P Y R 



P Y R 



common in women than in men ; fometimes it attacks preg- 

 nant women, and often thofe vvlio labour under leucorrhoca. 

 It feldom occurs in any one before the age of puberty, or 

 in thofe who are confiderably advanced in life : when it has 

 once taken place, it is very prone to recur occafionally for a 

 longtime afterwards. It is more common in Scotland than 

 in this country, and chiefly aftefts the lower clafles of the 

 people. 



While the fame diet is continued, it is not always eafy to 

 cure the difeafe. The paroxyfm is moll effeftually relieved 

 by anodynes, efpecially opium ; hyofcyamus, conium, &c. 

 anfwer a fin".ilar purpofe ; and with Icfs certainty ; otiier [li- 

 mulants and antifpafmodics, as fulphuric aether, ammonia, 

 the tinfture of guaiacum, &c. alleviate the lit. Thefe re- 

 medies, however, do not materially contribute to prevent the 

 recurrence of the paroxyfms ; and bitters, aromatics, and 

 the whole of remedies again!! indigcftion, have been often 

 employed in vain. A combination of aromatic laxatives, 

 ■with ilrong alkalies and narcotics, have appeared to the 

 writer of this article to be on the whole the moll cfFeftual 

 remedies. See Cullen, Firft Lines, vol. iv. p. l. 



Pyrosis is alfo a word ufed to exprefs an intenfe heat 

 and rednefs in the face, fuch as that of perfons who travel 

 in extremely hot weather, and the like. 



PYROSTRIA, in Botany, fo called by Commcrfon, 

 from the pear-fhaped llriated fruit. — JufT. 206. Willd. Sp. 

 PI. V. I. 614. Lamarck lUuftr. t. 6S. — Clafs and order, 

 Tetrandria Monogynia. Nat. Ord. Rubiaceit, Jull. 



Gen. Ch. Cal. Perianth fuperior, fliort, in four deep, 

 acute, broad legments, deciduous. Cor. of one petal, fome- 

 what bell-fhaped ; tube thrice as long as the cilyx, fwelling 

 gradually upwards ; limb of the fame length, in four acute, 

 equal, Ipreading fegments ; throat downy. Stam. Fila- 

 ments four, fhort, inferted into the tube of the corolla, al- 

 ternate with the fegments of the limb ; anthers oblong, 

 ereft, pointed, fliorter than the limb. Pijl. Germen tur- 

 binate, inferior ; ftyle fhort, cylindrical ; iligma capitate. 

 Peric. Berry fmall, dry, pear-(haped, with eight furrows, and 

 eight cells, deftitute of any crown. Seeds folitary in each 

 cell. 



EfT. Ch. Calyx four-toothed. Corolla bell-fhaped, four- 

 cleft, downy in the throat. Berry inferior, obovate, with 

 eight furrows and eight feeds. 



Obf. Juflieu, by an error which feems typographical, at- 

 tributes five fegments to the corolla, which Willd;now 

 copies. There are, however, but four, as the analogy of 

 the other parts, in this cafe, neceflarily requires. 



I. P. faUclfoHa. Willow-leaved Streak -berry. W'.lld. 

 n. 1. (Pyrollria clxoidcs ; Lamarck Illultr. v. i. 289. t. 68. 

 f. 2, (not f. 4.] — Gathered by Commerfon, in the ifle of 

 Bourbon ; not, as Willdenow has it, the Mauritius. A 

 Jhriib, with round, fmooth, greyifh, leafy branches. Leaves 

 oppofite, on lliort ftalks, rather crowded, two or three 

 inches long, elliptic- lanceolate, fliarpifh, entire, coriaceous, 

 fmooth, with one rib, and feveral lateral incurved veins, oc- 

 cafionally accompanied by an axillary gland-like tubercle, 

 that feems accidental ; paler beneath. Stlpulas between the 

 footftalks, and of the fame length, awl-lhaped, ereft, di- 

 lated at the bafe, deciduous. Floiver-Jlalis axillary, folitary, 

 fomewhat umbellate, bearing one or more fimple, fingle- 

 flowercd, partial ftalk<:, with a pair of oblong tapering 

 iraSeas at the bafe of the latter. Flotuers hardly a quarter 

 of an inch long, ereS, apparently white. Fruit, accord- 

 ing to Lamarck, near au inch in length, pear-(haped, umbi- 

 licated, with eight deep longitudinal furrows. "When cut 

 trnnfvcrfcly, it flievvs the eight feeds, compreiTed, and ra- 

 diating from the centre. 



