A text-book on agricultural chemistry, for the use of academies, schools, and agriculturalists: comprising that portion of elementary chemistry which is necessary to a full understanding of the changes connected with vegetable organization, and an examination of the different manures, soils, crops, &c.

Front matter

)/o FaFt^.— No, I.

aoy^ iGRICULTURAL CHEMISTEY,

FOa THE USE OF

Preface

The demand for a text-book on Agricultural Chemistry, embracing that part only of chemical science which is intimately connected with the process of vegetable organization, has long been urgent. 'I he publication of this volume is intended to supply that demand, and if it should prove the means of awakening a still greater interest in the beautiful changes connected with the phenomena of vegetable life, and of aiding the practical farmer in his endeavor to make fruitful the barren earth, the author will feel sufficiently rewarded.

There is a prejudice existing in the minds of some against " book farming" as it is called ; the cause of this prejudice has been pointed out in almost the last words of a departed statesman, who was endeared to many, respected by all. " In many cases visionary experiments have been introduced, based upon no philosophical investigation of cause and effect, but upon some accidental trial by a single individual, of some novel mode of culture, which, under the circumstances attending the experiment has met with success. This single experiment, without an inquiry into, or knowledge of the cause, which, in the given cases has secured the successful results, is at once recommended as an infallible rule of husbandry. The publication and dissemination of detached experiments of this character, for a long period constituted the most material additions to the stock of literary information, connected with agriculture, supplied to our farmers ; while many of the experiments were too intricate and complicated to be reduced to practice with any certainty of accuracy, and others were so expensive that the most perfect success would not warrant the outlay. Unsuccessful attempts to fuUow the directions given for making these, brought what came to be denominated "book farming" into great disrepute with the industrious, frugal and successful farmers of the country, and excited a jealousy of, and a prejudice against this de-

6 PREFACE.

scription of information upon agricultural subjects, which it has caused years of patient and unceasing effort in any measure to allay, and which are not yet removed."

The deductions of chemical science are not theories; they are well defined and immutable laws ; laws which never can be varied, for they were established at the dawn of time by the highest power, for the government of matter. The chemist sees changes occurring in the vegetable, animal, and mineral kingdoms, and it is his great inquiry, " What is the cause of this or that phenomenon I" In settling this question he has recourse frequently to theories ; by experiments he tests the validity of these ; if the true cause be once determined, he does not hesitate to assert that the same cause will ever produce a similar effect, in short he thus establishes the existence of a law.

It is true that there are very many points as yet unsettled in science, and many theories have been advanced to account for the phenomena connected with them ; but it is easy to distinguish between the unfailing deductions of science and the uncertain assertions of theory. If a crop flourishes vigorously upon one soil, but upon another either fails entirely or is of a sickly growth ; it is not impossible to ascertain the cause of the difference in agricultural capacity of the two soils ; and knowing the elements that are wanting in that which is sterile, by proper treatment we may render it equal in productiveness to that which is naturally more fruitful. Some study is required in order to gain the requisite knowledge of the chemical constitution of plants, soils, and manures, but there is a manifest unwillingness, on the part of the practical farmer, to bend the mind to the acquisition of that elementary knov,'ledge which is absoluttly essential to the full understanding of whatever is written upon agricultural science.

Practical agriculturalists complain, and not without reason, that those works which treat of this department of science, although written by the ablest chemists, are of no use to those who ought to be most benefited by them, because their works are so interspersed with technical terms and hard names that it is impossible for those who are not chemists to understand them. The fault is to be attributed in part to the writers, in part, to the readers, of these treatises. On the one hand, such men as Lieb^g, Johnsion, &c., have become so familiar with the use of chemical terms, that they do not consider that most men know very little of them,

PREFACE. 7

and hence they make use of such terms, even when common names might be substituted. On the other hand, many individuals have neglected to gain a knowledge of the elementary principles of chemistry, and therefore can not understand a general treatise upon the application of this science to agriculture, even if it is written in the simplest style possible^ for, to many of the elements and compounds concerned in vegetation, no common names are given, and therefore chemical terms must be applied.

