, or line of perpetual congelation,
varies less in proportion to latitude than altitude : thus it will
be seen by the table below, that this line is much lower at the
equator than in higher latitudes in proportion.

Table of Snow Lines from Mutter.

Coast of Norway, 2,340 feet above sea level.

Iceland, 3,042 " « " «

Alps, 8,801 " " " "

MtEtna, 9,441 « « « «

Himmalayas, 14,625 " x« « «

Mexico, 14,625 " " " "

Quito, 15,600 " " " "

There are three reasons given by Dr. Brande, why the cold
increases as we ascend, viz: 1. The absorption of the sun's
rays in the denser strata of the atmosphere near the surface
of the earth. 2. Radiation of caloric from the earth. 3. The
ascending current of air.

Configuration of the land varies the climate of a country :
a plain is hotter than an uneven surface, all other conditions
being equal. The sand on the desert plains of Africa some-
times attains a temperature of 122° F. The side of a moun-
tain or hill, which faces the sun, is warmer than the opposite

METEOROLOGY. 129

side, for the plain reason that its rays strike upon it more
vertically.

Proximity or distance from the ocean is another cause
which varies climate. Small islands and peninsulas have
milder winters and fresher summers than the interior of conti-
nents in the same latitude.

The refrigerating effect of winds blowing from the polar
seas is felt in countries at great distances : the reverberation of
winds among mountains also increases the cold and heat of
certain localities. The other causes upon which climate is
dependent, are considered in another place. The - following
table from Muller, shows the mean temperature of several
different places.

130

SCIENTIFIC AGRICULTURE.

Table showing the mean temperature of several places during
several years, — part of one from Mutter's Phys. and Me'ty.

**

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132 SCIENTIFIC AGRICULTURE.

EXPLANATION OF THE CUT.

This cut is designed to show the latitude and altitude at
which some of the most important plants flourish in the
greatest perfection. It shows also the latitude in which various
winds prevail, — the latitude where there is little or no rain
and also where there is almost constant rain. The scale of
miles on the left hand of the cut shows the height of the
mountains, the elevation at which plants grow on their sides,
and the line of perpetual snow. On the right hand are the
degrees of latitude. The locality of plants, as shown by the
table, nrj not perhaps strictly accurate in all cases; but they
approximate correctness sufficiently near for all ordinary calcu-
lations.

METEOROLOGY. 133

INFLUENCE OF AGRICULTURE ON THE CLIMATE AND THE ANNUAL
FALL OF RAIN,

The question, wlietlier the clearing away of forests and the
labors of the agriculturalist have had any influence in lessening
the annual quantity of rain and the quantity of water in streams,
as well as in modifying the climate, is one of considerable
interest and importance. The clearing away of forests, so as
to allow^of free evaporation of water from marshes, and per-
mit the access of the sun's rays to the soil, most certainly has
a tendency to equalize the distribution of heat, if it does not
actually raise the mean annual temperature. The mean tem-
perature of the whole earth, however, was much higher
formerly than at present. The tillage of the soil, by rendering-
it loose, and exposing a greater surface to the action of heat
and air, favors evaporation, and in this way makes a cold, wet
soil, dry and warm. It also increases the capacity of the soil
for heat, and favors nocturnal radiation and the formation of
dew : but perhaps this fact goes about as far to sustain one
side of the question as the other.

It is a fact universally admitted by geologists, that the level
of the waters of the earth have every where undergone a
change. The instances are numerous, in which rivers, lakes,
seas and marshes, have been greatly diminished or totally
dried up; this may be one of those phenomena which is
evident to all, but which is nevertheless difficult clearly to
explain. Islands have risen out of the sea, coasts have been
left dry by the receding of the waters, and the beds of large
rivers have become dry arable soil. This has of course been
in some instances owing to the actual elevation of portions of
land by some subterranean force: and it is also true that
portions have been submerged by similar causes. But these
causes are insufficient to account for the general drying of
streams and diminution of rains in cleared agricultural dis-
tricts. " In felling the trees which covered the crowns and
slopes of mountains, men in all climates seem to be bringing

12

134 SCIENTIFIC AGRICULTURE.

upon future generations two calamities at once, — a want of
fuel and a scarcity of water."— [Humboldt.]

The rainy season is less regular in countries where the soil
is dry and naked, than where it is moist and covered with
dense forests or luxuriant vegetation. In some parts of South
America, which are clothed with ancient and large forests, rain
is falling almost incessantly : but in the same country, where
there are wide extended plains and little vegetation, it seldom
or never rains. Boussingault states, that when he was in
Payta, in South America, the inhabitants informed him it had
not rained there in seventeen years. The conclusions to which
he arrived on this subject, part of them sustained also by
Humboldt and Dr. Hitchcock, are as follows.

1. "That extensive destruction of forests lessens the quan-
tity of running water in a country.

2. " That it is impossible to say precisely whether this dimi-
nution is due to a less mean annual quantity of rain, or to
more active evaporation, or to these two effects combined.

3. " That the quantity of running water does not appear to
have suffered any diminution or change in countries which
have known nothing of agricultural improvement.

4. "That independent of preserving running streams, by
opposing an obstacle to evaporation, forests economize and
regulate their flow.

5. "That agriculture established in a dry country, not
covered with forests, dissipates an additional portion of its
running water.

6. "That clearings of forest land of limited extent may
cause the disappearance of particular springs, -without our
being therefore authorised to conclude that the mean annual
quantity of rain has been diminished.

7. " That in assuming the meteorological data collected in
intertropical countries, it may be presumed that clearing off
the forests does actually dimmish the mean annual quantity
of rain which falls."

CHAJPTER IL

THE philosophical principles upon which the phenomena of
rain are immediately dependent, are not yet well settled : rain.
is supposed, however, by many of the best writers, to depend
upon the action of electricity for its origin. All causes which
have a tendency to reduce the temperature of the air, cause a
precipitation of moisture. When the aqueous vapor which is
held in suspension by the air becomes condensed by cold, the
minute vesicles coalesce and form drops, which by their gravity
descend through the air, which is no longer capable of sus-
taining them.

The drops of rain are said to be from one twenty fifth to
one third of an inch in diameter : when they descend through
a stratum of dry air, they are partly dissipated by evaporation.
This accounts in part for the fact that there is less rain on
plains than on mountains.

The same latitudes have not the same quantity of rain!
this, like climate, is modified by various local circumstances, —
as altitude, proximity to the sea, direction and prevalence of
winds, agricultural condition, forests, &c. The quantity of
rain which falls during the year is greatest at the equator, and
diminishes as we leave this point and approach the poles.

The quantity also which falls during the night and during
the day, varies at different places : in Europe more rain falls
during the day than during the night time; while in South

136 SCIENTIFIC AGRICULTURE.

America more falls during night thaji during day. The mean
quantity of rain is less as we ascend above the sea level : it is
more in the same latitudes where the mean temperature is
68° F., than at any point above or below this.

Rains become less periodical and regular as we leave the
equator. The mean annual quantity of rain in Europe, between
latitudes 35° and 50° north, (and probably the same would be
nearly true of similar latitudes in the United States,) is from
25 to 45 inches.

The mean quantity, as shown by the report of the Regents
of the University of New York to the Legislature, for the last
ten or fifteen years, as measured at thirty different places in
this state, is 35.84 inches. Of these various estimates, 43.65
was the greatest number of inches, — which fell at " Erasmus
Hall," Long Island: the smallest number was 28.14, which
fell in St. Lawrence county. We see from tables in Bous-
singault's work, that most falls in autumn and least in spring:
we see also that most falls in July and least in March of any
months in the year.

This table is from the record kept ly L. Wetherell, Esq., at
the Rochester Collegiate Institute.
Greatest annual mean temperature for 13 years, ending

with 1847, 39°99

Least do. - 25 46

Greatest mean temperature of one year, - - 48 60
Least " " " - - 43 71

Highest heat, July, 1845, - - 102

Lowest " Feb., 1836, 8° below zero.
Most rain in one month, Oct., 1846, 6.79 inches.

Least " " " « Jan., 1837, 0.16

DEW AND FROST.

All bodies in nature are constantly undergoing a change of
temperature : however hot or cold a body may be, it is eon-

METEOROLOGY.

tinually giving out heat,^ither by radiation or by contact, or
it is receiving and absorbing heat from other bodies. Upon
the principle that heat tends to seek an equilibrium, by means
of radiation and absorption among bodies, the production of
dew and frost may be accounted for.

During the absence of the sun, a great quantity of heat is
dissipated from the surface of the earth by ladiation: by this
means, when the night is clear, the temperature is considerably
lowered : when, however, the earth is overhung by a canopy
of clouds, they radiate in return, or reflect, and thus maintain
an almost uniform temperature. When the clouds are absent,
all the heat radiated by the earth is lost in the upper regions
of space, and the surface is reduced in temperature many
degrees below the atmosphere.

" The stratum of air which lies in contact with the surface
of the ground is then cooled by contact, and a portion of the
watery vapor which it had possessed in the elastic form, is
deposited as liquid water. If the temperature of the air be
itself low, and the night very clear, the cooling may proceed
so far that the drops of dew at the moment of their deposition
shall be frozen, and thus form frost." — [Kane.] The fact is
familiar to most observers, that dew and frost are formed only
in clear starlight and still nights, — and then only on the
surface of good radiators.

The cooling of the earth's surface by the loss of radiant
heat, is prevented by a covering of snow or any other sub-
stance which intercepts its passage, and no dew or frost is
formed. Thus plants may be protected against frost by
covering them with a blanket or layer of straw : the same end
may be attained by raising large fires by means of damp straw,
brush, <fec., so as to destroy the transparency of the air by a
cloud of smoke and watery vapor. This mode is practiced by
the Incas of South America, who seem to understand the
conditions under which dew and frost are formed. When

*12

138 SCIENTIFIC AGRICULTURE.

there is a current of air, there will be no condensation of
watery vapor so as to form dew or frost: hence they are
seldom or never seen on a windy night.

In some parts of the world, as in sections of South America
and Mexico, dews are so copious as to supply the place of
rains. The cold ascribed by many persons to the light of the
moon, is nothing but the consequence of nocturnal radiation.
JMists, fogs, and clouds, are only floating vesicles of watery
vapor, which obscure the transparency of the atmosphere;
they differ only in the degree of their density. " A fog, [says
a celebrated naturalist,] is a cloud in which one is, — a cloud is
a fog in which one is not" Fogs are not common in hot
countries, — they rise to a small height, and are prevented by
winds. In Peru dense fogs continue for half the year. Day
fogs are volcanic ashes and vapors diffused through the air by
wind. The appearances of clouds may be changed according
to their height, density, distance, and the angles at which the
sun's light strikes upon them, &c. They are moved about
and broken apart by winds, and assume various and beautiful
hues, according to the different colors of the sun's rays which
they reflect

Clouds, then, are merely floating, distant fogs, and arc most
frequently formed over some body of water or wet soil,
sxow.

Snow is congealed water, which descends from the upper
regions of the atmosphere. The precise conditions of atmos-
phere requisite for its formation, or the manner in which it
takes place, is not yet well understood. The most that is
known respecting it, is in relation to the form of its flakes:
these are stellate, and composed often of hexagonal prisms,
arranged at an angle of 60°, from each of which others fre-
quently shoot out at the same angle. The whiteness of snow
is said to depend on the minuteness of its crystals. In some
cases snow presents no appearance of crystalization.

METEOROLOGY.

139

Snow recently fallen has a bulk ten or twelve times that of
the water from which it is formed ; while common ice has a
bulk only about one-ninth greater than the water of which it
is formed. The temperature of the air in which snow is
formed, must be below freezing, — that is, 32° Fah. ; and if it
falls through a warmer temperature in its descent to the earth,
it is melted, — hence there is no snow in warm weather, nor in
the torrid zone, except on the summits of mountains which
reach above the line of perpetual congelation. It may there
snow above and rain below.

The snow line, or line of perpetual snow, varies greatly in
altitude, according to location and circumstances. On the
Himmalaya chain, according to Humboldt, the snow line on
the south side is 4,4000 feet below that on the north side ; so
that this line cannot be depended upon as a point by which to
estimate the altitude Of mountains.

[This figure from Muller shows a few of the forms of snow flakes or
crystals, all of which belong to the hexagonal system.]

SCIENTIFIC AGRICULTURE.
HAIL.

Hail is a well known meteor, which occurs most commonly
in spring and summer, and is often accompanied with thunder.
It is formed by the congelation of rain or vapor in the upper
regions of the atmosphere. Hail storms are of rare occurrence,
and seldom continue more than a quarter of an hour. Hail
clouds always float lower than rain clouds. Hail stones appear
to be composed of several spherules adhered together; those
of the centre being soft, sometimes nearly fluid water, and
those of the circumference solid and opake.

They are also occasionally laminated or radiated. Hail
stones are sometimes enormously large : the largest of which
we have seen any account, according to Dr. Brande, measured
14 inches in circumference, and weighed from 5 to 13 ounces.
Many ingenious speculations have been made to account for
the formation of hail, but none of them sufficiently satisfactory
to be entitled to implicit belief. The most probable cause of
this phenomenon now is, that " hail is produced by the mixture
of exceedingly cold air with a body of hot and humid air."

[Olmstead.

Whether a cold wind comes suddenly from the regions of
perpetual congelation, in contact with a body of hot air charged
with vapor, blows suddenly into the regions of perpetual frost,
and thus, by condensation of the vapor, produces hail, we can-
not determine. It is sufficient for this theory, that hot moist
air meets with intensely cold air in any way whatever.

LIGHTNING.

" This is an electric phenomenon produced by the passage
of electricity between one cloud and another, or between a
cloud and the earth." The zigzag form of the flash, the fre-
quency of its repetition, and the great length, or extent of sky
which it embraces, are not yet well understood or accounted
for.

METEOROLOGY. 141

The phenomena of lightning are best observed from the tops
of mountains which extend above the clouds; from such a
position the flashes have been obsevered to extend for several
miles in length. The frequency of succession, and length of
the luminous streaks, are supposed to depend upon the imper-
fect conducting power of the clouds and vapor between them.

The question is now settled, that lightning rods, by con-
ducting off the fluid, serve as a protection to buildings. The
rod protects a circle, the diameter of which is four times the
length it extends above the highest point of the building:
hence the failures of lightning rods have been owing to their
not extending sufficiently high.

THUNDER.

The noise produced by the passage of lightning or electricity
through the air, from one cloud to another, or from a cloud to
the ground, is termed in common language, thunder. The
.loudness of thunder depends upon the magnitude and prox-
imity of the explosion, the .relative position of the clouds, the
character of the surrounding country, and the position of the
observer.

The sharp crashing noise sometimes heard, is caused by
lightning striking near us : the low rumbling noise is the effect
of distant thunder : the rattling sound is occasioned by a quick
succession of explosions from a highly charged cloud. The
same species of snapping noise attends the discharge of sparks
from the prime conductor of a charged electrical machine.
"And when we consider how trifling a portion of electric
matter is put in action by the most powerful means of artifi-
cial excitement, compared with* the quantity stored up in a
full charged thunder cloud, the discrepancy between the
appalling crash of the one and the insignificant snap of the
other, it will appear surprising that both should originate in
the same cause." — [Brande.]

Lightning is the light attendant upon electrical action, and

142 SCIENTIFIC AGRICULTURE.

thunder the noise which succeeds it: the difference in time
between the two phenomena depends upon the distance of the
explosion from the observer, allowing the velocity of sound to
be 1,125 feet, and that of light about 200,000 miles in a
second of time. We give below an extract from the " Ency-
clopedia Brittanica," showing the various conditions under
which electricity appears in the atmosphere.
"1. In regular thunder clouds.
" 2. During fog with small rain.
" 3. During a brisk snow or hail storm.
" 4. During a smart shower on a hot day.
" 5. During a shower on a cold day.
" 6. In hot weather after wet days.
" 7. In wet weather after dry days.
" 8. In clear and frosty weather.
" 9. In clear warm weather.
" 10. During a cloudy sky.
"11. During a mottled sky.
" 12. In sultry weather with light hazy clouds.
" 13. In cold, damp nights.

" 14. During a north-west wind, which produces a sensation
of dryness and coldness, not indicated by the thermometer."

WINDS.

Wind is air put in motion. Rarefaction of one portion of
the atmosphere by heat, and condensation of another portion
by cold, are the principal causes of wind. Some local causes
of limited extent may produce wind, — such as large fires, &c ;
but these winds are limited to the locality where they origi-
nate. There, is no known cause, besides heat and cold, which
is capable of producing any general or extensive current in the
air.

A wind may be merely relative or apparent, and proceed
from the passage of the observer through the air, as by a
steam car or balloon. If the speed of his vehicle be twenty

METEOROLOGY. 143

miles an hour, he feels a current of air equal in velocity to his
own ; the wind appears to blow at that rate. The direction of
winds may be modified by various causes: when two or more
currents meet from different directions, the general direction
will be a resultant one, the consequence of the several forces,
as in the case of trade winds.

Winds have received various distinctive appellations accord-
ing to the phenomena which they present : thus we have the
trade winds, the land and sea breezes* the harmattan, the
monsoon, the simoon, the sirocco, whirlwind, hurricane and
tornado. A brief description only of each of these varieties
can here be given.

Land and sea breezes. — These winds prevail mostly among
the islands of the torrid zone ; but more or less in all maritime
countries. They are mild, balmy breezes, which blow towards
the shores during the day, and from off the land towards the
sea during the night time. Their phenomena is explained as
follows : during the day the land becomes heated by the rays
of the sun, — the heat of the ground rarifies the air, which
consequently rises to the higher regions, while the cold air
from off the ocean rushes in to supply its place ; thus producing
a breeze inland as long as the sun continues to warm the earth.
This is called the sea breeze.

During the absence of the sun, the earth, which radiates its
accumulated heat faster than the sea, becomes cooler, and the
direction of the breeze is changed : the air from off the ocean
rises, while the colder air from the land rushes in to supply its
place, just as in the case of the sea breeze. This night wind
which blows off the land is called the land breeze. As the
central part of an island becomes warmer than its shores, the
breeze will be the strongest in the midland : " its current will
also be performed in a constant gyration; so that the air which
flows in upon the land by day, rises, flows out above, and
returns again in the same current : and the process is similar

144 SCIENTIFIC AGRICULTURE.

by night, only the current is reversed." At the time when a
perfect equilibrium exists between the temperature of the land
and sea, the wind ceases, and there is for a time a dead calm.

Trade winds are produced by the same causes operating
upon a larger scale, and the revolution of the earth on its own
axis. These are tropical winds, which prevail only within the
limit of about 30° each side of the equator. Their general
course on the north side of the equator, is from north-east to
south-west, — and on the south side, from south-east to north-
west. The upward current of the air at the equator, in conse-
quence of its higher temperature, causes the colder air to rush
in from the north and south towards the point of greater rare-
faction; this produces the northward and southward currents.
These currents have now a westerly tendency given them by
the diurnal rotation of the earth on its axis towards the cast;
thus producing their general directions as above described.
When not changed by local causes, their direction is the same
throughout the year : but however they may be modified, they
always blow towards the point of greatest rarefaction, and
receive a relative motion from the earth's diurnal revolution.
Their velocity is greatest at the equator, where the earth's
motion is the most rapid, and diminishes towards the poles in
proportion as the circumference of the earth diminishes, and
the motion is less rapid.

The harmattan wind is a periodical easterly wind, which
olows irregulary in Africa: it occurs three or four times
yearly, and continues for a longer or shorter period, according
to circumstances. It blows with only a moderate velocity,
is peculiarly dry and unpleasant : it is attended by a haziness
of the atmosphere, which often obscures the sun most of the
day. During this wind there is no moisture in the air, and no
dew or fog; vegetation becomes parched, and droops. Not-
withstanding the depressing and disagreeable effects of the
harmattan, it is said to be a salubrious wind.

METEOROLOGY. 145

Monsoons are a modification of the trade winds, which occur
mostly in the Indian ocean, and north of 10° south latitude.
The south-east winds blow from April to October, and are
frequently attended by rain : from October to April they blow
from the north-east, and are dry. The change from one
monsoon to another is usually attended by violent storms.

The simoon is a hot, pestilential wind, which, during certain
seasons of the year, blows northward from the deserts of Africa
and Arabia. This wind, after being modified by passing over
the Mediterranean sea, is called in the south of Italy, the
sirocco; its poisonous effects are supposed to depend on its
dry ness.

Whirlwinds are such as have a rapid gyratory, as well as
progressive motion. Hurricanes are generally whirlwinds con-
fined to a narrow path, with a forward motion, sometimes not
exceeding 15 miles an hour.

A wind which moves at the rate of 4 or 5 miles an hour is
called a gentle breeze; when its velocity is 15 or 20 miles an
hour, it is a gale; when 30 to 40 miles an hour, a high wind;
and when 100 miles an hour, a hurricane or tornado, Hurri-
canes are more frequent on the shores of China and the Indies
than in any other part of the world.

13

CHAPTER III.

AURORA BOREALIS.

"Tins is a luminous meteor usually appearing in tlie northern
part of the sky, and presenting a light somewhat resembling
the dawn or break of day." The aurora exhibits such a variety
of forms at different times, that no general description can give
any definite idea of its appearance: this, however, may be
easily attained by observation of the meteor itsel£ It appears
to be a horizontal cloud extending towards the east and west,
and rising a few, degrees above the horizon. The lower part
of the cloud is often darkish,, and the upper part lu.minous and
whitish: from this part, streams or columns of light shoot
upwards with an unsteady, wave-like motion, reaching some-
times to the zenith, and at others only a few degrees above the-
horizon.

The "Northern Lights" usually appear two or three hours,,
or soon after sunset, and continue a few hours, and occasionally
the whole night : they, also sometimes appear for several sue- -
cessive nights, but are rarely seen after midnight or in the
morning. — [Brande.] They often succeed a change of weather
from heat and rain to cold and clear. They are sometimes
tinged with .green ;or orange, but more commonly with various
shades of red.; The aurora is sometimes seen in the southern \
hemisphere. The mean height of the luminous sheet has been •
variously estimated a^ from:100 to 400 miles. No satisfactory.

MKTEOROLOGr. 147

explanation of this phenomenon has yet been given; many
ingenious theories have been proposed, but as we have not
space to detail them for the gratification of the curious, we
must refer them to larger and more scientific treatises. The
probable cause, however, is electricity.

IGNUS FATUUS, OR "WILL O* THE WISP."

This is a nocturnal light, commonly known in this country
by the name of " Jack- Lantern:" it is seen floating over
marshy grounds, moors, grave yards, and along the margins
of rivers, and sometimes has a progressive motion, which is
probably given it by the passing breezes. The origin and
nature of this meteor have been the subject of many supersti-
tious theories and absurd speculations; it has often been
ascribed to supernatural causes. The most probable explana
tion of it is that given by Muller : he supposes it to be hydro-
gen gas which is mixed with phosphorus; and that conse-
quently it is nothing more than a phosphorescent light.

A HALO,

Is a luminous circle, usually of various and beautiful hues,
surrounding the sun or moon during certain conditions of the
atmosphere. There are two kinds of halo, depending upon
different physical causes. The first are small, their diameter,
according to Dr. Brande, not exceeding from 5° to 10°, and
composed of three or more concentric rings of different colors.
" These are usually called coronce; and they appear either
when a small quantity of aqueous vapor is diffused through
the atmosphere, or when light fleecy clouds pass over the sun
or moon." The second kind consists of a single luminous
circle whose diameter is about 45°.

A halo of the moon is usually a white circle with its inner
edge sometimes tinged with pale red. There is much truth
in the remark, that a dense halo close to the moon portends
rain. Lunar halos are most frequent, because the sun's rays

148 SCIENTIFIC AGRICULTURE.

arc too dazzling to admit of their being seen. The most
probable cause of this phenomena is, that it depends on the
refraction of light in passing through small transparent prisms
of ice, floating in the higher regions of the atmosphere.

PARHELIA.

Parhelia, or mock suns, consist of the simultaneous appear-
ance of several images of the true sun. They are at the same
height above the horizon as the sun, and are connected by a
horizontal circle, which is sometimes colored, but usually white-
The cause of these suns is not satisfactorily explained : they
are supposed, however, to depend in some way upon the reflec-
tion and refraction of the sun's rays. There may be parhelia
without rings, and rings without parhelia. They never appear
in an unclouded sky, — sometimes occur opposite to the sun.

FIRE BALLS.

These are "luminous bodies which suddenly appear in the
sky, usually at a great height above the earth, and shoot
through the heavens with immense velocity, and are sometimes
accompanied by the fall of an aerolite." Various hypotheses
have been proposed to account for these meteors : limit does
not admit of a detail of these opinions ; and it is perhaps suffi-
cient to say, that the true explanation of this phenomenon has
not, so far as we can ascertain, been given.

RAINBOW.

This well known and beautiful meteor consists of two con-
centric arches, formed of the colors of the solar spectrum. It
is caused by the refraction and reflection of the sun's rays
while falling on drops. of rain. The size of a rainbow depends
upon the height of the sun above the horizon. Inverted bows
are sometimes seen on the ground; they are formed by the
rays of the sun falling on the drops of dew or rain which are
suspended from the tops, of grass, or from spider' webs : they

METEOROLOGY. 149

are also seen about waterfalls and ship masts, forming a perfect
circle. Lunar rainbows are sometimes seen in the night time ;
but their colors are faint and indistinct In order to see a
rainbow, we must face a cloud and turn our back to the sun
or moon. The philosophical explanation of rainbows will be
found in works on natural philosophy and meteorology.

MIRAGE.

