Spermaceti, a flaky, whit ish, somewhat unctuous substance, of smell ; being obtained from the head of the Physeter macro-cephalus, L. a species of whale.

As the manner of preparing this expensive article is studiously concealed, we shall only observe, that good spermaceti is perfectly white, glossy, and semi-transparent; rather soft and oily to the touch, though friable and dry; its taste resembles that of fresh butter, and its smell is faint, like that of tallow. It is said to be often adulterated with wax; but such fraud may be speedily detected, by the peculiar smell of the latter substance, and by the dullness of the colour. A preparation of the oil obtained from the tail of the whale, is likewise vended for genuine spermaceti; but, as it assumes a yellow shade on exposure to the air, such imposition may he easily discovered. It will, however, be necessary, in all cases, to preserve spermaceti in vessels, closely secluded from the atmosphere; as this drug is apt to become rancid, and to acquire a disagreeable co-, lour ; though it may be restored to its original purity, by steeping it in a ley, composed of quick-lime and alkaline salts.

Coarse or raw spermaceti, pays, on importation, in British ships, the sum of 19s. 5 1/2d. per cwt. ; and, if refined, it is subject to the Sum of 8 1/2d. per lb. The quantity imported, however, being not only inadequate to the demand, but also grossly adulterated, Mr. Smith Gibbes (now Dr. Gibbes of Bath) proposed, in the 2nd Part of the Philosophical Trans-actions of the Royal Society, for 1794. to convert animal muscles into a fatty substance, resembling spermaceti: His chemical process consists in enclosing the carcass of a horse, cow, etc. in a box perforated with holes, and immersing it in a clear stream or river, for the space of a month, or longer; when it will be converted into a mass of unctuous matter. A certain portion of nitrous acid (aqua Fortis) is next poured on this cheesy substance, in order to discharge the offensive smell, and separate the fat in a pure, though somewhat yellowish, state. Such colour may, how-ever, be removed, and the whole tolerably bleached, by submitting it to the action of the oxygenated muriatic acid. Dr. Gibbes farther observes, that this remarkable version may be effected in the course of three days, by pouring nitrous acid on apiece of lean meat. Nay, the iMustrious Lord Bacon S the following curious circumstance in his work, entitled " Sy/va Sylvarum;" namely, that the flesh of animals may be changed into a fatty substance, by cutting it in pieces, which are to be put in a glass covered with parchment, and thus allowed to stand six or seven hours in boiling water. " it may be an experiment of profit (says Bacon) for making grease or fat, for many purposes; but then it must be made of such flesh as is not edible, as horses, dogs, bears, foxes, badgers, ice." It appears, likewise, from Dr. Gibbes's Memoir, that the-putrefactive process is not necessary for effecting this change ; as it would waste a considerable portion of flesh, that might serve to form a larger mass of waxy substance.

Great quantities of spermacet are annually consumed in the ma-nufacture of candles and tapers, which are preferable to those made of wax; as the former bum not only brighter, and are of a finer colour, but, when genuine, do Dot stain, or grease the finest silks, linens, or cottons. - This drug is also used as a cosmetic, for soften-ing and cleansing the skin. In medicine, it is chiefly recommend-ed in the form of an emulsion, with distilled waters and the yolk of eggs, for relieving various affections of the intestines; coughs arising from defluxions of acrid humours ; etc. - Spermaceti is also dissolved in oils, and beneficially applied to bruises sprains, and similar injuries; as it contributes to mitigate pain.