a well known inflammable substance, used in many parts of the world as fuel. There are two species:
1. A yellowish-brown or black peat, found in moorish grounds in Scotland, Holland, and Germany.—When fresh, it is of a viscid consistence, but hardens by exposure to the air. It consists, according to Kirwan, of clay mixed with calcareous earth and pyrites; sometimes also it contains common salt. While soft, it is formed into oblong pieces for fuel, after the pyritaceous and stony matters are separated. By distillation it yields water, acid, oil, and volatile alkali; the ashes containing a small proportion of fixed alkali; and being either white or red according to the proportion of pyrites contained in the substance.
The oil which is obtained from peat has a very pungent taste; and an empyreumatic smell, less fetid than that of animal substances, more so than that of mineral bitumens: it congeals in the cold into a pitchy mass, which liquefies in a small heat: it readily catches fire from a candle, but burns less vehemently than other oils, and immediately goes out upon removing the external flame: it dissolves almost totally in rectified spirit of wine into a dark brownish red liquor.
2. The second species is found near Newbury in Berkshire. In the Philosophical Transactions for the year 1757, we have an account of this species; the substance of which is as follows:
Peat is a composition of the branches, twigs, leaves, and roots of trees, with grass, straw, plants, and weeds, which having lain long in water, is formed into a mass so soft as to be cut through with a sharp spade. The colour is a blackish brown, and it is used in many places for firing. There is a stratum of this peat on each side the Kennet, near Newbury in Berks, which is from about a quarter to half a mile wide, and many miles long. The depth below the surface of the ground is from one foot to eight. Great numbers of entire trees are found lying irregularly in the true peat. They are chiefly oaks, alders, willows, and firs, and appear to have been torn up by the roots: many horse's heads, and bones of several kinds of deer; the horns of the antelope, the heads and tusks of boars, and the heads of beavers, are also found in it. Not many years ago an urn of a light brown colour, large enough to hold about a gallon, was found in the peat-pit in Speen moor, near Newbury, at about 10 feet from the river, and four feet below the level of the neighbouring ground. Just over the spot where the urn was found, an artificial hill was raised about eight feet high; and as this hill consisted both of peat and earth, it is evident that the peat was older than the urn. From the side of the river several semicircular ridges are drawn round the hill, with trenches between them. The urn was broken to shivers by the peat-diggers who found it, so that it could not be critically examined; nor can it be known whether any thing was contained in it.
With peat also may be classed that substance called in England stone-turf; which hardens after its first exposure to the air, but afterwards crumbles down.—The other common turf consists only of mould interwoven with the roots of vegetables; but when these roots are of the bulbous kind, or in large proportion, they form the worst kind of turf. "Although it may appear incredible (says M. Magellan), it is nevertheless a real fact, that, in England, pit-turf is advantageously employed in Lancashire to smelt the iron-ore of that county. Mr Wilkinson, brother-in-law to Dr Priestley, makes use of pit-turf in his large smelting furnaces. I have seen in the possession of Mr S. More, secretary to the Society of Arts, a kind of black tallow, extracted by the said Mr Wilkinson from pit-turf. It was very soft, and nearly of the same consistence with butter. It burnt very rapidly, with a smoky flame in the fire; but the smell was very disagreeable, like that of pit-turf." The great cause of the differences of peat most likely arises from the different mineral admixtures. Some sorts of peat yield in burning a very disagreeable smell, which extends to a great distance; whilst others are inoffensive.—Some burn into grey or white, and others into red ferruginous ashes. The ashes yield, on elixiation, a small quantity of alkaline salt, with sometimes one and sometimes another salt of the neutral kind.
The smoke of peat does not preserve or harden flesh like that of wood; and the foot, into which it condenses, is more disposed to liquefy in moist weather.
Peat ashes, properly burnt for a manure, are noble improvers both of corn and grass land; but the substance from which they should be got is an under-stratum of the peat, where the fibres and roots of the earth, &c. are well decayed. Indeed the very best are procured from the lowest stratum of all. This will yield a large quantity of very strong ashes, in colour (when first burnt) like vermillion, and in taste very salt and pungent. Great care and caution should be used in burning these ashes, and also in preserving them afterwards. The method of burning them is much the same as burning charcoal. The peat must be collected into a large heap, and covered so as not to flame out, but suffered to consume slowly, till the whole substance is burnt to an ash. The ashes thus burnt are held in most esteem; but the peat-ashes burnt in common firing are in many places used for the same purposes, and sold at the same prices.
Peat ashes are found excellent in sweetening poor meadow land, destroying rushes, and other bad kinds of grass, and in their stead producing great quantities of natural grass. They burn great quantities of peat-ashes in some parts of Berkshire and Lancashire, and esteem them one of the best dressings for their spring crops.