Mirage is an optical illusion often observed at sea, especially
in high latitudes ; it sometimes also appears on the land, par-
ticularly in Egypt and Persia: it is seen also on the margins
of rivers and lakes. It consists in the appearance in the air
over the surface of the sea, of multiplied images of objects on
the surrounding coast

" It arises from unequal refraction in the lower strata of the
atmosphere, and causes remote objects to be seen double, as if
suspended in the air." These images are sometimes inverted:
ships, whale fisheries, and other objects, are sometimes descried
by means of mirage at considerable distances. The mathe-
matical theory of this phenomenon will be found in works on
optics, &c.

SHOOTING STARS.

These are common and well known meteors, some of which
resemble fire balls in every respect. We shall not attempt
any description or explanation of them, as their origin and
nature are involved in great obscurity and uncertainty.

AEROLITES.

These are mineral masses which fall to the earth apparently
from the upper regions of the atmosphere. They have a dark
or blackish color externally and a grayish hue internally.
They have a specific gravity more than three times that of
water : chemical analysis of one specimen shows its constituent
elements to be, iron, sulphur, silex, nickel, magnesia, and some-
times chromium. These meteors have, with some probability,

*13

150 SCIENTIFIC AGRICULTURE.

been supposed to come from volcanoes in the moon : but there
is still great obscurity hanging about the whole subject

COLOR OF THE SKY.

The general color of the unclouded sky is azure or blue:
this is explained on the supposition that the particles of the
atmosphere, when illuminated, reflect mostly the blue rays.
Whenever the prevailing color of the sky is anything but a
pure blue, it is discolored by smoke, vapor and clouds; the
more dense these clouds, the nearer the color -of the sky
approaches to black. The deep red of the morning and
evening sky is explained by supposing the atmosphere permits
only the red and yellow rays to pass, and reflects the blue
rays. — [Muller.]

The fiery red of morning is caused by an excess of moisture,
which, notwithstanding the tendency of the sun's rays to
disperse it, forms clouds in the atmosphere, and hence indi-
cates rain. A gray sky at morning and a red sky at evening,
on the contrary, foretell fine weather. The various other
beautiful hues which tint the sky and fringe the massive
clouds, so as to produce all the varied gorgeous drapery of
the heavens, are caused by the absorption, refraction and
reflection of the different rays of the solar spectrum.

TWILIGHT.

Twilight is the diminished light of day, which is seen from
the setting of the sun on its sinking below the western hori-
zon, till the last faint gleaming of day has disappeared. The
time at which twilight begins and ends, is altogether arbi-
trary, and must depend very much on the acuteness of the
vision of the observer. It has been said to commence at the
moment of sunset, and terminate when the first small stars
are visible. Twilight is short in countries having a pure sky :
in Chili, it lasts only a few minutes. In high latitudes it is

METEOROLOGY. 151

of longer duration, on account of the sun's orbit being much
inclined to the horizon. In countries lying in the vicinity of
50° of latitude, twilight continues until the sun has descended
from 15° to 20° below the horizon.

The moon's light is only the reflected light of the sun, and
is estimated to be, when in its greatest intensity, only
part as much as the light of that vast luminary.

i

PART V.

AGRICULTURE

CHAPTER I.

FORMATION AND ELEMENTS OF SOILS.

THE soil is composed of disintegrated rocks, animal and
vegetable matters : most soils are made up of successive layers
of fine sand and organic matters, loam, fine gravel, clay, coarse
gravel, and occasional masses of rock of various sizes. Various
causes have concurred to produce the alluvial deposit on the
surface of the earth, which must ultimately have been formed
entirely of the rocks which constitute the solid basis and prin-
cipal bulk of the globe.

The running water of rivers and the great ocean current
which sweeps across the earth had denuded the rocks which
it washed in its course from the high Lpds to the plains and
valleys : in this way, ravines have been excavated, valleys filled
up, and vast level plains formed. The floods formed by rains,
and the torrents resulting from melted snow and ice, which
flow down the mountains' sides, wash away all loose matters,
and often undermine and tear away fragments of rock : these

154 SCIENTIFIC AGRICULTURE.

are swept along by the impetuous stream, tlieir corners worn
off, and they, together with the finer particles, are deposited
on the plains or in the valleys, in the form of sand, gravel and
"boulders."

The action of the air contributes powerfully to the decompo-
sition and crumbling of rocks. Water, also, which falls into
the cleavage or crevices of rocks, and becomes frozen, often
cleaves large masses asunder by its expansion in passing into
ice : these masses are again subdivided in the same manner*
until entire hills of marble, slate, and other rocks, 'are com-
pletely pulverized. The affinity of the gases of the air and
water for these elements of the various rocks produce the same
effect. The combined action of ice and water in transporting
masses of rock is another powerful agency in the formation
and distribution of soils. Immense blocks of rocks are fre-
quently frozen into ice, which is subsequently broken up and
floated by streams and freshets to great distances from their
original locality : these, in process of time, become pulverized,
and add their elements to the soil.

The action of fire in volcanic districts produces immense
effects in chaging the character of rocks, leveling hills, and
filling up valleys with ashes and lava: so vast is the quantity
sometimes thrown out at a single eruption, that the whole
country for many miles around is covered with the melted
rocks, scoria, ashes and cinders.

In this way Pompeii, Herculaneum and Stabia were inhumed
A. D. 79, by a single eruption of Vesuvius. Whole strata of
rocks are sometimes broken up by earthquakes, and are after-
wards disintegrated and mingled with the soil. The agency
of winds in wafting fine particles of alluvium and sand has in
many places entirely changed the character of the soil; in
some places vast barren plains have keen formed, " dunes " or
sand hills raised, fertile fields stript of alluvium, and others
coveted by sand containing no other elements of a fertile soil.

SCIENTIFIC AGRICULTURE. 155

It is apparent now, that the soil bears no necessary resem-
blance in all cases to the rocks on which it lies, except when
derived directly from them ; then it partakes of their nature.

After the surface of rocks has by these agencies become
sufficiently pulverized and decomposed to form a thin layer of
soil, lichens and mosses succeed in fixing their roots in it,
causing at the same time further disintegration of the rocks, ,
and increase of the soil" by their annual decay. When the-
soil becomes in this way of sufficient depth and fertility to
nourish other, larger, and more perfect species of plants, vegetai-
tion becomes more abundant: the decay of this, together with;
the organic and earthy matters of animals, which are returned
to the soil, combined with the art. and industry of man, — a
soil sufficiently deep and fertile for successful cultivation, is in«
process of time produced.

A general knowledge of the rocks, metals and earths, is of
great value to the agriculturist, in enabling him, by the indi--
cations which they afford, to discover springs, mineral waters,
ores, mines of coal or metal, marl, lime, valuable stones, &c. ;
and also to direct him. to the best locations for lime kilns, glass-
houses, brick kilns, potteries, foundries,; salt works, bath houses
and stone quarries. Modern chemistry has shown that almost
every substance is a compound of several others, — and future-
experiment may yet show us the compound nature of many
bodies which are now considered elementary. There would be
little difficulty in determining the character of any soil, had we
only to consider the constitution of the rock from which it was
originally derived.

But, during the lapse of ages, the various causes which have
been in operation have so changed them that their primitive
character has almost disappeared, and they must be considered
in thehvpresent actual conditions. Arable soils consist mainly
of silex and alumina, with some lime, iron,, sodium, potassium.

156 SCIENTIFIC AGRICULTURE.

manganese, magnesia, animal and vegetable remains in various
proportions and different stages of decomposition. The ele-
ments of the soil must exist in different proportions, in order
to render them available for agricultural purposes.

CHAPTER II.

METALS, METALLOIDS, AND ORGANIC ELEMENTS OF
SOILS.

SILICON.*

SILICON is one of the most abundant and widely distributed
substances, constituting probably one sixth of the entire mineral
weight of the globe. It is never found pure or in an uncom-
bined state, but always combined with oxygen, forming oxide
of silicon, or silicic acid. The vast mountains of granite, gneiss,
porphyry and sandstone, — mica, feldspar, crystal quartz, nearly
all precious stones, -the sands of the sea shore and desert, and
all stones that emit sparks on being struck by steel, are mainly
silicon.

It is contained in a crystaline state in the outside bark of
many plants, particularly in cane, bamboos and the grasses. It
is with difficulty separated from its oxygen, — but when sepa-
rated and pure, it is a fine whitish powder, destitute of taste
or odor: it undergoes no change, except becoming darker and
denser, by any common degree of heat, but melts before the
blow pipe into colorless glass ; it has no affinity for pure water,
so that it is not dissolved in it in the smallest degree ; it absorbs

* Recent investigations appear to show that silicon is neither a metal
nor a metalloid.

14

158 SCIENTIFIC AGRICULTURE.

water slowly, and allows it to escape easily. It is neither dis-
solved nor acted upon by any acid except the fluoric, — with
which it unites find forms a fluoride of silicon.

The equivalent number of silicon is 22.22, — its specific
gravity 2.GG. The fixed alkalies easily unite with silicon, and
form silicates, as the silicate of potash, lime, <fcc. It forms an
important ingredient in porcelain, glass, and the enamel or
glazing of stone ware. The salts of silicon are not numerous;
they are all insoluble in water, (according to Prof. Johnston,)
except those of potash and soda.

As silicon is so important an element in plants, and so inva-
riably present in all productive soils, a knowledge of its chemi-
cal character, and the best means of rendering it available to
the roots of growing vegetation, is indispensable.

ALUMINUM.

This metallic earth is found in greater abundance in nature
than lime, being one of the principal ingredients in nearly all
rocks, except the purest limestone : it is the principal element
of clay, and exists largely in garnet, albite and mica: it is found
also in the ashes of most plants. In its native state it is usually
found in combination with silica, and sometimes with sulphuric
or phosphoric acid: it is also found nearly pure, or uncombined,
in the ruby and sapphire, two beautiful precious stones. Alu-
mina is an oxide, and the only one known of the earth alumi-
num ; it is white, tasteless and inodorous ; its equivalent num-
ber is 13.7.

It dissolves in acids and in solutions of caustic alkalies; it
has a strong tendency to unite with organic matters, and has
fcbo a greater affinity for water than any of the other elemen-
tary earths. "When mixed with silica in the proportion to
form clay, it is easily molded into any form, as in stone and
earthen ware: it loses part of its tenacity by fire,. — hence the
benefit of burning clay soils. Alum is a salt formed by the
union of potash, alumina and sulphuiic acid, — this salt is

SCIENTIFIC AGRICULTURE. 159

extensively used as a mordant in calico printing. Alumina is
supposed to contribute but little to the nourishment of plants:
it is said by Liebig to be an absorbent of ammonia: this,
however, is doubted by Prof. Johnston. Its principal agency
as ji.i element of soils, is of a mechanical kind. The salts of
alumina are few; they have not been sufficiently tested as
fertilizers to determine precisely their value in this respect:
Sprengol considers them highly deserving of trial in practical
agriculture.

MANGANESE,

This mjtal is diffused widely through nature, although not
in great abundance: it is found mostly in the mineral, — but
traces of it also exist in the animal and vegetable kingdoms.
It has a very strong affinity for oxygen, and is therefore with
difficulty reduced from its oxides and ores, — which, however,
may be done by a long continued and intense heat

It is hard, brittle, granular, grayish white, and has a specific
gravity of 8 : it is very infusible, soon tarnishes by the absorp-
tion of oxygon, and after a while falls into a black powder.
There are several oxides, two acids, and many salts of manga-
nese, some of which are soluble and others insoluble in water.
It is used in the arts, and is probably a necessary ingredient
in soils. Its equivalent is 27.G7.

IRON.

This is the most important of all the metals, and is the most
extensively distributed over the earth. It is sometimes found
in loose blocks of pure metal on the surface ; but mostly in
veins and mines, combined with sulphur, forming a gold
colored ore, called sulphuret of iron, — and with oxygen in the
form of the black and red oxides : it is also extensively com-
bined with carbonic acid, constituting the clay iron ore. Native
arsenites, phosphates, sulphates and other salts have been,
found.

Nearly all reddish soils and stones are colored by oxide of

160 SCIENTIFIC AGRICULTURE.

iron. Pure iron is bluish white, brilliant malleable and ductile,
the strongest of all metals, and has a specific gravity of 7.8 ;
its equivalent is 27.14.

Iron oxidizes readily when in contact with moisture, and
also by heat. Only two of the oxides are of any interest to
the agriculturist, viz: the black and the red. The black oxide
rarely occurs in the soil, except in combination with some acid ;
and this, when exposed to the air, absorbs oxygen and changes
to the red oxide. When the black oxide or sulphate is present
in moist boggy soils, it proves injurious to vegetation: the red
is less injurious. Both are insoluble in pure water, and both
are soluble in acids. The red oxide is said to absorb ammonia
from the atmosphere, and by thus bringing it within the reach
of plants, it is in this way useful, when the soil contains any
considerable quantity.

A red soil containing much iron should be turned over fre-

iD

quently, so as to keep it pervious to the air ; and, according to
Johnston, such soil "may occasionally be summer fallowed with
advantage, in order that the oxide may absorb from the air
those volatile substances which are likely to prove beneficial
to the growth of future crops."

The sulphate of iron (green vitriol,) is often found in soils,
particularly in bogs and marshy places, and it is said to be
very injurious to vegetation: these effects are counteracted by
lime, marl, and plaster, which decompose the sulphate and
unite with the sulphuric acid and form gypsum. In this way
it is beneficial to soils containing lime, and may be used as a
manure. Iron is found in the ashes of nearly all plants, and
to a small extent in animal bodies. It is probable that some
of the soluble salts of iron are requisite to the growth of most
plants.

SODIUM.

Sodium exists in vast quantities, and is widely diffused
through nature : it is found combined with chlorine, forming

SCIENTIFIC AGRICULTURE. 1G1

common salt, of which great quantities are found in Poland,
England and elsewhere. It is the principal saline ingredient
in the waters of salt lakes and the ocean. It is found in many
minerals, most plants, and in all the animal fluids. Sodium is
found in vast quantities in South America in the form of a
nitrate.

The pure metal -sodium is lighter than water, its specific
gravity being 0.972; its equivalent number is 23.3. It is a
silvery white metal, resembling potassium closely in its appear-
ance. The compounds of sodium are numerous and important
This metal is soft at common temperatures, melts at 194° F.,
and oxidizes rapidly in the open air.

As soda exists in most soils, and is found in some form in
most if not all plants, it is probably a necessaay ingredient in
soils ; many of its salts, particularly the nitrate, sulphate, chlo-
ride and phosphate, are valuable fertilizers.

POTASSIUM.

This is the metallic basis of potash : it is bluish white when
not exposed to the air, but by the contact of ajr it instantly
oxidizes and becomes covered by a crust of the alkali, potash:
when thrown in water, it takes fire and burns, with a violet
flame. At common temperatures it is soft and may be
molded into any form, like wax: "at 32° it is quite brittle,
and crytalizes in cubes;, at 70° it is pasty, and at 150°, per-
fectly liquid. At a dull, red heat, it boils, forming a green
vapor, and may be distilled."

Like sodium, it is lighter than water; its specific gravity
being 0.655. Potassium has a remarkable affinity for oxygen,
which it abstracts from almost all other bodies. Its equiva-
lent number is 39.3. Potash is a strong fixed alkali: it neu-
tralizes the strongest acids, and its salts are numerous and
important Potassium is not found in an uncombincd and
pure state in nature, but in the form of an oxide : it exists in

*H

162 SCIENTIFIC AGRICULTURE.

many minerals, nearly all plants, and in animal bodies. It is
most abundant in the green and tender parts of plants, — the
timber of forest trees contains comparatively little.

Its powerful action on other metals and earths, its caustic
action on vegetable substances, and its almost universal pre-
sence in soils and vegetation, show it to be an indispensable
element of good soils, and a powerful fertilizer. Potash is
rendered more caustic by mixture with quick lime, — in this
way it is beneficial in compost by facilitating the decomposition
of vegetable matters.

MAGNESIUM.

Magnesium is found in the minerals, serpentine, talc, steatite,
asbestos, augite, chrysolite and hornblende: it is always found
combined with acids, or other earths, — it is found also in marl,
and in small quantities in animal substances. It is a white,
silver-like metal when pure, malleable, and fusible at a red heat,
not changed by dry air, but slowly oxidized by damp air: it
dissolves in dilute acids, giving off hydrogen gas, and forming
a salt of magnesia.

Its equivalent number is 12.7. When heated to redness in
the air, or in oxygen, it burns with brilliancy, and forms mag-
nesia, or oxide of magnesium: it inflames spontaneously in
chlorine. It exists in considerable quantity in nature, par-
ticularly in magnesian limestone.

Magnesia slowly but entirely neutralizes acids ; it is inodorous,
white, has a slightly alkaline taste, absorbs and retains water
to nearly the same degree as lime, but is less caustic and
alkaline. There are several important salts of magnesia, some
of which are valuable as fertilizers, and indispensable to the
growth of vegetation.

CALCIUM.

Calcium is a white silvery metal, heavier than water, —
having a strong affinity for oxygen, with which it combines

SCIENTIFIC AGRICULTURE. 103

only in one proportion, forming lime. The equivalent number
of calcium is 20.5.

Lime is the most important and abundant of all the earths,
being extensively distributed through the mineral kingdom,
and constituting the principal earthy ingredient in the shells
and bones of animals, and also existing in all plants. It is
found in nature combined with carbonic acid, as in marble,
limestone and chalk, in quantities so large as to form entire
mountains. It is found combined with sulphuric acid, consti-
tuting gypsum or plaster of paris: it is also combined with
phosphoric, fluoric and arsenic acids.

The minerals, calcareous spar, gypseous spar, arragonite, and
many others, are composed of lime. All natural waters con-
tain more or less of this earth. Lime is a pure, white, alkaline
earth: when burned lime is exposed to the air, it rapidly
absorbs water, and falls into a line powder, which is called
"slaked lime," or hydrate of lime. This earth has a strong
affinity for acids, with which it forms several salts. It is only
sparingly soluble in water, and less so in hot than in cold
water : when completely dissolved in clear water, it is called
lime water: this, when exposed to the air, unites with the
carbonic acid of the air, and a thin pellicle or layer of carbon-
ate of lime is formed on the surface, — this soon falls to the
bottom, and another layer is formed ; and so the process con-
tinues until the lime ail becomes a carbonate, and is thus
precipitated from the water.

Lime attacks and destroys both animal tissues and vegetable
substances with rapidity, and without the exhalation of those
noxious gases and offensive odors, which result when putre-
faction goes on without the presence of lime. Lime is valua-
ble as a manure in soils destitute of this earth, by supplying
an indispensable element to plants, and also by neutralizing
r.cidity, dissolving silica, and decomposing insoluble organic

16-i SCIENTIFIC AGRICULTURE.

m liters, such as woody fibre, humus, peat, ulmine, <kc. The
salts of lime arc also of great value as fertilizers.

MARL.

Marl is a compound of lime and clay, so intimately mixed
that their respective particles cannot be distinguished. The
exact process by which nature combines the two elements is
not known; for if clay and lime -be mixed together artificially,
they form a substance quite different from natural marl: &nd,
according to Timer, "it does not possess the faculty of losing
its aggregation when exposed to the influence of the atmos-
phere, and crumbling to dust like natural marl."

The proportions of the two elements are various: sometimes
the lime predominates, sometimes the clay, and in some speci-
mens they are equal. When the clay predominates greatly, it
is called clay marl: when the lime predominates, it is called
Iim2 ra ii-1. M irl is found in considerable variety, both of com-
position and color: it assumes a blue, red, yellowish or whitish
hue, according to the oxides of iron, or other matters which it
may contain : it is found in greater or less quantities in almost
all countries, — sometimes on or near the surface, and in other
cases at considerable depths in the earth.

"It is confined [says Dr. Hitchcock,] to the alluvial and
tertiary strata, and differs from many varieties of limestone,
only in not being consolidated." It often contains salts of
potash and soda, fragments of shells, bones, and some vegeta-
ble matter: that which contains a large quantity of shells is
called shell marl: several other species of marl are described,
the most important and valuable of which is greenstone marl

Nearly all the varieties, except stone marl, are easily pene-
trated and their particles separated by water: frost is also an
active agent in pulverizing it, — it is therefore often laid on
land at the beginning of winter. Marl may be detected by
the acids, with which it effervesces and forms salts. It is
evident from the character and composition of marl, that it is.

SCIENTIFIC AGRICULTURE.

a valuable fertilizer, especially on lands deficient in clay and

lime.

GYPSUM.

Gypsum is a compound of sulphuric acid, lime and water:
it is sometimes found in the form of a soft yellowish white rock,
with a texture resembling that of loaf sugar ; " but sometimes
[says Lyell,] it is entirely composed of lenticular crystals." It
is insoluble in acids, and does not effervesce, for the reason
that it is already combined with sulphuric acid, for which it
has a stronger affinity than for any other. A variety called
anhydrous gypsum sometimes occurs, which contains no water.

Gypsum is nearly insoluble in pure water; — when deprived
of its water by heat, it is called calcined gypsum, or " plaster
of paris," — in this state, if mixed with water, it may be formed
into molds or casts, and it soon solidifies into a hard, white,
compact mass. When calcined gypsum is long exposed to the
air, it absorbs moisture, and is no longer fit for casts and stucco
work, until calcined afresh. Gypsum can only be fused by a
high degree of heat, — it does not then part with its sulphuric
acid, but only loses its water. The origin of this rock is diffi-
cult to explain ; its found mostly among the new red sandstone,
but occurs also among other rocks.

It is found in most countries in great abundance, and in
various forms, as gypseous spar, gypseous stalactites and sta-
lagmites, compact gypsum, &c., and in combination with clay
and lime. Gypsum cannot be formed artificially. Water con-
taining gypsum is called hard water. The decomposition of
gypsum can be easily effected by the alkaline carbonates: if
powdered gypsum be boiled in a solution of carbonate of
potash, a double decomposition, and also reunion, takes palce ;
the sulphuric acid of the gypsum unites with the potash, and
forms sulphate of potash, while the carbonic acid unites with
the lime of the gypsum and forms carbonate of lime. Gypsum
is one of the most valuable fertilizers known.

106 SCIENTIFIC AGRICULTURE.

CLAY.

Clay is a compound of the t\vo earths, silica and alumina, in a
state of chemical union: it usually contains, also, an excess of
uncombined silica in the form of sand. Proper clay is formed
by nature alone, for no chemical process is known by which
silica and alumina can be made to unite so as to form real clay.
It is usually colored by some of the oxides of iron, so as to
present a bluish, yellow, red or brown hue.

The two elements of clay are rarely contained in equal
quantity ; the silica almost always predominates, — sometimes
to the amount of 93 per cent. Clay sometimes contains an
insoluble carbonate or phosphate of iron, which are both
thought to be injurious to vegetation. It sometimes contains
also manganese and sulphate of iron, the last of which, unless
in a limy soil, is injurious to plants: organic matters are often
found in clay, giving it a blackish hue and astringent properties.
Clay has been form ad by the decomposition of rocks, such as
granite, feldspar, clay slate and argillaceous schist.

Clay which contains neither iron nor vegetable matter, does
not change color by heat: if it contains vegetable matter, it
becomes lighter colored by heat; if colored dark by oxide of
ircn, it may become lighter by burning, on account of the iron
changing its proportion of oxygen. White clay, which does
not change color by heat, is nearly or quite pure. When clay
is dry, it absorbs water rapidly, becomes tenacious and adhe-
sive, so as to retain any form or impression given to it: when
saturated with water, it no longer allows that fluid to pass
through it: it is from this cause that water stands long on the
surface of the ground in swamps having a clay_ subsoil, — and
this is why we find springs and water veins before we come to
solid rock.

When wet clay is exposed to frost, it is cracked or fissured,
and sometimes completely pulverized, by the expansion of the
water it contains, during freezing. It retains water with more

X

SCIENTIFIC AGRICULTURE. 107 -

tenacity than any other earth, and after being deprived of its
water by- heat, becomes hard. After being heated to red
clay loses its ductile properties, is insoluble in water, and is of
no use in the soil, urtil, by long action of the atmosphere,
moisture, and animal manure, it is changed to its former con-
dition. Clay does not effervesce with acids, unless it contains
lime or carbonate of iron : it requires a high degree of heat for
its fusion. Clay is often found in combination with gypsum.
There are several varieties of clay, of which we notice only a
few.

Kaolin, or porcelain clay, is the purest and finest, and is
used in the manufacture of porcelain ware: it is of a yellowish
or grayish white hue, and is supposed to be formed by the
decomposition of feldspar.

Pipe day ranks next to kaolin in fineness, and is of various
hues.

B^le is a species of red clay, used in the manufacture of
brown earthern ware.

Potter's clay is used for bricks and stone ware.
CLi'j iron ore contains carbonate and phosphate of iron, and
has been described under the head of iron.

TEAT.

"Peat usually consists of soluble and insoluble geine, with
a mixture of undecomposed vegetable matter and some earths."
It is usually limited to the colder parts of the globe: it results
mostly from the accumulation and decomposition of mosses,
but also from any other vegetable matters which become
mixed with it

The lower stratum of peat beds decays, while the plants on
the surface continue to grow, thus adding new matter annually
until they attain the thickness, in some cases, of thirty or forty
feet. In tropical climates, the heat produces decomposition so
speedily that vegetables are resolved into their elements before
peat can be formed.

.

1G8 SCIENTIFIC AGRICULTURE.

Pe.it is usually found also in low boggy or marshy districts.
According to Dr. McCulloch, "by the long continued action of
water and other agents, the geine of peat is changed into bitu-
men and carbon, which constitute lignite and bituminous coal :
in a few instances the process of bitumenization has been found
considerably advanced in beds of peat."

Peat is remarkable for its power of preserving animal mat-
ters from putrefaction.

The following is an analysis of a specimen of peat from
Massachusetts.

