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generally believed that charcoal, as an inanimate body, incapable of decay, contributed in no degree to the nourishment of plants, and that charcoal dust could only serve, at most, to make the earth looser and warmer. But it has been ascertained by experiments that the charcoal in which plants grow by degrees undergoes decomposition, and at last becomes a sort of humus. This obviously takes place merely because the charcoal dust acts as humus, and, with the co-operation of water and air, continually gives out to the plants oxide of charcoal, or carbonate, together with the saline particles which are in the charcoal, and remain in the ashes after burning.
"4. Antiseptic power of charcoal.
"In judging of the effects of charcoal on vegetation, its antiseptic properties are of great importance, for it has very little power of retaining water, and the little it retains is partly absorbed by the roots, and partly evaporated. This property deserves the greatest attention of gardeners in respect to recovering the health of plants the roots of which have become injured by being in a clayey soil, and too frequently watered, or after continued rain, or being in contact with manure not sufficiently decomposed. They should be immediately transplanted into charcoal powder, as the most effectual method of cure.
Liebig, though not offering any lengthened explanation, but speaking as if the point were more a matter of long established notoriety than of recent experiment and theory, gives his powerful testimony in the same direction as Buchner, and says: "Charcoal, in a state of powder, must be considered as a very powerful means of promoting the growth of plants on heavy soils, and particularly on such as consist of argillaceous earth." "The free access of the carbonic acid gas of the atmosphere to the plants promotes their growth, increases their vigor, and enriches their secretions. The application of the same gas to their roots, although it has not been examined with the same care as its action upon their leaves, is yet evidently attended with the highest advantage. Thus the gas is one of the constant products of putrefaction. Wherever this is going on-as over stagnant drains, dung heaps, and other putrefying matters-there vegetation is sure to be rankly luxuriant; and that, too, in situations where the roots of the plants are far removed from immediate contact with the decomposing organic matters. This may be easily shown by the repetition of a very simple experiment which was first made by Sir H. Davy. This great chemist filled a glass retort, capable of containing three pints, with the hot fermenting dung and litter of cattle, and examined the elastic fluids which were generated. In thirty five cubic inches, which were thus produced in three days, he found twenty-one of carbonic acid gas, the remainder being chiefly nitrogen; and after thus ascertaining the composition of these gases, he introduced the beak of another retort, filled in a similar manner, in the soil, under the roots of some grass growing in the border of a garden. In less than a week a very remarkable effect was produced on the grass exposed to the action of these gaseous matters of putrefaction; their color became deeper, and their growth was much more luxuriant than the grass in any other part of the garden. And hence, too, is derived one of the chief advantages of applying organic matters to the soil, and that in as immediate contact with the soil as possible, just as is effected when manures are added to to the soil by the drill; for the roots or leaves of the plants are, by the
adoption of this plan, immediately in contact with the evolved carbonic acid, and other gases of putrefaction. They are thus readily absorbed as they are generated, and nothing is lost by escaping in the atmosphere; the gas, in fact, is instantly, yet gradually, transmuted from the putrefying products of the farm yard into the flour of the wheat. Owing to its peculiarly porous texture, charcoal possesses the property of absorbing a large quantity of air, or other gases, at common temperatures, and of yielding the greater part of them when heated."
M. F. Towers thus speaks of charcoal and carbonized substances: "To whatever quality may be ascribed the fertilizing powers of wood charcoal, certain it is that when newly made it absorbs given quantities of gases."
By the experiments of M. Laussure, it was proved that after charcoal was again heated to a red heat, then suffered to cool under mercury, and instantly plunged in a vessel of the gas, on being taken from the mercury it absorbed, (assuming 1 to represent a single volume of charcoal,)
It is stated, also, that if wood charcoal remains in contact with valerian, galbanum, balsam of Peru, or musk, it destroys their peculiar odor.