The superiority of chemical names over these in common use, is not justly appreciated ; the latter usually mean nothing ; the former generally indicate the exact constitution of the substances designated or their peculiar properties. In the following pages, the common name is used whenever any such exists, and the chemical term is given in connection with it. Rules also are given which enable the learner by a very little study, to determine the constitution of a compound from its name, or its name from its constitution.

It has been the endeavor of the author to introduce only that portion of elementary chemistry which is essential to a full understanding of the changes occurring in the vegetable world ; in the last part of the work the principles of the science are applied, and the nature and action of different manures, the capabilities of different soils, and the kind of food demanded by different plants, successively examined.

Acknowledgements are due to the various authors quoted in the course of the work ; no apology to the reader is required for compiling from the writings of such chemists as Johnston, Petzholdt, Draper and Liebig.

Little Falls, Dec. 1847.

AGRICULTURAL CHEMISTRY.

PART L

ELEMENTS.

Section 1. Constitution Of Matter

Notwithstanding the variety o^ forms which the matter constituting the world assumes, there are, in reality, only about fifty-eight different simple substances, and the combination of these has produced most of the objects which we see around us. These simple substances are called elements. Gold, silver, copper, mercury, iron, sulphur, &c., are elementary substances, whilst air, water, earth and most kinds of matter with which we are familiar, are compound, formed by the combination of different elements.

There is a mineral — iron pyrites — that very nearly resembles gold, but, by subjecting it to certain tests, it is resolved into two substances, iron and sulphur. It is not then an element, because, by decomposition we obtain from it two different elementary substances : but goldy though very similar to this mineral in appearance,^ is an element, because it has never been decomposed.

How many different simple substances are there 1 How are most of the objectswhich we see around us, produced 1 What name is given to these simple substances 1 Mention some elements — some substances that are not elements. What is said of a certain mineral resembling gold T Is it an element 1

Those bodies, whether solids, liquids or gases, which have never been decomposed, or divided so as to produce two or more different substances are called elements ; some of these, by farther investigation matf prove to be compound.

The science of Chemistry owes its origin to the fact that the number of simple substances is limited. Did^ the earth consist of but one elementary substance — iron for example- — such a science would be uncalled for. If it were composed of as many as it seems to be to the uneducated, it would be almost impossible to establish such a science.

It is the legitimate object of Chemistry to point out the elements of which matter is composed, the laws which govern the union or separation of those elements, and the properties of the compounds formed by their combination.

By applying this science to the vegetable forms which flourish upon the earth, and to the manner in which they are nourished, we ascertain the elements of which plants are composed ; the constituents of the soil, and the substances which it is necessary to supply to the soil, a& food for the plant.

It is the province of Agricultural Chemistry then, to treat of those elements of which plants are composed^ and the manner in which they are obtained, retained and united, to form vegetable substances.

In treating of the simple substances in this work, we shall dwell upon those only which are concerned in the formation of plants, since we do not wish to burden the mind with that which does not pertain to Agricultural

What substances are called elements ? May some now called elements, prove to be compound ? If the earth consisted of but one element, would there be any necessity for such a science as Chemistry 1 What would be the result if there were as many different simple substances' as there are different forms of matter % What is the object of chemistry % What is the province of agricultural chemistry %

ELEMENTS.

Chemistry. A list is given, however, of all the elements known, with the abbreviation or symbol, which is generally written instead of the whole name.

Elements with their Symbols and Atomic Weights.

Oxygen

Hydrogen

Nitrogen

Carbon

Boron .

Silicon .

Sulphur

Selenium

Phosphorus

Chlorine

Iodine .

Bromine

Fluorine

Metallic Elements.

Potassium

Sodium

Lithium

Barium

Strontium

Calcium

Magnesium

Aluminum

Glucinum .

Yttrium .

Zirconium

Thorium .

Cerium

Lanthanum

Didymium

Symbols.

At. wts.

H.

1-000

N.

14-19

C.

B.

10-91

Si.

22 22

S.

Se.

39-63

P.

15-72

CI.

35-47

L

126-57

Br.

78-39

F.

18-74

K.

39-26

Na.

23-21

L.

6-44

Ba.

68-66

Sr.

43-85

Ca.

20-52

Mg.

12-89

Al.

13 72

G.

26-54

Y.

Z.

33-67

Th.

59-83

Ce.

La.

