Elements of scientific agriculture; or, The connection between science and the art of practical farming

Front matter

I [SMITHSONIAN BEPOSIT.]

! UNITED STATES OF AMERICA a

ELEMENTS

Preface

This little treatise is an attempt to supply a great and growing want in our country; a want of some elementary work, that shall clearly and distinctly explain the great principles that are involved in the applications of science to agriculture. The necessity for such a work has become apparent to all who have engaged in the dissemination of knowledge upon this subject; to all who have endeavored to arouse the farming community, by bringing forward incitements to the study of this new science.

The agricultural interest is now awaking to a full sense of its deficiences, and demands imperatively, that knowledge, in clear and comprehensive forms, be placed within its reach.

We have large works of great merit, in Johnston's Lectures, and Stephens's Farmers' Guide; but these are too bulky for the man who has just begun to entertain the idea that there may, after all, be something learned from books. A small work of this kind is far more likely to attract his attention, and gradually to

IV PREFACE.

lead him on, till he ends by an eager study of the larger treatises.

In the general arrangement of the chapters, I have followed that marked out in Prof. Johnston's admirable Catechism of Agricultural Chemistry and Geology. The expressed opinion of many teachers, " that the catechetical form was not adapted to the schools of this country, and that they needed a work of more fullness and detail," induced me to think of an effort to supply their w^ants.

The approbation bestowed by the New-York State Society upon the essay, which, with some additions and alterations, has assumed its present shape, led to a more speedy completion of my half-formed plans, than I had anticipated.

The teacher will perceive that the experiments, and the illustrations, occasionally recommended, are of the most simple character. No expensive materials are needed, and, excepting a few cheap chemicals, almost any house could furnish every requisite article.

No questions are appended to the chapters, for the reason that they would be a disagreeable interruption to the general reader, and would perhaps confine the teacher to a routine in his examinations. The chapters are, however, divided into sections and paragraphs, in a way calculated to fix the attention of the reader upon leading points.

Questions should be asked with the distinct intention of impressing at least the chief conclusions and

PREFACE. V

facts of each chapter, in such a manner that they can not soon be forgotten.

My aim has been, to furnish a complete sketch of scientific agriculture, in plain and intelligible language^ accompanied by as many details and explanations as seemed desirable in a purely elementary work.

As such, I beg leave to present it to the American farmer, and to the American teacher, with the hope that it may be found adapted to their use.

JOHN P. NORTON.

New-Haven, April 16, 1850.

Contents

True meaning of the word A&rictjltttre, page 1

Division of bodies into organic and inorganic substances, ... 4

Organic elements of plants.

Chapter I

INTRODUCTION. ORGANIC ELEMENTS OF PLANTS.

True meaning of the word agriculture : how much more it means than is commonly understood. Plants divided into an organic and inorganic part : meaning of these words. Names of organic elements : Carbon and its properties ; hydrogen and its properties-, oxygen and its properties; nitrogen and its properties, with modes for obtaining all. Importance of these bodies.

Section I. Definition Of Agriculture

Agriculture, according to the usually accepted raeaning of the word, signifies the art of cultivating the soil. It is unnecessary to say that this is its true meaning, and yet how few of those who would promptly give the above definition seem to have any adequate idea of all that is involved in the words " cultivating the soil."

A soil that is cultivated, is thoroughly and more or less deeply ploughed according to the situation, is mellow, is free from stumps and large stones, is dry and clear of hurtful weeds. How many fields in this condition are to be seen in most American villages? Are they in the majority, or do they constitute a very small minority? It is to be feared that there are few neighborhoods, even of limited extent, fitted to challenge inspection,

2 DEFINITION OF AGRICULTURE.

How frequently and how largely do weeds, bu&hes^ brambles, uneven surfaces, unsightly stumps, and stones scarred with many a mark of plough and harrow teeth, enter into the composition of our rural scenery; and this not in new settlements alone, but in older and long inhabited districts!

Even if we suppose that we have our farm thoroughly cultivated in the manner first described, is it sufficient? No, the art of cultivating the soil involves something beyond this. The thoroughly accomplished farmer must study the nature of various crops, until he finds those which are best suited to his land; if these are not such as pay him best, he must seek to bring about some change by means of which he can profitably grow those that will. This done, he must set himself to increase the quantity grown per acre, for on this increase depends his profit. It costs little more to cultivate the ground for a crop of 30 bushels^ than for one of 10 bushels.

