in Agriculture, denotes a certain kind of mixture designed to assist the soil in the way of vegetation, instead of dung. The requisites for a compost are, 1. That it ought to be cheaper than the quantity of dung required for an equal extent of soil. 2. It ought to be less bulky; and, 3. It ought to produce equal effects.

Under the article Agriculture we have endeavoured to show, that the true vegetable food consists in reality of the putrid effluvia proceeding from decayed animal and vegetable substances. If this theory is admitted, the hope of making composts as a succedaneum for dung is but very small, unless they are made of putrefied animal and vegetable substances; in which case, unless in very singular circumstances, they will prove much dearer than dung itself. Several attempts, however, have been made by those who had other views concerning the nature of the true vegetable food. An oil compost is recommended in the Georgical Essays, upon a supposition that the food of vegetables is of an oily nature. It is made as follows: "Take of North American potash 12 lb. Break the salt into small pieces, and put it into a convenient vessel with four gallons of water. Let the mixture stand 48 hours; then add coarse train oil 14 gallons. In a few days the salt will be dissolved, and the mixture, upon stirring, will become nearly uniform. Take 14 bushels of sand, or 20 of dry mould; upon these pour the above liquid ingredients. Turn this composition frequently over, and in six months it will be fit for use. When the liquid ingredients are put to one or two hogheads of water, a liquid compost will be formed, which must be used with a water cart."

This compost, however, the inventor himself owns to be inferior to rotten dung, as indeed may very naturally be supposed; yet in some cases it seems capable of doing service, as will appear from some of the following experiments which we extract from the essays above mentioned.

Exp. I. By the author of the essays. "I took four pots, No. 1, 2, 3, 4. No. 1 contained 12 lb. of barren sand, with 1 oz. of the sand oil-compost. No. 2 contained 12 lb. of sand without any mixture. No. 3 had 12 lb. of sand with half an ounce of flaked lime. No. 4 had 12 lb. of sand with 4 oz. of the sand oil-compost. In the month of March I put six grains of wheat into each pot, and during the summer I occasionally watered..." watered the plants with filtrated water. All the time the plants were consuming the farina, I could observe very little difference in their appearance. But after one month's growth, I remarked that No. 1. was the best; No. 2. the next; No. 3. the next; and No. 4. much the worst." The same differences were observed in August, when No. 1. the best, had five small ears, which contained a few poor grains of wheat."

Exp. II. By the same. "In the month of June, I selected four lands of equal goodness in a field intended for turnips. The soil was a light land, with a tolerable quantity of vegetable earth amongst it. It was ploughed out of furland in November, and had not borne a crop for many years. I shall distinguish my experimental lands by No. 1., 2., 3., 4. No. 1. was manured with rotten dung; No. 2. with oil compost; No. 3. with lime; No. 4. was left without any dressing. On the 20th of June they were all sown with turnip seed broadcast, and during the course of the season were twice hoed. In November I viewed the field, and made the following remarks. No. 1. the best; No. 2. the next; No. 3. the worst; No. 4. better than No. 3." Here the oil compost appears in a favourable light; but other trials, made with equal accuracy, seem rather to prove, that it is not proper for turnips, barley, or quick-growing vegetables. It requires being meliorated by the atmosphere, and therefore is better adapted for winter crops."

Exp. III. By the same. "In the month of May, I planted 12 alleys that lay between my asparagus beds with cauliflower plants. Each alley took up about 30 plants. One of the alleys I set apart for an experiment with the oil-compost, prepared according to the directions already given. About an handful of the compost was put to the root of each cauliflower plant. In all other respects the alley was managed like the rest. The plants in general flowered very well; but those to which I applied the compost sprung up hastily with small stalks, and produced very poor flowers. I imputed this unfavourable appearance to the freshness of the compost, which was only a few weeks old. In the September following this unsuccessful experiment, I planted the same alleys with early cabbages. The necessity of meliorating the compost was in this trial fully confirmed: For the cabbages that grew upon the alley, which in May had received the compost, were larger and in all respects finer than the others."

Exp. IV. by James Stovin, Esq. of Doncaster. "In the year 1769, I made the following trial with the oil-compost, prepared as above directed. One acre sown with barley, and manured with oil-compost at 18s. produced five quarters five bushels. An acre adjoining, sown with barley, and manured with 12 loads of rotten dung at 3l. produced four quarters three bushels and two pecks. The compost barley was bolder and better corn than the other. In the year 1770, the dugged acre produced of rye, three quarters. The compost acre of ditto, two quarters six bushels. In the year 1771, the same lands were sown with oats, and the produce was greatly in favour of the dugged acre. These experimental lands were in a common field that had been long under the plough."

Exp. V. by Richard Townley, Esq. of Belfield. "In the spring 1770, I prepared a piece of ground Compost for onions. It was laid out into five beds of the same size, and which were all sown at the same time. Over two of them, the oil-compost was scattered in a very moderate quantity. Over other two, pigeon's dung; and over the remaining two, some of my weed compost (formed of putrid vegetables), which I esteem one of the best manures, for most vegetables, that can be made. The onions came up very well in all the beds; but in about six weeks, those that were fed with the oil compost, plainly discovered the advantage they had over the rest by their luxuriancy and colour, and at the end of the summer perfected the finest crop I had ever seen, being greatly superior to the others both in quantity and size. The same spring I made an experiment upon four rows of cabbages, set at the distance of four feet every way. Two were manured with oil-compost, and two with my own. All the plants were unluckily damaged, just before they began to form, by some turkeys getting into the field and plucking off the greatest part of the leaves. However, they so far recovered, in the September following, from 22 to 28lb. a-piece. The rows proved so equal in goodness, that I could not determine which had the advantage. The same year, one part of a field of wheat exposed to the north-east winds, which that spring continued to blow for a month or five weeks, appeared very poor and languid at the time of tillering. Over it I ordered some of the oil-compost to be sown with the hand; which not only recovered, but also pushed forwards the wheat plants in that part of the field, so as to make them little inferior, if any, to the rest. The same spring, I made a comparative experiment, upon four contiguous lands of oats, between the oil-compost and my own weed-compost. The latter had manifestly the advantage, though the other produced a very large and fine crop. I also tried the oil-compost upon carrots, and it answered exceedingly well. I did the same this year (1771) both upon them and my onions, and have the finest crops of these vegetables I ever saw anywhere upon the same compass of ground."