D.

Metallic £leiiaents,

Erbium

Terbium

Manganese

Iron

Cobalt .

Nickle .

Zinc

Cadmium

Lead .

Tin. .

Bismuth

Copper .

Uranium

Mercury

Silver .

Palladium

Rhodium

Iridium

Platinum

Gold .

Osmium

Titanium

Tantalum

Tellurium

Tungsten

Molybdenum

Vanadium

Chromium

Antimony

Arsenic

Symbols.

E.

Tr.

Mn.

Fe.

Co.

Ni.

Zn.

Cd.

Pb.

Sn.

Bi.

Cu.

U.

Hg.

Ag.

Pd.

R.

Ir.

Pt.

Au.

Os.

Ti.

Ta.

Te.

W.

Mo.

V.

Or.

Sb.

As.

22-72

29-57

29-62

32-31

55-83

103-73

58-92

71-07

31-71

217-20

202-87

10831

53-36

52-20

98-84

98-84

199-2

99-72

24-33

184-90

64-25

99-70

47-96

68-66

28-19

64-62

37-67

It will be seen that these elements are divided into metallic and non-metallic, 13 of the latter, 45 of the former. The column of atomic weights gives the supposed comparative weight of an atom of each elementary substance. It is supposed that there is a limit to

For what are symbols used ? How are the elements divided ? What is indicated by the numbers in the column marked " atomic weights]"

the divisibility of matter, and those exceedingly minute particles of which a substance is supposed lo be made up, are called atoms. The comparative weight ot an atom of zinc and one of sulphur, are as the numbers 32 31, and 16-12, or, as they are generally given, 32 and 3 6. This is inferred from the circumstance, that if we decompose the simplest combination of these elements, which is an ore called zinc hknde ; we shall obtain 32 parts by weight of zinc, and 16 of sulphur from 48 parts of the ore.

The following list contains the names of those elements only, which are concerned in the production of vegetable 'forms. The atomic weights are given approxiraatelv.

Elements which constitute Plants.

Non-Metallic EUmeiits,

Oxygen . . .

Hydrogen . . .

Nitrogen . . .

Carbon , . .

Silicon . , . .

Sulphur . . .

Phosphorus . .

Chlorine . . .

Iodine . . . ,

Bromine . . .

Fluorine . . .

Symbols.

At.Wts.

H.

N.

C.

Si.

s.

p.

CI.

I. Br

F.

Metallic Elements.

Symbols.

Potassium . . .

K.

Sodium . . .

Na.

Calcium . . .

Ca.

Magnesium . .

Mg.

Iron ....

Fe.

Manganese . .

Mn.

Aluminum . .

Al.

At.Wti

40 24 20 12

28 28 14

These 18 elements are the only ones concerned in the process of vegetation, and of these, the first, second and fourth, form by far the larger proportion of the plant, — from 88 to 99 per cent. But notwithstanding the minute quantity of the other elements, a certain proportion, though very small is absolutely required : except a few of the elements which occur in certain plants only.

What are atoms'? Why are 16 and 32 given as the atomic weights of sulphur a-nd zinc ] How many elements are concerned in vegetation ? Which of these constitute the greater share of the plant? What proportion 1 Are the other elements essential to the perfection of the plant i

OXYGEN. 17

it is of the first importance that the student should pursue this study systematically, and in order to do this, he should first obtain a knowledge of these elementary substances, then of the compounds formed by the union of the same, and lastly, of those agencies by which the various changes are wrought, which are continually going on in the vegetable world. In this way he will obtain a knowledge of that part of elementary chemistry which is directly applicable to agriculture.

Section II. Oxygen, Hydrogen, Nitrogen, & Carbon

Oxygen. 0=8o Fig. L

If we introduce a portion of red precipitate into a retort^ {a, Fig. 1,) and apply heat by means of a spirit lamp, a bright metal will soon begin to accumulate in the receiver (6) ; it is a liquid at ordinary temperatures, and is called Mer^mry. Whilst this metal is dis-

What is the symbol for Oxygen 1 What its atomic weight ? What substance is placed in the retort, in the process represented by Fig, 1 ? What metal distills over and accumulates in the receiver ?

tilling over from the retort, bubbles will appear at the end of the tube (c) which passes into the water of the cistern. The tall glass jar is filled with water, and inverted with its mouth over the end of the conducting tube ; as the bubbles of gas pass from the tube, they rise in the jar and displace the water.