The main end seems to be, in numerous cases, to obtain indeed a great yield of valuable produce, but with the least possible investment of money. Many, too many farmers go entirely upon this principle; they ought, however, to think farther, and then they would see that there is another point worthy of consideration. That point is, the keeping of the land in good condition. Cheapness in obtaining a present crop is not every thing : the prudent man will have an eye to the future; he will see that if he always takes away without adding, the richest land must ultimately become poor, or at least greatly reduced in value.

The man who does this is like that one in the old fable who killed the goose that laid him daily a golden egg. He thought that there must be many eggs within the goose, but there was of course only one; and he found, when it was too late, that he had destroyed the source of his riches in a most foolish and shortsighted

ART OF CULTIVATING THE SOIL. &

manner. So will it always be with the farmer who pursues a like system. Tempted by the idea of obtaining a few crops with little expense now, he ruins his land for the future.

The good farmer, then, desires to grow large crops with the least necessary cost, but at the same time never forgets that it is the best economy to keep his land in good condition, and even improving. In order to accomplish this, he must do something more than merely plough and harrow, sow, plant and reap : he must think and study also, a. He must learn the nature of the various crops he raises or wishes to raise : these crops differ; he should seek to understand the diiferences, and how they are caused. 6. One field he will find to vary much in its nature from another; a certain crop grows here, and fails there : are these things accidental, or can he discover the reasons'? c. In adding certain substances called manures to the soil, he finds diverse effects, not only in their application to different fields, but also to different crops : here is another subject for study, d. His animals thrive on some kinds of food, and derive little benefit from others. A small bulk of some varieties sustains and increases their size or strength, while upon great quantities of other varieties they grow poor. What are the properties upon which these effects depend?

Thus we perceive that the farmer who really washes to understand the " art of cultivating the soil,^^ must go a long way beyond ploughing. He must, it is true, know how to get his soil into a good state; but he must also know something as to the nature of his crops, of the various soils on which they grow, of the manures which are applied to increase that growth, and of the food which he supplies to his animals.

This, it may be said, involves too much study for a practical working man. I reply, that it is not necessary for him to learn the minute details of scientific

ELEMENTS OF PLANTS.

researches and discoveries. It is enough to begin with the leading principles that have been established; with these he will be able to work more intelligently than ever before, and to go on continually adding to his knowledge,

SECTION n. PLANTS DIVIDED INTO AN ORGANIC AND AN INORGANIC PART.

In endeavoring to explain, in a simple manner, something of this desirable branch of knowledge, we will commence with the plant, and give in a clear connected shape the information that has been collected by the most approved writers and experimenters concerning it. Hard words and obscure phrases will be avoided whenever it is possible.

We commence our examination with some inquiry into the nature of the materials which compose all of our crops. The first result arrived at is the existence of two grand classes of bodies, to one of which, or to a mixture of both, belongs every part of the plant.

In connection with this fact, there is one peculiarity in all vegetable substances, that early attracts our attention. Whether we take the hard wood, the soft flexible straw, the leaf, or the root, we find that all are more or less combustible. When dry they generally burn readily, and with a flame, but we see at the same time that all does not disappear : the stalk of straw, or the piece of wood, for the most part burns away; but after the flame has gone out, there is always an ash left. Thus we establish a grand division : one part burns and disappears; another part is incombustible, and remains. Chemists have named the part that burns away, organic matter; and the part that remains, or the ash, inorganic matter.

Fire, then, is one test, by means of which we dis-

ORGANIC ELEMENTS. O

tinguish organic from inorganic substances. To the first of these two classes we will now attend.

The name organic is given, because organic bodies, being products of life, have an organized structure that can not be produced by artificial means. What is meant by an organized structure, may be seen by examining a cross section from the stem of a tree : this will be found to consist of little tubes and cells, all arranged in a regular manner. Under the microscope, a potato will appear made up of cells having grains of starch contained. So with other plants or parts of plants, they all have an organization that is a product of life, and which we therefore can not imitate. Inorganic bodies have no such structure, and can in many cases be produced by chemical processes.

Section III. Organic Elements Of Plants

The organic part in plants is by far the largest, as is plainly to be seen on burning any form of vegetable matter. It ordinarily constitutes from 90 to 97 lbs. in every hundred.

During the burning, this solid organic matter disappears : it is driven off into the atmosphere, until nothing but a little ash remains; that which has gone, then, has evidently become air. It is easy to see that this part of the plant can only have been formed from air at first. Such a conclusion may seem very strange at first, but a little reflection will show that we can arrive at no other. When we have made up our minds to this, it becomes important to know what kind of air it is that forms so large a part of our plants, or if there is more than one kind.