Soluble geine, - 26.00

Insoluble do. - - 59.60

Sulphate of Lime, - - 4.48

Phosphate of do. - - - - 0.72

Silicates, - 9.20

100.00

When the decay is far advanced, the peat is a dark colored
and sometimes solid mass; when less advanped in decomposi-
tion, it is light brown, spongy, and contains pieces of vegeta-
bles not yet disorganized, — in this state it is used in some
countries as fuel. Peat is sometimes sour, from the presence
of phosphoric and acetic acids : it sometimes also contains am-
monia; it decomposes slowly in the open air. When mixed
with lime or potash and fermenting barn-yard manure, it
becomes a valuable fertilizing agent, and may be used on any
soil which requires the addition of vegetable matter.

HUMUS.

Humus is a brown or blackish colored substance, composed
of vegetable matter in a state of decay. " Humus [says Bous-
singault,] is the last stage in the putrefaction of vegetable
organic matter : its elements have acquired a stability which
enables them to resist all fermentation." It is of a spongy
texture, easily pulverized, and nearly insoluble in water: it

SCIENTIFIC AGRICULTURE. 169

absorbs water with such avidity as to contain three fourths of
its own weight without being moist

Weak acids have little effect on humus, except to dissolve
the alkaline and metallic or earthy matters which are usually
mixed with it Potash and soda dissolve humus entirely, with
the evolution of ammonia: from this solution, acids cause a
precipitate of a brown inflammable powder resembling ulmine.
Humus contains more carbon and nitrogen than the vegetables
from which it is derived : the nitrogen may be partly formed
from the excrements of insects which live in the humus.

Humus contains, besides some mineral elements, carbon,
oxygen, hydrogen and nitrogen, phosphoric, sulphuric and
humic acids. Humus is dissipated when exposed to the air by
a slow combustion, with the disengagement of carbonic acid.
This, and all vegetable earths, are entirely destructible. Salts
are formed during the decomposition of humus, by the union
of bases with the humic acid, — these are called humates.

Besides the above elements, humus contains, according to
Berzelius, humic, crenic and apocrenic acids, and traces of
glairin. Humus is an indispensable ingredient in all fertile
soils, hence the necessity of replacing it in the soil as fast as it
is exhausted.

Agriculturists who think to supply the place of manure by
frequent and deep ploughing, have been disappointed, and
their fields have been gradually impoverished by crops, until
they became barren. When humus is put on a clay soil, it is
retained with such tenacity by the clay, that the free contact
of air is prevented, and it decomposes more slowly, — for this
reason clay requires a larger quantity, other things being
equal, to produce the same effects, than other soils.

Sand allows free access of air to the humus, which is incor-
porated with it, and thereby favors its decomposition and
consequent fertilizing power. Lime and potash destroy the
acidity of sour humus, and favor its decomposition: sour

15

170 SCIENTIFIC AGRICULTURE.

humus contains an insoluble extractive matter, which is inju-
rious to vegetation. A soil which abounds in sour humus
produces little but reeds, rushes, flags, sedge, and other poor
and unpalatable plants: such soils are rendered fertile by
draining, burning and alkalies,

CHAPTER III.

PHYSICAL PROPERTIES OF SOILS.

THE physical properties of soils necessary to be considered
are, density, weight, state of division, firmness and adhesive-
ness, power of imbibing moisture, power of containing water,
power of retaining water, capillary power, contractibility on
drying, power of absorbing gaseous matters, power of absorb-
ing heat, power of containing heat, and power of radiating
heat.

The weight of a soil depends upon its density, or the
proximity and density of its particles. Dense soils retain heat
longer than light ones, and afford a firmer support to the roots
of plants.

The following table, from Johnston, shows the relative
weight of several soils.

A cubic foot of dry silicious or calcareous sand weighs 180 Ibs.

" " Half sand and half clay " 95

" " Of common arable land " 80 to 90

" " Of pure agricultural clay " 75

" " Of rich garden mold " 70

" " Of a peaty soil "39 to 50

The state of division of the particles composing the soil has

an effectvupon its weight, as well as money value. A soil

eomposecTof clay, sand, coarse and fine gravel and vegetable

172 SCIENTIFIC AGRICULTURE.

mold, is superior in all respects to to one composed of either of
these ingredients alone.

Firmness and adhesiveness. — Most soils become hard and
stiff in some degree, by the cohesion of their particles after
being thoroughly wet. Clay soils become hard and difficult to
pulverize when thoroughly dried, while pure sand soils scarcely
cohere at all. This varies according to the relative amount of
sand and clay or lime in the soil. The practical inference is,
that a sandy soil is improved by clay, and a stiff clay soil is
ameliorated by sand.

The power of imbibing moisture is possessed by all fertile
soils. In dry weather, this quality in soils is highly important,
in order that moisture may be absorbed from the dews of the
night, to compensate to the roots of plants what they had lost
by exhalations from their leaves and evaporation from the soil,
during the day.

During a night of twelve hours, when the air is moist,
according to Schubler,

1000 pounds of perfectly dry quartz sand will gain 0 Ibs.
" " Calcareous " " 2

" " Loamy soil " 21

" " Pure agricultural clay " 27

" " Rich peaty soils, still more.

Power of containing water, in dry climates, constitutes one
of the most important characteristics of arable soils. A good
soil for ploughing or tilling must be capable of containing from
30 to 70 per cent, of its weight of water: soils which allow
their moisture to sink down immediately after rains, below the
reach of the roots of plants, are valuable only " for pine plan-
tations or laying down to grass." — [Johnston.]

The following table from Schubler shows the relative capacity
of soils for containing water. By this, we mean, the amount
of water which a given quantity of earth will imbibe and

SCIENTIFIC AGRICULTURE. 173

contain, before it is saturated or full, so as to allow the water
to drop or run out

From 106 Ibs. of dry soil, the water will begin to drop, if it
be a quartz sand, when it has absorbed 25 Ibs.

Calcareous sand, " " " " 29

Loamy soil, « " " " 40

English chalk, « " « « 45

Clay loam, « « " « 50

Pure clay, " « " « 70

Power of retaining water. — Evaporation is constantly going
on from the surface of the earth, except when the atmosphere
is saturated, or rain or dew is falling. The rapidity with which
soils become dry after rains, depends upon the tenacity with
which chey retain water : as a general rule, those soils which
are capable of containing the most water, also retain it with
the greatest tenacity. Thus a sand soil will lose as much
water in one hour as a clay in three, or peat soil in four hours.
On this property depends in a great degree the warmth or
coldness of a soil.

The capillary power of the soil is exhibited by pouring
water into the bottom of a flower pot, when it will be seen
that the earth gradually takes up the water, and the moisture
soon appears on the surface. In the same way the surface
soil absorbs moisture from the subsoil ; and when this contains
an excess of water, the surface is also too wet and cold. Open,
porous soils, -such as sand, peat and humus, possess greater
capillary power than stiff clay. Upon this action the soil is
dependent for its supply of moisture during dry weather:
upon this, also, the roots of plants are dependent for a supply
of soluble saline matters, which, during rains, have been
washed down into the subsoil beyond their reach. This is the
principal means by which, in hot, dry climates, where rains
seldom or never fall, the soil obtains sufficient moisture to
produce vegetation. This capillary action explains the exis-

*15

174 . SCIENTIFIC AGRICULTURE.

tence of the thick crusts of nitrate, carbonate and chloride of
soda, which are met with in Peru and other parts of South
America, India and Egypt These salts are brought to the
surface by capillary action, in a state of solution, and deposited
as the water evaporates.

Contractibility on drying. — Some soils contract or shrink
on becoming dried after rains, much more than others; and
this appears to be in proportion to their power of retaining
•water. Thus clay and peat diminish in bulk one fifth on being
perfectly dried after saturation, while sand maintains the same
bulk in either state. — [Johnston.] This contraction in clay
soils has a tendency to tear and injure the small and tender
roots of plants.

Power of absorbing gaseous matters.— rThe necessity of free
access of air to the soil has already been noticed; and in
proportion to the amount of air which is admitted into the soil,
will be the oxygen and other gases absorbed and made avail-
able to the roots of vegetation. Clays, peat and humus absorb
more oxygen than sandy soils ; this is due partly to difference
in porosity, and partly to the chemical character of each. Be-
sides oxygen, soils absorb carbonic acid, ammonia, nitric acid,
and other vapors which contribute to fertility. All soils absorb
gaseous substances the most readily when in a moist state ; so
that dews and showers are of great benefit, in bringing the soil
into a condition to extract from the air fresh supplies of the
gases.

Power of absorbing heat. — The earth is capable of absorbing
lieat during sunshine, so as to attain a temperature above the
surrounding air. Dark colored, brown and reddish soils absorb
heat most rapidly, and become warm the soonest They also
become from three to eight degrees warmer than other colored
soils, and by this means they promote the growth of vegetation
better than those of other colors. This property gives an
additional value to dark soils over light ones, in countries

SCIENTIFIC AGRICULTURE. 17-">

where sunshine is deficient, and in fields which bavo a northern
aspect

Power of retaining heat. — As heat always tends to seek an
equilibrium, it follows that after the sun has disappeared, and
his rays cease to shine on a particular part of the earth, the
amount of heat which it has absorbed above that of the air is
gradually given off again to the latter, until their temperature
is equal, or until the air becomes the coldest, — as in frosty
nights. A peat soil cools more quickly than clay, and clay
more quickly than sand. This difference must have an influ-
ence on the growth of crops. In cold, wet soils, the property
of radiating heat slowly compensates in some degree for the
injury done (o plants by these conditions. It also prevents the
formation of dew and frost, as soon as would otherwise be the
case. On the contrary, soils which radiate heat faster promote
the formation of dew by becoming cooled below the dew point
sooner, and in this way compensate in some small degree, for
deficiency of rain.

The absorbing, as well as radiating power of the soil, may
be increased by a top dressing of soot, charcoal, muck, or some
dark colored manure. The principle of absorption and radia-
tion as dependent upon color, holds true in relation to plants,
as well as to soils: and, if all other conditions are favorable,
the light colored, (white straw,) crops should be cultivated on
dark colored soils, and the dark colored, (green straw,) crops
on the light colored soils*

The study of the mechanical and physical properties of
soils is of more importance than has generally been supposed.
These have now been discussed as fully as limits would admit,
and we conclude the subject by stating finally, what are the
ultimate uses and relations of the soil to plants.

* This idea is original with the author, so far as he knows : whether
of any value or not, others may judge and decide.

176 SCIENTIFIC AGRICULTURE.

First, the soil serves as the foundation for upholding and
giving mechanical support to the vegetable structure.

Secondly, it absorbs light, heat, air and moisture, which are
indispensable to healthy vegetation.

Thirdly, it supplies both the organic and inorganic elements
required by the plant as food.

Fourthly, it is a chemical laboratory, in which these ele-
ments are constantly being prepared to be taken into the plant
by its roots.

CHAPTER IV.

TILLAGE.

ALL operations upon the soil for its improvement and prepa-
ration for crops, may be included under the two heads of
tillage and stercology, or manuring. Tillage includes the
operations of draining, irrigation, paring and burning, rotation
of crops, fallow, extirpation of weeds and insects, ploughing,
ribbing, lapping, laying in beds, scarifying or grubbing, subsoil
ploughing, trenching, rolling, harrowing, hoeing, spading, &c.

The objects of tillage are, — 1. To loosen the soil and render
it permeable to air, water and the roots of plants. 2. To bring
up the subsoil and mix it with the surface. 3. To incorpo-
rate manures with the soil. 4. To allow free access of the
heat and light of the sun. 5. To pulverize the coarse and
compact portions. 6. To destroy weeds and insects. V. To
bury green crops designed for manures. 8. To render wet
soils dry and arable. .9. To supply a sufficiency of water to
dry soils. 10. Tojix movcable and light blowing soils. 11. To
clear the soil of roots ami stones. 12. To cover seeds with
soil "after sowing. t -. .5^%*$**"— ^.

The following operations are described by Colman, and are,
part of them, peculiar to the agriculture of Europe.

Lapping consists in turning a furrow upon an unploughed
surface, so that when the field is finished, it is only half
ploughed.

178 SCIENTIFIC AGRICULTURE.

Ribbing resembles lapping, except that two furrows, instead
of one/ are turned upon the same unploughed space.

Stitching or laying in beds consists in turning two furrows*
back to back, and then ploughing alternately on either side,
until the bed is from 5 to 60 feet wide, and leaving deep fur-
rows between all the beds.

Trench ploughing consists in making a deep furrow, by
ploughing one furrow directly in another.

Subsoil ploughing consists in breaking up and loosening the
subsoil with a plow for that purpose, and without inverting the
surface.

Scarifying or grubbing differs from harrowing only by being
performed with a cultivator or similar instrument, which goes
deeper into the earth than the common harrow, for the purpose
of pulverizing the soil, and bringing up roots and stones to the
surface.

The other operations of tillage need not be described, as
they are common and well understood. There can be no
question that much of the success of productive agriculture
depends upon the perfection of tillage. A perfect tillage
requires the combination of patient labor, mechanical imple-
ments of the best construction, and skill in the operations.

A poor soil well tilled may produce better crops than a good
soil without tillage. Thorough tillage, by mixing and pulveri-
zing the soil sufficiently, is a means of saving manures and
greatly increasing the return of the harvest: it is not, however,
true, as once supposed, that tillage will supercede the neces-
sity of all manures ; it only compensates for part of the manure
requisite, and facilitates the operation of that which is applied.
The Chinese, and some nations of Europe, have, by a perfect
svstem of tillage, rendered barren soils fertile, and caused
fertile soils to vield harvests of almost incredible amount.

flCIENTIFIC AGRICULTURE. 179

IRRIGATION.

Irrigation has been practiced by the Chinese and Egyptians
from the remotest antiquity. In countries where rains seldom
fall, and the ground becomes dry and parched, irrigation is of
immense value. It consists in taking water from lakes, sewers,
running streams or reservoirs, and causing it to flow over the
land by means of small canals or furrows, then by proper out-
lets to carry it off again. It is confined, according to Colman
and Johnston, almost exclusively to meadow lands.

The benefits of irrigation in a country where rain falls fre-
quently and abundantly, are the same as those of manuring.
When the water used holds in suspension any organic matters,
they subside while the water remains on the fields, and leave
a visible layer of manure on the surface, after the water is
drained off. An example of the fertilizing effects of irrigation
is seen in the lands along the banks of the Nile and Ganges.
But the effects of irrigation with water that contains no organic
sediments, must be considered the same as that of rains. Run-
ning water furnishes to plants some gasses, which are absorb-
ed, and in this way are beneficial. Crops of young and ten-
der plants should be irrigated by pure water : it may be re-
peated every two or three weeks when there is any want of
rain, and the water be allowed to lie on the field only three or
four days. It is thought by English Agriculturists to be inju-
rious to meadows to flood them immediately after mowing.

Warping is a process similar to irrigation: the object of
this, however, is more especially to obtain the sediments of
muddy streams, &c. ; the water should never be allowed in
either process to remain on the field until stagnated. Irriga-
tion is most beneficial on land which is well drained beneath,
so as to allow the water to penetrate the subsoil, and not stand
too long on the surface. Meadow lands are sometimes water"
ed in the winter to prevent the injurious effects of frost upon
the roots of the grass. Irrigation is not practiced to much ex-

180

SCIENTIFIC AGRICULTURE,

tent in the United States; and the remoteness of many farms
from streams, as well as the expense attending the operation,
will prevent its universal application, even where it would be
beneficial.

PARING AND BURNING.*

Paring and Burning is much practiced in many parts of
Europe, particularly in Great Britain; but, so far as we are
informed, it is but little practiced in the United States. It is
done mostly upon sward, peat and turf soils. The operation
consists in removing, with a plow or spade, a slice from the
surface, from one- to three inches thick : this is piled up in
small heaps along with other combustible matters, such as
brush, weeds and decayed wood ; these, when sufficiently dry,
are fired and allowed to smoulder and burn slowly until the
whole is reduced to ashes. The ashes are then spread evenly
over the surface of the soil. The quantity of ashes which is
sometimes obtained in this way at a single burning, is stated
by Colman to be 2660 bushels, or about 77 tons per acre.

The benefits of paring and burning are, — 1. It disentegrates
and reduces to fineness, some stones and hard clay. 2. It de-
stroys insects, with their eggs and larvae. 3. It reduces vege-
table matter to ashes and gases, which are available for the
immediate food of a crop of plants. There are some objec-
tions to this process, which ought to be stated, as it involves
some principles not wholly understood.

One objection is that it consumes too much of the vegeta-
ble and organic matters of the soil: another is the amount of
labor required in the operation. The benefit however, of par-
ing and burning upon cold, moist, sour, peat and turf soils, is
unquestionable. The lime and potash produced, serve to neu-
tralize acids in the soil, and the iron, if it contain any, is brought
to a higher degree of oxydation.

On light, sandy, gravelly soils, where vegetation is thin and

* This operation is very little practiced in America.

SCIENTIFIC AGRICULTURE. 181

there is little organic matter present, this practice is injurious.
The process of burning, according to Boussingault, ought to
cease after the organic matters are reduced to a blackish ash ;
for when carried beyond this, so that incineration is complete
and a red ash is left, it may materially injure, if not render
the soil barren.

DRAINING.

The draining of wet lands has become one of the most im-
portant branches of mechanical agriculture. An excess of
water in the soil prevents the access of air, reduces the tem-
perature, favors the formation of frost, fogs and mildew, and
renders tillage difficult or impossible. Soils may be rendered
too wet in various ways, as, by the tides of the sea, by the
setting back of rivers, by permanent springs in the soil, by
small subterranean streams, and by the compact and retentive
nature of the soil or subsoil. The advantages of draining, and
the various modes by which it is best accomplished, are well
described by Johnston and Colman, from whose works the fol-
lowing facts in relation to the operation are derived.

1. It carries off all stagnant water, and gives a ready escape
to the excess of what falls in rain. 2. It prevents the ascent
of water from below, either by capillary attraction, or springs.
3. It allows the water of rains to penetrate, and find a ready
passage from the soil, instead of washing the surface. 4. The
descent of water through the soil is followed by fresh air, which
occupies the space just left by the water. 5. The soil after
thorough draining becomes looser, more friable and easily
broken ; this is especially true of stubborn clays, which in
practice become altogether another soil. 6. By freeing the
soil from the excess of water, it becomes warmer, and thereby
advances the crop to an earlier harvest: thus it is "equivalent
to a change of climate" 7. When the autumn is wet, drain-
ing carries off the superabundance of water, and prepares the
land for sowing fall crops, which would otherwise be retarded,

16

182 SCIENTIFIC AGRICULTURE.

or altogether prevented. 8. In its consequences it is equiva-
lent to an actual deepening of the soil. 0. In wet soils, bone?,
wood-ashes, rape dust, nitrate of soda, and other artificial ma-
nures are almost thrown away. 10. He who drains confers a
benefit upon his neighbors also. 11. It produces a more salu-
brious climate, and conduces greatly to the health and moral
happiness of the whole population.

Several different modes of draining are practiced in Great
Britain, which are worthy of notice — some of them arc also
known and practiced in the United States. The, process of
draining by open ditches is the rudest, and was doubtless the
first form of draining. Covered drains were next substituted,
of various construction. One form of these is made by dig-
ging a ditch, and then filling it with straw or faggots, and cov-
ering it over with the earth which was thrown out. Another
form is excavated so as to taper to a point at the bottom, and
having a shoulder left at the height from the bottom which it
is desirable to cover the waier-course. This is then covered
by an inverted sod, which rests on the shoulders; after which
the earth thrown out in excavating is returned, and the surface
levelled. Another process is by the mole plow : another by
filling the bottom of a ditch with small stones of uniform size.
Two other forms, called in England tile and pipe drains, are
constructed by means of tile and pipes made of brick clay,
and are said to form water-courses which are both cheap and
durable.

FALLOWING.

"By fallowing, it has been known in all ages that the produce
of the land was capable of being increased. How is this in-
crease to be accounted for t We speak of leaving the land to
rest, but it can really never become wearied of bearing crops.
It cannot, through fatigue, lie in need of repose. In what, then,
does the efficacy of naked fallowing consist?" (Johnston.)

Some agriculturists reject the practice of fallowing as use-

SCIENTIFIC AGRICULTURE. 188

less, upon the supposition that all the objects accomplished by
it, may be also by the application of manures. The proposal
to substitute manures, is of course equivalent to an admission
that fallow is beneficial to the soil. Now if any change takes
place in the soil while lying in fallow, we must first know what
that change is before we can determine whether manures will
affect the same change : and in order to know this, we must
have an exact analysis of the soil, before the fallowing begins,
and at the end of its term ; this will show what new elements
are formed, and what old ones are decomposed.

If, tlven, we have a manure which will furnish to the soil all
the elements which were formed by chemical action during fal-
low ing, it will fulfil the same indication. But in either case,
an analysis of the soil is requisite before the fact can be estab-
lished : and inasmuch as those who discard fallowing, have
made no such analysis, they have made no demonstration of
the truth of their position. And until farther facts are de-
veloped by chemical experiment, it may be fairly questioned,
whether, on all soils, and under all circumstances, fallow can be
dispensed with. The benefits to be derived from allowing land
to lie in naked fallow are enumerated by Johnston as follows :

1. In strong clay soils, fallow affords opportunity for destroy-
ing weeds, which it is difficult to extirpate while the land is
continually bearing crops. 2. The weeds and herbage which
spring up during summer, afford an abundant crop for green
manure : they should be ploughed under before their seeds
ripen. 3. Land which is continually cropped, becomes ex-
hausted of certain elements within the depth to which their
roots extend. By leaving the soil at rest, the rains which fall
and circulate through it, equalize the distribution of the solu-
ble substances which it contains. The water which in dry
weather, ascends by capillary attraction from below, brings up
Baline compounds and deposits them as it evaporates. 4. Some
subsoils require to be turned up and exposed to the action of

184 SCIENTIFIC AGRICULTURE.

the air for some time, before they can be safely mixed with
the surface soil. 5. The soil often contains more or less
organic matter which is inert, or decays so slowly as to be
almost unavailable to vegetation : by leaving this to decompose
and become fitted for the food of plants, the crop which fol-
lows will grow more luxuriantly and yield more abundantly.
6. The nitrates, which are very favorable to vegetable growth,
are more rapidly formed when the land lies in naked fallow
than when covered with crops. 7. The fragments of rocks of
various kinds are disintegrated and decomposed faster during
fallow than during cropping. 8. The saline and other sub-
stances, such as ammonia, magnesia, the nitrates, &c., which
are brought down by rains, accumulate in the soil during fal-
low. 9. The clay, oxide of iron, and organic matter of the
soil, have the power of extracting ammonia from the air; and
this is the more rapid, the greater the extent of surface which
is uncovered and exposed to the passing air. 10. The light
soils sometimes become too loose to afford sufficient mechani-
cal support to the roots of crops, and require time to settle
together and resume their cohesion and compactness.

No doubt the period usually allowed to land to lie in fallow
may in many cases be very much abridged, and in some cases
altogether dispensed with. Whenever follow is beneficial, it
must be ascribed to some one or more, if not all the above
causes combined.

ROTATION OF CROPS.

By rotation of crops, is implied, the alternate production of
different plants in regular succession on the same land. Expe-
rience has shown that the same crop cannot be produced
successively on the same field for an indefinite period of time.

The grasses and forest trees seem to present an exception
to this principle : but it must be observed that the grasses are
mowed or pastured down before arriving at maturity, — for, if
they were allowed to perfect their growth and ripen their

SCIENTIFIC AGRICULTURE. 185

seeds, tho same result would follow as in other crops. And
with regard to forest trees, it has been observed that where an
oak forest has been cut down, a growth of pine will succeed;
and where a pine forest has been cleared away, a growth of
oak will spring up in its place : where beech and maple are
cut, poplar and basswood often succeed them. Thus it appears
that the soft and hard woods alternate with each other.

The reasun formerly given for the necessity of rotation was,
that all plants throw off certain matters or excrements by their
roots, which prove injurious to another crop of the same kind
of plants j but which are beneficial rather than injurious to
crops of a different kind.

This beautiful theory originated with the distinguished bota-
nist, Decandolle, and explains, apparently, in an easy and satis-
factory manner, all the reasons for the necessity of rotation
of crops. The simplicity and high authority of this theory
obtained for it, for many years, an unquestioned assent; and
the only objection which lies against it now is, that it is not
supported by a. single fact

The objections to it are, — 1. That plants do not excrete so
great an amount of noxious matters as supposed by Decan-
dolle. 2. No evidence exists of their injurious effects upon
the plants from which they are excreted. 3. There has been
no demonstration of their nutritive effects on other plants.

This theory, then, must be abandoned, and we must look
for one which is supported by facts: and if one cause be found
adequate to explain all the effects produced, we are not bound
to seek for another.

The necessity of rotation does not depend upon there being
too much, but too little, of some particular elements in the
soil. (Johnston.) All plants require certain elements for food,
and these are indispensible to their growth and maturity : one
plant requires them in certain proportions and another requires
these and others besides, in quite different proportions.

*16

186 SCIENTIFIC AGRICULTURE.

"If we assume, [says Petzholdt,] that the utility of the rota-
tion of crops depends exclusively upon the circumstance that
all cultivated plants withdraw from the soil unequal amounts
of certain ingredients for their nutrition, all the observed facts
are at once satisfactorily explained, and the possibility of deter-
mining the rotation of crops, or of avoiding it altogether, if
desirable, made evident."

It is useless to remark, that no plant can vegetate in a soil
which does not contain all the elements which it requires for
its food. Some species of grass contain, and therefore require
for their growth, a large amount of silica : a soil which contains
no silica cannot produce them. A soil may contain just enough
silica for one crop, but not enough for a second, so that a second
could not be produced; but a crop of some other plant requiring
much less silica, might be grown upon it as successfully as the
grass before.

