SALTS. 69. Mirabile. 217 



fcldom found pure, but ufually mixed with Toda, common 

 fair, Epfom fak, or felenite: the fides of the cryftals arc 

 commotiiy gro{n'ed, and when expofed to a warm atmofphere 

 they foon lole their tranfpfirency and water of cryftallization, 

 ard fall into a white opakc powder: when expofed to heat it 

 firft meltt, and after the evaporation of its water becomes a 

 white powder, and in a red heat mehs. Its ufe as a cooling 

 purgative is fufficcntly known. Contains acid 27, foda 15. 

 water 58, Bergfnan. 



potasilnum, Oi a bitierlih taPie, decrepitating when placed on hot coals 



and melting in a red heat, folublc in 16 times its 

 weight of co'd water, its cryftals not mouldering in 

 the air. 



Prouft heytr chem. annal- 3. ^, 466. . 



Tartar vitrioh-itc. Kir^i^an /niner. 2. ^ 8, 



Sulphat of Potafs. Thorn fon chem. 2. p. 347. 



2- With an excefs of aciJ. 



Superfulphdt of Pot.fs. Thomfonchem. 2. p. 349. 



Found in various parts of Spain, of a greyifh-white colour, and 

 fometimcs luminouis in tlie dark : when its diluted folution is 

 evaporared it uffords 6-fided pyramids, or fhort.hexangular 

 prifms terminated by one or more hexangular pyramids; the 

 the fuperlulphiUe of pat a fs from its excels of acid turns blue 

 vegetable juices red, and is foluble in twice its weight of 

 water. It wa.s formerly ufed as a purgative, under the name 

 of Sal polychreft and vitriolated, tartar. Specific gravity 

 2,298 contains acid -']0. potafs 52. water of cryftiillization 

 iS. Bergman. 



seminjolatik Of an acrid tafte, evaporating in fumes when heated, de- 

 liquefcina; in the air, emitting an alkaline odour when 

 rubbed tOi^edier with quicklime. 

 Found rarely in the vicinity of volcanic mountains. 



iulphureum. Evaporating in fumes w^nen heated, deliquefcing in the air, 

 when rubbed together with quicklime emitting an al- 

 ' kaline odour, and when fprinkled with nitric acid an 

 odour like burnt fulphur. 



Vitriolic ammoniac. Kirivan miner. 2. p, lo. 



Sulphuric acid united to ammonia. Schmeifser, \. p, 268, 



Sulphat of ammonia. Thofnj'on chem. 2. p. 356. 



Found in the neighbourhood of volcanos, in fome lakes in 

 Tufcanyy at the bottom of a burning well in Dauphignyy and 

 on the furface of the earth near Turin, It is generally found 

 mixed with fulphur, alumina, alum, or vitriol, and hence its 



VOL. Vir. — E e 



