You are of course aware that they divide into two grand theories. Liebig favors that known as the "mineral theory," whilst Messrs. Lawes and Gilbert oppose to it the "nitrogen theory." The mineral theory rests its entire reliance on the importance of mineral or saline substances, and maintains that, if the inorganic constituents of the plant be sufficiently supplied, the plant will find itself in nitrogen and carbon, the one in the form of nitric acid and ammonia, the other in that of carbonic acid, from the atmosphere. Whereas the nitrogen theory, assuming the existence in the soil of an inexhaustible supply of saline substances, with constant accessions from rocky decomposition and disintegration, holds in fact that there is already a surplus of plant food or pabulum in the soil, requiring only the addition of ammonia to develop the growth of plants. That there are soils more or less destitute of the mineral food of plants this theory does not gainsay; it holds, however, that in general there exists an excess of this, of which plants are precluded from participating because of the difficulty of absorbing ammonia from the air, whilst the addition of ammoniacal salts in the soil supplies the stimulant that enables the crop to become more productive. No doubt the truth lies somewhere betwixt these conflicting theories. It is certain that of an excess of mineral matter the plant cannot take advantage without a corresponding excess of gaseous food, and that this last can only be supplied by adding to the soil substances whence the roots of the plant may obtain it. To this demand we are obliged to conform, under an advanced condition of cultivation, which asks a yield of thrice or four times the amount with which the farming of only a few years ago would have remained content. In a well-cultivated soil, the plant, however, finds not only mineral food, but the decomposing remains of plants grown in former years, which supply carbonic acid and ammonia, that add materially to its development. Agricultural chemists formerly thought that whatever was taken up from the soil by the roots of the plant must be soluble in water, and that nothing else was available for the growth of the plant; but Leibig's more recent doctrine is, that the roots themselves possess an inherent power of solution over mineral substances, although it is indispensable that water should be present.

Farmyard manure has been termed by Dr. Voelcker a universal and perfect manure, because it contains all the elements to be found in the soil. Manures, in the form of cattle-dung and ordinary farmyard compost, have indeed been known and employed from time immemorial for

and were it not that excellent fixers of the ammonia are formed within the heap whilst this is going on, considerable deterioration would ensue from the process. This manure, as we all know, is composed of excrementitious matters of the live stock of the farm, intermixed with straw or other materials used as bedding or litter for the animals. Thus, whilst 100 lb. of farmyard manure are considered equal to 125 lb. of the solid'excrements of the cow they are equal only to 91 lb. of the liquid excrements of the cow, to 73 lb. of the solid, and to only 16 lb. of the liquid, excrements of the horse. Still it is found that to apply for any length of time any one manure is distasteful to the soil, and such continued application, however rich in nitrogen, is productive of failure and disappointment in the results. It has been estimated, in regard to the production of dung, that one horse or cow yields per annum 10 loads for a two-horse wagon, and a young ox or cow 5 loads; that one horse fed in the stable yields 15 loads of dung, and one turned out to grass 7 loads; so that, calculating at the rate of 20 loads of cattle-dung per acre, or 18 of horse-dung, an ox may be said to manure half an acre, a young ox a quarter of an acre, and a stable-fed horse as much as five-sixths of an acre. A horse fed, however, principally on corn, will yield dung equal in value to one which consumes twice as much weight of hay; and it is quite obvious how the food of the animal affects the excretions, and why the excreta from corn or cake should be vastly superior in value to that of an animal subsisting on straw. The age and character of the animal produce also corresponding results. A full-grown animal abstracts from its food only the materials necessary to replace the waste of its body. A growing animal not only does the same, but, moreover, the additions required to build up its skeleton, muscles, and tissues. The matured animal does not separate the phosphate of lime required for the bones, or

so much gluten and nitrogenous compounds for its flesh. Thus with a full-grown animal the manure may be taken to represent all the constituents present in the food, with exception of the carbon wasted in respiration. All breeding and milk-producing animals severely impoverish the food they receive, and hence their manure is of less value. These facts I adduce to show you that the conditions under which farmyard manure may be produced differ so materially as to render analysis useless. Of course also the proportions existing between the straw or litter used and food consumed alter and affect its value. Everything depends upon the management. Dr. Voelcker in one experiment found 961 lb. of dry manure reduced in six months to 689 lb., and in one year to 507 lb. The soluble organic matter he at first found to be 70 lb.; in the course of six months it became 86 lb.; but exposure to rain in three months reduced it to 50 lb. In other experiments 100 cwt. of fresh dung became reduced to 80 cwt. when half rotted; 60 cwt. when "fat and cheesy;" and to about 45 when completely decomposed. 100 cwt. of dung contains, when fresh, 40 lb. of nitrogen; but these are dissipated, in the form of volatile ammonia, during fermentation, in the first period 5 lb., in the second 10 lb., and in the third 20 lb. Thus it is that theorists maintain that, since dung when fully decomposed may suffer a reduction of onehalf in bulk and value, it is better to apply it fresh to the land, to prevent the loss of its volatile gases and drainings from the heap. Thus, also, the protected manure formed on the box-feeding plan is contrasted with the farmyard dung of the open pit, is richer in ammonia and in soluble constituents, both organic and inorganic. According to Dr. Voelcker,

Nitrogen-ammonia. 1 70.