This gas is called Oxygen, and is the first in the list of elements.

It will be seen at once that it is very similar to air in its physical properties, being transparent, colorless, tasteless and inodorous. It is heavier than atmospheric air in about the ratio of 11 to 10. In its chemical properties it differs widely from air, as will be indicated by the following experiments.

Fill a small jar or a tumbler with this gas, and having covered its mouth with pasteboard, place it with the Fig. 2. mouth upward. Remove the pasteboard and introduce an extinguished candle, (fire still remaining in the wick,) it will be instantly relighted, with a slight report, (Fig. 2.) If the gas is pure, this can be done several times in succession.

Oxygen then is a supporter of combustion. This property can be illustrated more brilliantly by another experiment. A piece of lighted phosphorous placed in a jar of oxygen, burns with a light so brilliant, that it is insupportable to the eye. A piece of charcoal ignited and placed in a vessel of this gas, burns rapidly, throwing off" bright scintillations.

Its power to support combustion is not confined to those substances which we call combustibles, but many substances which are generally considered incombustible, are burned rapidly and with brilliant effect in oxy» gen.

What is collected in the inverted jar? What is said of the physical properties of this gas % In what ratio is it heavier than air? How is it shown that oxygen is a supporter of combustion ? What different substances will burn brilliantly in oxygen ?

OXYGEN. 1^0

Zinc, iron and steel wire, the diamond and other things called incombustible, are consumed if the temperature is sufficiently raised before they are placed in the gas.

To prepare the iron wire for burning in oxygen, it should be coiled about a small cylinder to give it a proper shape, and the end dipped in melted suU Fig. 3. phur. The sulphur is ignited, and the coil placed in the bottle of gas, as in (Fig. 3.) A fine watch spring arranged in this way burns bril-l liantly, throwing off a shower of sparks. 1

Such is the heat of the globules of melted matter that drop off during the combustion of! the iron wire, that after passing through a considerable portion of water in the bottle, they melt the glass, and are embedded in it.

The bottle in which the experiment is tried, should contain 2 or 3 inches depth of water to prevent its destruction by these globules. The cork to which the spiral wire is attached should fit loosely in the bottle.

Oxygen is not only a supporter of combustion in the experiments here given, but is the great supporter of combustion wherever it goes on. Supplied from the atmosphere, it feeds the fires of the furnace and the forge, the flame of the lamp and the gas light. Even the animal frame is warmed by a kind of combustion within, carried on by means of oxygen.

If a bird be placed in a confined portion of oxygen gas, it will live five or six times as long, as in the same volume of atmospheric air. It is, therefore, a supporter of animal life. If blood be agitated in oxygen, it changes to a bright vermillion color, and the same change is effected by the oxygen of which the air is in

Describe the experiment with a steel watch spring. Does ordinary combustion depend upon the presence of oxygen ] Whence is it supplied ? How is it shown that oxygen is a supporter of animal life 1 What is the effect of oxygen upon hlood, agitated in a vessel of this gas ?

AGRICULTURAL CHEMISTRY.

part composed, in the blood of living animals. This is supposed to be the cause of animal heat ; the nature of the change will be mentioned hereafter more particularly.

Oxygen appears to exist nowhere in nature in a disengaged state, but in a combined state it is more generally diffused than any other element.

It constitutes eight ninths of the water upon the surface of the earth, one fifth of the surrounding air, more than one third of the mineral crust of the globe, more than one half of ail animal substances, and nearly one half of the vegetable forms growing upon the face of the earth.

This gas is absorbed by water ; 100 measures ot the latter taking up 6 | of oxygen.

Oxygen acts an important part in the production of vegetable forms, but this is not the proper place to enter into an examination of its influence upon plants. This part of the subject is deferred until the pupil is supposed to understand the nature of some of the more important compounds of Oxygen with other elements.

The process given for obtaining this gas, is not the one usually adopted, but it is given here on account of the simplicity of the changes connected with it.

Fig. 4.