" A single crop of wheat may deprive the soil so completely
of one of its mineral constituents, that another crop of wheat
could not grow upon it; and yet this soil may contain abundant
mineral constituents for the production of a good crop of clover
or turnips." An analysis of a soil and the ashes of plants
desired to be produced upon it, will determine negatively,
whether it is eligible to their growth: but the only positive
proof is a trial of the crop upon the soil.

All plants draw certain mineral elements from the soil, but
do not all equally exhaust its fertility. All knowledge respect-
ing the application of manures, and the adaptation of certain
plants to particular soils, is based upon these facts. The
necessity for rotation may sometimes be obviated by allowing
the land to lie in fallow for a year, after which the crop
may be successfully repeated. Manuring may also sometimes
answer the same purpose; but as a general rule in practice,
however it may be explained in theory, a judicious rotation is
beneficial.

SCIENTIFIC AGRICULTURE. 18

Boussinganlt states that ho saw in South America, fields on
which good crops of wheat were said to have been produced
annually for more than two centuries ; and also that potatoes
arc cultivated continually on the same soil. It is stated also
by Colman, that onions yield more and more abundantly the
oftener they are grown on the same field. These statements
either contain some hidden fallacy, or they prove that the fields
in question contained an inexhaustible amount of the elements
necessary to the plants produced ; for they do not, nor were
they designed to prove, that rotation is unnecessary.

It is unquestionable that a perfect system of agriculture,
and the maximum production of all crops, requires a system
of alternation, regulated according to circumstances, and in
accordance with the principles of Chemistry. A valuable end
to be obtained by rotation is the destruction of certain weeds
and the insects which inhabit them.

The following table shows a system of rotation which is
practiced in Pennsylvania.

First year — Grass or clover.

Second " Pasture.

Third " Indian corn.

Fourth " Oats or barley — (manured.)

Fifth « Wheat.

Sixth " Grass— (plastered.)

The tables below are from Colman, and show some courses
of rotation practiced in England.
First year — Turnips — (manured.)
Second " Barley.
Third " Clover.
Fourth « Wheat.

0)i a Clay Soil.

First year — Swedes turnips and Mangel Wurtzel.
Second " Wheat and beans, (i. e., part of land in each.)

188 SCIENTIFIC AGRICULTURE.

Oil a Clay Soil — continued.
Third year — Clover.
Fourth " Wheat and oats.
Fifth " Vetches, rye and turnips.
Sixth « Wheat.

On a Sandy Soil.

First year — Swedes and Mangel Wurtzel.
Second " Barley.
Third " Clover.
Fourth " Oats.

Fifth " Cabbage and potatoes.
Sixth " Wheat.

On a Limestone Soil.
First year — Rye and turnips.
Second " Barley.
Third " Clover.
Fourth « Oats.
Fifth " Turnips.
Sixth " Wheat

The table below is from Mr. J. J. Thomas' Prize Essay : it
gives three courses, which are said to be well adapted to the
State of New York.

First Course.

First year — Corn and roots, well manured.
Second " Wheat sown with 15 Ibs. clover seed per acre.
Third " Clover one or more years, according to fertility
and amount of manure at hand.

Second Course.

First year — Corn and roots with manure.
Second " Barley and Peas.
Third " Wheat, sown with clover.
Fourth " Clover, one or more years.

SCIENTIFIC AGRICULTURE. 189

Third Course.

First year — Corn and roots, with manure.

Second " Barley.

Third " Wheat, sown with clover.

Fourth " Pasture.

Fifth " Meadow.

Sixth " Fallow.

Seventh " Wheat.

Eighth " Oats sown with clover.

Ninth " Pasture or meadow.

It will be evident, on a little reflection, that no definite rules
can be given, and no set of tables devised which shall apply to
all soils and under all circumstances. The frequency of any
crop in the course of rotation, must, therefore, be determined
by a consideration of the character of the soil and subsoil, the
amount of manure applied, and the other crops which come
in the course.*

* " In wheat farming districts and with the wheat farmer, who depends
for his sales and profits solely upon wheat and wool, the following rota-
tion with slight variation, is often adopted.

Divide all the available land into three, six or nine enclosures: let
one-third be always in wheat, one-third in pasture and meadow, and
one-third in summer crops well manured, — which may be followed with
wheat the same fall, or may be put in barley the next spring, and fol-
lowed with wheat and well clovered in all cases. The general practice
is, to summer fallow the clover after spring pasturing. There should
be about one sheep to the acre of all the available land ; the manner of
cropping the fallow is important.

Others make a four years' rotation, letting the clover lay two years, —
one for pasture and one for meadow. On this system no more ealtle
should be kept, or butter and cheese made, or corn, oats or potatoes
grown, than is required for the farm use; everything is made subser-
vient to the wheat crop." — L. B. Langworthy.

CHAPTER V.

STERCOLOGY.* MANURES.

ALL agents used by the Agriculturist to preserve or restore
the productiveness of the soil, are properly called manures.
All soils, after being long cultivated and subjected to the ex-
hausting- influence of continual harvests, become deficient in
mineral and organic elements, which must be replaced artifi-
cially or total barrenness will ensue. Manuring is the process
by which this end is accomplished, — and for it, there is no
substitute.

If the supply be less than the crops require, the soil increases
in barrenness : if it just replaces what lias been removed by
the crops, the fertility remains the same: if more be added
than the crops require, the fertility of the land is increased.

*A NKW TERM — STERCOLOGY, — Mr. Editor: I wish to propose,
through your paper a new term, which I think will supply a deficiency
in agricultural language. We have no generic term which embraces in
its signification, the science or art of enriching the soil. 1 therefore
propose the term STERCOLOGY, which is compounded from the word
stercus, which means manure, and logos, a discourse.

Although hardly general enough in its strict meaning, this word may,
by a little extension, be understood to embrace everything under the
head of manuring, enriching, ameliorating or amending the soil. And
although words are only the signs of ideas, and technical language
should not be used unnecessarily, — still a systematic division of any
branch of science into parts embraced under generic heads is always
convenient.

Yours, respectfully,

M. M. RODGERS."

Genesee Farmer, August, 1847.

SCIENTIFIC AGRICULTURE. 191

The remains of plants, together with the excrements and car-
m of animals, if returned to the soil before decomposition,
must contain all the mineral, organic and gaseous elements,,
which the plants derived from the soil or the atmosphere.
These must pass through the different processes of decompo-
sition, before they assume their original gaseous and earthy
forms, and become again available for the food of plants.

The whole science of manuring consists in supplying to the
soil, those indispensible elements which have become exhaust-
ed. The richest manure may be applied to a failing soil, and
if it lacks a particular element which the crops require, and
which the soil does not contain, the soil grows barren notwith-
standing the manuring. Farm-yard manure, probably contains
the greatest number of elements necessary to fertility ; but par-
ticular plants require special manures.

Manures operate beneficially on the soil in several ways.

1. By serving directly in some instances as the food of plants.

2. By causing chemical changes in the soil, by which other
substances are prepared to be taken up as nutriment by their
roots. 3. By neutralizing noxious substances in the soil which
prevent the growth of vegetation. The operation of lime on a
cold, sour, peat soil, or one which abounds in sulphate of iron,
is an example of this principle. 4. Manures change, accord-
ing to their bulk and texture, the mechanical properties of
soils, 5. They may change more or less, according to their
various properties, the physico chemical character of a soil, in
relation to light, heat, air and water. Sand, used upon a clay
soil, for the purpose of rendering it more loose and friable,
would be as properly a manure, as farm yard, or any other
variety. Clay used to ameliorate a sandy soil, is also in effect
a manure.

Manures have been classified in various ways, according to
their supposed operation and nature. The most simple and
convenient division, and one which is usually adopted at pre-

192 SCIENTIFIC AGRICULTURE.

sent, is that which arranges all of them into three classes, viz:
animal, vegetable and mineral manures. The first class includes
all substances of animal origin : the second includes all those
of vegetable origin; and the third, all those derived directly
from the mineral kingdom.

O

ANIMAL MANURES.*

Animal substances are better fertilizers than those of veget-
able origin, on account of their chemical constitution and the
facility with which they decompose : they furnish more manure
in proportion to their bulk, and act more promptly and rapidly.
The properties and value of these substances are given mostly
on the authority of Johnston and Boussingault.

The flesh of animals, after and during its decomposition, is a
rich and active manure: the lean flesh acts more energetically
than the/a£.

Blood is similar in its properties to lean flesh ; it is sometimes
applied as a top dressing in the form of dried powder, and
sometimes mixed with other matters, to form composts. The
scraps of skin among1 the refuse of curriers' shops are also
used as manure.

Wool, hair, horns and hoofs found in large quantities among
the refuse of various manufactories, contain large proportions
of carbon and nitrogen, as do most animal substances, and are
therefore highly concentrated manures. The refuse of fisheries,
soap and candle factories, slaughter houses, kitchens, sugar
manufactories, &c., all contain matters rich in those elements
which characterize good fertilizers.

Animal charcoal, which is to be obtained in considerable
quantities at sugar refiners' shops, in a state of mixture with
blood and lime, is a manure of considerable value.

Bones are valuable on account of both the organic an.d
mineral matters which they contain, The bones of different

* See tables at the end of the chapter.

SCIENTIFIC AGRICULTURE. 193

animals differ somewhat in composition: phosphate of lime
constitutes the largest proportion of the matter of dry bones ;
the amount is from forty to sixty per cent of their weight
Eight pounds of bone dust are equal in phosphates to 1000
pounds of hay or wheat straw.

The value of bones is not dependent alone on the phos-
phates, but partly upon the gelatine and other organic matters
which enter into their composition : these latter operate in the
same way as the other organic tissues of animals. Bones are
prepared for manure by boiling, by maceration in sulphuric
acid and water, and by grinding; the last of which methods is
thought on all accounts to be preferable. In soils deficient in
phosphates, bones are of great value ; and from the compara-
tively small quantity of phosphates which most crops require,
the effect of a large manuring with bone dust is manifest upon
the land for. many years: " 260 pounds of bone dust, (less than
six bushels,) are sufficient to supply all the phosphates con-
tained in the crops which are reaped from an acre during an
entire fourshift rotation of turnips, barley, clover and wheat
Some lands remember a single dressing for fifteen or twenty
years.'* (Johnston.)

The prolonged effect of bones is due to the organic as well
as mineral matters. Bones should not be ground too fine:
they are particularly applicable to turnip crops and pasture
lands : the milk of cows contains about half a pound of phos-
phates to every ten gallons ; hence the necessity of these salts
in the soil of pastures. Animal tissues, when used as manures,
ought to be well covered with earth, or ploughed under, in
order to facilitate their decomposition, and at the same time
prevent the escape of the gases formed during this process.

Solid excrements of animals, — Night soil, or human ordure,
is a highly valuable fertilizer. It is best prepared for use by
mixture with powdered charcoal, half burnt peat, or scil which
is rich in vegetable matter : quick lime has been used for the

194 SCIENTIFIC AGRICULTURE.

same purpose ; but, although it destroys the odor, it dissipates
at the same time a large portion of its ammonia. During the
decomposition of night soil, an evolution of carbonic acid,
ammonia, sulphuretted and phosphuretted hydrogen takes
place. After the escape of these gases, the odor ceases, and
the remainder, when dried, constitutes what is sold in large
cities under the name of poudrette. The odor of recent night
soil may be destroyed, and the volatile elements retained, by
adding to it gypsum or dilute sulphuric acid. This manure is
used in the form of compost, and as a top dressing in the form
of poudrette.

The excrements of horned cattle are more valuable and
enduring in their operation than those of the horse and sheep.
It ferments more slowly on account of its smaller quantity of
nitrogen; hence it retains its virtue longer, and produces a
more lasting effect on the soil. It is colder in its nature than
that of the horse, which is owing partly to the amount of water
it contains, and partly to its peculiar constitution.

The excrements of the horse abound more in nitrogen com-
pounds than those of cattle. Even where both are fed upon
the same food, those of the horse are more valuable than those
of the cow. It begins to heat and ferment in a short time, and
in two or three weeks, according to Johnston, loses nearly half
its original weight. On account of this rapid fermentation and
the consequent loss of volatile matters, it should be mixed as
soon as possible with charcoal, peat, sawdust, or earth rich in
vegetable matters, or be sprinkled with gypsum or dilute
sulphuric acid. For the same reason, this kind of manure
ought, contrary to popular opinion, to be spread upon and
ploughed into the soil before any signs of fermentation take
place ; unless it is mixed with some other matters to form com-
posts. Erom its tendency to ferment and develop heat, it is
. admirably adapted to enter into all composts. An additional

SCIENTIFIC AGRICULTURE. 105

quantity of water prevents too rapid fermentation and pre-
serves the virtues of this manure to a considerable extent

The excrements of the hog are said to be a rich manure ; but
they have a strong and unpleasant odor, and often impart a
rank taste to the crops upon which they are used: for this
reason it has been advised not to use them on crops, particu-
larly of roots, which are designed for food. They are colder
and less inclined to ferment than those of the cow, and should
be combined with other manures or made into composts.

The excrements of sheep form a richer and more fermentable
manure than those of the cow : they are said to be most bene-
ficial on soils which contain much vegetable matter, which
absorbs the volatile matters which would otherwise pass off
during fermentation.

The value of all animal manures depends much upon cir-
cumstances, viz : the food upon which the animal is fed ; the
age and condition of the animal ; the amount of labor he per-
forms; the length of time and manner in which the manure is
kept Since, then, their value is affected by so many condi-
tions, it is evident that no general conclusions can be drawn,
which shall not be liable to exceptions; and no set of analyses
can furnish tables which shall in all eases agree. The following
tables may be relied upon as being as nearly correct as can be
obtained, and sufficiently so for all practical purposes.

Excrements of birds. — These are among the most powerful
fertilizers. The excrement of pigeons is said to be particularly
valuable to flax crops, for which it is held in high esteem in
some parts of Europe. This, like most other manures, loses
much of its value by being allowed to ferment without the
admixture of some other matters to retain its volatile elements.
The principal value of this, as well as the excrements of all
birds, which have been analyzed and used as manures, is
dependent mainly on the large proportions of ammonia and
phosphates which they contain. The excrements of hens,

196 SCIENTIFIC AGRICULTURE.

geeso, turkeys and ducks, are of less value than those of the
pigeon.

Guano is the excrements of sea fowls, and is an earthy sub-
stance of a grayish brown color: it is mostly found in Africa
and South America. It is found on the islands and coasts of
those countries, in latitudes where the weather is so dry that
decomposition has proceeded slowly, and it has consequently
accumulated in large quantities. Guano is said to be efficacious
as a manure, applied to almost any crop : it is, however, accord-
ing to Johnston, more advantageous to root crops than to grain
or grass crops. It is conveniently applied as a top dressing,
mixed with gypsum, wood ashes or powdered charcoal. Two
or three hundred pounds to an acre is sufficient for a single
dressing.

The urine of men and animals is the most valuable and the
most neglected of all manures. That of the cow and hog is
said to be more valuable, because it contains more solid soluble
matter than that of any other domestic animal. The efficacy
of urine as a manure is due to the large quantity of urea,
ammonia and phosphates, and consequently of nitrogen, which
it contains. Recent urine generally exerts an unfavorable
influence on growing vegetation ; it is most beneficially applied
after fermentation has fairly commenced, and before it reaches
the final stage of the process. (Johnston.)

Decomposition is attended with a diminution of urea, and an
increase of ammonia. It is important that the urine collected
should be fermented in tightly covered cisterns to prevent the
escape of volatile matters : it has been proposed to add gyp-
sura, sulphate of iron, or sulphuric acid, to the fermenting
urine, in order to fix the ammonia; the mixture of vegetable
mold with it has been also recommended as equally effective
and more economical. The loss of manure in waste urine in
densely populated countries and large cities, is immense, as is
shown by the following calculation.

SCIENTIFIC AGRICULTURE. 197

[If we allow the quantity of urine voided by each indvidual to be
COO pounds yearly, the city of Rochester, which contains 30,000 inhabi-
tants, would furnish yearly 1,200,000 pounds, or 540 tons. This, esti-
mated at the price of guano would be worth $21,600. Now if we esti-
mate the number of horses and cows of the city to 500 of each, and
that each animal voids as much urine as two persons, the amount would
be 80,000 pounds, or 40 tons, which would be worth $1,600. Here
then is a loss, if we reckon guano at $40 per ton of $23,200: or of
manure enough to produce, in addition to the ordinary crop, over
16,000 bushels of wheat in a single year. These calculations may not
be correct, but they approximate this point sufficiently for our purpose.]

VEGETABLE MANURES.

Organic vegetable matters in various conditions, constitute
the largest part of manure in use. The form in which they
are prepared and applied has an important influence on their
fertilizing effect. The principal difference between dry and
green vegetable matter is, that the latter decomposes more
rapidly and therefore acts more promptly. Unripe plants fur-
nish a more valuable manure than ripe ones.

Straw and chaff, when ploughed into the soil dry, are slow
in decomposing, and act more slowly than when previously
fermented. The question of applying straw without previous
decomposition, is, in practice, only a question of time. It is
doubtless true that it furnishes about the same amount of
manure in both cases ; but in the one case it has a more
speedy and powerful, and in the other a more prolonged effect

Saw dust, is a cheap, and on some accounts a valuable ma-
nure : it ferments slowly in the soil, and cannot, therefore, be
much relied upon the first year or two. It is beneficial in ab-
sorbing gases and liquid manures, and its effect is felt gradually
by the soil as decomposition proceeds : . it is also beneficial to
stiff clay land by rendering it more loose and light

Dry leaves and decayed wood, operate as manures in a man-
ner similar to saw dust ; they are however better fitted by
decomposition in compost heaps.
*17

198 SCIENTIFIC AGRICULTURE.

Oil calces, from cotton and linseed exhausted of their oils,
are valuable as fertilizers ; but their value for fattening animals
perhaps exceeds that as a manure, and may prevent their
direct use for this purpose.

Peat, is used with benefit on soils which are deficient in
organic matters : it decomposes slowly, especially if sour or
applied alone to a wet soil containing little lime. Its action,
when properly decomposed and prepared, is the same as that
of other vegetable matters : it usually contains more or less
mineral and gaseous matters, which have their own peculiar
operation ; but these are not to be considered as affecting the
vegetable character of peat as a manure. On account of the
slowness with which it decays, it should be mixed with lime,
gypsum, wood ashes, or some vegetable matter which decom-
poses rapidly, such as farm-yard manure : swamp muck and
humus are similar in properties to peat.

Tanners' bark, is used as a manure, but is liable to the
same objection as peat 'in respect to its slow decay: it is bes^
brought into a state of fermentation by mixture with lime and
farm-yard manure in composts.

Soot, is a complicated substance, as will be seen by refer-
ence to the table : it contains many things necessary to vegeta-
tion, and is a manure of some value ; but experiment has not
yet determined its precise character and operation.

Charcoal, on account of its power of absorbing gases and
destroying offensive odors, is a valuable addition to the soil :
its operation is not so direct as that of some other manures;
that is, it is not so useful on account of any element which it
furnishes to plants, as by the intermediate office which it per-
forms of absorbing and retaining in the soil those volatile mat-
ters which plants require, and which would otherwise escape
and be lost. It is beneficial as a top dressing, and as an in-
gredient in composts : it evolves carbonic acid in its decompo-
sition, and is in this way directly useful to plants. Its power-

SCIENTIFIC AGRICULTURE. 199

ful antiseptic properties render it very beneficial to young and
tender plants ; by keeping the soil free of putrefying sub-
stances which would otherwise destroy their spongiolos and
prevent their growth.

Farm-yard manure. The manner and state in which farm-
yard manure should be applied, has been a subject of much
experiment and controversy. The conclusions of Johnston ia
relation to this subject, appear rational and satisfactory. This
kind of manure is made up of the solid and liquid excrements
of animals together with straw and hay, some of which are in
a state of decomposition, and the remainder fresh and un-
changed. The question as to which condition these manures
should be used in, must depend upon circumstances. If the
object is to furnish the greatest amount of organic matter to
the soil, the sooner the manure is applied after it is made, the
better this object is accomplished. On compact clays, the
mixture of straw and coarse manure is beneficial, as it renders
them looser and lighter, while the products of decomposition
are more completely retained in the soil than they would be in
a loose one. But coarse manures render loose soils more loose,
and lose more of their elements in decomposing : for these
reasons, compact fermented manures are preferable in such
soils. For manuring crops which grow rapidly and attain
maturity in a short time, well fermented manures and fine
composts are felt more immediately and powerfully than re-
cent ones. Such crops as turnips, buckwheat, clover, and
many garden vegetables, might nearly attain maturity before
decomposition would be sufficiently advanced in new and coarse
manures to render them beneficial. When it is desired to force
and quicken the growth of a crop, a well fermented, or fine
heating manure should be used; such as rich compost, bone
dust, or the excrements of the horse and sheep.

Top dressing for pastures, meadows and turnip crops, should
usually be of the same kind as these just named. But farm.

200 SCIENTIFIC AGRICULTURE.

yard manure is not subject to any special law, but is to be used
according* to its quality and condition, and adapted to circum-
stances. Vegetable substances are all similar in their nature
and operation, and are modified by conditions and circum-
stances. They are all subject to the same laws, and their
relative value depends on their constitution and adaptation to
each particular case.

GREEN MANURES.

By green manures, is understood those plants which are
grown for the purpose of being ploughed in and mixed with the
soil before being harvested or used as food for animals. This
plan of manuring is by no means of recent origin ; it was
known and practiced among the Romans. The plants most in
•use for this purpose in the United States are red clover, buck-
wheat and grass in the form of green sward. Several other
plants are used in Europe, viz., rape, lupine, vetches, rye, tur-
nip, carrot and beet tops, borage, spurry, sea weeds and fresh
water plants.

The advantages of green manures, according to Johnston,
are, — 1. They undergo decomposition sooner than dry vegeta-
ble matter, and consequently become sooner available for the
food of succeeding crops. 2. The nitrogen and carbon which
they contain, if allowed to decay in the open air, are lost ;
while if the plants had been buried, before decay, these gases
would have been mostly retained in the soil for the use of suc-
ceeding crops. 3. By ploughing in a crop of plants, the or-
ganic matter is more equally distributed through the soil than
could be done by any other means. 4. Green manures are
available where other manures are scarce, and in soils deficient
in organic matter. 5. The plants used as green manures, bring-
up towards the surface by their roots, matters which had sunk
into the soil too deep to be of much service. 6. It restores to
the soil all it took from it, in a more soluble and available con-

SCIENTIFIC AGRICULTURE. 201

dilion ; and in addition to this, those gases also which the plants
extracted from the air during growth. 7. A green crop yields
more manure than the same crop could do in any other form.
8. A grain crop is greater on the same field when green, than
when fermented manures are used. The best plants for
green manures are those which grow the fastest, produce the
most vegetable matter, and with the smallest expense.

Sufficient seed should be sown, that the plants may coyer
the ground completely; the crop should be ploughed in before
the time of full blowing, because the flowers give off nitrogen,
which is wasted in the air. Agriculturists agree that a seconJ
and third crop of green plants still continue to improve the
soil; but there must be a limit, beyond which this practice
cannot be carried with benefit and profit Green manuring
might perhaps secure a field against barrenness for an indefi-
nite period of time, providing nothing was ta!*en off: but if a
crop was occasionally carried away, in must of course be im-
poverished to the amount of what is taken off in mineral
matters. It is probably true that lands in a state of nature,
which are covered with forest trees or other vegetation, never
become barren.

The soil may in time become deficient in a particular mineral
element which the incumbent plants require ; but when these
die out, others immediately spring up by a natural rotation,
and, requiring elements slightly different from the first, grow
as luxuriantly as they did. Thus one race of plants succeeds
another, each in turn exhausting the soil of certain elements,
and leaving it richer in others. The question may arise, What
becomes of the mineral elements, which are lost, if nothing is
taken off the soil, since they do not escape into the air? The
probability is, they sink down deeper and deeper into the soil
in the form of soluble salts, until beyond the resell of the
roots of plants.

202 SCIENTIFIC AGRICULTURE.

IMPROVEMENT OF THE SOIL BY PASTURE.

Pasture may be either temporary or permanent Tempo-
rary pasture consists in laying down a field to pasture for one,
two or three years, or more. The soil is benefitted by pasture
in several different ways. The roots of the grass which remain
furnish a large amount of organic matter, which, to a soil poor
in this constituent, is of great benefit. Land which lies several
years will be more benefitted than when it lies but a single
year; but the first year enriches it more than any succeeding
one. The result to the land will be nearly the same, whether
the grass be mown or eaten off by the stock, " That farming
is the most economical, where the land will admit of it, which
permits the clover or grass to occupy the land for a single
year only."

Permanent pasture consists in the suspension of grain crops,
and the occupation of the land by grass or clover, for an indefi-
nite period of time. Besides the benefit which the soil derives
from the organic matters left in it, some of its mineral con-
stituents are, by the action of air, moisture, and the roots of
the grass, brought into a more soluble state to be used by
succeeding crops. Another advantage of pasture, especially
on stiff clay soil, is that it renders it more loose and friable.
On dry, sandy soils, pasture is beneficial, by retaining the
moisture longer, and also the dry organic matters and fine
sand upon the surface, which would otherwise be blown away
by the winds. Insects perform a part in improving pasture
lands, which is by no means insignificant.

They subsist upon the organic matters of the soil, which,
they bring into a minute state of division and deposit on the
surface as they ascend by night through their holes. They
furnish also, considerable organic matter, which is rich in
nitrogen, by the death and decay of their own bodies. Thus
these earth worms and insects, in the lapse of a few years,
furnish a vast amount of the richest manure without the

SCIENTIFIC AGRICULTURE. 203

smallest expense. The time which land may lay in pasture
and still increase in richness, must have a limit, — and this
depends upon the quality of the soil and the kinds of grass
which occupy it.