.71.00 1.04

To read this analysis, we must have recourse to the market values of fertilizers as set down by Professor Way (Royal Agricultural Society's Journal, xvi. p. 539)—viz., nitrogen, 7 3-10d. per lb., ammonia, 6d., phoshate of lime, d., soluble phosphate of lime, 34d., potash, 3 3-10d.; whence we make out the manure, when fresh and unfermented, to be worth 13s. 6d. per ton, and worth only 12s. 6d. when well rotted. But the fertilizers form only, in each case, 473 lb. to the ton, against 6 cwt. 1 qr. 10 lb. of fresh, and 4 cwt. 1 qr. 27 lb. of well-rotted, materials, besides 13 cwt. 0 qr. 26 lb., and 15 cwt. 0 qr. 9 lb. respectively of water. It may be said, then, that in farmyard manure the fertilizers exists in a very bulky shape, since we have to carry to the land, with 48 lb. of actual manure, from 13 to 15 cwt. of water, and from 4 to 6 cwt. of inferior matter. But whilst this may entail a large amount of carriage and labor, the machanical effect of the mere form of farmyard manure must not be ignored, since we find it exerting an

Inorganic do.-viz.,

of the soil, admitting atmospheric air, admitting changes of temperature, and evolving gases, promoting vegetation, as well as by its fermentation yielding the heat which produces germin

false opinion that the value of our active manures are considerably increased by their more complete distribution in the soil; and farmyard manure,

sistence of a paste. Completely decomposed and reduced to the state of rotten dung, horse-dung appears much reduced in bulk, and in many cases would be found too concentrated a manure for plants in the first stage of growth. The dung of horned cattle, being naturally more cool and moist, ferments more slowly; such also is its effect on the soil, but it has invariably been considered as a more durable manure than horsedung. When used alone, however, it is found so devoid of energy that in Essex six acres with horse-dung were found to yield more than nine with cow-dung, which suits best, therefore, for being included into a compost along with the other contents of the farmyard. Strong pigmanure, it may be mentioned, has been discovered to be quite a specific for growing clover. But for that matter, a gentleman not unknwn to you, my friend Mr. Duckham, editor of the "Hereford Herd-Book," has found a rich dressing of farmyard manure itself the very best specific for clover sickness. He had suffered greatly from his land being clover sick, and had tried lime to a considerable extent, mixed with soil, both as topdressing and otherwise, with obvious benefit, still he was not to be satisfied without finding out the perfect cure; and, as he at one time thought, he did so, for the most marked effect was produced last spring with a rich topdressing of farmyard manure. The plant had been decidedly "going" in different parts of the field prior to the introduction of the manure-cart; but he does not think than one root went afterwards. Why, it looks as if nature found us fools, and left us so when we reject her hints; and that the natural droppings of animals are, after all, the natural cure for the serious evil alluded to. I regret to find that in subsequent attempts Mr. Duckham has not, however, found this remedy infallible. But to return to our dunghill. Straw employed as litter may be termed the principle medium, or, as the doctors express it, vehicle, through the help of which we mix and administer our home-made manure. Trodden down into the dung by the weight of the animals walking and lying on it, acquiring value by absorption of urine, as well as by combination with dung at various stages of its decomposition, straw becomes thoroughly embodied in the general mass, imparts consistence to the whole, and carries it more evenly through the process of fermentation and putrefaction. Were it not for the straw the dung would rot unequally, imperfectly, indeed with difficulty. Bakewell's favorite notion of converting the whole straw of a farm into food for stock, and that in passing through the animal body it be

came more highly enriched as a manure, is now exploded. In Berwickshire, a county standing foremost in correct feeding practice, although the reliance on turnips is rather too exclusive, the straw is not much used as food, but is almost entirely broken down in the fold-yards. (TO BE CONTINUED)

Clover as Manure.