What is the effect of this change when it is produced in the animal system ? What proportion of water and air, also mineral, animal and vegetable substances, does oxygen constitute ?

HYDROGEN. 21

A more economical method for obtaining oxygen is represented by (Fig. 4.) A substance, known as black oxide of manganese, is introduced into an iron bottle, to which an iron tube (&) is fitted. The conducting tube (c) is connected by means of a tube of india-rubber, (e.) The bottle arranged in a furnace as represented in the f]jg:ure, is made red hot, and oxygen is disengaged in the bottle, and collected in the jar. A common gun-barrel may be used instead of a bottle, where small quantities only are required.

Fig. 5 represents another process for obtaining loxygen. The flask {a) contains a mixture of black oxide of manganese and oil of vitriol, two parts of the former to one of the latter. By the application of heat, oxygen is generated, and is collected as in the preceding processes.

If a substance called chlorate of potash be mixed with the manganese, instead of oil of vitriol, the gas will be obtained much more easily and rapidly ; if this mixture be used, an iron bottle or gun-barrel may be substituted for the flash, and arranged as in Figure 4.

Hydrogen, H= 1 .

In (Fig. 6,) we have a retort (a) containing water, connected with an iron tube, (cc.) This tube is filled with iron wire, and kept at a red heat by a furnace. If we apply the heat of a spirit lamp to the retort until the water boils, bubbles of gas will begin to appear, rising from the end of the connecting tube and filling the jar. This gas is called Hydrogen, and like Oxygen, is an element. It is colorless, transparent, and when pure, inodorous.

Give other processes for obtaining oxygen What is the symbol for hydrogen? Its atomic weight? Describe the process for obtaining it? What are its properties ?

AGRICULTURAL CHEMISTRY.

Fig. 6.

Fig. 7.

It is absorbed by water in very small quantity, 100 measures of water absorbing only l^ of hydrogen.

The most striking physical property of this gas is its extreme lightness, being 200,000 times lighter than Mercury, and 14 times lighter than common air. This property renders the gas applicable to aerostatic purposes, and balloons are generally inflated with it.

The principle of balloons is aptly illustrated by blowing soap bubbles by means of a bladder filled with hydrogen, and a tobacco pipe, as represented in (Fig. 7.) The bubbles will rise rapidly through the air, and if a lighted candle be applied, the gas will burn with a yellowish flame. Here we discover a new property of hydrogen — its inflammability.

If a jar of this gas be held with the mouth downwards, (on account of the levity of the gas,) and a lighted candle be immersed in it, the gas will be fired at the surface, and the candle will be extinguished in its passage into the jar, and relighted again at the surface as it is withdrawn. By this experiment, we are made acquainted with another property of hydrogen — it is a

What is said of its lightness? For what purposes is it used on account of its lightness 1 How is this illustrated 1 If a lighted candle be applied to the rising bubbles, what will be the result ? What is the effect when a lighted taper is introduced into an inverted jar of hydrogen 1

HYDROGEN. 23

non-supporter of combustion. It will not burn unless oxygen be present. If we make a mixture of hydrogen and air — 2 volumes of the former and 5 of the latter— and, confining it in a strong tube, fire it by applying a lighted taper to a small aperture, a violent explosion will take place.

When a jet of hydrogen is burned at the Fig. 8. extremity of a small tube, musical sounds can 1 be produced by covering the flame with a .^^'^^ large tube of glass or metal, as in (Fig. 8.) '

These tones are occasioned by the rapid succession of slight explosions within the tube, which produce a vibratory movement of the air.

In this experiment the gas is obtained by placing in the bottle fragments of zinc, or iron filings, and pouring on a mixture of one part of oil of vitriol, and three of water. The jet should not be ignited until the air is expelled from the bottle lest an explosion ensue. The musical tones may be varied by moving ^^'

the tube up or down, or by taking tubes of different sizes.

Hydrogen is UKSually obtained by the action of dilute oil of vitriol upon zinc or iron, as in the experiment with the jet, and the apparatus may be arranged as in (Fig. 9.)

It is a non-supporter of respiration, although it does not prove instantly fatal when inhaled. This gas is not as extensively diffused as oxygen, constituting but a small proportion of the mineral crust of the globe, one ninth of water, and from 5 to 7 per cent, of vegetable substances.