The soil will require an occasional top dressing, or the pas-
ture will deteriorate: on account of the exhaustion of certain
elements in the soil, grasses, as well as forest trees and other
plants, tend to a natural rotation; one species, after flourishing
a few years, begins to decline and finally dies out, and is
replaced by another, and this, in time by another, — and so on,
indefinitely. All pasture lands whatever, which are arable,
can, after a series of years, be subjected to grain crops; and
this in most cases would doubtless be expedient. This how-
ever, must be determined in each particular case, by an appre-
ciation of all the circumstances and conditions.

CHAPTER VI.

MINERAL MANURES.

MINERAL manures are divided, for the sake of convenience?
into saline and earthy ; the former including pure salts whose
composition is exactly known, such as common salt and car-
bonate of soda ; and the latter including the various earthy
matters used to ameliorate the soil, such as lime, wood ashes,
and marl. The mineral manures are all supposed to have a
specific mode of action, which is "peculiar to each respectively:
the theory of their action, however, as fertilizers, cannot, for
want of space, except in a few cases, be detailed. But few,
comparatively, of the known mineral fertilizers are in common
use, and those only will be described.

SALINE MANURES.

Carbonate of soda. — This salt, according to Johnston, is
beneficial on lands abounding in sulphate of iron, or overgrown
with mosses and other noxious vegetation ; and also as a top
dressing to fields of young grain, and wherever wood ashes
would be useful. It is said to be peculiarly beneficial to the
strawberry. From forty to sixty pounds may be applied to
an acre, either in powder mixed with other manure, or in
solution.

Sulphate of soda, or Glauber's sail, has been used with
much benefit on fruit trees, rye, beans, beets, and some other
crops. The quantity used should be at least one hundred

SCIENTIFIC AGRICULTURE. 203

pounds per acre, cither in solution or in powder just before a
rain. [It must not be inferred, that this, or any other manure,
because it is recommended for a particular species of plants, is
not therefore adapted to the growth of others; but those only
are mentioned, upon which they have been tried sufficiently to
warrant a conclusion as to their efficacy.]

Sulphate of magnesia, or epsom salts, is said to be useful to
young crops of wheat, clover, peas and beans: one or two
hundred pounds to an acre should be used.

Sulphate of lime, or gypsum. — This salt of lime, usually
called "plaster," has been long known and much employed as
a fertilizer on almost all crops and soils. It requires much
water for its solution. The beneficial operation of gypsum is
supposed to depend upon several circumstances. This, like all
the sulphates, furnishes sulphur, which is important in the
nutrition of plants, especially those of the liguminous order.
Gypsum prevents the escape of ammonia which is deposited
in the soil by rain, and evolved by the decomposition of ani-
mal and vegetable matters. In soils deficient in lime, it supplies
this element in an available state for their nutrition. It has
been thought to operate most beneficially on red clover and
Indian corn.

Nitrate of soda is on some accounts a good fertilizer; it has
not come into general use, and is not as well understood in its
relations to soils and to plants as it should be. Several results
are theoretically attributed by Johnston to the action of the
nitrates on vegetation. 1. They give a dark green color to
the leaves. 2. They hasten and sometimes prolong the growth
of vegetation. 3. They increase both the straw and the grain
of the cereals. 4. They impart a saline taste to hay and
straw, which causes cattle to eat them with more avidity.
5. Grain which has been manured with the nitrates yields
more bran and less flour than those manured with other salts
The nitrates increase the oat crop ; they should not, however,

18

206 SCIENTIFIC AGRICULTURE.

be used for any crop on land which is already disposed to
produce too much straw. They are exceedingly soluble, and
are for this reason not so beneficial on loose, light soils, because
more easily washed away than on close, compact soils : for the
same reason they produce little effect after the first year.
They furnish a large amount of nitrogen, and are most bene-
ficial to poor soils which are deficient in organic matters.

Chloride of sodium, or common salt, has been used with
yarious results as a fertilizer. Plants require for their growth
both of the elements of common salt, viz, — chlorine and soda ;
and in soils which are deficient in one or both of these ele-
ments, there can be no doubt as to its efficacy ; but in a soil
which contains them in sufficient quantity in a soluble state, it
cannot be expected that this salt will be of any service. It is
most likely to prove beneficial on lands lying remote from the
sea, and which, consequently, would be more apt to require it.
This salt is of more benefit to green crops than cereals; and
also to hasten and increase the growth of the herbage of plants
than the seeds.

The chlorides of lime and magnesia contained among the
refuse of chemical manufactories, are also used as manures
with good effects. The chlorides are destructive to both ani-
mal and vegetable life, when used in large quantity; they
have consequently been used to destroy weeds, worms and
insects in the soil.

The silicate of potash and soda, and the various salts of
ammonia, are, without question, powerful fertilizers, particu-
larly on the grasses; but they are not in general use, on
account of their high price, as well as doubtful reputation
among those practical men who have not tested them.

EARTHY MANURES.

Wood ashes. The ashes of wood and all other vegetable
matter, contain various proportions of several different salts, all
of which are necessary to the growth of plants. The following

SCIENTIFIC AGRICULTURE. 207

table presents an analysis of the ashes of the red beech and
oak, by SprengeL

Red Beech.

Oak.

Silica,

5.52

26.95

Alumina,

2,33

Oxide of Iron,

3.77

8.14

Oxide of Manganese,

3.65

Lime,

2o.OO

17.38

Magnesia,

5.00

1.44

Potash,

22.11

16.20

SooX

3.32

6.73

Sulphuric Acid,

7.64

3.36

Phosphoric Acid,

5.62

1.92

Chlorine,

1.84

2.41

Carbonic Acid,

14.00

15.47

100. 100.

It will be seen by the table, that one kind of ash is richer
in one element, and another in some other element : the value
of each must be estimated accordingly. The ashes of the oak
and beech, both contain more lime than they do potash, and
would therefore be as efficacious on a soil deficient in lime, as
on one deficient in potash. We see, then, that, contrary to
popular opinion, the ucility of this manure does not depend
solely upon the action of potash, but on several other elements
also.

Ashes, as a general rule, are used with benefit on the
grasses, lugurninous and Indian corn crops. They may be
mixed with an equal quantity of gypsum or bone dust, and
applied to the amount of ten to thirty bushels to an acre; or,
if the ashes have been leached, fifty, sixty, or a hundred
bushels may be used to an acre. According to Johnston, only
about one fifteenth part of the weight of ashes are immediately
soluble ; their effects are therefore more permanent than those

208 SCIENTIFIC AGRICULTURE.

of any of the soluble saline manures, being felt by the land for
more than ten years.

The following mixture is said to be nearly equal in efficacy
for a year or two, to one ton of wood ashes.

Crude potash, 60 pounds.

Grystalized carbonate of soda, 60 "

Sulphate of soda^ 20

Common salt, 20 "

160

Leached ashes are nearly destitute of potash, and cannot, of
course, supply this substance to vegetation; they are said,
however, to be of service to oat crops in particular, and are
beneficial to clay soils. The ashes of coal, peat, turf, straw
and cane are also valuable as fertilizers, according to their
constitution and the crops to which they are applied.

Crushed or pulverized rocks of various kinds could be used
with the same benefit and in the same cases, according to their
elementary composition, as other mineral manures: crushed
granite would furnish a considerable amount of potash ; it is
easily ground after being heated to a red heat. Crushed trap
contains much lime, and is a good manure : crushed lavas are
also valuable on most soils.

Marl. The composition and other chemical characters of
marl have been described : it consists of lime, clay, and often
sand, shells, and other matters. The object and effect of
marling are similar to those of liming land. Marl should be
used according to its constitution ; clay marl should usually be
put on sandy soils, and lime or sandy marl on clay soils. The
best time for laying on marl is at the end of autumn, so that
it may be pulverized by frosts during the winter Boussin-
gault says, land which contains ten per cent, of carbonate of
lime can dispense with marl.

The effect of marl is not unlimited, but, like lime, requires

SCIENTIFIC AGRICULTURE. 209

to be repeated once in 10 or 12 years. With regard to the
quantity of marl which should be used to an acre, we must be
governed by the same rational considerations as the use of all
other manures ; viz., it should be applied where it is required,
and in quantity equal to the demand of the soil. The opin-
ions of practical men vary greatly on this subject : according
to Johnston, ten or fifteen, to one hundred and twenty tons
are used to an acre ; while Boussingault says, " allowing the
broadest margin, and judging from the composition of the ashes
of the plants of ordinary crops, we can see that the quantity
of three and a half bushels of marl of the usual composition
per acre, which is assumed as the average quantity to be laid
on, is vastly more than can be absolutely necessary."

This discrepancy has arisen partly from the extravagant
notions about the virtues of marl, and partly from the nature
of the marl and the soils to which it has been applied by dif-
ferent experimenters.

Chalk is much used as a fertilizer in some parts of Europe
where it is cheap and abundant ; but, from its scarcity and
price, it can never be expedient to use it in this country while
we have such an abundance of lime in various other forms.
When used, it is subject to nearly the same laws as lime and
marl. Its composition varies ; some specimens contain more
phosphate of lime, magnesia and silicates, than others. Ehren-
berg has made the remarkable discovery, that chalk to a con-
siderable extent, is composed of the shells or skeletons of ma-
rine microscopic animals.

Lime. The chemical and physical properties of lime have
already been described, and it remains for us to examine briefly
the principles of its adaptation to the soil as a fertilizer. Much
discussion has been had, and many long essays written on this
subject; but no chemist claims for this substance any excep-
tion to general chemical laws, or attributes to it any action
more specific than that of any other manure. There is no

18*

210 SCIENTIFIC AGRICULTURE.

doubt that all our present knowledge of lime as a manure,
can be expressed in a few known and plain principles: we do
not assume that all is known about lime that may be known at
some future time, but that the facts can be much more briefly
and perhaps more clearly set forth than is done by most wri-
ters on agriculture.

Lime is perhaps the most important mineral used as a ma-
nure. When applied to a soil entirely destitute of lime, the
quantity will necessarily be larger than at subsequent periods.

The quantity used must be determined, as in all other cases,
by circumstances. No general rule can be given for its use,
but each one must judge from the facts in the case and pro-
ceed accordingly. Johnston says, "if we suppose one per cent
to be necessary, then upwards of 300 bushels of slaked lime
must be mixed with a soil six inches in depth, -to impart to an
acre this proportion." On wet, peaty, marshy, or clay soils,
more lime will be necessary than on dry, sandy and loose soils :
on soils which contain much organic matters also, more may be
used than on those nearly destitute of them. It is consider-
ed better economy to apply lime in smaller quantities and at
shorter intervals, than to use it in large quantities at more dis-
tant period?.

Caustic lime should be applied to marshy and clay soils im-
mediately after slaking: when allowed to slake in the open air
spontaneously, without the use of water, it is more mild, and
better adapted to grass lands and young crops; but W7hen ap-
plied to naked fallow and mixed with the soil, it may be used
in either state. Burned lime is well adapted to the compost
form of manures. As quick lime dissipates the ammonia of
fermenting manures in the soil, it ought not to be applied at
the same time, nor to come in immediate contact with them :
it is best applied usually in the fall, or as long as possible be-
fore the next crop is sown.

These principles apply only to caustic lime : unburned lime,

SCIENTIFIC AGRICULTURE. 211

marl, gypsum, chalk, and composts containing Urn?, may be
applied at any time. Lime, in order that it may produce its
full effect and most lasting benefit, should bo kept near the
surface. This may be done by sub-soil ploughing, by which
the lime is thrown up to the surface; and also by sowing deep
rooted crops, which will reach it after it has sunk too deep to
benefit others of shorter roots. The amount of lime in the
soil gradually diminishes from several causes, when it is not
occasionally replenished : it is removed to a small extent with
the annual harvests, and by assuming new forms by chemical
action ; a portion is also carried away in solution with the
water which falls by rain and filters through both the surface
and subsoil.

The beneficial effects of lime, although more permanent, are
not felt as soon as those of some other mineral manures : it is
of little service on soils deficient in organic matter. The length
of time which lime shows its effects upon the crops and soil, is,
according to circumstances, from ten to thirty years. Its use
is sometimes attended by unfavorable results when not judi-
ciously used: light, loose soils are rendered too loose; and the
growth of certain noxious weeds favored by its-presence : an
ov(r-doso destroys too much organic matter, hardens certain
soils, ^id injures the spongioles of young plants. It is said to
operate injuriously upon flax, by causing tenderness of its cor-
tical fibre.

These remarks on the use of lime as a manure, are conden-
sed from Johnston, who has given perhaps the best treatise on
lime extant. As the subject is both important and interesting,
it may be well to recapitulate briefly.
Recapitulation.

1. Lime increases the fertility of soils deficient in this element.

2. It causes the soil to produce grain which yields more flour
and less bran, and improves the quality of all other crops.

212

SCIENTIFIC AGRICULTURE.

3. It increases the effect of other manures by hastening de-
composition. "

4. It destroys noxious insects and worms.

5. It destroys noxious weeds and mosses, and gives rise to
sweet grasses and herbage.

6. It prevents smut in wheat and other crops.

7. It hastens the maturity of the crop.

8. It neutralizes the acidity of sour soils and renders them
productive.

9. It makes cold wet soils dryer and warmer.

10. It renders tight stiff clays loose and friable

11. It destroys noxious gases and promotes health.

12. It stiffens loose sandy soils.

13. It brings inert organic matters into a state of fermen-
tation.

14. It causes the evolution of carbonic acid.

15. It serves directly as the food of plants.

16. It causes the formation of several salts in the soil.

COMPOSTS.

It was formerly supposed, that great advantage was derived
from the combination of several different substances together,
and forming what are called composts. The recipes for these
compounds are numerous, and go to prove that the diswvcry
of a good compost requires but little scientific or practical skill.
AVhen a compost heap is made up of several materials which
are all separately good manures, it follows of necessity that
the resulting compound must be a good fertilizer. But it is
impossible to supply any more in this way than if these seve-
ral ingredients were applied to the soil separately. And a
little knowledge of chemistry w^ill show that by this means,
no new elements can be generated. Neither can any new pro-
perty be developed which could not be done by their separate
action. -We see that whenever a substance which has little or
no fertilizing power, is in this way manufactured into a good

SCIENTIFIC AGRICULTURE. 213

manure, it is done at the expense of some powerful fertilizer
which is diluted by the mixture, and consequently loses just
as much of its efficacy as the other gaiss. Thus, although
this process serves to dilute and extend manures which are
too powerful or too expensive, it absolutely supplies none.

Now, although it is evident that this method does not aug-
ment in the slightest degree, our quantity of available ma-
nure,— yet it has several advantages. Caustic lime and wqpd
ashes are sometimes too strong for young and tender vegeta-
tion ; and when this is the case, the object of their use is
much better attained by mixing and diffusing them through
some other substance, such as saw-dust, sand, barn manure or
humus, or allowing them to lie in a heap together with any
vegetable matters, such as leaves, straw, chaff, rotten wood or
turf; or with animal matters; until decomposition is completed.

Another advantage is, that a manure which is valuable and
scarce, as guano, poudrette, and some chemical salts, may be
extended by mixture so as to be applied to a much larger space
than would be practicable if used singly. Thirdly, this mode
enables the agriculturist to spread his manure on the soil more
even and uniformly. And lastly, by making compost we are
enabled to hasten the final decay of animal and vegetable
matters, so as to gain considerable time. By mixing quicklime
with barn manure, straw, leaves, &c., decomposition goes on
more rapidly, and these substances are transformed to availa-
ble manures in a comparatively short space of time. But
much discretion is necessary in this respect, otherwise some
valuable elements are wasted ; the object is to fix and retain
the volatile elements — and not to dissipate them. A great
objection to composts is, the amount of labor retired in ma-
king, turning, and transporting them to the fields.

No definite formula can with any propriety be given for
making composts, as the agriculturist must determine for him-
self in each particular case, as to what elements his fields most

214 SCIENTIFIC AGRICULTURE.

require, and also his time and the resources at his command.
With these considerations, and an adequate knowledge of his
business, he will be able to make a more judicious disposition
of his manures than by the aid of any prescribed rules which
can be laid down in books.

CHAPTER VII.

TABLE OF THE COMPARATIVE VALUE OF MANURES,

FROM ANALYSES BY MESSRS. PAYEN AND BOUSSINGAULT.

Kind of Manure.

M

~ /:

i- -°

fi

> i— i

Nitrog
00 of ir

Dry.

en in

latter.

Wet.

Q,ual'y
ding to

Dry.

accor-
state.

Wet.

Squival'nt
ccord.do.

Dry. i Wet

Farm-yard manure,

79.3

1.05 0.41

100

100

100

100

Water from do.

99.6

1.54 0.06

78

2

127

68

Wheat straw,

19.3

0.30 0.24

15

60

650

167

Rye straw,

12.2

0.20 0.17

10

42.5

975 235

Oat straw,

21.0

0.36

0.28

18

70

542

143

Barley straw,

11.0

0.26

0.23

13

57.5

750

174

Wheat chaff,

7.6

0.94

0.85

48

212.5

207

47

Pea straw,

8.5

1.95

1.79

1001447.5

100

22

Buckwheat straw,

11.6

0.54

0.48

27

120

301

83

Dried potato tops,

12.9

0.43

0.37

22

92.5

453

108

Oak leaves,

25.0

1.57

1.18

80

293

125

34

Beech leaves,

39.3

1.91

1.18

78

294

102 34

Burnt sea weed,

3.8

0.40

0.38

20 95

488| 105

Oyster shells,

17.9

0.40

0.32

20

80

488J 125

Sea-side marl,

1.0

0.52

0.51

26.5

128

377

78

Oak saw-dust,

26.0

0.72

0.54

36

135

250

74

Oil cake of linseed,

13.4

6.00

5.20

307

1300

33

8

Refuse of cider apples

6.4

0.63

0.59

32

147

309

68

Cow's ordure,

85.9

2.30

0.32

117

80

84

125

Cow's urine,

88.3

3.80

0.44

194

110

51 1 91

Excrements of horse,

75.3

2.21

0.55

113 137.5

88

73

Urine of do.

79.1

12.50

2.61

641 652.5

15.5

15.3

Excrements of pig,

8.14

3.37

0.63

172J157.5

58

63

216

SCIENTIFIC AGRICULTURE.

Kind of Manure.

B.»

».£

|i

Nitrogen in
100 of matter.

dual')- accor-
ding to state.

Equivalent
accord. do.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet

Excrements of sheep,

63.0

2.99

Lll

153

277.5

65

36

Do. of goat,

46.0

3.93

2.16

201

540

5018.5

Poudrette,

12.5

4.40

3.85

225

962

44*10.3

Urine of public vats,

9.6

17.56

16.83

900

4213

111 2.3

Excrements of pigeons,

9.6

9.02

8.30

462

2075

21.5

5.0

Guano,

19.6

6.20

5.00

323

1247

31.5

80

Dried muscular flesh,

8.5

14.25

13.04

730

3260

13.5

3

Liquid blood, ,81.0

2.95

795

736

13.3

Fresh bones,

30.0

6.22

1554

6.5

Dregs of glue,

33.6

5.63

3.73

288.4

933.5

35

11

•Sugar refiners' scum,

67.0

1.58

0.54

81

134

127

75

Horn shavings,

9.0 15.78 14.36

809

3590

12.3

3.0

Wood soot,

5.6! 1.31

1.15

67

287.5

149

35

TABLES OF ANALYSIS.

Talks showing the relative proportions of inorganic com-
pounds In the ashes of several cultivated plants.
The tables are taken from Prof. Johnston's Agricultural
Chemistry, — and are supposed to be nearly correct: analysis
of different varieties and qualities of the same plants, vary-
slightly ; but still, for all practical purposes, the tables here
given are sufficiently accurate, being probably as near the real
constitution of them, as it is possible to obtain.

ASH OF WHEAT.

According to Sprengel's analysis, 1000 Ibs. of wheat leave
11.77 Ibs. of ashes,— and 1000 Ibs. of straw leave 35.18 Ibs.
of ash. after burning.

This ash consists of

Potash,
Soda,
Lime,
Magnesia,

Grain of Wheat.
2.25 Ibs.
2.40
0.96
0.90

Straw of Wheat.
0.20 -Ibs.
0.29
2.40
0.32

SCIENTIFIC AGRICULTURE.

21T

ASH OF WHEAT — Continued.

Grain of Wheat. Straw of Wheat.

Alumina and a trace of Iron, 0.26 Ibs.

Silica, 4.00

Sulphuric acid, 0.50

Phosphoric acid, 0.40

Chlorine, 0.10

11.77 Ibs.

0.90 Ibs.
28.70
0.37

1.70
0.30

35.18 Ibs.

ASH OF BARLEY.

100 of grain of barley leaves 23.49 Ibs, — 1000 Ibs. of straw
52.42 of ash.

Grain.

Straw,

Potash,

2.78

1.80

Soda,

2.90

0.48

Lime,

1.06

5.54

Magnesia,

1.80

0.76

Alumina,

0.25

1.46

Oxide of iron,

a trace

0.14

Oxide of manganese,

0.20

Silica,

11.82

38.56

Sulphuric acid,

0.59

1.18

Phosphoric acid,

2.10

1.60

Chlorine,

0.19

0.70

23.49 Ibs. 52.42 Ibs.

ASH OF OATS.

1000 Ibs. of the grain of oats contain 25.80 Ibs. — and of

straw, 57.40 Ibs. of ash.

Grain.

Potash, 1.50

Soda, 1.32

Lime, 0.86

Magnesia,
Alumina,

0.67
0.14

Straw.
8.70
0.02
1.52
0.22
0.06

19

218

SCIENTIFIC AGRICULTURE.

ASH OP OATS — Continued.

Oxide of iron
Oxide of manganese,
Silica,

Sulphuric acid,
Phosphoric acid,
Chlorine,

Grain.

Straw.

0.40

0.02

0,02

19.76

45.88

0.35

0,79

0.70

0.12

0.10

0.05

25.80 Ibs. 57.40 Ibs.

5.32

ASH OF RYE.

1000 Ibs. of rye straw contain 27.93 Ibs., and of grain 10.40

Ibs. of ash.

Grain.
Potash,
Soda,

1.22

1.78

0.24

0.42

0.34

1.64

Lime,

Magnesia,

Alumina,

Oxide of iron,

Oxide of manganese,

Silica,

).24 )
).42 f

Straw.
0.32
0.11
1.78
0.12

0.25

Sulphuric acid,
Phosphoric acid,
Chlorine,

0.23
0.46
0.09

22.97
1.70
0.51
0.17

10.40 Ibs. 27.93 Ibs.

ANALYSIS OF PEAT BY BOUSSINGAULT.

Silica,
Alumina,
Lime,
Magnesia,
Oxide of iron,
Potash and Soda,

65.5
16.2
6.0
0.6
3.7
2.3

SCIENTIFIC AGRICULTURE. 219

ANALYSIS OF PEAT, BY BGUSSINQAULT — Continued.

Sulphuric acid, 5.4

Chlorine, 0.3

100.0

ANALYSIS OF COAL ASHES BY BOUSSINGAULT.

Argillaceous matter insoluble in acids, 62

Alumina, 5

Lime, 6

Magnesia, 8

Oxide of manganese, 3

Oxide and sulphuret of iron, 16

100

ASH OF THE BEAN AND PEA.

100Q Ibs. of seed and straw, dried, contain —

Field Bean.

Field Pea.

Seed. Straw.

Seed. Straw.

Potash,

4.15 16.56

8,10 2.35

Soda,

8.16' 0.50

7.39

Lime,

1.65 6.24

0.58 27.30

Magnesia,
Alumina,

1.58 2.09
0.34 0.10

1.36 3.42
0.20 0.60

Oxide of iron,

0.07

0.10 0.20

Oxide of manganese,
Silica,

0.05
1.26 2.20

0.07
4.10 9.96

Sulphuric acid,
Phosphoric acid,
Chlorine,

0.89 0.34
2.92 2.26
0.41 0.80

0.53 3.37
1.90 2.40
0.38 0.04

21.36 31.21 24.64 49.71

ASH OF THE TURNIP AND POTATO.

10,000 Ibs. of the roots, stalks and leaves, when taken before
drying, contain —

220

SCIENTIFIC AGRICULTURE.

Potato.

Turnip.

Roots.

Tops.

Roots.

Leaves.

Potash,

40.28

81.9

23.86

32.3

Soda,

23.34

00.9

10.48

22.2

Lime,

3.31

129.7

7.52

62.0

Magnesia,

3.24

17.0

2.54

05.9

Alumina,

0.50

00.4

0.36

00.3

Oxide of iron,

0.32

00.2

0.32

01.7

Oxide of manganese,

Silica,

0.84

49.4

3.88

12.8

Sulphuric acid,

5.40

04.2

8.01

25.2

Phosphoric acid,

4.01

19.7

3.67

9.8

Chlorine,

1.60

05.0

2.39

8.7

82,83 308.4 63,03 180.9

ASH OF THE CARROT AND PARSNEP.

Carrot.

Parsnep.

Potash,

53.33

20.79

Soda,

9.22

7.02

Lime,

6.57

4.68

Magnesia,

3.84

2.70

Alumina,

0.39

0.24

Oxide of iron,

0.33

0.05

Oxide of manganese,

0.60

Silica, *

1.37

0.84

Sulphuric acid,

2.70

5.40

Phosphoric acid,

5.14

4.01

Chlorine,

0.70

1.60

66.19 82.83

ASH OF GRASS AND CLOVER.

100 Ibs. of dry hay and clover contain —

Rye Grass. Red Clover.

