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nitrogen exists as an ultimate element, is to supply this extraordinary form of matter to growing plants; hence it is found that wheat, grown upon soils chiefly manured with nitrogenous matters, contains a relatively large proportion of gluten; and the same remark is applicable to the growth of other vegetables, for it does not appear that any of them have the power of secreting nitrogen directly from the air; it enters their living structure indirectly from the decomposition of dead organic matter, and when the season of maturity is attained, such vegetables become the food of animals; nitrogen enters into the composition of their flesh, and this, conjoined with the use. of vegetables as food, aided by proper culinary operations, then enters into the constitution of the human body; at least so it is presumed, according to the observations and experiments of the ablest physiologists and chemists.

The use of quick-lime as a manure is on account of its causticity, soon rendering dead organic matters soluble, and fit for the nutrition of growing vegetables; and having performed this office, it gradually absorbs carbonic acid from the atmosphere, reverts to the state of neutral carbonate of lime, and then sustains the office of absorbing the water of the shower, or the aqueous vapor of the air, by capillary attraction, and thus preserves a reservoir of nutriment for the plants that it supports.

The offal of the stable and fold-yard is invaluable as manure, because it returns to the soil a very large proportion of the proximate and ultimate elements, that were taken from it by the growth of the hay and corn-crops; it returns them in a state fitted for affording vegetation the support that it demands; these facts regarding manures are not of such recent date as some persons imagine;

they are to be found in the works of the chemist who first devoted his unrivaled talents to agriculture upwards of thirty years ago, and to whom the agriculturist is deeply indebted for the rational principles upon which he now successfully conducts his labors.

Very few vegetables are destitute of Gum; it contributes to their nutritive powers, and when pure, is wholly soluble in cold or hot water, forming a mucilage; it frequently exudes spontaneously from the stems and barks of trees, as from the plum, cherry, apricot, and almond; but the substance most popularly known as a gum, is the produce of the "acacia vera," a plant that is

ant in Morocco.

very abund

As gum exists in vegetables, it appears to have some nutritive properties, and it is said that during the gum harvest the Arabs subsist principally upon it; and moreover, that a large caravan of Abyssinians would have starved, had they not fortunately discovered among their merchandize a large stock of gum, upon which one thousand persons subsisted for two months.

The sweet and luscious taste of fruits may be chiefly, if not exclusively, referred to the presence of the proximate principle well known as Sugar, and it is possessed of considerable nutritive powers; it is soluble in hot and cold water, forming a syrup, which, if concentrated, will yield four and six sided prismatic crystals as seen in sugar-candy, and thus materially differs in its physical state from gluten, starch, and gum, which are uncrystalizable.

The composition of all the proximate principles that have been considered, including sugar, will be evident upon reference to page 34; the source of the enormous supplies of sugar, is well known to be the "sugar cane,'

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or "arundo saccharifera," and therefore demands no detailed mention here; the annual consumption of sugar furnished from this plant, and the vast amount of carbon that it contains, are shown at page 88.

Sulphuric acid has a strong attraction for water, and in combining with it as at page 220, a great elevation of temperature results; but the chemist discovers that the acid has no attraction for carbon; now analysis teaches him, that all the proximate principles of which mention has been made, consist of the elements of water, viz., ` oxygen and hydrogen combined with carbon.

He therefore reasons as follows:-if sulphuric acid be presented to such proximate principles of vegetables, say to sugar for example, it might probably combine suddenly with the oxygen and hydrogen or water, and liberate or educe the carbon; he tries the experiment and discovers the truth of his supposition.

Place a quarter of an ounce of powdered sugar in a small gallipot, and add sufficient sulphuric acid to moisten it perfectly, stirring the two substances together with a piece of stick; this will appear as if charred, and it really is so, by the sulphuric acid decomposing it first in preference to the sugar, which will then change into a gumlike mass, and afterwards blacken by the evolution of its

carbon.

Or, the experiment may be rendered more striking by moistening another portion of sugar with a few drops of water and then adding the acid, stirring as before; this purposely added water will combine so energetically with the acid, as to induce the oxygen and hydrogen, or actual water of the sugar, to accompany its combination, and the sugar thus decomposed will yield a large mass of carbon.

The stick should be about one foot long, and the gallipot set upon an earthenware plate, lest it break by the heat of the action; and the operator must not hold his face directly above the arrangement, for sometimes portions of the materials are thrown from the vessel and might do serious injury.

Sugar has been frequently obtained from the " sugarmaple" or the "acer saccharinum," also from the "beetroot" or "beta vulgaris," and it may be extracted from many vegetables and fruits that have a sweet taste, but it does not uniformly assume the crystaline, form; thus, for example, "grape sugar" is not crystaline, neither is "honey sugar;" accordingly such varieties of saccharine matter are called "granular sugars.'

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A solution of absolutely pure sugar in water will undergo no change by keeping for a great length of time, but recently expressed saccharine juice, that of the sugar-cane, for example, will rapidly become acid; this is owing to a curious and complicated change that is induced by extraneous matters, which are simultaneously present in the juice, and therefore the "sugar-boilers" evaporate it as rapidly as possible to obtain a large product of sugar before it spontaneously changes.

Sugar must be present in all cases of vinous fermentation, a process which appears to consist in a portion of the carbon and oxygen of the sugar escaping as carbonic acid, whilst the remainder and the whole of the original hydrogen combine to form alcohol.

In the case of vegetable matters not containing sufficient sugar, its formation is induced in them artificially by partial germination; thus, barley is converted into malt, or in other words its original starch transmuted

into sugar, as that of the "cotyledons" of the bean wa changed during germination.

The process of malting consists in moistening barle with water, heaping it up, and thus inducing germinatio to a certain extent; that is, to let the seed grow or vege tate up to that point at which it contains its maximum of sugar if allowed to continue growing, the sugar a first formed is afterwards consumed by the young plant, so that, at the proper period, vegetation is checked or destroyed by the heat of a kiln, and then the barley is said to be "malted;" it has an exceedingly sweet

taste.

The juice of the grape, when first obtained in the "wine-press," is technically called "must," and it will spontaneously ferment, because grape juice contains a peculiar form of gluten," which extraordinary substance induces this change and production of alcohol in wine.

An infusion of malt, or "sweet-wort," on the other hand, does not contain this peculiar gluten, and accordingly a portion of ferment containing nitrogen in the form of "yeast," must be added to induce fermentation and the production of alcohol in malt liquor.

The froth or scum that is so well known to arise upon the surface of fermenting liquors, consists of carbonic acid gas; hence the danger of entering a room in which the process is going on, because its atmosphere becomes contaminated with the mephitic vapor, which is as eminently fatal to life as the carbonic acid produced by the direct combustion of charcoal in air.

If a few lighted shavings be thrown into the carbonic acid arising from fermenting liquor, they will be instantly extinguished, as effectually as though they

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