These points have been determined through the assistance of certain chemical experiments, by means of which it has been proved that the organic part of plants consists of four substances. 1*

CARBON.

Their names are Carbon, Oxygen, Nitrogen and Hydrogen.

The whole of the organic part of vegetables and plants, the whole of the atmosphere, all water, and a very large part of the solid rocks which make up this globe, consist of one, two, three, or all of these four substances united in different proportions. These names then stand for bodies of immense importance; and it is very necessary that every farmer should at least know something about them. The three last, oxygen, hydrogen and nitrogen, we find in their pure state as gases : gas is the chemical term for the diferent kinds of air. The other substance, carbon, is found in nature as a solid, and to this we will first direct our attention.

Carbon is a solid, usually of a black color, and having no taste or smell. All the varieties of carbon burn more or less freely in the air, and, while burning, are converted into a gas called carbonic acid gas: this w^ill by-and-by be described.

One very abundant form of carbon is common charcoal; another is lampblack; others are coke and blacklead: the most beautiful form is the diamond. This, strange to say, though it looks so pure, clear and beautiful, and bears so high a price, does not differ at all in its composition from common charcoal! A diamond can easily be burned by a high heat, and the product of the burning will be carbonic acid gas, just as when charcoal is burned. Charcoal seems to be soft; but if the fine powder in small quantity be rubbed between plates of glass, it is found that the little particles are very hard, and able to scratch the glass almost as easily as the diamond itself.

Charcoal has strong disinfecting properties : liquids that are quite offensive in smell, when filtered through it, become pure and sweet. The color is also extracted from many liquids by it. Some of these effects are

HYDROGEN. 7

owing to its power of absorbing gaseous and other substances, itself being full of pores.

Both the flame that we see in wood, and the bright glow of coal fires, are owing to the burning of carbon; the flames of candles, of oil lamps, of ordinary coal gas, are ail colored by the combustion of this substance. It will soon be seen that it constitutes a very large proportion in the organic part of all vegetables and trees.

Hydrogen, as I have said, is a gas, or kind of air. It is transparent, tasteless, colorless and inodorous. As we can not smell, taste or see it, we can only judge of its properties by its action with other bodies. For this purpose it is obtained by putting pieces of zinc or iron hlings into water, and then adding sulphuric acid, that is, the common oil of vitriol. About a third as much acid as water should be used. The mixture will soon grow warm, and hydrogen gas will at once commence rising to the surface in little bubbles.

a. If a glass be laid upon the top of the tumbler containing the mixture, so as to prevent the too rapid escape of the gas, the tumbler will in a fev/ moments become so filled that the gas will burn when a fiame is brought into contact with it.

b. By far the most satisfactory method is to conduct the operation as represented in fig. 1. In the bottle are placed tjie sulphuric acid, zinc, and w^ater. The mouth of the bottle is stopped

tightly by a cork, through which passes one end of the tube a (this may be of glass or tin); the other end passes under water in the cistern &, its course being

O METHOD OF COLLECTING GAS.

marked by the dotted lines c (this may be a common pail, or shallow water tub). A tumbler or other convenient vessel is now filled with water, and inverted under the surface, so that it may contain no air, being filled entirely with water : it is'then brought carefully over the orifice of the tube, and the ascending bubbles of gas displace the water until it is entirely driven out, the gas remaining confined. If a little shelf, hollowed somewhat underneath, and with a hole through it at the highest point of the hollow, be placed in the cistern, three or four vessels in succession may be filled over this hole and set aside for use, keeping the mouths always under water. A common tub of a shallow form will answer the purpose of a cistern.

I have been thus particulai' in describing this little apparatus of the cistern, because all of the other gases concerning which we are to study may be received in the same way. It is perfectly effective, yet at the same time simple and cheap.

The hydrogen being thus collected, we are next to ascertain what are its properties.

1. It is inflammable : if a lighted taper be plunged

into a jar of it, the gas will instantly take fire, and

burn with a pale flame. This may also be shown by

pjg 2. removing the cork from the bottle a

in fig. 1, and substituting another cork

with a short tube coming to a point

as fig. 2. A match will kindle the

jet of gas issuing from the orifice a,

and it will continue to burn so long

as the generation of gas within the

bottle is active.

2. Although inflammable itself, it is not a supporter of combustion. The taper which kindles a jar of it, is itself extinguished. 3. It is much lighter than common air, being the

OXYGEN.

lightest of known bodies. This can be shown by turning the mouth of a jar filled with it suddenly upward, and at the same moment applying a taper. There will be a slight explosion, and a body of flame rising from the jar. On the other hand, if the jar be gently lifted and the flame applied beneath, the burning will be inside of the jar, and quite gradual. This property may also be shown by filling a bladder with the gas, and allowing it to rise. It is often used for filling balloons, its lightness giving them very great buoyancy.

