1820.] M. Stromeyer on Polyhalite. AT! 



by those names, before 1700, when Camerarius published a 

 treatise, De Panacea Mercuriah, which was probably an inaugu- 

 ral thesis on that subject as a celebrated nostrum. 



In respect to the etymology of the name, Gmelin, in his conti- 

 nuation of Murray's Apparatus Medicaminum inclines to the 

 use of calomel, in Latin, rather than calomelas, for Mercurius 

 dulcis, whence it should seem as if he considered it as a combi- 

 nation of xaXoj and ju-sAi, the latter referring, as he supposes, to 

 its honeylike sweetness ; and agreeably to this idea, some 

 authors call it manna Mercurii. 



Article VII. 



On Polyhalite, a new Species of Saline Mineral. By M. Fred. 

 Stromeyer. (Read at the Anniversary Meeting of the Royal 

 Society of Gottingen, Dec. 5, 1818.) 



Experience sufficiently proves to us that nothing certain 

 can be established or affirmed respecting the real nature of unor- 

 ganized bodies, or their specific differences, from the mere 

 inspection and examination of their external and physical marks; 

 that mineralogy must have recourse to the aid of chemistry in 

 order to corroborate and assert those proofs which are deducible 

 from the physical configuration of such bodies ; and that the for- 

 mer science, unless assisted by the latter, is inadequate to the 

 attainment of sufficient data. Yet notwithstanding that, from 

 the intimate connexion observable between the chemical compo- 

 sition of mineral substances and their physical properties, it 

 appears to be indubitably proved what great advantage the 

 science of mineralogy has already derived from chemistry, and 

 particularly, how greatly chemistry has of late assisted us in 

 attaining a true knowledge of mineral bodies, there are certain 

 naturalists who believe that mineralogy has no need of chemistry 

 in order to arrange and characterize the different species of mine- 

 rals, and that the indications atf orded by the external appearances 

 or internal structure of such bodies is quite sufficient in order to 

 class them, and become acquainted with them. Yet the fallacy 

 of this opinion, and its tendency to promote error, will, it is 

 presumed, become apparent fiom a chemical analysis of the 

 polyhalite, a new species of saline mineral hitherto classed as 

 a variety of the anhydrites. This mineral is found at Ischel, a 

 town of Upper Austria, not far from the borders of Saltzburg, 

 where it is met with among strata of rock salt. 



It was at first supposed to be a variety of the gypsum fihrosum. 

 Subsequently Werner, that illustrious mineralogist, whose death 

 must be deplored by all who cultivate and admire the science, 