PYROTARTAREOUS Acid, or Empyreumatic acid of 

 tartar, a fpecies of empyreumatic acetous acid, very dif- 

 ferent from Taiitaheous aW^/; which fee. To procure thif 

 acid, dilUl any quantity of cream of tartar in a glaf» or 

 earthen retort, as in the procefs for Pvroml'cols Acid: the 

 retort being half full of the tartar, on raifing the fire very 

 flowly, the firil produc" is a limpid, acidulous, fomewhat 

 bitterifh water, after which, as the heat increafes, a moft 

 prodigious volume of the inflammable gas is given out, to- 

 gether with a llrongcr acid, and more empyreumatic liquid, 

 and at laft a black oil, and fome volatile alkali. 



The whole quantity of liquid acid procured from tartar in 

 this method, is generally not more than about a quarter of the 

 weight of the tartar, and is not quite fo brown, nor fo highly 

 empyreumatic as the pyromucous. This acid, and alfo the py- 

 roligneous and pyromucous acids, are capable of very confi- 

 derablc purification by eafv methods, fo that they lofe their 

 empyreuma, their peculiar tafte and fmell, in which confift their 

 charafteriftic differences, till at lail, when brought into the 

 moft concentrated ftate by fome of the modes in which vine- 

 gar is dephlegmated, they exhibit the charafters of acetous 

 acid fo unequivocally, that no doubt can be entertained of 

 their identity. Simple rectification, or rediftillation in a 

 very gentle heat, and flopping the procefs when the liquor at 

 lafl comes over much coloured, will purify, to a very 

 great degree, the pyromucous and pyrobgneous acids : the 

 latter, by this procefs, from being of a dark coffee colour, 

 affumcs the hue of very pale clear brandy. But on long ex- 

 pofure to light, it again becomes brown, for it retains its 

 empyreumatic charafter more than any other. Charcoal, 

 newly burnt and powdered, contributes very much to the 

 purification of all thefe acids , they may be either gently 

 diftilled off it, or even merely filtered through a flratum of 

 it. But the moft effeftual method of purification is by uniting 

 thefe acids with lime, or a fixed alkali, evaporating to drynefs, 

 and then expelling the acid by means of the fulphuric acid, in 

 the fame manner as the concentrated vinegar is prepared. 

 The acid vapour that rifes in this procefs has. now loll its em- 

 pyreuma almoft entirely ; has both the ftrength and the 

 powerful odour of radical vinegar ; when again united to 

 potafh, forms acetated potafh, which may be obtained white 

 by repeated cryftallization, or by charcoal powder, and in 

 fhort is perfeft acetous acid. Aikin. 



PYROTECHNY, derived from the Greek words ctj, 

 Jire, and ■^x^'^y '"''> '' ^ term applied to the art or fcience 

 which teaches the management and application of fire in 

 certain operations. Although this term has been ufed in 

 a very extcnfive fenfe by fome writers, and applied to the 

 ufe and ftrufture of fire-arms and artillery employed in the 

 art of warfare, yet it is commonly confined, as it wiU be in 

 this work, to thofe articles and inftruments made ufe of for 

 amufement, and for grand public occafioiis, as the cele- 

 bration of viclories, the demonftrations of public joy on 

 account of peace, after long continued w-ar, &c. 



Of the origin of artificial fire-works there is nothing 

 certain recorded. In Europe the invention of them is of 

 recent date, and is given to the Italians. The ufe of fire- 

 works in China was very general long before they were 

 known in European countries : and from an account given 

 of fome recent exhibitions at Pekin, it fhould feem that 

 they have attained to a degree of perfeftion not furpaffed 

 even by the artifts of England, France, or Italy. " The 

 fire-works, in fome particulars," fays Mr. Barrow in his 

 Travels in China, " exceeded anv thing of the kind I had 

 ever feen. In grandeur, magnificence, and variety, they 

 were, I own, inferior to the Chinefe fire-works we had 

 feen at Batavia, but infinitely fuperior in point of novelty, 



neatne£3. 