Potash,
Soda,

8.81
3.94

19.95
5.29

SCIENTIFIC AGRICULTURE.

221

ASH OF GRASS AND CLOVER — Continued.

Lime,

Magnesia,

Alumina,

Oxide of iron,

Oxide of manganese,

Silica,

Sulphuric acid,

Phosphoric acid,

Chlorine,

7.34
0.90
0.31

27.72
3.53
0.25
0.06

27.80
3.33
0.14

3.61
4.47
6.57
3.62

52.86 74.78

The practical inferences from these tables are, — first — the
kind of soil in which each will grow best, — second — the kind
of inorganic matter necessaiy to be supplied artificially, —
third— their nutrient properties, and the kind of stock they
are best adapted to nourish. ;v

The following table from " Liebig's Agricultural Chemistry,"
shows the relative proportions of potash, lime and silica in
several cultivated plants.

SILICA PLANTS.

Oat straw and seeds,
Wheat straw,
Barley straw and seeds,
Rye straw,
Good hay,

Tobacco,
Pea straw,
Potato tops,
Meadow Clover,

ills of Potash Salts of Magne-
and Soda. sia and Lime.

34.00

4.00

22.50

7.20

s, 19.00

25.70

18.65

16.52

6.00

34.00

LIME PLANTS.

24.34

67.44

27.82

63.74

4.20

51.40

39.20

56.00

19*

Silica.
62.00
61.50
55.30
63.89
60.00

8.30

7.31

63.40

4.90

222

SCIENTIFIC AGRICULTURE.

Wheat.
37.72

Oats.
19.12

Barley.
20.70

Rye.

37.21

1.93

10.41

3.36

2.92

9.60

9.98

10.05

10.13

1.36

5.08

1.93

0.82

1.25

9

9

9

49.32

46.26

40.63

47.29

0.17

0.26

1.46

3.07

21.99

0.17

POTASH PLANTS — Continued.

Corn stalks, 72.45 6.50 18.00

Turnips, 81.60 18.40

Beetroots, 88.00 12.00

Potatoes, 85.81 14.19

The following table from Johnston, shows the composition of
the ashes of several grains without the straw.

Potash and soda,
Lime,
Magnesia,
Oxide of iron,
Oxide of manganese,
Phosphoric acid,
Sulphuric acid,
Silica,

101.35 93.92 98.92 100

There appears to be some mistake in the figures of this
table, as will be seen on adding up the columns ; but still, for
want of a more accurate one we must take this as it is, being
sufficiently accurate for all practical purposes.

ASHES OF THE FAECES OF THE HORSE \ ANALYSIS OF JACKSON.

Phosphate of lime, 5.00

Carbonate of do., 18.75

Phosphate of magnesia, 36.25

Silicic acid/ 40.00

100.

URINE OF THE HORSE '. ANALYSIS OF YAUQUELIN.

Carbonate of lime, 1.1

Carbonate of soda,
Hippurate of do.

.9
2.4

Muriate of potash,

Urea,

Water,

.7
44-0

50.0

SCIENTIFIC AGRICULTURE. 223

ASHES OF THE FAECES OF THE COW : ANALYSIS OF IIAIDLEN.

Phosphate of lime, 10.9

Phos. magnesia, 10.0

Phos. iron, 8.5

Carbonate of potash, 8.5

Sulphate of lime, • 3.1

Silicic acid, 63.7

Loss, 2.3

107.0

URINE OF THE COW : ANALYSIS OF BRANDE.

Muriate of potash and ammonia, 1.5
Sulphate of potash, 0.6

Carbonate of potash, 0.4

Phosphate of lime, 0.3

Urea, 0.4

Water, 96.8

100

ASHES OF HUMAN FJ2CES ! ANALYSIS OF BERZELIUS.

Sulphate of lime and phosphate of lime and magnesia, 67
Sulphate of soda and potash and phos. of soda, 5

Carbonate of soda, 5

Silicic acid, 11

Carbon and loss, 12

100

HUMAN URINE : ANALYSIS OF BERZELIUS.

Urea, 30.10
Lactic acid ( ?) lactate of ammonia ( ?) extractive

animal matter, 17.14

Uric acid, 1.00

Mucus, 0.32

Sulphate of potash, 37.01

Sulphate of soda, 3.16

Phosphate of soda, 2.94

224 SCIENTIFIC AGRICULTURE.

HUMAN URINE — Continued.
Muriate of soda,

Phosphate of ammonia,
Phosphate of magnesia and lime,
Muriate of ammonia,
Silicic acid,
Water,

1000

GUANO : ANALYSIS OF VOLKEL.

Muriate of ammonia, 4.2

Oxalate, do. 10.6

Urate do. 9.0

Phosphate do. 6.0

Sulphate of potash, 5.5

Sulphate of soda, 3.8

Phosphate of ammonia and lime, 2.6

Phosphate of lime, 7.0

Oxalate of do. 14.3

Residue soluble in uric acid, 4.7
Loss, (water, ammonia and organized matter,) 32.3

100

BONES OF THE OX : ANALYSIS OF BERZELIUS.

Animal matter, (gelatine,) 33.30

Soda with common salt, 1.20

Carbonate of lime, 11.30

Phosphate of do. 51.04

Fluoride of calcium, (?) 2.00

Phosphate of magnesia, 1.16

100

COAL SOOT I ANALYSIS OF BRACONNOT.

Ulmic acid, 302.0
A reddish brown substance containing nitrogen,

and yielding ammonia when heated, 200.0

Asboline, 5.0

SCIENTIFIC AGRICULTURE.

225

COAL SOOT — Continued.

Carbonate of lime with a trace of magnesia, 146.6

Acetate of lime, 56.5

Sulphate of lime, 50.0

Acetate of magnesia, 5.3

Phosphate of lime, with a trace of iron, 15*0

Chloride of potassium, 3.6

Acetate of potash, 41.6

Acetate of ammonia, 2.0

Silica, 9.5

Charcoal powder, 38.5

Water, 125.0

100

WOOL, HAIR, HORN \ ANALYSIS OF JOHNSTON.

Carbon,

Hydrogen,

Nitrogen,

Oxygen and sulphur,

Wool.

Hair.

Horn.

50,65

51.53

51.99

7.03

6.69

6.72

17.71

17.94

17.28

24.61

23.84

24.01

100

100

100

DRY OX BLOOD AND MUSCULAR FLESH I ANALYSIS OF PLAYFAIR
AND BOECKMAN.
Dry Flesh.

Carbon, 51.83

•* Hydrogen, 7.57

Nitrogen, 15.01

Oxygen, 21.37

Ashes, 4.23

100

Remark. — We have, all through the course of this treatise,
adhered to the principle that nature preserves a uniformity in

226 SCIENTIFIC AGRICULTURE.

the execution of all her laws, and that she does nothing by
accident. And whenever we find an apparent exception to
this principle, it is evident that our knowledge is deficient or
our conclusions erroneous.

Hence, although plants may be made to maintain a transi-
tory and sickly existence without all the usual elements, and
to absorb both by their leaves and roots, substances unneces-
sary and pernicious to their growth, still from the uniformity
of the elements and their proportions, as shown by analysis of
the plants and the soils in which they thrive best, we are com-
pelled to conclude, that each and all of these elements, are in-
dispensible to their healthy growth and maturity. And who-
ever practically disregards this principle, and hangs his hope
of success on some contingent circumstance, must correct his
error at his own cost.

CHAPTER VIII.

ANALYSIS OF SOILS.

THE agriculturist may, by long experience and close obser-
vation of the character and productions of his lands, become
acquainted with their general character and fertility, — and
also what plants are best adapted to them. But it is desirable
that a more accurate knowledge of the elementary constitution
and the relative proportions of those elements which constitute
the food of plants, should be attained.

The only direct and certain means of arriving at this result
is chemical analysis. Without this process, it could only be
known by a trial of various crops upon different soils, whether
they were adapted to them or not: and, in order to determine
the value of soils in this way, several crops and much labor
might be lost in unsuccessful experiments.

Analysis of plants shows with absolute certainty what sub-
stances they have drawn from the soil and atmosphere for
food; these substances vary in different plants, both in their
nature and proportions: the same is also true in relation to
the elementary composition of soils. No two plants and no
two soils have precisely the same chemical composition. The
absence of a single element in a soil may render it totally bar-
ren for a particular crop, while it may produce some others in
great abundance.

A chemical difference in two soils, which might appear

228 SCIENTIFIC AGRICULTURE.

insignificant, would, by experiment, be found to alter entirely
their relative agricultural value.

By referring to tables of the analysis of plants, and then
analyzing the soil, we can see at once what plant the soil is
adapted to produce. A soil containing all the organic and
inorganic elements of a particular plant, may be supposed
capable of producing the plant: but a soil deficient in one or
more of these elements cannot be expected to yield a crop.
A soil containing very little silica could not yield grass, but
might still contain enough for a crop of turnips. .

An exact analysis of the quality of a soil, with the quantity
of each element, requires the skill of a practical chemist, and
the apparatus of a laboratory: but the most important qualities
of a soil may be determined by a few plain and simple experi-
ments, which are easily made by any one, whether acquainted
with chemistry or not

The soil is made up, as before said, of various proportions of
animal, vegetable, mineral, earthy and gaseous matters. As a
general rule, the earthy part of the soil is estimated at from
90 to 96 per cent The salts of these earthy matters are in
small quantities. The amount of vegetable matter varies
greatly in different soils: in some, as in peat and muck soils, it
constitutes from one half to three fourths of their entire
weight ; while in sand and clay soils, it amounts to only from
one to five per cent The principal bulk of all soils, (except
peat, humus and muck soils,) is sand, clay and lime ; and on
the proportions of these, their peculiar properties, both chemi-
cal and physical, depend. The fertility of a soil is not depen-
dent upon any one of these, but upon the proportions and
state of mechanical division of all the other necessary elements.
The mixture of sand and lime with the other elements, (except
the alumina,) is usually entirely mechanical: in the various
kinds of clay, the silex and alumina are often chemically com-
bined, constituting a silicate of alumina.

SCIENTIFIC AGRICULTURE. 229

The first process in the analysis of a soil is to weigh a given
quantity with apothecaries' scales; it should then be spread
out on a piece of clean paper and subjected to a heat not suffi-
ciently high to burn the vegetable matters which it contains,
until thoroughly dried : after drying, the soil should be again
accurately weighed, and the second weight subtracted from
the first, when the remainder will show the amount of water
lost

To find the amount of organic matter which it contains, put
the dried soil into an earthen crucible and heat it over a fire
to "redness, till the organic matter is burned out and the ash
only remains ; after cooling, it should be again weighed, — the
loss by burning shows the amount of organic matter it con-
tained, allowing a trifle for the charcoal which remains with
the earthy part If a black soil loses nothing by burning, it
probably derives it color from black oxide of iron or graphite.

To detect humic acid, boil a small quantity of peat or muck
in a solution of carbonate of soda, until it attains a brown
color, then add muriatic acid till the solution has a distinctly
sour taste, when brown flocks of humic acid will fall to the
bottom.

Ulmic acid may be obtained from the same soil, after the
humic acid is separated, by digesting it over a gentle heat in a
solution of caustic ammonia, and then adding muriatic acid as
before ; — brown flocks are precipitated, which are ulmic acid.

To detect crenic and apocrenic acids, digest a quantity of
soil in hot water until organic matter is dissolved out sufficient
to give the water a yellow color. When this solution is evapo-
rated to dryness, there remains a brown residue, which con-
tains the soluble saline matters of the soil, some extractive
matter, humic and ulmic acids, and the crenic and apocrenic
acids: these four acids are all in combination with alumina
and other bases. When this residue is dried at 220° F., the
compounds of the humic and ulmic acids become insoluble,

20

230 SCIENTIFIC AGRICULTURE.

while the compounds of the crenic and apocrenic acids remain
soluble, and may be separated by washing in water. (Johnston.)
To detect the presence of lime, take 100 grains of a soil and
mix well with half a pint of cold water, and then add half an
ounce of muriatic acid, stirring the mixture frequently : let it
stand a few hours to settle, then pour off the water and fill the
vessel with water to wash out the excess of acid ; when the
water is clear, pour it off, dry the soil and weigh it; — the loss
from the first weight will show the quantity of lime sufficiently
near for all practical purposes. (Gaylord.)

To determine the amount of sand, take a given quantity of
soil and boil it in water till it is thoroughly incorporated with
it, then pour the whole into a glass vessel and leave it till the
sand subsides: the clay remains in a state of mixture with the
water, which should be poured off and the sand dried and
weighed. If the sand contains lime, it may be separated by
muriatic acid as above directed.

The amount of clay may be very nearly ascertained by
evaporating the water which was poured off of the said, —
the residue will be mostly clay.

To detect the presence of oxide of iron, mix a quantity of
soil with water, pour on muriatic acid and stir the mixture ;
let it stand a few hours and dip a piece of oak bark into the
solution, — if the bark is colored brown or black, iron is present.
" To detect the presence of other salts, boil a portion of soil
in water, pour off the water and evaporate it, when the salts
may be obtained in crystals.

If the salt is a nitrate, it has a cool pungent taste, and
ignites when thrown on coals of fire.

If it be common salt, (muriate of soda,) it burns with a
crackling noise, and is also known by its taste.

Sulphate of soda puffs up by heat, gives off a watery vapor
and leaves a dry white mass."

These directions are sufficient to enable any one to make a

SCIENTIFIC AGRICULTURE. 231

rough analysis of a soil, which, although not strictly correct,
may be of much service in determining the general character
of a farm, when a rigid and exact analysis cannot be obtained.
We give below two tables, — one showing the composition of a
barren, and the other of a fertile soil. Taking the mineral
constituents of plants as a basis on which to predicate our rea-
soning in relation to the productive value of soils, we see at
once, that one of these tables shows a soil rich in all the
elements of fertility, while the other exhibits one almost irre-
deemably barren.

ANALYSIS OF A NEW SOIL ON THE BANKS OF THE OHIO RIVER,
POSSESSING GREAT FERTILITY.

Quartz sand and silicates, 87.143

Alumina, 5.666

Oxides of iron, 2.220

Oxides of manganese, 0.360

Lime, 0.564

Magnesia, 0.312

Potash and soda, 0.145

Phosphoric acid, 0.060

Sulphuric acid, 0.027

Chlorine in common salt, 0.026

Humie acid, 1.304

Insoluble humus, 1.072

Organic matters containing nitrogen, 1.011

Carbonic acid united to the lime, 0.080

ANALYSIS OF A SANDY SOIL, UNFIT FOR CULTIVATION.

Silica and quartz sand, 96.000

Alumina, 0.500

Oxides of iron, 2.000

Oxides of manganese, trace.

Lime, 0.001

Magnesia, trace.

232 SCIENTIFIC AGRICULTURE.

ANALYSIS — Continued.

Potash, do.

Soda, do.

Phosphoric acid, do.

Sulphuric acid, do.

Carbonic acid,

Chlorine, trace.

Humic acid, 0.200

Insoluble humus, 1.299
Water,

100

Chemically considered, a soil must contain all the inorganic
elements which plants require, and none that are injurious to
them. If the addition of a certain manure render a soil more
fertile, it is evident that the soil was deficient in one or more
of those substances which it furnished. If the addition of a
given manure or salt to a defective soil, fail to improve its fer-
tility, it is because enough of this substance is already present,
or because some other substance is wanting to render this
application available. A soil may sometimes show more or
less fertility for certain crops than analysis would indicate, on
account of some mechanical and physical conditions : in this
way the supply of certain elements may be cut off, although
they are present in the soil : the deficiency of others may also
be partially compensated by the same causes.

CHAPTER IX.

MECHANICAL PHILOSOPHY.

Mechanical philosophy treats of the equilibrium and motion
of bodies: its great object of inquiry is, into the causes which
produce or prevent motion, and the manner in which it takes
place. " That part of mechanics which relates to the action of -
forces producing equilibrium or rest, in bodies, is called statics;
that which relates to the action of forces producing motion is
called dynamics"

The practical value of this branch of science consists in the
application of a few simple mechanical powers, either single or
combined in some kind of machinery, in overcoming resistances,
and producing and applying motion to useful purposes.

" Power is the means by which a machine is moved and
force attained ; thus we have horse power, water power, steam
power, <fec.

Force is the means by which bodies are set in motion, kept
in motion, and when moving are brought to rest The force
of gunpowder sets a ball in motion and keeps it moving until
the resisting force of the air, and the force of gravity bring it
to rest"

A few simple instruments or machines variously combined,
produce all the complicated, powerful and beautiful pieces of
machinery which have ever been constructed.

20*

234 SCIENTIFIC AGRICULTURE.

These few elementary powers are, the lever, the wheel and
axle, the pulley, the inclined plane, the wedge and the screw.

The lever is a straight bar placed upon a supporting point
called a fulcrum, with the resistance which i's to be overcome,
at one end, and the power applied, at the other.

The wheel and axle is somewhat more complex than the
lever ; it consists of two concentric wheels, one of which is
larger than the other, and both revolving on a common axis.
•This power acts like a succession of levers, and is therefore a
a modification of the lever.

The pulley consists of a flat disc, with a groove on the edge,
through which a rope passes, and a hole in its centre, through
which a fixed axis passes, on which it revolves: when several
pulleys are combined, they constitute a system of pulleys, or a
compound pulley. The power of a system of pulleys increases
in proportion to the number of pulleys employed.

The inclined plane, as its name implies, consists merely of a
plane surface, with one of its ends higher than the other, so
that the plane forms an angle with the horizon.

The wedge may be considered as two inclined planes with
their bases placed together, and their apices forming an acute
point. The power of the wedge depends upon its relative
length compared with the width of its base, — or upon the de-
gree of taper from the base to the point.

The screw is the sixth mechanical power, and may be con-
sidered a continuous spiral wedge, or a modification of the in-
clined plane. The power of the screw depends upon the rela-
tion between its circumference and the distance between its
threads.

OBJECTS AND ADVANTAGES OF MACHINERY.

No actual power is ever generated by machinery ; force and
velocity may be gained, but they are always gained at the
expense of the motive power applied to work the machine:
the power and force must always be in exact proportion to

MECHANICAL PIIILOSOPII V. 235

each other, so that, if one is increased, the other is diminished
in the same proportion. Great velocity in a machine, or in any
of its. parts, is incompatible with great power also; for whatever
js gained in speed is lost in strength, — that is, it is gained at
the expense of power or force.

It is not expected to gain power, force and velocity at the
same time by tho use of any mechanical contrivance whatever,
— but, by taking a philosophical advantage of the few simple
mechanical powers, to obtain one or the other of them, accor-
ding to the labor to be performed.

The advantages of machinery are numerous.

1. By the aid of machinery we can apply force to much
better purpose than by our unassisted hands.

2. A man can perform a work by its aid, to which he would
be wholly incompetent without it

3. It often enables men to exert their whole force, where
without it they could exert only a small part of it.

4. It enables us to employ animals in the execution of many
kinds of work which must otherwise be performed by man
himself.

5. It enables us to employ several inanimate motive powers,
such as water, steam, wind," heat, electricity, &c.

6. Many manufacturing operations are performed with much
greater facility and exactness than they could be by hand.

7. Machinery saves a considerable part of the materials used
in the manufacture of many fabrics.

ON REGULATING THE MOTION OF MACHINERY.

The motion of machinery, to operate to the best advantage,
should be perfectly regular and uniform. Variations of motion
consist principally in variations of power, weight or resistances,
and changes of velocity in different parts of the machine itself.
The different instruments used to obviate these effects, and
secure uniform motion, are called regulators. There can be
little doubt that water, where it is abundant and available,

236 SCIENTIFIC AGRICULTURE.

furnishes the most economical motive power, and one which
propels machinery with greater uniformity than any other
which we possess.

Among the instruments used fcr modifying and regulating
motion are, the fly wheel, governor, ratchet wheel, universal
joint, crank, eccentric wheel, arch head, pendulum, knee joint,
fusee, &c.

Every part of a machine ought to be proportioned to the
stress it is to bear, and the strength it requires, — and should
be no heavier than necesssary: all parts should bear their
relative proportion of the work and wear, so that when the
machine fails, all parts shall be worn out. Every machine
should consist of as few parts as possible ; because, when parts
are multiplied, friction is increased in the same proportion, and
the machine is more liable to get out of repair. All mechanical
obstacles and errors have a less ratio to the motion in great
than in small machines ; the former, therefore, work with more
uniformity and exactness, but are proportionally weaker and
more liable to be broken.

Motion and rest are both equally accidental states of matter:
bodies are no more disposed to lie at rest than to put them-
selves in motion : they maintain a state of rest so long as there
is an equilibrium of all the furces acting upon them ; and when
they assume a state of motion, it is because they are acted
upon by some extrinsic force, which is stronger than the com-
bined action of all those which tend to keep them at rest.
When once in motion, bodies would continue moving forever,
if no force obstructed them to destroy the equiblirum between
accidental resistances and the propelling force : in other words,
they never would come to rest, unless brought to rest by some
power superior to that which set them moving.

Motion may be absolute or relative: absolute motion is a
change of place by a body, in relation to some fixed point:

MECHANICAL PHILOSOPHY. 237

relative motion is a change of place by a body in relation to
some other body which is in absolute motion.

Simple motion results from the action of a single force upon
a body, while compound motion is produced by two or more
forces acting different directions. Motion, when once attained
would be onward in a straight line unless changed or destroy-
ed by some force secondary to the one by which it was pro-
duced : a ball projected from a cannon, assumes a curved line
towards the earth, because acted upon by the attraction of
gravity ; and this sufficiently strong to overpower the propel -
ling force of the powder which gave it motion, and finally bring
it to rest.

OBSTRUCTIONS TO THE ACTION OF MACHINERY.

Friction arises mostly from the elevations of one surface
entering into the depressions of another; but partly also from
the mutual cohesion of the surfaces.

Sliding friction is produced when pinions or axes revolve on
their support

Rolling friction occurs when a round ball or wheel rolls
along a surface. Friction is greater between two surfaces of
wood where their fibres lie parallel than where they run across
each other: it is also greater between two surfaces of the same
metal than between those of different metals : two surfaces of
iron would produce more friction than one of copper and one
of iron : cast steel is said to be an exception to this rule.

The ristance of friction may be diminished by the use of fine
smooth and oily substances ; the particles of which fill up the
cavities and lubricate the asperities of the surfaces. For this
purpose oil is best adapted to metals and tallow for wood.

Extent of surface makes no difference, in a given body, in
regard to the amount of friction developed. Friction is in-
creased between two bodies by their remaining some time in
contact; in some cases it does not attain the maximum in four
or five days. In the contact of two metals, the friction attains

238 SCIENTIFIC AGRICULTURE.

its highest point in a few seconds: two pieces of wood attain
their utmost friction in one or two hours : when iron runs upon
oak the friction will increase for four or five days.

Friction is less after motion becomes well established and
rapid, than when it first commences. The whole efficacy of
the screw depends upon the friction between the threads of
the external and internal screw: the screw being an inclined
plane, if there was no friction, it would unscrew, or the inter-
nal screw would descend by its own gravity when placed ver-
tically. Query ? What relation has the development of fric-
tion to. electricity ?

The resistance of the atmosphere, which in some machines
must be considerable, is another obstruction to the action of
machinery. The weight or gravity of a machine itself, or of
some of its parts, is sufficient in some cases to require a consi-
derable part of its power to overcome it.

STRENGTH OF MATERIALS.

It is important, in the construction of all pieces of archi-
tecture and machinery, that the mechanic should know the
strength of the materials which he is to employ in the work.
By strength, we understand the power which a body has, by
the cohesive force of its particles to resist fracture : stress is
the power or tendency in a body to produce fracture by its
own weight.

A joist eight inches wide and two inches thick, is four times
as strong when laid on its edge as when laid on its side.

" A triangular beam is twice as strong when resting on its
broad base as when resting on its edge."

" The strength of a column in the direction of its length, is
directly proportional to the area of its transverse section."

" Half the length of a beam supported at both ends, will
bear four times as great a pressure as the whole beam ; and a
prop placed under the centre of a beam increases its strength
in the same ratio."

MECHANICAL PHILOSOPHY.

The strength of a beam increases from the centre towards
the ends or points of support, and the stress increases from
the. ends towards the centre; hence, a beam to be equally
strong at every point, should be eliptical, or the largest in the
middle and taper regularly towards both ends.

The strongest form in which a given quantity of matter can
be disposed, is that of a hollow cylinder: this, however, is true
only when the transverse sections of the cylinder are perfectly
circular. In this way nature economizes material, avoids too
great weight, and at the same time augments strength.

"A great column is in greater danger of being broken than
a similar small one ; an insect can sustain a weight many times
greater than itself, — whereas a much larger animal, as a horse,
eould scarcely carry another horse of his own size."

It is not regarded as safe to load a stone structure with more
than one-sixth the amount of pressure which it requires to
crush it: iron may be loaded to one-fourth that amount In
building bridges, <fec., which are to span considerable space
without as much support as might be desirable, it is important
to calculate accurately, both the strength and stress of the
beams : bridges apparently strong, and perfect in construction,
sometimes fall by their own weight: in such cases there is an
unnecessary violation of a philosophical principle of which no
mechanic should be ignorant For suspension bridges, the
strongest material for spanning a wide stream is cast steel
wire, — the next strongest is malleable iron, and k-ast of all
metals, lead. A piece of cast steel wire one-eighth of an inch
in diameter will sustain a weight of 16,782 pounds; or 4,931
feet of its own length : malleable iron wire of the same size,
9,008, or 2,467 feet of its own length: lead wire of the same
size sustains only 228 pounds, or 42 feet of its own length.

