the other mulberry, or even on those of the lettuce. The silk worm remains in its larva state about six weeks, changing its skin four times during that period, and like other caterpillars, abstaining from food for some time before each change. When entirely full grown, the animal ceases altogether to feed, and begins to form itself a loose envelope of silken fibres in some convenient spot, which it has chosen for the purpose, and afterwards proceeds to enwrap itself in a much closer covering, forming an oval yellow silken case, or ball, about the size of a pigeon's egg, in which it changes into a chrysalis, and after lying thus enclosed for the space of fifteen days, gives birth to the moth. See SILK-worm.

PHALANX, in Grecian antiquity, a square battalion, consisting of eight thousand men, with their shields joined, and pikes crossing each other, and which it was almost impossible to break.

PHARMACY, the art or science of choosing, preparing, and mixing drugs; constituting one branch of the therapeutic" branch of medicine.

PHAROS, or PHARE, a light-house, or lofty building near the sea, where a fire is kept burning during the night, to serve as a beacon to vessels. See BEACON.

The Pharos of Alexandria, built in the reign of Pharos, was one of the most celebrated works of antiquity, and from this circumstance the name is given to edifices of a similar description. The tower of king Pharos stood at the mouth of the Nile, it consisted of several stories or galleries, surmounted with a lantern, and was seen for many 'leagues at sea, and all along the coast.

PHASIANUS, the pheasant, in natural history, a

genus of birds of the order Gallina: of which there are ten species: the Phasianus gallus, or wild pheasant, inhabits the forests of India, has been seen in almost all the Indian and South sea islands, and is unquestionably the origin of all the domestic varieties throughout Europe. The most interesting animal of this species is the dunghill cock, which is found in greater vigour and perfection in England, than in any other country: the irascibility and jealousy of this animal have in almost all ages and countries, occasioned it to be employed in the sanguinary practice of cockfighting. The female is remarkable for great fecundity, and for the most exquisite parental fondness and sensibilities. In Egypt chickens are produced from eggs by means of the artificial heat of ovens, in lieu of the natural temperature of the hen.

PHETON, the tropic-bird, is of the order Anseres. There are three species of this genus. The Photon æthereus, or common tropical bird, is always found within or at least very near the tropics. They frequently soar to a prodigious height, but generally near the surface of the water, watching the movements of the flying-fish, whose escape from the pursuit of the shark, porpoise, &c. is attended with destruction from the frigate, or man-of-war-bird, the pelican and tropic bird. They occasionally repose upon the backs of the drowsy tortoises, as the latter float in the water, and in these circumstances they are taken with the greatest ease.

PHILOLOGY, the love or pursuit of language, a science of which grammar, rhetoric, poetry, and criticism are branches. As the illustration of these

topics involves every object of literature, its history and that of its authors, philology is a sort of universal science: yet its particular character may be easily distinguished. A philologist is anxious about the history of chemistry, but he is no chemist himself: he learns the history of painting, but he does not paint: in a word, while other sciences are the sciences of things, this is the science of books.

Philology is what is now called, from the French,, belles-lettres. In some universities it is called humanities. In the old sense, it was a part of grammar, and might be called the science of words, including etymology, or the derivation of words.

PHILOSOPHER, a lover or pursuer of wisdom, one who applies himself to the accumulation of knowledge, that is, the discovery of truth.

PHILOSOPHER'S stone, the principal object of alchemy, a preparation which, when found, will be able to change other metals into pure gold.

PHILOSOPHY, the love or pursuit of knowledge or wisdom. In a general sense, the term philosophy includes observation and reflection on every sub-. ject; in particular senses, it applies to any peculiar study which has for its object the reason of things. The name originated with Pythagoras, who declined the title of Wise, which had been given to his predecessors, Thales, Pherecydes and others, and contented himself with the name of a "friend "or lover of wisdom."

Philosophy is of three principal kinds : 1. Intellectual or metaphysical, which treats of the Deity and of mind; 2. Physical, to which belongs every object of the senses; 3. Moral, which regards the conduct of human life.

Perspiration is essential to health, and when deficient may be promoted by exercise, the warm bath, or friction. At ordinary times, it should never fail of encouragement from the washing of the hands and face. Under the article ABLUTION, it has been observed that the use of linen has in some measure superseded the necessity of bathing; but as this succedaneum has not extended to the parts of the body here mentioned, the uses of ablution to these, for opening the pores, and cleansing the skin of the salts, mingled with dust from the atmosphere, which are left upon it by perspiration, are evident. The vessels through which perspiration is performed, he obliquely under the scarfskin; and are so amazingly small that according to a calculation made by Lewenhoeck, it appears that the mouths of one hundred and twenty-five thousand may be covered with an ordinary grain of sand. The matter of perspiration is a fine subtile fluid, for the excretion of which there are no glands; and which exhales from the body to the quantity of half that of the food.

PERUVIAN bark. See CINCHONA.

PETARD, in military economy, a metalline engine, somewhat resembling, in shape, a high-crowned hat. The petard may be considered as a piece of ordnance. It is made of copper mixed with brass, or of lead with tin; and its charge is from five to six pounds of powder, which fills it to within three finger-breadths of the mouth. Being stopped with a wooden tampion, and the mouth bound over with a cloth very tightly tied with ropes, it is covered with a madrier, or wooden plank, pierced to receive its mouth, and fastened down with ropes.