Exp. VI. by Mr J. Broadbent of Berwick, in Elmet near Leeds.—"On the first of October 1771, I sowed two acres of a light chalkeney soil with wheat, and harrowed in the compost with the grain. Being at a considerable distance from a large town, we find it very difficult and expensive to procure rotten dung in sufficient quantity for our tillage lands, for which reason we have recourse to land dressings both for our winter and spring corn. Rape-dust and foot are principally used; but the present price of both these articles is a heavy tax upon the farmer. To obviate that inconvenience, I resolved to make trial of the oil-compost; and from what I have observed in this one experiment, I am encouraged to make a more extensive use of it the next year. Being well acquainted with the nature and efficacy of foot, I am satisfied, that the above two acres produced as good a crop of wheat as if they had been dressed with that excellent manure."

On the supposition that vegetables are supported by matters of a saline nature, composts formed of different sorts of salts have been contrived, but with less success than the one above treated of. A famous composition... position of this kind was lately sold by patent, under the name of Baron Van Haak's Compost. The following experiment is mentioned in the Georigal Essays, as made with a view to determine the virtues of it compared with the oil-compost and foot mixed with ashes.—"In the beginning of April 1773, an acre of land was sown with early oats. I pitched upon one land in the middle of the piece, which I deemed better than any of the rest, and upon this I scattered Baron Van Haak's compost, in the quantity directed in his instructions. On one side I manured a land with the oil-compost, but rather with a less quantity than directed; and, on the other side, I manured two lands with dry coal-ashes fitted fine, and an equal quantity of foot. The lands upon which this experiment was made, were much worn out with a long succession of crops. The lands which had the benefit of the ashes and foot produced an exceeding fine crop; the oil-compost produced a tolerable good one; but that which had only the affluence of the baron's compost, produced a very poor one. It could not have been worse had it been left destitute of every assistance."

Composts, made with putrid animal substances will no doubt answer much better, in most cases, than any other kind of manure, but they are difficult to be procured. The following is recommended by Dr Hunter of York.—"Take a sufficient quantity of sawdust, incorporate it with the blood and offal of a slaughter house, putting a layer of one and a layer of the other till the whole becomes a moist and fetid composition. Two loads of this compost, mixed with three loads of earth, will be sufficient for an acre of wheat or spring-corn. Being a kind of top-dressing, it should be put on at the time of sowing, and harrowed in with the grain. The present year I have a field of wheat manured in this manner, and have the pleasure to say, that it is extremely clean, and has all the appearance of turning out an excellent crop. As this kind of compost lies in a small compass, it seems well adapted for the use of such farmers as are obliged to bring their manures from a distance. It is besides extremely rich, and will probably continue in the land much longer than fold-yard or stable-dung. I apprehend that it is capable of restoring worn-out land to its original freshness; and I am induced to be of that opinion, from the appearance of the above crop, which is now growing upon land much impoverished by bad management."

Another compost, prepared from whale flesh, is recommended by Mr Charles Chaloner.—"I have a particular pleasure (says he) in describing and making public the best method of forming a compost from whale flesh, as recommended to me by Dr Hunter. Having marked out the length and breadth of your intended dung-hill, make the first layer of earth about a foot in thickness. Moor-earth, or such as is taken from ant hills, is the best for this purpose. Over the earth lay one layer of long litter, from the fold-yard or stable, above 12 inches in thickness, then a layer of whale-flesh, and over that another layer of dung. Repeat the operations till the heap be raised about six feet, then give it a thick covering of earth, and coat the heap with fods. In this manner each layer of flesh will be placed between two layers of dung. In about a month turn the whole in the usual manner, which will occasion a strong degree of heat and fermentation. When turned, coat with earth as before, with a view to confine the putrid steam which would otherwise escape. In a month or two the heap will be found to be considerably fallen, when it should have a second turning as before. The operation of turning must be repeated at proper intervals, till the whole becomes an uniformly putrid mass. The whale-flesh is of different degrees of firmness, some of it being almost liquid; and, in proportion to its firmness, the heap will become sooner or later fit for use. In general, the compost should not be used till 12 months old; but that depends upon circumstances. Guard the heap from dogs, pigs, badgers, and vermin, as these animals are remarkably fond of whale-flesh. This animal compost may with great advantage be applied to all purposes where good rotten dung is required. I have used it with great success for cabbages, and find it an excellent dressing for meadow-ground. According to the best computation, one hoghead of whale refuse, will make eight loads of dung; which when we consider the great facility with which this basis of our dung-bill may be carried, is a momentous concern to such farmers as lie remote from a large town." See Manure, under Agriculture, where the method of preparing it from peat earth, is particularly detailed. We may here recommend a most ingenious thermometer, invented by Mrs Lovi of Edinburgh, for regulating the temperature of compost dunghills, which the farmer will find of great use in managing the process.

in Gardening, is a mixture of several earthy substances and dungs, either for the improvement of the general soil of a garden, or for that of particular plants. Almost every plant delights in some peculiar mixture of soils or compost, in which it will thrive better than in others.