What is the consequence of firing a mixture of hydrogen and air confined in a tube 1 How may musical tones be produced 1 How are they occasioned] How is hydrogen usually obtained ? Will it support respiration 1 To what extent is it a constituent of plants?

AGRICULTURAL CHEMISTRY.

Nitrogen. N— 1 4.

Fig- 10. Place a float upon the surface

of the water in the cistern ; lay a piece of phosphorus upon it, and having ignited, place an empty jar over it as in (Fig. 10.) As the phosphorus burns, white fumes will fill the jar, and the water will rise and occupy one fifth o-f the space, at first occupied by air. The white fumes will disappear in a short time, and leave a colorless gas called Nitrogen. It is devoid of taste or smell, and sparingly soluble in water — about the same as hydrogen in this respect.

Nitrogen is lighter than air in the ratio of 97i to 100. A lighted candle immersed in this gas is immediately extinguished. Animals die in it, not from any poisonous quality of the gas, but on account of the absence of oxygen. From its incapability of supporting life, it is called azote, A moistened mixture of iron filings and sulphur may be substituted for the phosphorus in the process given, but a considerable length of time is required in this case, for effecting the required result.

This gas is an essential constituent of the atmosphere, forming about 80 per cent, of its bulk— does not occur in the mineral masses of the earth in any notable quantity, but forms a part of many animal and vegetable substances, and probably exerts a very important influence in the organization of plants.

How is nitrogen obtained 1 Describe its appearance and properties. How much lighter than air? Its effect upon flame and animal life? What may be substituted for phosphorus in the process for obtaining nitrogen? What proportion of the atmosphere does this gas constitute? What influence does it exert in the vegetable world ?

CARBON — SILICON. 25

Carbon. 0=6.

When wood is burned without free access of air, a substance called charcoal is produced. This charcoal consists of carbon, with a slight admixture of earthy matter. This form of carbon is light and porous, but other forms occur, such as plumbago, (black lead,) and the diamond, which are much denser. Newly prepared charcoal possesses the peculiar property of absorbing in large quantity, the moisture and various gases contained in the atmosphere. Its importance as a fertilizer seems to depend in a great measure, upon this property.

Carbon is an essential ingredient in all animal and vegetable substances, forming from 40 to 50 per cent, of the latter, and is found every where in air, sea, and earth, in combination with other elements.

Charcoal when applied to soils greatly promotes vegetation ; not principally however, by supplying nourishment from its own substance, for it can not immediately enter the roots of plants, but as a medium through which many necessary gaseous constituents are conveyed to the plant.

Section III. Silicon, Sulphur, Phosphorus, Chlorine, Iodine, Bromine, Fluorine

Silicon. Si=22.

Silicon is a dull brown powder, obtained from silica by an intricate and difficult process. Silica is a com-

What is charcoal ? What other forms of carbon are mentioned ? What important property does newly prepared charcoal possess ? To what extent is carbon a constituent of plants ? How does charcoal promote the growth of plants ? Describe silicon 1 pound of oxygen and silicon, and is familiar to all under the forms of sand, quartz, flint, &c. Silicon when heated in the open air, takes fire on account of the union of oxygen with it, and forms silica again.

This element constitutes about one sixth of the mineral crust of the earth, and is always found combined with oxygen.

The compound silica is devoid of color, taste or smell, and is infusible except by the strongest heat. It is one of the most abundant substances constituting a portion of almost all soils, and occurs in the ashes oi all plants.

Sulphur. 5=16.

This elementary substance is too well known to require a description. The sulphur of commerce is obtained from the craters of volcanoes. It is brought up or sublimed by heat, and condenses in the fissures of the crater. Sulphur is heavier than water in the ratio of 199 to 100. It is found very extensively combined with the different metals, and is a constituent of animal and vegetable substances. It is insoluble in water, and is met with under three different forms : flowers of sulphur, lac sulphuris, and roll brimstone.

Although a constituent of plants, sulphur does not exert any very important influence, in its uncombined state, upon vegetation.

Phosphorus. P=16.

Phosphorus is a solid, usually of a pale yellow color, but when pure, transparent and colorless. At ordinary temperatures it is of the consistence of wax, but at a