This absorbent power appears to depend upon the great porosity of charcoal, which itself is produced by the action of heat. Wood is composed chiefly of the elements of carbon, oxygen, hydrogen, with some salts of potassa and lime. When acted upon in iron cylinders, oxygen and hydrogen are expelled, and water is formed; also, some carbonaceous compounds, amongst which are pyroligneous acetic acid, pyroxilic spirit, and tar. The remaining charcoal retains the exact form of the wood employed. It is, however, lighter than water, and full of pores. When thus completely decomposed, it consists chiefly of carbon, with a little silica, and the bases of the salts above alluded to. Many years ago, a process was discovered by which the carbonate of soda, (Sesqui carbonate,) then just coming into practical use, might be much improved. Crystals of the purest soda were exposed, on flat shallow trays, having canvas bottoms, to the vapor of ignited charcoal, and conveyed into close leaden vessels through a leaden cylinder. The combustion was effected in iron crucibles regulated by an air-stopper. The gas developed was pure carbonic acid. It acted upon the crystals of soda, combined with the neutral salt, and displaced the water of crystallization which drained through the canvas. In the fire crucible the residue of the combustion was very small in bulk and weight, and consisted of silex, lime, and potassa, which constitute the impurities of common charcoal. From these and corresponding data, we infer that wood charcoal is very inferior to the carbonized matter of peat, containing vegete. animal matters, either in respect to depurating, deodo.izing, or fertilizing properties.
"Not only does it," to use the language of Liebig, "surpass all other substances in the power which it possesses in condensing ammonia within its pores, but it is at the same time the most unchangeable substance known. It must constitute, therefore, one of the most powerful applications known, but really the most durable one in existence."
Several of the practical purposes to which this valuable article may be advantageously applied are so important, that they may be specially adverted to with advantage.
1. As a covering for manure and compost heaps, no other substance is more suitable. Its capacity for absorbing ammonia and carbonic acid gas renders it the efficient means of preserving much of the effluvium which is usually permitted to escape into the air during the fermentation of manure. Much has been written on the necessity of due care on this branch of farm economy, and many suggestions have been offered on the best methods of remedying the evil. To prevent, in a great measure, this loss of fertilizing power in manure, no agent is more certainly efficient than charcoal. Equal in capabilities to any other, it is accessible to almost a nominal cost; easily applied to the surface of the manureheap, its action is not impeded by any irregularity in the application, as would be the case with many chemical agents which are recommended for the purpose of fixing the gases, substances of which the cost-in the first instance not insignificant-is augmented by the injudicious use of them, arising from imperfect knowledge or inattention. Of itself, also, it carries to the heap, and afterwards to the soil, physical and chemical properties which have been stated to be favorable to vegetation.
2. As an auxiliary to artificial or highly azotized manures, charcoal is a substance much esteemed.
For the purpose merely of giving bulk, these manures frequently require to be mixed with other substances. By this step an even distribution, either by drill or hand, is facilitated, and danger to the seed from contact with the manure is avoided. Charcoal is eminently capable of insuring these advantages, and, at the same time, it is materially useful, when applied in conjunction with potent and active manures, in absorbing the ammonia that may happen to be liberated more freely than can be appropriated by the plant in its early stages. Mixed with guano, an inodorous compound is formed; and numberless experiments with this and other azotized manures, in conjunction with bulky carbonaceous substances, have been successfully carried out
With reference to its agricultural value as an absorbent, its uses upon the liquid and solid manures indicate how easy it would be, by a simple but well-regulated system, to mix the valuable excrementitious substances, that exist in such enormous quantities in towns, with charcoal, and thus prevent all escape of noxious effluvia, and convert it into a useful, portable, and inodorous manure.
Urate. This substance has been highly extolled as a manure. It is only within the last ten years that it has been used by English agriculturists. It derives its name from being a compound of urine and plaster of Paris, and is formed by mixing sand and burnt gypsum with urine, and forming a hard compound, which is afterwards reduced to powder.
The Royal Society of Agriculture at Paris caused some experiments to be made with this manure, for the purpose of comparing it with some of the most effective manures then in use. The result was in favor of
the urate for the duration of its effect on lucern in a light soil. The portion manured with the urate produced the greatest return at the third and fourth cuttings; when that manured with night soil and pigeon's dung had lost a portion of their effect. It requires a moist season to act powerfully. When mixed with dried night soil its effect on various crops is very great-more especially upon potatoes, carrots, and turnips. For the latter it is particularly adapted, as it promotes a rapid growth, and rarely fails to produce a full plant and great weight per acre.
The urate of the London Manure Company, of which a specimen was exhibited, has now been used successfully for nearly ten years. It is now prepared in a concentrated form; one ton will be found sufficient for six to seven acres of land; at seven guineas per ton. It can be sown either by the hand or by the drill, and in either case it is desirable that it should not be placed more than two or three inches from the surface. Unlike guano, it does not destroy the seed if in immediate contact; though in all cases it is better to mix it with a few ashes, to make it drill more equally. The following is a testimonial as to its effects:
OAKLEY BEDS, August 29, 1849.