It has been justly remarked that the red clover plant is the foundation of successful farming. The remark will apply to all portions of the country, except it be to the neighborhood of cities where land is worth several hundred dollars per acre, and where stable manure may be obtained in abundance for the growth of garden crops, and other high priced products. Agricultural chemists, as well as observing farmers, have given it as their opinion that the manure of animals fed on good clover hay, is worth five times as much per load as manure from straw fed animals. Taking it as granted that the estimate is approximately correct, it is obvious that the turning under of a green crop which produces such rich manure, must in itself add greatly to the fertility of the soil. If a ton of green clover is worth five times as much for fertilizing purposes as a ton of common yard manure made by animals fed on straw or timothy hay, and with straw litter largely intermixed, then a good crop of clover might be rated in value about as follows: Two tons of stalks and leaves, estimated when converted to dry hay, would be equal to at least four tons of the green material; and half this amount in roots would be two tons more-the whole, six tons, multiplied by five to bring it to the standard of common manure, would show a heavy crop of clover to be worth thirty tons of ordinary yard manure. This estimate may not be strictly correct, and it cannot always be, as yard manure varies much in its value according to age, amount of straw or cornstalks used, and mode of heaping or preserving. But let the estimate be varied so as to meet the differing circumstances, and it will still be seen that clover possesses eminent advantages. The influence which the roots possess in loosening and rendering mellow the heavy soils in which they grow, is one of great importance— assisting as it does the diffusion of the manure of the leaves and stems through the soil in the process of decay. Those who have been in the practice of working heavy or clayed land, can appreciate the great difference between the condition of an inverted sod turned over like brick clay, when nothing but timothy or grass has

grown upon it, and another sod thoroughly loosened and pulverized by the roots of clover, which have everywhere penetrated through it. The one is like clammy, unleavened bread; the other like the spongy texture of a well raised loaf. It is in this way that clover may exert a beneficial influence, either in the ordinary processes of cultivation, or in favoring the intermixture of common manure through the soil, nearly as great as its enriching value.

Estimating the value of a good clover crop as equal to thirty loads of yard manure, cultivators may easily figure which will be most economical in application, including the drawing and spreading. On hills, or on parts of large farms remote from stables, the balance will be found to be much in favor of the green crop. Every thrifty farmer manufactures and saves all the yard manure which he can; but in common mixed husbandry it is insufficient of itself to keep up a high state of fertility in all the fields. A rotation comprising the frequent turning under of a growing crop, becomes absolutely essential to a successful and profitable husbandry. Such a rotation will usually be found most advantageous if the crop is ploughed under at two years of age. The plants will then have obtained full size. It may be cut for hay the first year and if cured without becoming wet, will not only make an excellent nutritive feed for cattle and sheep, but the manure resulting from this feeding, as we have already remarked, will be of high value. Since the introduction of mowing machines, hay tedders, horse rakes and horse forks, there is little necessity of allowing a crop of clover to become blackened and spoiled by rain.

During a recent visit to the nurseries of Geneva, N. Y., we had occasion to observe the great efficiency with which clover manuring was managed in preparing ground for planting trees. The comparatively small quantity of manure furnished by the village rendered the mode of enriching by clover an absolute necessity, and the excellent, healthy and vigorous growth of the young trees proved its great value. The crop is ploughed under when in full blossom; if done sooner, there is too much succulence and not enough substance; if later, the stems have become too hard and woody, and do not become so well pulverized in decay, nor diffused through the particles of the soil. Before ploughing, the crop is well harrowed, which not only lays the plants flat on the ground, but draws them in the same direction as the course of the plough, allowing the sod to carry its own crest of plants when inverted. A log chain attached to the forward part of the plough, and to the right

handle, and hanging in a loose loop between these points, and dragging on the ground, assists in completely turning under the otherwise straggling plants. It is thought best not to turn them under with a very deep furrow; and rolling the furrows flat immediately afterwards, prevents the drying of the leaves and stems, and hastens decay and intermixture. As young trees require a good depth of soil, the sod is again inverted with a larger plough, or to a greater depth, after the lapse of several weeks.

Clover is generally too thinly seeded. There is no expenditure more economical than the purchase of an abundant supply of clover seed. One peck per acre is not too much-we have found a half bushel to yield an increase worth much more than the additional cost of the seed. But a heavy seeding alone will not answer the purpose, unless the soil is in a proper condition.

The practice of top-dressing wheat fields with fine manure applied in autumn, when the grain is sown, is not only highly advantageous to the wheat, but insures the germination and vigorous growth of the clover. The practice of brushing the surface very early in spring with a fine tooth harrow, would doubtless be of great ad ditional use.- Country Gent.

Super-Phosphate of Lime.

Bones are among the most potent fertilizers, and should be carefully saved on every farm, and in every city, and village, for the enriching of the lands of the country. Their composition chemically is as follows: In one hundred parts there are of earthy matter sixty-six, of organic matter thirty-four. The earthy part consists of phosphate of lime, and the animal or organic is a substance called gelatine or glue. Both of these are fine manures, indeed the very richest. The bone is unavailable, however, until it is decomposed, and but few know how to effect this. When ground to a powder the combined action of air, and moisture, and earth will effect this object-but the grinding is a difficult matter, and involves considerable expense to prepare for it; undoubtedly the best and cheapest form of bone fertilizer is what is termed superphosphate of lime, (sulphuric acid and raw bone). This substance is manufactured and sold widely, and, where you can rely upon its purity, we most heartily recommend it to our readers.

We feel like giving our readers a simple recipe, and if they choose to do so they can manufacture it for themselves. Take 100 pounds of bones, break them as fine as you can with a hammer, put them into a two bushel tub; to fif