«-g CHEMICAL ANALYSIS OF SOME CALAMINES^ 



certainty; they were evidently, however, rhomboids, whofefac^e 

 were very nearly, if not quite, redangular, and which were in- 

 complete along their fix intermediate edges, apparently like 

 Fig. 78. Plate IV. of Rome de L'Ifle. 



22.1 grs. of thefe ciyftals, at a heat of 57° Fahrenheit, dif- 

 placed 6.1 grs. of water, which gives their denfity =4..333. 

 Heat did not excite any ele^ricity in thefe cryftals. 

 I rimcncs ^- ^^^^re the blowpipe, they grew more yellow and opaque, 



and fpread flowers on the coal. They diflblved wholly in borax 

 and microcofmic fait, with effervefcence. 



c. 22.0 grs. during their folution in vitriolic acid, efFervefced, 

 and loft 7.8 grs. of carbonic acid = 0.354. This folution was 

 colourlefs, and afforded 26.8 grs. of arid vitriol of zinc, which, 

 rediffolved in water, fhot wholly into clear colourlefs prifms of 

 this fait. 

 Component </_ 92 grs. of thefe cryftals, ignited in a covered tobacco-^ 



addlnd'^oxklc ofP'pe, loft 3.2 grs. = 0.3478 ; hence thefe cryftals confift of, 

 zinc. Carbonic acid - > - 0.348 



Calx of zinc - - , - - 0.652 



1 .000. 

 EleSirical Calamine. 

 Elfftrical ca- The Abbe Hauy has confidered this kind as differing from 

 JRcgbania. ^^^ Other calamines only in the circumftance of being in diftind 

 cr3ftals; but it has already appeared, in the inftance of the 

 Derby (liire calamine, that allcryftals of calamine are not e}e6iric 

 by heat, and hence, that it is not merely to being in this ftate 

 that this fpecies owes the above quality. And the following 

 experiments, on fome cryftals of eledric calamine from Reg- 

 bania in Hungary, can leave no doubt of its being a com- 

 bination of calx of zinc with quartz; fince the quantity of quartz 

 obtained, and the perfe6t regularity and tranfparency of thefe 

 cryftals make it impoftible to fuppofe it a foreign admixture in 

 them. 



a. 23.45 grs. of thefe Regbania cayftals, difplaced 6.8 grs. 

 of diftilled water, from a ftopple-bottle, at the temperature of 

 G 1° Fahrenheit ; their fpecific gravity is therefore = 3.434. 



The form of thefe cryftals is reprefented m Figure I, Plate 

 V. where the angle formed by the planes a and c was 90°, that 

 by a and e — 150°, that by b and c:-\\b'', and that by c and 

 d ~ I 30°. 



They were not fcratched by a pin ; a knFfe marked them. 

 3 h. One 