SIR: I beg to furnish you with an account of a field of ten acres, manured in 1845 with six hundred weight of the urate per acre. The first crop was Swedish turnips, and by far the best crop in the parish. In 1846 the crop of barley was great, both as regards straw and yield. In 1847 white clover; fed until 20th May by sheep, and in the autumn mown for seed; the crop very good. In 1847 the same field was wheat, and a most excellent crop. The field the following year was again turnips, grown with six hundred weight as before, and again the best crop in the parish. I have used this year four tons of urate for turnips, on another part of the farm, and am happy to say they are very fine, and have escaped the ravages of the fly, which is not the case with some manured with dung.
I am, yours, &c.
Nitrate of Soda has lately engaged much attention, and is supposed to exert its favorable action upon vegetation by yielding nitrogen. The experiments hitherto made do not warrant us in concluding with positive certainty that it is the nitrogen alone to which it owes its efficacy; but they certainly render this a plausible explanation of its virtues. The usual effect produced by nitrate of soda is to increase the intensity of the green coloring matter, to augment the quantity of straw, but to produce a light grain. There is nothing opposed to the supposition that nitric acid may be decomposed by plants, and its nitrogen assimilated. We find that vegetables possess the power of decomposing carbonic acid, and of appropriating its carbon for their own use. But this acid is more difficult to decompose than nitric acid. There are other circumstances which oppose the adoption of the view that nitrate of soda acts by virtue of the nitrogen which enters into its composition. Were this the case, the action would be more uniform than it has hitherto been found to be. On some soils the salt does not possess the smallest influence; whilst on others it affords great benefit. We can only furnish an explanation of this seeming caprice by a reference to the chemical composition of the
soil to which it is applied. If the advantages attending the application of nitrate of soda are due to the alkaline base which it contains, then it is evident that this manure can be of small value on soils containing a quantity of alkalies sufficient for the purposes of the plants grown upon thein; whilst, on the other hand, such as are deficient in these must experience benefit through its means. In certain cases in which nitrate of soda has failed, nitrate of potash (saltpetre) has been very successful. Analyses of wheat grown with nitrate of soda and nitrate of potash would be of interest, in order to determine whether a mutual substitution of their bases is effected.
On light barley soils, the effect of nitrate of soda has been universally successful when applied at the rate of three-quarters of a hundred weight, or one bushel, per acre. Much, however, remains yet to be proved: whether, for instance, a still smaller proportion per acre, either in its simplest state or mixed with other manures, such as with ashes or gypsum, when it is used for the grasses, or when employed for corn crops by merely well incorporating it with a sufficient quantity of finely sifted earth to insure its uniform distribution over the field, would not render it more efficient.
Patent Inorganic Manures; prepared at Bow, London.
If we may judge from the numerous flattering testimonials respecting the use of these manures, we should say at once that the farmer can have no better compound in the shape of manure than the inorganic. A distinct manure is prepared for the different crops, so that the agriculturist has but to name the crop he wants to produce, and a manure is prepared especially adapted for that crop, which hitherto, so far as we can learn, has not failed of success.
The company, in their prospectus, state that their principle is to supply, in special and distinct manures, all the substances required to be present in the soil for the production of the largest crops. A separate manure is prepared for each crop, adapted to its particular wants, in order to supply the soil with all the food or elements required from it. As far, therefore, as manure can, they insure good crops; because, unlike other artificial dressings, their effects are to enrich, and not to exhaust land. Every crop grown takes from the soil nine or ten inorganic elementary substances. If only one, two, or three of these be supplied, as happens in the use of guano, nitrate of soda, bones, saltpetre, wool, rape, rags, soot, salt, lime, &c., the crops can only be obtained by impoverishing the soil; and if the use of such substances as manure were continued alone on the same land year after year, their true character and action would soon be seen; for they must always ultimately fail, by exhausting and rendering barren the land. The use, too, of one manure for all crops is almost as much a quackery as one medicine to cure all diseases; for the rotation system of cropping fully proves that different elements of the soil are required by, and ought to be supplied to, the various plants. A few hundred weight of manure applied per acre may seem to some insufficient; but it must be remembered that plants are formed chiefly of matter drawn from the atmosphere and water; the ash left after their combustion being really all that is taken from the soil. Dung, as it decays, acts as a manure, by again supplying to the soil the substances found in the ashes of plants; and it is by the presence of these ashes in the soil, or by the supply