P YB 



604 



pyx 



depending on the same ultimate principle. 

 Homberg's pyrophorus, the best known, is 

 readily prepared by calcining together 

 3 parts alum and 1 part sugar, or flour, in 

 a bottle of stone or other lilting material, 

 until no product appears to be given off; 

 the mouth of the bottle is then to be 

 stopped, and the whole set aside to cool : 

 the bottle will now be found to contain a 

 black powder, which will spontaneously 

 take fire when poured out. 



PYRO-PHOS'PHORIC ACID. The acid 

 formed when phosphoric acid, or any of 

 its salts, is subjected to a heat of 415 F. 



PYKOR'THRITE, from we, flre, and or- 

 thrite (q. v.). A mineral resembling or- 

 thrite, but differing: from it essentially. 

 Pyrorthrite burns like charcoal before 

 the blow-pipe, whereas orthrite melts. 



PYR'OSCOPE, from jri/o, fire, and trxoxita, 

 to view. An instrument for measuring 

 the intensity of heat radiated from a fire. 



PYRO'SIS, from weou, to burn. A dis- 

 ease called in Scotland irater-brash, and 

 in England black-wnier : known by a sen- 

 sation of heat in the stomach, attended 

 with copious eructations, generally of a 

 watery insipid fluid. 



PYROSO'MA. A floating polypus, differ- 

 ing from xhe coral in being locomotive, 

 and is so named from !j-y,fire, and trZujx., 

 body, because it emits a sort of phospho- 

 rescence which is considerably augmented 

 when the animal is irritated. The pyro- 

 somtc unite in vast numbers, and arrange 

 themselves in the form of a hollow cylin- 

 der, open at one end and shut at the 

 other, and in this form the body moves 

 about by the alternate dilatation and con- 

 traction of the individual animals. 



PYRO-TARTAR'IC ACID. An acid ob- 

 tained by exposing tartaric acid to heat 

 in a retort. When the tartaric acid in 

 the retort is kept at a temperature of 

 374, a liquid passes into the receiver, 

 which yields by evaporation crystals of 

 pure pyro- tartaric acid. 



PYR'OXENE, from jj-yj, fire, and ^ivo;, 

 a stranger. The name given byHaiiy and 

 Brongniart to augite, because it is not 

 altered by fire. 



PYROX'ILIC SPIRIT, ) Pyrolignous spi- 



PYROX'YLIC SPIRIT, j rit. Pyro-acetic 

 spirit. A liquid often improperly termed 

 naphtha. It is one of the products ob- 

 tained by subjecting wood to destructive 

 distillation. When the pyrolignous acid 

 is saturated with quick lime, and dis- 

 tilled, it yields 1 per cent, of this spirit. 

 See PYRO-ACETIC SPIRIT. 



PYROX'ILINE. A name given by Dr. TJre 

 to pyroxanthine or eblanine, because 

 obtained from pyroxilic spirit. If pot- 

 ash be added to unrectified pyro-acetic 

 spirit, ft precipitate of pyroxiline falls, 

 mixed with tarry matter. From this im- 



purity it is freed by washing wtth ^co- 

 no! of sp. gr, 0'84. It has an omnge rc4 

 colour closely resembling ferro-prussiate 

 of potash. 



PYRR'HIC. TIvgpi%iof, from fruypi^f), 

 an ancient military dance. A poetical 

 foot consisting of two syllables. 



PYHRHOCO'RAX. A genus of passerine 

 birds belonging to the family &entiro*tres, 

 Cuv. Name a corruption of pyrocorax, 

 the ^rjeoxooa^ of Pliny, from TI/, fire, 

 and jjs^al, a crow, the feet and beak 

 being flame-coloured, and their other 

 characters coinciding nearly with those 

 of the crows, to which they were for a 

 long time united. 



PYRRHO'NIAXS, I A sect of ancient phi- 



PYRR'HONISTS. j losophers, founded by 

 Pyrrho, a native of the Peloponnesus. 

 They were also called Sceptics, because 

 they professed to doubt everything, and 

 although they seemed always in search 

 of truth, they never acknowledged that 

 they had found it. Hence the term* 

 scepticism and pyrrhonism became syno- 

 nymous. 



PYR'CLA. A genus of marine pyriform 

 univalve shells, belonging to the family 

 Canalifera, Lam. Pyrulae occur both re- 

 cent and fossil ; the former on muddy 

 bottoms, and the latter in the London, 

 Clay. 2. In arnitltulogy, the bull-finch. 



PY'RUS. An extensive genus of trees of 

 the natural order Poniaceae, and arranged 

 by Linn6 in the class Icosandria, and 

 order Pentagynia, of the sexual system. 

 Namepyms, a pear ; the pear tree being 

 the type of the genus. The apple, quince, 

 whitebeam, mountain-ash, &c. trees are 

 also species. 



philosophers, so called from their being 

 followers of Pythagoras of Samos, who 

 lived in the reign of Tarquin, the last 

 king of Rome. Pythagoras first taught 

 that the sun was a moveable sphere, 

 situated in the centre of the universe, 

 and that the planets revolved about this 

 centre. This doctrine was revived by 

 Copernicus, and has in consequence been 

 named the Coperiiican system of astronomy. 



PYTH'IA, 1 The priestess of Apollo, 



PYTH'ONES?. } who delivered oracular 

 answers at Delphi in Greece. 



PYTH'IAN GAMES. One of the four 

 national festivals of Greece, celebrated 

 every fifth year near Delphi, in honour of 

 Apollo, who vercame the dragon Python. 



PYX, from n-u|;s, a box. The name of 

 the box in which the consecrated host is 

 kept by the Romish priesthood. The 

 trial of the pyx, or pix, at; the Mint, is a 

 trial of the coins previous to their being 

 put into circulation, and i to called from 

 the box in which the coins to be tried 

 are kept. 