4. Mixed with common air, this gas is dangerously explosive. The first portions which pass over from the bottle are therefore to be rejected; and a match ought never to he applied to a jar or bottle containing it, or in which it is being made, without having first tested the purity of a small quantity collected in a little tube. If this burns quietly when a taper is placed beneath its mouth, the gas is suflSciently pure to use with safety.

5. This gas can be breathed without very injurious effects, but it will not sustain life. In an atmosphere of pure hydrogen, every animal would soon die.

The next of these three gases is one of exceeding importance : its name is Oxygen. It is colorless, tasteless and inodorous, like hydrogen, that is, when pure: as ordinarily made, it has some impurities. The easiest way of preparing it is to mingle some chlorate of potash with a small portion of the black oxide of manganese. Both of these substances can be procured at the shops in our cities and large towns. Half a teacupful of the mixture will produce quite enough gas for ordinary experimental purposes. The chlorate of potash should be powdered and dried, before mixing with the manganese. When all is ready, the mixture is to be put into a flask with a thin bot-

OXYGEN.

torn, like those often used for holding sweet oil, and called Florence flasks. These will bear the heat of a lamp gradually applied, without breaking. Flasks of this kind, made expressly for such purposes, are now to be obtained in many places. When the mixture is introduced, a cork with a bent tube should be fitted in, and the gas collected over water in a cistern as before. The heat requires to be continued for some time, before the oxygen will begin to come off with much rapidity. Having collected a sufficient quantity, the qualities mentioned above will first become obvious. It will then be seen,

2. That on applying a lighted taper, the gas does not inflame as did the hydrogen, nor is the taper extinguished; on the contrary, it burns with greatly increased and extreme brilliancy: it may be blown out and relighted by immersion in this gas, so long as the least particle of coal remains upon it. So intense is its action as a supporter of combustion, that many substances ordinarily incombustible take fire in it, and burn with great splendor. A spiral roll of small iron wire being tipped with sulphur, the latter lighted, and then the whole plunged into this gas, the wire is ignited, and burns with the utmost brilliancy. This, then, is a most powerful supporter of combustion.

3. It is no less important to the support of life, whether animal or vegetable. Both plants and animals speedily die when introduced into any atmosphere which does not contain it. In five gallons of common air, there is about one gallon of oxygen : when this is greatly diminished, animals die.

If animals are brought into an atmosphere of pure oxygen, the effect is found to be too powerful; the vital functions are so stimulated as in a very short time to wear themselves out by a kind of fever, all of their powers being made to act with too much energy. A mouse or other small animal, placed in a jar of oxygen,

NITROGEN. li

will breathe very quick, become highly excited, and spring about with the greatest activity. Its powers, however, are greatly over-stimulated : exhaustion and death consequently soon ensue.

4. It is much heavier than hydrogen, and somewhat lighter than common air.

5. This substance is not only the grand supporter of combustion and of life, but is also the most powerful agent of destruction; for it has a property called by chemists oxidizing, that is, of uniting with nearly all other bodies and forming new combinations, leading either to a changed state or to decay. Thus it is not only the promoter of life, but of death and decomposition.

It might be expected that a body of such immense importance should be abundant, and accordingly we find that oxygen gas is in larger quantity than any other element that is known. It forms, as has been said, a fifth of the atmosphere; in nine lbs. of water, there are eight of this gas; it exists largely in all plants, and, in combination with various inorganic bodies, it constitutes a large proportion of the solid crust of our earth. We meet it in all places, and see its effects on almost every known body. As the reader proceeds, he w^ill find numerous references to its action, and will become better acquainted with its properties. In the very next paragraph below is an instance of its oxidizing phosphorus.

The last of these four most important organic substances, is Nitrogen. This gas is easily prepared in sufficient purity for purposes of experiment, by a very simple process. Common air, or our atmosphere, has been stated to contain one-fifth of oxygen; the remaining four-fifths are nitrogen. In order to separate this nitrogen, we invert an empty glass jar, and place the open mouth in water, thus confining within the.

12 NITROGEN.

jar a portion of air. Into this air is to be brought a piece of ignited phosphorus, contained in a little cup so as to float on the surface of the water. Phosphorus, as is well known, is very inflammable. While burning, it unites with the oxygen of the air, and forms an important white acid compound called phosphoric acid : to this we shall have occasion to refer again. When the burning phosphorus is brought under the jar, the above described process at once commences, and continues till all of the oxygen in the air within the jar has combined with phosphorus. The nitrogen is now left nearly pure. A portion of the confined air expanded by heat, of course escapes at first, and the jar is filled with white fumes of phosphoric acid. These are gradually absorbed by the water, until at last the interior of the jar is quite clear.