Of the different kinds of wood, the strongest are, the ash,
oak, teak, beech and larch, — the strongest of these is the ash.
We see by these few facts in relation to mechanical philoso-

240 SCIENTIFIC AGRICULTURE.

phy, that almost every practical mechanical operation can be
reduced to scientific rules, and the result calculated with
mathematical certainty before the work is commenced. We
see also how much more easily and economically many opera-
tions might be performed, and how much disappointment and
money might be saved by a knowledge of this branch of sci-
ence, to the visionary inventors of patent rights, the only fault
of which is, that they refuse obstinately to perform any part
of the work designed for them, — and the greatest misfortune of
whose inventors is their ignorance. A knowledge of mechani-
cal philosophy is indispensible to the accomplished mechanic or
agriculturist

GLOSSARY.

Agriculture, the science and art of productive farming.

Affinity, attraction— that force which causes two bodies of dif-
ferent properties to unite and form a compound.

Annual, yearly.

Aerial, pertaining to the air.

Axis, the centre or point on which a body does or may revolve.

Acotyledonous, without a colyledon.

Appendage, something added.

Albumen, an organic principle resembling white of eggs.

Altitude, height or elevation.

Arterial, pertaining to the arteries.

Acerose, needle shaped.

Axillary, growing in the angle between the stem and leaf.

Arragonite, a simple mineral composed of carbonate of lime.

Ament, flowers collected on chaff-like scales and arranged on a
slender stalk.

Assimilate, to become similar.

Anemia, want of blood — in botany want of sap.

Absorption, the act of imbibing or absorbing. ,

Anthracite, a species of mineral coal.

Aluminum, a metalic earth, the base of alum.

Albite, a species of feldspar.

Arseniate, a salt of arsenic.

21

242 GLOSSARY.

Asbestos, a fibrous incombustible mineral.

Analysis, separating the elements of a compound.

Azure, sky blue.

Alluvium, the sediment of rivers such as sand, vegetable mat-
ter, mud, &c.

Augite, a simple mineral of a dark green or black color, found
as a constituent in many volcanic rocks.

Amygdaloid, one of the trap rocks through which are scatter-
ed agates and simple minerals.

Agate, a translucent silicious mineral of many varieties.

Apocrenic acid, an acid found in peat and humus soils.

Atmosphere, the air which we breathe.

Aggregate, the sum of several particulars.

Anhydrous, destitute of water.

Aurora Borealis, Northern Lights.

Aqueous, wateiy.

Aerolite, a meteoric stone falling through the air.

Alternate, leaves growing on opposite sides of the stem at dif-
ferent distances, but not opposite each other, are alternate.

Alburnum, sap-wood.

Accretion, increasing in size by the addition of new matter.

Alchemy, the pretended science from which chemistry origina-
ted : its operations consisted in trying to change the baser
metals into gold ; to find a universal solvent and a remedy
for all diseases.

Attenuation, the act of making fine, thin, minute.

Angle of incidence, the angle at which a moving body strikes
another.

Angle of reflection, the angle at which a moving body leaves
or bounds from another.

Aquafortis, nitric acid.

Aqua-ammonia, spirit of hartshorn.

Acrid, sharp, pungent, biting.

Acid, sour, having chemical properties opposite to alkalies.

GLOSSARY. 243

Alkali, in common language, lye.

Apotheme, extractive matter.

Adjective colors, such as require a mordant

Alizarine, the basis of the red coloring principle.

Arable, fit for tillage or cultivation.

Avidity, greediness, eagerness.

Asboline, one of the elements of soot

Botany, the science of plants.

Boulder, a rounded fragment of rock lying on the surface.

Blowpipe, an instrument used in chemical experiments.

Bole, a species of reddish earth.

Bitwnenization, the process of furnishing bituminous coal

Biennial, once in two years.

Biternate, twice ternate, — two petioles, each bearing three

leaves.
Barometer, an instrument for measuring the pressure of the

atmosphere.
Base, the substance which combines with an acid to form a

salt
Bed, a term used in Geology to denote the extent of a stratum

of coal or other rock
Basalt, a dark green rock divided in columnsL

Climatology, a treatise on climate.

Caloric, the agent which produces heat

Coalesce, to unite or run together.

Condense, to make more dense.

Clouds, floating particles of water or other matter.

Congeal, to freeze or harden.

Crystalization, the act of forming crystals.

Concentric, having a common centre.

Cohesion, the force which holds the particles of bodies together.

Corona, a luminous circle round the sun or moon.

Cleavage planes, the flat surface formed by the cleavage of
rocket.

244 GLOSSART.

Continuity, unbroken, continuous texture.

Carboniferous, any bed or rock containing coal.

Coral, a maritime production composed of lime, and the habi-
tation of insects.

Cuboidal, in the form of a cube : square.

Columnar, having the form of columns.

Chalcedony, a species of quartz-like mineral.

Calcareous spar, crystalized carbonate of lime.

Crater, the opening of a volcano through which its eruptions
take place.

Chlorite, a simple mineral of a green color.

Crucible, an earthen or metallic po<» in which ores are melted
and purified.

Crenic acid, an acid found in peat and humus soils.

Calcareous, limy, composed mostly of lime.

Caustic, corrosive, biting, burning.

Calcine, to burn.

Cuticle, the outside bark or skin.

Capillarity, the property of absorbing by capillary attraction.

Carbonate of potash, pearlash.

Chlorine, a simple substance.

Calorific, producing heat.

Capacity for caloric, power of containing latent heat.

Combustion, the act of burning.

Conductors, substances which conduct caloric or electricity.

Carbon, charcoal.

Clarify, to make clear or clqan.

Carbonic acid, a compound of carbon and oxygen.

Complex, having many component parts.

Coniferous, bearing seeds in cones, like the pine.

Carmine, a coloring matter of a pink color.

Casiene, an organic ekment the basis of cheese.

Caramel, a substance produced by heating sugar.

Carburetted hydrogen, a gas composed of carbon and hydrogen.

GLOSSARY. 246

Carbonic oxide, a gas composed of carbon and oxygen.

Corrosive, having- the property of corroding and destroying.

Ce/htlar, composed of small cells.

Cryptogamous, having flowers too minute to be seen with the
naked eye.

Cotyledon, a seed lobe.

Carnivora, the class of animals which live on flesh.

Cruciform, having the form of a cross.

Calyx, a cup, the bottom part of a flower.

Corolla, the closed leaves of a flower.

Crude, raw, immature.

Cordate, heart shaped.

ChlorophyUe, the green coloring matter of plants.

Cambium, the descending sap which forms wood.

Centripetal, tending towards the centre.

Cereals, the white straw grains, as wheat and rye.

Chrysolite, a simple mineral, of gold color.

Centrifugal, tending to recede from the centre.

Corymb, a cluster of flowers whose stalks spring from different
heights, and form a flat top.

Cyme, a cluster of flowers whose stalks rise from a common
centre, and afterwards subdivide irregularly.

Contagion, an infectious or pestilential disease which is com-
municated by contact or through the atmosphere, from one
animal or plant to another.

Denude, to make naked or bare.

Dunes, hills of blown sand.

Disintegrate, to separate into integral parts.

Ductile, capable of being drawn into wire.

Dilute, to make thin or reduce in strength.

Deciduous, falling off in the usual season : not persistent.

Dissemination, the act of sowing or scattering.

Dilate, to expand, extend, enlarge.

Digestion, the act of assimilating food to the body.
*21

546 GLOSSARY.

Digitate, divided like the fingers.

Dip, the inclination of a stratum of rock from the horizon.

Dyke, a mass of rock which appears to have been injected into

the fissures of other rocks.
Drift, masses of sand or other matters driven together by

water.

Deleterious, injurious, noxious.

Duramen, the inside, brown heart of wood of forest trees.
Decompose, to separate into parts or elements.
Data, known or admitted facts or principles.
Deutoxide, a chemical compound containing two proportions of

oxygen.

Daguerreotype, a process of taking pictures by means of light.
Dynamical, pertaining to strength or power.
Deliquiesce, to dissolve gradually by attracting and absorbing

moisture from the air.
Distillation, separating essential oils or alcohol from other

matters, by means of heat,
Diurnal, daily, occurring daily.

Disinfecting, purifying and preventing contagion or infection.
Extant, now in use.
Extirpate, to destroy or eradicate.
Excavate, to dig or wear out a hollow or cavity,
Excrements, matters voided or excreted by animals.
Endogens, plants which grow from the inside.
Electricity, a principle in nature usually called lightning.
Elasticity, power of resuming form after compression.
Elective affinity, that affinity which causes an acid or alkali to

abandon one with which it is already united, and unite with

another.
Ether, a subtil matter which is much lighter than air, and

supposed to exist beyond the limits of the atmosphere.
Emit, to send off, give out or discharge.
Expansion, the act of enlarging or increasing in bulk.

GLOSSARY. 247

Equivalent number, the particular quantity of any substance

required to combine with or saturate another substance.
Emanate, to issue or flow from.
Electric, a substance capable of giving off electricity.
Electrical repulsion, that property which causes bodies in the

same state of electrical excitement to separate: opposite

attraction.

Exude, to run out or issue from.
Equilibrium, balance of forces or properties.
Epiphytes, plants growing- upon the trunk and branches of

other plants and deriving nourishment mostly from the air.
Epidermis outside skin or bark.
Excrete, to eject or throw out.
Embryo, the germ of a plant or animal.
Elliptical, an oval figure with pointed ends.
Exogens, plants which grow by layers on the outside.
Exhalation, breathing out, giving off, emitting.
Evolution, emission, giving off, discharging.
Element, a component part, first principle.
Equator, an imaginary line dividing the earth into two halves ;

the equinoctial line.
Effloresce, to become a dry powder.
Eremacausis, slow combustion or decay.
Evaporation, becoming volatile, flying off with the air, drying

up.

Escarpment, a steep ledge of rocks.
Eurite, a white mineral.
Eject, to throw out, discharge.
Effervesce, to foam, bubble, ferment.
Fasicle, a small bundle.

Flora, the goddess of flowers, a flower or book of flowers.
Functional, pertaining to the office or use of a part of any

organism.
Filament, the slender, thread-like part of the stamen.

548 GLOSS Any.

Fibrils, minute branches of roots.

Fibrous, composed of fibres.

Fusiform, spindle- shaped, tapering.

Fasciculated, collected in heads or bundles.

Fundamental, original, elementary, first principle.

Fructification, the flower and fruit with their parts, the act of
making fruitful.

FAHRENHEIT, the inventor of the thermometer which bears
that name.

Fault, a cleft or fissure in a rock.

Fossil, the remains of animals and plants found buried in the
earth.

Formation, a group of any kind of rocks referred to a common
origin or period.

Fossiliferous, containing fossils.

Fissure, a crack or cleft.

Fuse, to melt, become fluid from heat.

Faggot, a bundle of sticks or brush.

Friable, easily crumbled or pulverized.

Fertilizers, substances used to enrich the soil.

Focus, the point at which rays of light or heat meet

Fluor spar, a mineral compound of lime and fluoric acid.

Fibre, a slender, thread-like organ or substance.

Fumes, vapor, gas or smoke.

Freezing point, this is placed at 32° Fahrenheit.

Feldspar, a simple mineral which constitutes a principal ingre-
dient of most rocks.

Fire damp, light carburetted hydrogen.

Fibrine, the colorless part of the blood which when separated
from it becomes jelly-like.

Geology, the science of the earth's structure, (fee.

Graphite, black lead.

Galvanism, a species or modification of electricity.

Glutinous, sticky, visced, having the characters of glue.

GLOSSARY. 249

Generate, to produce or create.

Gelatine, a proximate principle in plants and the bodies of ani-
mals, usually called jelly.

Guano, a species of manure composed mostly of the excre-
ments of sea fowl.

Granite, an unstratified primary rock.

Greenstone, a variety of trap rock composed of hornblende
and feldspar.

Gneiss, a primary stratified rock composed of the same mate-
rials as granite.

Garnet, a simple crystalized mineral, generally of a deep red
color.

Gypsum, plaster of paris, sulphate of lime.

Graphic granite, is a species of granite in which the quartz is
so arranged as to give the surface the appearance of having
letters.

Gorge, a deep fissure or valley.

Gyration, turning in a circular or spiral direction.

Glossology, the application of names to the various organs of
plants.

Granulated, consisting of small grains, granules, or masses.

Genus, the subdivision of an order.

Gland, an organ in animals and vegetables which performs the
function of secreting a fluid.

Germination, the unfolding of the seed and development of
the embryo.

Geine, a substance obtained from decayed wood, and contain-
ing an acid called the geic acid.

Glanular, consisting of grains.

Grayivacke, an ancient fossiliferous rock, generally of a gray
color.

Gravity, weight : specific gravity, the weight of a particular
body compared with some standard.

Gas, an elastic fluid, or air.

250 GLOSSARY.

Gelatinous, containing gelatine.

Homogeneous, of the same nature, consisting of similar parts,
all alike in structure.

Hornblende, a simple mineral of dark green or black color.

Humid, moist, wet

Harmattan, a dry easterly wind in Africa.

Haziness, foggy, smoky, misty.

Horizon, the line where the earth and sky appear to meet.

Hydrogen, a gas, the lightest of all known bodies.

Hues, tints, colors.

Hurricane, a violent storm or tempest.

Halo, a circle appearing around the sun, moon, or stars.

Hypothesis, a supposition or theory assumed but not proved :
used for the purpose of argument.

Hexagonal, six sided : having six sides and six angles.

Hydracid, an acid formed by the union of a substance with
hydrogen without oxygen.

Hematoxyline, the coloring principle of logwood.

Hydrate, a compound containing water.

Humic acid, an acid obtained from humus.

Herbaceous, herb-like, not woody.

Herbarium, a book in which dried plants are preserved.

Imbibe, to take in, absorb.

Irrigation, the act of watering, moistening.

Incineration, the act of reducing to ashes.

Intersect, to meet and cross each other.

Isoincric, bodies which differ in properties but agree in com-
position.

Inter stratified, stratified between or among other bodies.

Infusible, that cannot be fused or melted.

Incas, inhabitants of Peru and some other parts of S. America.

Inf. ate, to blow up, fill with wind.

Isothermal lines, lines which pass through points on the sur-
face of the earth at which the mean temperature is equal.

GLOSS ARV. 251

laochlmencd lines, lines passing through points on the earth at

which the mean temperature of the winter is equal.
Intertropical, between the tropics.
Jf/ nis fatuus, Jack 0' Lantern.
Inverted, turned upside down.
Igneous, rocks, such as have been melted by fire or volcanic

heat

Infusoria, animalcules too minute to be seen by the naked eye.
Interlace, to tangle or lace together.
Inflorescence, the manner in which flowers are connected with

the plants.

Indigenous, native of, or growing wild in a country.
Joint, the parting lines in rocks, often at right angles with the

planes of stratification.
Kaolin, a species of potter's clay.
Lignite, wood converted into a kind of coal.
Lava, the melted stone which is thrown out of volcanoes.
Lichens, cryptogamic plants, of a crusty texture, growing on

rocks and the trunks and branches of trees.
Lenticular, having the form of a lens.
Longevity, length of life.
Laticiferous, the system of vessels in the bark of plants, which

circulates their fluids.
Latex, the fluid formed from the sap, and which nourishes all

parts of plants.

Lanceolate,- in the form of a lancet

Lyrate, pinnatified wiih a. large roundish leaflet at the end.
Linear, long and narrow with parallel sides, as in the leaves of

the grasses.

Leguminous, having legumes or pods, as the bean and pea.
Liber, the inner bark of plants.
Lamina, layers, thin plates or leaves.
Longitude, the distance of places on the globe in an east and

west direction.

252 GLOSSARY.

Latitude, distance or degrees north and south.

Laminated, in lamina, layers or leaves.

Lunar, pertaining to the moon.

Limpid, pure, clear, transparent: thin when used in reference
to some fluids.

Marine, pertaining to the sea.

Microscopic, objects which are too small to be seen without the
aid of the microscope.

Macerate, to soak, dissolve.

Maximum, the greatest number or quantity attainable in any
given case.

Magnetism, the power or force which causes the magnetic
needle to point north and south.

Molecules, the ultimate or minute particles of matter.

Mirror, a looking-glass.

Mercury, quicksilver.

Mucilage, a slimy fluid, one of the proximate elements of plants.

Mordant, any substance used by dyers to set colors, or render
them permanent.

Must, the juice of grapes which has not fermented, new wine.

Metamorphosis, change, transformation.

Meteorology, the branch of science which treats of changes of
weather and other atmospheric phenomena.

Meteor, any appearance or phenomena observed in the atmos-
phere.

Mean temperature, that point which lies midway between the
two extremes of heat and cold.

Mist, fog, vapor.

Maritime, relating or pertaining to the sea.

Monsoon, a periodical wind which blows six months in one di-
rection, and then changes and blows six months in the op-
posite direction.

Moor, a marsh or fen, or land overgrown with heath and other
shrubs.

GLOSSARY. 253

Mirage, an optical illusion described in meteorology.
Mineral, in common language, the metals and rocks.
Metalloid, a name applied to some of the metallic bases of the

earths.
Mica, a rock which is divided or laminated in its shining scales,

and of various colors.
Metamorphic, rocks which have been altered by the action of

fire.
Muriate of magnesia,, & salt formed by the union of magnesia

with muriatic or hydrochloric acid.
Mammalia, vertebrated animals, which have warm blood,

breathe by means of lungs, bring forth living young and

nourish them by milk.
Membrane, a thin delicate skin.
Midrib, the main or middle rib of a leaf, running from the base

to the point

Medullary, pertaining to the pith or marrow.
Morphology, that part of botany which treats of the formation

and metamorphosis of organs.
Malleable, a metal which can be hammered and drawn out

into various forms by the hammer, as iron.
Nutrient, nourishing, or pertaining to nutrition.
Noxious, hurtful, injurious, unwholesome.
Nomenclature, a system of naming or applying technical terms

in any art or science.
Nutrition, the act or process of supplying the proper matter

for the growth of animals and plants.
Nitric acid, aquafortis.
Nitrate of potash, salt petre.
Node, a knot or protuberance.
Nocturnal, nightly, occurring every night
Nickel, a grayish white brittle metal.
Nodular, having nodes or knots.
Napiform, resembling a turnip in form,

22

254 GLOSSARY.

Ovary, a name in botany given to the outer covering of the

germ.
Ovules, little eggs, the rudiments of seeds which the germ

contains before its fertilization.
Orbicular, round, circular.

Organography, a description of the organs of plants.
Organic, composed of various parts or organs which perform

separate offices.

Oxidize, to become rusty or combine with oxygen.
Observatory, a place or building for making observations on

the heavenly bodies.

Opake, not transparent, not pervious to rays of light
Optical, pertaining the eye, to vision, or the science of optics.
Orbit, in astronomy, the path of a comet or planet.
Outcrop, the naked ends of strata of rock which protrude

above the surface of the earth, as on the side of a hill.
Oolite, a limestone composed of rounded particles like the eggs

of fish.

Organic remains, the fossil remains of plants and animals.
Olivme, an olive colored simple mineral often found in grains

and crystals in basalt and lava,

Oxide, a chemical compound of metals with oxygen, &c.
Oxygen, a gas.

Oxalute, a salt composed of oxalic acid and a base.
Oxalic acid, an acid obtained from sorrel.
Ordure, excrement, faeces, manure.

Permeate, to penetrate or pass through the pores of a body.
Phospkuretted Hydrogen, a compound of phosphorus and hy-
drogen.

Poudrette, a manure prepared from ordure.
Philosopher's stone, an imaginary mineral sought by the alchy-

mists, which was supposed to be capable by mixture with
the baser metals of transmuting them into gold.
Proximate, near; "proximate elements," those elements of

GLOSSARY. 255

plants, such as starch, gum, &c., which are composed of the

immediate elements, viz : the gases and mineral matters.
Protoxide, a compound containing one proportion of oxygen.
Photographic, pertaining to light; photographic pictures are

taken by light.
Phosphorescence, a peculiar luminous matter without fire or

combustion, as the light given out by phosphorus, decayed

wood, putrifying flesh, <fec.
Parabola, a conic section arising from cutting a cone by a

plane parallel to one of its sides.
Prism, in optics, a triangular glass instrument for separating

the rays of light.
Polarity, that property which causes one end of a body to

repel and the other to attract, as in bodies magnetized or

electrified; pointing towards the poles.
Putrefaction, decomposition or decay of organic bodies.
Pungent, biting, hot, sharp.
Ponderable, possessing weight.
Precipitate, to throw down or separate.
Phosphates, compounds containing phosphorus.
Parallelism,, the state or quality of being parallel.
Petrify, to become stone.
Pebble, a small stone.
Plutonic, pertaining to subterranean heat
Porphyry, an unstratified igneous rock.
Pegmatite, primitive granite rock,
Pumice stone, a species of lava.
Plumbago, black lead, graphite.
Pulverulent, consisting of fine dust or powder.
Phenomena, an appearance.
Phase, an appearance, exhibited by the illumination of the

moon or other planets.
Polar elevation, height of latitude, or approach towards the

poles.

256 GLOSSARY.

Pestilential, infectious, spreading pestilence. .

Phosphorus, a simple combustible body of a yellowish color,

and the consistence of beeswax.
Physical, pertaining* to matter or physics.
Parhelia, mock suns, or luminous spots near the sun.
Pistil, the central organ of most plants consisting of the

stigma, style and germ.
Perianth, a sort of calyx, the floral envelops, consisting of the

calyx and corolla, which are placed around the pistils and

stamens.
Pollen, the dust contained within the anthers of flowers, and

necessary to fructification.

Placenta, a part of the ovary to which the ovules are attached.
Pericarp, the seed covering.

Parasite, a plant or animal which grows on another.
Perennial, lasting more than two years, evergreen.
Phenogamia, plants which bear visible flowers.
Petal, a, flower leaf which is part of the corolla.
Plumule, the ascending part of a germinating plant.
Perforate, to make a hole, having holes, to pierce.
Parenchyma, the principal and proper substance of any organ

in a plant or animal.

Pervious, porous, or capable of being penetrated.
Pellicle, a thin skin, film or crust.
Pyrogen, the matter or generator of electricity.
Porcelain, a fine kind of earthen ware.
Peat, decayed and decaying vegetables, usually buried below

the surface of the ground.

Peduncle, the stem which bears the flower and fruit.
Panicle, a loose, irregular bunch of flowers, as in the oat
Propagate, to produce, or multiply by shoots, &c.
Physiology, the science which explains the laws o£ life and
"the uses and offices of all the various organs of plants and

animals.

GLOSSARY. 257

Ptdpt the soft juicy part of fruits and berries.

Quartz, a simple mineral composed of silex or flint

Quartzose, containing quartz.

Quiescent, in a state of quietude or repose.

Quadruple, four times, four fold.

Radiate, to shine, to proceed in direct lines from a point, like

rays of light or heat.
Repulsion, the act of repelling or driving off, as in bodies in

the same electrical state : opposed to attraction.
Rarity, the opposite of density, thin, light.
Refrangibility, capable of being refracted.
Respire, to breath.

Residual, remaining after a part is taken, sediment which sub-
sides from a watery, mixture.

Reagent, a substance employed to precipitate another from solu-
tion, or to detect the presence of some other substance.
Rape, a plant of the genus brassica, allied to the cabbage.
Ramify, to branch off, divide.
Radiation, the act of radiating, throwing off rays.
Refrigerating, producing cold.
Reverberate, to return, rebound, resound, re-echo.
Rays of light, the brilliant luminous lines which proceed or

radiate from a luminous body.
Rarify, to make less dense, to make thin or light.
Rarifaction, the process of ratifying, making more porous by

expansion.
Refraction, the act of bending or breaking, diviating from a

direct course, as in rays of light
Receptacle, the end of the flower stalk to which the organs of

fructification are usually attached.
Ramous, branching, having lateral divisions.
Ramification, branching, minute division.
Ravine, a deep hollow or valley worn out by water.
22*

258 GLOSSARY.

Ruby, a precious stone, a simple mineral of a carmine red color.

Rachis, the common stalk to which florets and spikelets are at-
tached, and in the grasses and wheat.

Raceme, a cluster, that variety of inflorescence in which the
flowers are arranged by simple pedicels on the sides of a
common peduncle, as the currant.

Respiration, breathing, or the act of absorbing or inhaling, and
exhaling carbonic acid and oxygen.

Rosacea, an order of plants, including the rose tribe.

Radicle, the descending part of a germinating plant, a small
root.

Rudimental, consisting of the first principles, or simple elemen-
tary parts.

Reniform, kidney shaped.

Silicate, a salt containing silica united to a base.

Silecious, containing silex.

STERCOLOGY, the science of manuring, enriching, or improving
the soil.

Smoulder, to burn and smoke without vent.

Sewer, a drain to convey off water underground.

Sulphate of iron, green vitriol, copperas.

Spurry, a plant of the genus spergula, allied to duckweed and
tares.

Spiral, in the form of a screw, gyratory like the thread of a
screw.

Subordinate, of minor importance, a secondary or inferior part.

Synthesis, the act of combining, contrary to analysis.

Spectrum, a visible image continuing after the eyes are closed:
the seven primary colors constitute the solar spectrum.

Statical, in a state of rest, the branch of mechanics which
treats of bodies at rest.

Sterile, barren, unproductive.

Solvent, a substance or fluid which dissolves other substances.

GLOSSARY. 259

Safety lamp, a lamp surrounded by wire gauze, invented by
Dr. Davy to prevent explosions from the ignition of gas in
coal mines.

Solar, pertaining to the sun.

Sublimated, brought into a state of vapor by heat.

Stamen, a slender threadlike organ in the centre of flowers.

Summit, the apex or top.

Stigma, the summit or top of the pistil.

Style, the part of the pistil between the stigma and germ.

Stomata, mouths, or orifices.

Spongioles, the minute spongy suckers or extremities of roots.