The sulphureous and saline particles with which the ashes abound have a most happy effect in promoting vegetation; and if used with discretion, the increase procured by them is truly wonderful. All ashes are of a hot, fiery, caustic nature; they must therefore be used with caution. With respect to peat-ashes, almost the only danger proceeds from laying them on in too great quantities at improper seasons. Nothing can be better than they are for dressing low damp meadows, laying to the quantity of from fifteen to twenty Winchester bushels on an acre; it is best to sow them by hand, as they will then be more regularly spread. This should be done in January or February at latest, that the ashes may be washed in towards the roots of the grass by the first rains that fall in the spring.
If they were spread more forward in the year, and a speedy rain should not succeed, being hot in their nature, they would be apt to burn up the grass, instead of doing it any service. The damper and stiffer the soil, the more peat-ashes should be laid on it; but in grass lands the quantity should never exceed thirty Winchester bushels, and on light warm lands less than half that quantity is fully sufficient.
On wheat crops these ashes are of the greatest service, but they must be laid on with the utmost discretion. Were they to be spread in any quantity before the winter, after the sowing the corn, they would make the wheat too rank, and do more harm than good; was the spreading this manure, on the contrary, deferred till the spring, the corn could not possibly during the winter season be benefited by it. About the beginning of November, before the hard frosts set in, seems to be the proper season for this purpose; and it will be found necessary to sow on every acre of heavy clayey wheat land about eight Winchester bushels of these ashes; on lighter warmer lands in wheat, four will be sufficient for this season. The winter dressing is thought by practical farmers to be of great service; trifling as the quantity may seem, it warms the root of the plants, brings it moderately forward, preserves its verdure, and disposes it to get into a growing state the first fine weather after Christmas.
About the latter end of February, or the beginning of March, on heavy lands in wheat, another dressing of ashes, by sowing of them on every acre eight bushels more, will do much good; on light lands, in this second dressing, six bushels may be allowed.
These ashes laid on in the spring are of the greatest service, without any probability of danger: if rain falls within a few days after the dressing is laid on, it is washed in, and has a happy effect on the succeeding crop, co-operating with the manure that was laid on in November; if, on the contrary, dry weather for a long continuance succeeds, the first winter dressing has its full effect, and the quantity laid on in the spring is in fact so small, that there is very little probability of its burning or hurting the crop. This excellent manure is also of great use in the turnip husbandry on many accounts, particularly as it much contributes to preserve the young crop from being devoured by the fly.
But one of the principal advantages derived from these ashes, not yet mentioned, is the very great service they are of to every kind of artificial pasture. Sainfoin receives great benefit from this manure, and so does clover, rye-grass, and trefoil, provided it is laid on with discretion: the proper season is about the month of February. The quantity must be regulated by the nature of the crop and soil; but it ought scarcely in any instance to exceed thirty Winchester bushels. Clover, with the help of this manure, grows with great luxuriance, insomuch that there have often been two large crops of hay from the same field in a year, and good autumn seed afterwards. They have an excellent effect on tares or vetches: to peas they seem to be hurtful.
The effects of this manure will be visible at least three years, nor does it, like some others, leave the land in an impoverished state, when its virtues are exhausted and spent. Peat-ashes are not, however, so certain a manure for barley and oats as for the winter corn: for as these are quick growers, and occupy the land but a few months, this warm manure is often apt to push them forward too fast, and make them run too much to coarse straw, yielding only a lean immature grain. Oats, however, are not so apt to be damaged by it as barley.
Peat-ashes approach, in their effects on the several crops on which they are laid, to coal-ash; but two-thirds of the quantity that is used of foot will be sufficient of the ashes, as they are in a much stronger degree impregnated with a vegetative power; and they are besides in most places easier procured in quantities, and at a cheaper rate.
Peat-ashes are almost, as we have already observed, a general manure suited to every soil. On cold clay they warm the too compact particles, dispose it to ferment, crumble, and of course fertilize, and, in fine, not only assist it in disclosing and dispensing its great vegetative powers, but also bring to its aid a considerable proportion of ready prepared aliment for plants. On light lands these ashes have a different effect: here the pores are too large to be affected, or farther separated by the salts or sulphur contained in them; but, being closely attached to the surfaces of the large particles of which this earth is generally composed, this manure disposes them, by means of its salts, to attract the moisture contained in the air: by this operation, the plants which grow on these porous soils are prevented from being scorched up and burnt; and if they want, which they generally do, more nourishment than the land is of itself capable of affording, this is readily and abundantly supplied by this useful manure. In large farms it is very usual to see all the home-fields rich and well mended by the yard dung, &c whereas the more distant lands are generally poor, impoverished, and out of heart, for want of proper manure being applied in time. See Chemistry, p. 1448.
PEUCETIUS, in anatomy, a name given by Winslow, in his Treatise on the Head, and by some of the French writers, to the muscle called by Albinus stiffe-mus-colli; and by others deirahens quadratus, and quadratus genae. Santorini has called the part of this which arises from the cheek musculus risorius novus; and some call the whole platysma myoides.