1. It is then to be perceived that this gas, like the two preceding ones, is colorless, inodorous, and tasteless. It has so few marked qualities that it is much more easily distinguished from the others by saying what it is not, than what it is. Among its negatives, then, we find,

2. That it does not support combustion : a lighted taper, plunged into it, is extinguished instantly

3. It does not burn itself, but remains unaltered after contact with flame.

4. It is a little lighter than atmospheric air. It will for this reason remain some time in a jar held with the mouth downward, but at once escapes if the jar be inverted. Both of these facts may be shown by a lighted taper.

5. It wmII not support vegetation alone, and animals soon die when placed in it. They do not seem to suffer from any active poisonous influence, but from a species of suffocation as in water.

This gas is admirably adapted to the purpose which it serves in the atmosphere, of tempering the too great

IMPORTANCE OF THfi FOUR ORGANIC ELEMENTS 13

energy of the oxygen. Being incapable of burning or supporting combustion, it prevents the general con* flagration which would occur in pure oxygen, and also reduces its strength to the proper proportion for sustaining animal and vegetable life, without bringing in any poisonous or deleterious influences, as many other gases would do. We see then that its negative properties just fit it for its office.

I have been thus particular in describing simple processes for obtaining these gases, because every mind is better satisfied by direct and practical proofs. The experiments here given are so easy that the most inexperienced experimenter could soon perform them without difficulty. There are few places of any size where the necessary materials and apparatus can not be found, and obtained with little expense. Every teacher should illustrate his explanations by these proofs; thereby impressing an idea of each substance upon the mind more indelibly than could be done in any other way. Many farmers could make them for their own satisfaction in leisure hours.

The reader will now understand why it is that I have urged the necessity of becoming acquainted with these organic bodies; for he has seen that they not only compose by far the larger proportion of the vegetable world, but that mixtures of two or three of them constitute the air we breathe, the water we drink, and, in one shape or another, a large part of the earth upon which we live. Are not these eminently bodies with which all of every profession ought to be well acquainted; and most of all the farmer, who depends on them under various forms for all success, who can not engage in the most simple operation without being influenced by them in different and most important ways? The man who knows the principal properties and the peculiar energies of the materials with which

14 CHEMISTRY AN ADDITIONAL SENSE.

he has to do, provided he also has practical skill, is obviously in a much better position than the one who knows nothing of them, and scorns the very idea of learning anything from books. The former shapes his course from certainties, from actual reasoning based on his own knowledge; the latter does any particular thing only because he has seen it done before, or perhaps because some other person recommends it.

Carbon is the only one of these four substances that is visible or tangible to our unaided senses, but w^e see that there are means of recognizing the others; that we are able to perceive their properties, and even to reason upon their various uses, with no less certainty than if we were able to grasp them in our hands and hold them up for inspection. Chemistry may thus be considered an additional sense.

CHAPTER 11.

INORGANIC PART OF PLANTS,

The ash, or inorganic part of plants. Names of substances which constitute this part : Potash, Soda, Lime, Magnesia, Oxide of Iron, Oxide of Manganese, Silica, Chlorine, Sulphuric acid, Phosphoric acid. Description of their several properties.

Section I. Substances Which Constitute The Inorganic Part Of Plants

It will be remembered, that although by far the larger portion of the plant disappears when fire is applied, there is always something remaining called the ash, or, as has been before explained, the inorganic part. This name inorganic was given to denote a striking difference between these two great classes of bodies, the organic and the inorganic : the one being products of life and living organs; the other only taken by the organs to answer certain purposes, not having been formed by them, and not like them liable to quick destruction.

This ash constitutes so small a part of all living plants, that it was for a long time thought to be a species of accidental impurity; but after a time, it was found that certain substances were almost always present in the ash of every cultivated plant. The ash of the same plant, grown on different soils, was found to have a composition of nearly the same nature; thus showing that it did not take in indiscriminately every thing that might come in contact with its roots, but had a certain power of selection.

The organic part of plants, although so much the larger, consists at most of four substances; but in the ash, we occasionally find as many as ten. These are named as follows : Potash, Soda, Lime, Magnesia, Oxide of Iron, Oxide of Manganese, Silica, Chlorine, Sulphuric Acid (oil of vitriol), and Phosphoric Acid,