Spores, the seeds of cryptogaraous plants, bodies analagous to
the pollen grains of flowering plants.

Sepal, a leaf of the calyx.

Sagittate, arrow form.

Segment, a part or principal division of a leaf, calyx, or corolla.

Stellate, star form.

Succulent, juicy.

Shale, a solid form of clay, which usually divides into lamina.

Saccharine, sweet, containing sugar.

Spadix, an elongated receptacle of flowers, commonly proceed-
ing from a spathe.

Scoria, volcanic cinders.

Silicon, the substance which combined with oxygen constitutes
silicic acid or flint

Sapphire, a hard mineral, consisting of crystalized alumina: it
is of various colors ; the Hue being generally called the sap-
phire ; the red, the oriental ruby ; the yellow, the oriental
topaz.

Saline, salt, containing some salt.

Sodium, the metallic base of soda.

Steatite, soapstone, a hydrated silicate of magnesia and alumina.

Snow-line, the lowest point on mountains at which there is per-
petual snow.

260 GLOSSARY.

Subterranean, underground, below the earth's surface.

Submerge, to plunge under water, to overflow.

Strata, layers of rock.

Spherule, a little sphere, or ball.

Simoon, a hot suffocating wind, that blows occasionally in Af-
rica and South America.

Sirocco, a pernicious wind that blows from the south-east in
Italy.

Salubrious, healthful, favorable to health.

Supernatur al, miraculous, out of the usual course of nature.

Solar spectrum, the seven primary colors as seen in the rain-
bow.

Stratified, arranged in strata or layers.

Silurian, a series of rocks forming the upper subdivision of
the sedimentary strata found below the old red sandstone,
and formerly designated the graywacke series.

Scape, a stalk which springs from the root, and supports
flowers and fruit, but no leaves.

Saturate, to fill with a fluid, absorb, soak.

Sedimentary rocks, are those which have been formed by
their materials having been thrown down from a state of
suspension or solution in water.

Syenite, a kind of granite so called because it was formerly
brought from Syene in Egypt.

Serpentine, a rock usually unstratified, containing much mag-
nesia, and often speckled of various colors, like a serpent's
back.

Sculpture, the art of carving wood or stone into the images of
men or animals.

Stucco, a fine white plaster, to plaster with stucco.

Stalactite, a variety of carbonate of lime in the form of icicles,
produced by the filtration of water containing lime in solu-
tion, from the crevices of rocks in the roofs of caverns.

Stalagmites, are similar to stalactites, but formed by the drop-

GLOSSARY.

261

ping of water on the floors of caverns, and having their
points upwards.

Twilight, the light at the close of day after sunset and before
dark.

Tortuous, crooked, convoluted.

Tertiary, a series of sedimentary rocks, lying above the pri-
mary and secondary, and having characters which distin-
guish them from these two classes.

Trachyte, a variety of lava essentially composed of greenstone :
it frequently contains detatched crystals of feldspar, and
sometimes hornblende and augite.

Titaniferous, an iron ore containing titanium.

Talc, a species of magnesian earth, consisting of smooth shining
lamina, translucent or transparent. *

Transparent, admitting rays of light to pass through.

Transverse, crosswise, across.

Terrestrial, belonging to, or pertaining to the earth.

Tillage, includes all mechanical operations on the soil.

Tropical, belonging to the tropics.

Torrid zone, the hot country included between the Tropic of
Cancer, and the Tropic of Capricorn.

Tornado, a high wind, a whirlwind.

Theory, an exposition of the principles of any science; the
science without the art or practice.

Tissue, connection or organization, the proper substance of an
organ.

Terminal, situated at the end.

Thyrse, a loose irregular bunch of flowers.

Tenacity, toughness, having strong cohesion,

Tap root, the main root, the axis.

Tuber, a fleshy knob or tumor on a rcot.

Trifolium, the genus of plants to which clover belongs.

Ternate, leaves which are arranged in threes are called ter-
nate.

262 GLOSSARY.

Transmit, to permit to pass, to convey through.

Tint, shade, hue, color.

Transition, rocks which appear to have been formed while the
earth was in a state of transition, from a state of desolation
to a habitable condition. They have a texture partly me-
chanical and partly chemical.

Urea, the principal element, next to water, in the composition
of the urine.

Vhnic acid, a substance formed by the action of acids on
sugar.

Unconsolidated, soft, not consolidated.

Umbel, a kind of infloresence in which the flower stalks diverge
from one centre, as the wild parsnep.

Volcano, a burning mountain.

Vision, sight, the act of seeing.

Veins, cracks or fissures in rocks which are filled with sub-
stances different from the rock, either mineral or earthy.

Volcanic, pertaining to volcanoes, produced by volcanoes.

Vertical, perpendicular, overhead.

Vapor, mist, fog, small particles of water.

Vesicles, small particles or drops.

Verticil, whorled, having leaves or flowers in a circle round
the stem.

Volatile, evaporating or flying off easily.

Vascular, made up of vessels, or full of vessels.

Vasiform tissue, is made up of large tubes.

Venation, the arrangement of the ribs or veins in leaves.

Viscid, stringy, sticky, slimy.

VerticiUate, whorled.

Verdure, foliage, herbage.

Vibrate, to swing or oscillate.

Vacuum, an empty space, a space from which the air has all
been removed.

Vitality, life, the vital or living principle.

GLOSSARY. 263

Vital functions, those functions or actions which arc indispen-
sable to organic life.

Vetches, a liguminous plant allied to the pea, bean, and lentil

Warping, a process in agriculture similar to irrigation.

Wealden, a fresh water group of rocks, composed of clay, lime
marl, &c.

Zigzag, in a crooked direction, forming short angles.

Zenith, that point in the sky or celestial hemisphere which, is
vertical to the spectator.

Zanthine, a substance found in urinary calculi

Zeolite, a mineral composed of silica, alumina and lime.

INDEX.

ANALYSIS, - 23

Affinity, chemical 28

Affinity, simple 28

Affinity, elective - 29

Attraction, chemical - 28

Atmosphere, "" * 47

Acid, nitric - 50

Aquafortis, - 50

Ammonia, - - 51

Acids, properties of - • 55

Alkalies, properties of 55

Albumen, - 60

Acids, vegetable, - 63

Alkalies, vegetable 63

Apotheme, - - 64

Alizarine, - 64

Alluvium, - 78

Amygdaloid, - 84

Appendages of plants, 96

Anther, "• -•' - 99

Albumen, - ".»••• - 101

Aerial roots, 105

Annual roots, - 105

Alburnum, - 108

Absorption, - 117

Agriculture, influence of on climate and fall of rain, 133

Aerolites, - 149

Aluminum, - - - - - 158

23

26G INDEX.

Alum, - 158

Analysis of soils, - 227
Analysis of soils to determine the quantity of vegetable

matter, . 228
Analysis of soils to determine the quantity of sand and

clay, - 228

Analysis of soils to determine the quantity of water, - 228

Analysis of soils to determine the quantity of humic acid, 229

Analysis of soils to determine the quantity of ulmic acid, 229
Analysis of soils to determine the quantity of crenic and

apocrenic acids, 229

Analysis of soils to determine the quantity of lime/ - 230

Analysis of soils to determine the quantity of silica, 230
Analysis of soils to determine the quantity of oxide of iron, 230
Analysis of soils to determine the quantity of different

salts, - 230

Analysis of a fertile soil, - 231

Analysis of a barren soil, 231

Aurora Borealis, 146

Analysis of beech and oak ashes, - 207

Ashes of coal, peat, <kc., as manures, - 208

Analyses, tables of 216

Analysis of wheat, - 216

Analysis of barley, 217

Analysis of oats, - 217

Analysis of rye, - 218

Analysis of peat, - - 218

Analysis of coal ashes, - 219

Analysis of bean and pea, - 219

Analysis of turnip and potato, - 219

Analysis of carrot and parsnep, - 220

Analysis of grass and clover, 220

Analysis of silica plants, - 221

Analysis of lime plants, - 221

Analysis of potash plants, - 222

Analysis of fseces of horse, 222

Analysis of urine of horse, - 222

Analysis of feces of cow, 223

Analysis of urine of cow, - 223

Analysis of human fseces, 223

Analysis of human urine, - 22B

INDBX. 267

Analysis of guano, * 4 * - . . • - 224

Analysis of bones of the ox, . - J, - 224

Analysis of coal soot, - 224

Analysis of wool, hair, horns, 225

Analysis of ox blood and muscle, . - , - - 225

B

Bed, .' - . - 74

Basalt, - 84

Botany, - 91

Botany, divisions of - • , * *»-'•'< - - 91

Breeze,- - •• • 145

Bridges, > •- • - •• •»/ ».'•• *•"*'. - - 239

Biennial roots, . - - 105

Buds, > - •• , if * ;• * ,.. *v - 107

Bole, - * - 167

Blood, as manure, '*'•' - * - 192

Bones, as manure, .... „ -..*>«] 192

Calcium, - - - 162

Charcoal, animal » * ; ' . - - 192

Chaff as manure, ' - ; - - - 197

Charcoal as manure, ' 198

Carbonate 'of soda* as manure, • * ** • 204

Chloride of sodium, or 'common salt, as manure, - 206

Chloride of lime and magilesia as manures, - - 206

Crushed rocks," as manure, - •« 208

Chalk as a' manure*, - - 209

Composts, - 212

Comparative value* of manures, table of - - 215

Chemistry, - * - ' - +'• •• » - 23

Capillarity, - ' 4; -.^J; * * - > * *• iw** 24

Cohesfon, v 25

Combination, laws* of 'f - 80

Caloric, - - 84

Caloric, expansive power of - 34

Caloric, conductors of - 34

Caloric, specific, - 35

Caloric, capacity for 85

Caloric, radiant > ,' • « . • *. - 9$

268 INDEX.

Caloric, latent, . . . . . 35-

Caloric, transmission of . . . .36

Cold, 37

Carbon, t % . . . . .42

Carbonic acid, ..... 43

Carbonic oxide, . . . . .48

Carburetted hydrogen, . . . . 49

Cerine, ...... 61

Camphor, . . . . . 61

Caoutchouc, • . . . .62

Coloring matter, ..... 64

Chlorophylle, ... .64

Colors, adjective . . . . . 65

Colors, substantive, . . . . .65

Carmine, . . . . . 65

Chlorine, ...... 65

Compounds derived from the inorganic elements of plants, 67
Caramel, ...... 71

Cleavage planes, ..... 75

Clay slate, ...... 86

Chalk, ...... 87

Coal, . . . . . . .87

Coal, varieties and origin of ... 89

Coal basin in Wales, . * . . .89

Class denned, ..... 93

Corolla, ...... 97

Calyx, ...... 98

Cotyledon, ...... 101

Cellular integument, . . . . 108

Cambium, ...... 109

Cryptogamous plants, . . . . 110

Chlorophylle, . . . . .111

Climate, ...... 126

Clouds, ...... 138

Corona, ...... 147

Clay, 166

D

Divisibility, . . . • . 25

Density, ...... 27

Diastase, . . . . . 68

INDEX.

269

Dip 75

Dyke, 76

Drift,

Duramen, . . . . . .108

Dissemination of seeds, . . . . 120

Digestion, . . . . . .118

Day, longest in different latitudes,

Dry leaves as manure, . . . .197

Decayed wood as manure, . • ' . 197

Draining, its objects . ' « . . . . 181

Draining, varieties of . . . 182
Dynamics, ...... 233

Dew, ...... 136

E

Elasticity, . . . . . 27

Equivalent number, . . . . .31

Electricity, . . . \. *.* . ./*'. 3?

Electricity, negative . , » ' . . 38

Electricity, positive . . . . 38

Electricity, conductors of. . . .38

Electrical excitation, . . . . 38

Electrical repulsion, . . » - »

Electricity, statical . . V;' • 39

Electricity, dynamical . ,* . . 39

Eremacausis, . . . . . 44

Elementary bodies, . . . . .53

Elements, organic . . . . 57

Elements, proximate . . . .57

Elements, immediate . . . . 57

Extractive matter, . . . . .64

Escarpment, . . . ': -Jr '• . 75

Embryo, . . . v V- \.V . 94

Epidermis, . . * . . 96

Embryo, . . , . . .101

Epiphytes, . . . . . 105

Epidermis, . . . . . .108

Exhalation, . . . . . 117

Excrements of plants, theoiy of ... 185

Excrements as manure, . . . « 193

Excrements, human . . ».' .193

24

270 INDEX.

Excrements of horned cattle, . . . 194

Excrements of the horse, . . . .194

Excrements of the hog, . . . . 195

Excrements of sheep, . . . .195

Excrements of birds, . . . . 195
Epsom salts as manure, .... 205

Earthy manures, ..... 206

Fire damp, . . . . . 49

Fermentation, . . . . .69

Fermentation, vinous, . 69

Fermentation, acetous . . . .70

Fault, 76

Formation, . . . . . .76

Fossil, ...... 76

Feldspar, composition of . . .87

Flower, . . . . . . 97

Filament, ...... 99

Fruit, ...... 100

Fibrils, . . . . . . 103

Fusiform roots, . . . . . 104

Fibrous roots, . . . . .104

Faciculated roots, . . . . 104

Floating roots, . . . . . .105

Flowers, terminal . . . . 118

Flowers, axillary . . . . .118

Flower, solitary . . . . . 119

Forests, their influence on climate and the fall of rain, 134

Frost, . . . * . . .136

Frost, cause of . . . . ^137

Fogs, . . . . . . ~ 138

Fire balls, ..... 148

Fallowing, . . . . . .182

Fallowing, benefits of . . . 183

Flesh as manure, . . . . . 192

Fat of animals as manure, . . . 192

Farm-yard manure, . . . . .199

Force defined, ..... 233

Friction, . . . . .237

INDEX. 271

Gravity, . . . . . . 26

Gravity, specific .'

Galvanism, ..... 39

Gases, properties of . . . . .40

Gum, '.,.... 59

Gluten, .'..... 60

Geology, .... .73

Gorge, . .' . .76
Granite, . . J . .

Greenstone, . .' . . . 83

Gneiss, ...... 85

Graphite, ....

Genus, defined ..... 93

Germination, . . . . . .101

Granulated roots, . . . . . 104

Gale, . . 145

Gypsum, . ., ;. ^ ,_ . 165

Gelatine as manure, . *. . . .193

Guano, ...... 196

Green manures, ..... 200

Green manures, uses of . . 200

Glauber's salts as manure, . , jf .-; . 204

H

History, natural . . t » . . 21

Hydrogen, . . . . . .41

Hartshorn, spirits of . . . 51

Haematoxyline, . . . . .65

Hornblende slate, ..... 86

Hornblende, basaltic, composition of . . A * " 87

Herbs, 106

Hail, .... ,; . - . . . 140

Harmattan, . . --;. ' j.'>, . • 1^4

Hurricane, . . . . . .145

Halo, . . . , \ . . 147

Humus, . . . . . .168

Humus, its composition . . . . 169

Hair as manure, . . . . .192

Horns as manure, . . ..'. . 192

Hoofs as manure, . . * . * . 192

272 INDEX.

I

Isomeric bodies, ..... 58

India rubber, . . . . .62

Indigo, . . . . . . 64

Inorganic elements of plants, . . .65

Iodine, ...... 66

Idial section of the earth's crust, . . .79

Integument, . . . . . 101

Inflorescence, . . . . .118

Inflorescence, centripetal . . . . 119

Inflorescence, centrifugal . . . .119

Isothermal lines, . . . . . 127

Isochimenal lines, ..... 127

Ignis fatuus, . . . . . 147

Iron, ....... 159

Irrigation, . . . . . 179

Inclined plane, . . . . .234

j

Joint, - 75

K

Kaolin, . - 167

L

Light, - 32

Light, nature of - 32

Light, reflection and refraction of 32

Light, origin of - - 33

Light, heating rays of 33

Lignine, 58

Lava, - 84

Limestone, primary 86

Latex, - .... 108

Liber, - 108

Leaf, - - - 111

Leaves, deciduous - 111

Leaves, evergreen - 111

Leaves, scattered - 111

Leaves, alternate - 111

Leaves, opposite - 111

INDEX. 278

Leaves, verticillate 111

Leaf, orbicular - 112
Leaf, eliptical

Leaf, lanceolate - - - 1 1 2

Leaf, cordate - - 113

Leaf, sagittate - - 113

Leaf, reniform - , •• 113

Leaf, linear - - - - -113

Leaf, deltoul - 113

Leaf, acerose - 113

Leaf, pinnatified - - 113

Leaf, lyrate - 114

Leaf, connate - - 114

Leaf, digittate - 114

Leaf, stellate 114

Leaf, lobed - - - - 114

Leaf, compound - - 115

Leaf, sinuate - 115

Leaf, emarginate • -' 115

Leaf, tubulate, - 115

Leaves, biternate 115

Leaves, ternate - 115

Lightning, 140

Lighting rods, - - 141

Lightning, conditions under which it is developed, <fec. 142

Land and sea breezes, - * .«._* - - 143

Lime, - * • - 163

Lapping, - - - - - 177

Leached ashes as manure, • ,'••»> • - 208

Lime as manure, - - - - 209

Lime, mode of applying, - - - 210

Lever, - - - >. . 234

Latex, - - - - - - 117

M

Myricine, ...... 61

Mordant, ...... 64

Miea slate, . . . . . 86

Mica, composition of . . . . .87

Midrib, . . . . . v» 111

Meteorology, . . . ' *•*', ' +* . 125

24*

274 INDEX.

Meteor, ...... 125

Mirage, . . . . . .149

Mists, . . . . . . 138

Monsoons, . . . . . .145

Manganese, . . . . . 159

Magnesium, . . . . .102

Magnesia, . . . . . 162

Marl, ....... 164

Manures, . . . . ". 190

Manuring, objects of . . . . .191

Manures, animal . . . . . 192

Mineral manures, . . . . .204

Marl as manure, ..... 208

Mechanical philosophy, . . . .233

Machinery, objects of . . . 234

Machinery, on regulating motion of . .235

Motion, species of . . . . 236

Machinery, obstructions to the action of . .237

Materials, strength of . . . 238
Materials, beams and columns .... 238

Materials, cylinder . . . . 239

Materials, metals, . . . . . .239

Materials, woods . . . . . 239

Materials, stone . . . . .239

N

Nitrogen, ...... 45

Napiform roots, . . . . . 103

Nerves, . . . . . .111

Night soil, . . . . . 194

Nitrate of soda as manure, . . . .205

0

Oxygen, ...... 41

Oxalic acid, . . . . . .48

Organic bodies, mutual relation of . . 60
Oils, fixed ...... 62

Oils, volatile . . . . . 62

Organic elements, metamorphosis of . . . 70

Outcrop, ...... 75

Olivine, , . . 84

INDEX. 275

Order defined, ..... 93

Ovary, ......

Ovules, ......

Oil cake as manure, . . . . .198

Philosophy, natural, ... . • . 21

Physics, \ *• .$ . .21

Prism, . f . ; >' . . 33

Pyrogen, . , * • » r . . . 39

Phosphorus, . • »• . . . 66

Phosphoric acid, *^ .$ . . .67

Primary rock, . . . . . 78

.Porphyry, . . . . .83

Plants, divisions of _ *' ... 92

Plants, classification of . • • .92

Plumule, . ...*-. . 94

Pistils, *^ . ' . " ,. * .97

Perianth, . .' .' *' . /£ . 97

Petals, . .. ' ./ '•';-.- * • . 97

Pollen, . •"." V'. ... 99

Placenta, . V . ." . .99

Pericarp, . "/ ;' * : . . . 100

Parasitel, .* ' • ?-* ^ '.. . . . 105

Perennial roots, . »" .* ;" . 105

Pith, . . ; v* . ^, ' . . 107

Parenchyma, . . . * . . 116

Peduncle, . . . / ', / . .119

Panicle, . . . ;; , " , . 120
Plants, curious phenomena of . /; . ',' > . . 122

Plants, locality of . . . ' . * ^ , .. 123

Plants, diseases of . . -^, ' ^* , . 123

Parhelia, . . . l.V * -^* • 148

Potassium, . . . .. * *7 . IQI

Peat, . . . . . * . ] . 167

Potter's clay, . . . : , ,* . 167

Pipeclay, . . . ^ . * ^, " . 167

Peat, composition of . . . -' . .168

Paring and burning, . . . . 180

Phosphate of lime, . . .. .193

276 INDEX.

Peat as manure, . . . . .198

Pasture, improvement of the soil by . « 202
Pasture, temporary ..... 202

Pasture, permanent .... 202

Power defined, . . . . .230

Pulley, ...... 234

Q

Quartz, . . . . . .85

B

Rarity, . . . . . .27

Resin, ...... 61

Rocks, classification of . . . .77

Rocks, aqueous ..... 80

Rocks, volcanic ... . . .80

Rocks, plutonic ..... 80

Rocks, rnetamorphic . . . . .80

Rock salt, ..... 88

Radicle, . . . ... .94

Rain tables, . . . . . 136

Rotation, courses from Colman, . . » 187

Receptacle, . . . . . 97

Radicle, ...... 101

Root, 102

Ramose roots, . . . , .103

Root, functions of . . . . 106

Respiration, . . . . .118

Rachis, . . . . . 119

Rain, . . . . .135

Rain, its cause, . . . . . 125

Rain, its quantity, &c., . . . .135

Rainbow, . . . . . 148

Rainbow, inverted . . . . .148

Ribbing, . . . . . 178

Rotation of crops, . . . . .184

Rotation, objects of . . . . 185

Rotation, courses of . . . . .188

INDEX. 277

s

Science, natural . . . . .21

Synthesis, .....

Spectrum, solar . . . . .33

Salts, properties of . . . . 56

Salts, acid . . . . . .* 56

Salts, neutral ' . * * * . . 56

Salts, basic . * . " . "*" . . . 56

Salts, double . . . 56

Salts, deliquescent, , . . . .57

Salts, effervescent, .... 56

Starch, ...... 58

Sugar, ...... 29

Stratification, . . . . .74

Seam, „ . . . . 75

Sulphur, . . . .66

Syenite, ...... 83

Serpentine, . ' \ . * , . . 84

Slate, talcose, , , . . . . 87

Species defined, <» .V . . .94

Stamens, ,«• . . . . 97

Style, ,.'"• . *• >. 5 . . 99

Stigma, . . * ' . . . 99

Seed, , 4 • £* • • .101

Spongioles, # » . . . 103

Shrubs, . . . . . .106

Stem, exogenous . . . . . 107

Sap, . . . •, -• . . .108

Scape, . . •*••; ; •. % * , "-. _ • 119

Seeds, longevity of . . . v - .122

Snow line, . ». . « 0 128

Snow lines, table of . * * + • ' « • . 128

Snow, . . . v v- • 138

Snow crystals, system of ?.'• • ».v »'* . 139

Simoon, . . .*•. . ;• *4 . 145

Sirocco, . ; . •• •* «• .'^ . 145

Shooting stars, . . V ./ • . 149

Silicon, . ./> . .-.* . .157

Sodium, . . . . . 160

Stalactites, . . . . • . .165

Stalagmites, . . »* V" ; * 165

278

INDEX.

Spar, gypseous, . . . . .165

Stitching, . . . . 1%8

Scarifying, . . . . . .178

Soils, physical properties of . . . 171

Soils, weight of . . . .171

Soils, state of division of . . . 171

Soils, firmness and adhesiveness of . . .172

Soils, power of imbibing water . . . 172

Soils, power of containing water . . .172

Soils, power of retaining water, . . . 173

Soils, capillary power of . . . .173

Soils, their contractibility on drying, . .' 174

Soils, their power of absorbing gaseous matters, . 174

Soils, their power of absorbing heat, . . 174

Soils, their power of retaining heat, . . .175

Soils, their power of radiating heat, . . 175

Soils, their ultimate uses to plants, . . .176

Subsoil ploughing, . . . . 178

Stercology, . . . . . .190

Skins of animals as manure, . . . 192

Straw as manure, . . . . .197

Saw dust as manure, . . . . 197

Soot as manure, . . . . .198

Saline manures, ..... 204

Sulphate of soda as manure, . . . 204-

Sulphate of lime, or gypsum, as manure, . . 205

Silicates of potash and soda as manures, . .206

Salts of ammonia as manure, . . . 206

Screw, . . . . . 234

T

Tenacity, . . . . . .28

Tannin, ...... 64

Tertiary strata, . . . . .78

Transition rocks, . . . . . 78

Tissue, cellular . . . . .95

Tissue, woody . . . ... 95

Tissue, vasiform . . . .95

Tissue, vascular ..... 95

Tissue, laticiferous . . ... .96

Tendrils, . 120

INDEX. 279

Trade winds, -. . . ... . 144

Trachyte, ..... 83

Tap root, . . . . . .103

Tuberous roots, . . . . * 104

Trees, 107

Temperature, table of . . . . 130

Thunder, ...... 141

Thunder, cause of . . . . 141

Tornado, . . . . . .145

Tillage, varieties of . . . . 177

Tillage, objects of . . . .177

Trench ploughing, . . . . 178

Tanner's bark as manure, . . . .198

Top dressing for crops, . . . . 199

u

Urine as manure, . . . . .196

Urine, waste and value of . . . . 197

V

Vein, 76

Variety defined, ..... 94

Veins, ...... 112

Venation, . . . . . . 112

w

Water, . . . . . .46

Wax, ...... 61

Wood, 107

Weather, ...... 125

Whirlwind, . . . . . .145

Warping, . . . . . 179

Wood ashes as manure, .... 206

Wheel and axle, . . . . , 234

Wedge, ...... 234

Winds, .... . . 142

Wool as manure, . . . , .192

x

Xanthine, ..... 64

¥
Yeast, ....

•

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UNIVERSITY OF CALIFORNIA LIBRARY