2 Elements of Mineralogy* 



PART I. 



Of EARTHS and STONES. 



By Earths are commonly underftood tafte- 

 lefs* inodorous, dry, brittle, uninflammable 

 fubftances, whofe fpecific gravity does not 

 exceed 4,5. which are incapable of being 

 metal ized, are fcarcely foluble in water, and 

 give no tinge to Borax when melted with 

 it. However Quicklime is ufually called an 

 Earth, though it has a pungent tafte and is 

 very perceptibly foluble in water, fo alfo are 

 limeftone and gypfum, though they both 

 contain a purely faline principle, and there- 

 fore in my opinion they and fome other fuch 

 fuhftances may be claffed both among Salts 

 and among Earths. Nay it appears that all 

 Earths are foluble in fome very large pro- 

 portion of water. Hence I think with Mr. 

 Bergman, that in the ftri&eft fenfe the term 

 Earth, fhould, exclufively of any other deno- 

 mination, be appropriated to fubftances of the 

 above defcription, that require above one 

 thoufand times their weight of boiling water 

 to diffolve them, and that thofe which are 

 foluble in between four hundred and one 

 t&oufand times their weight of water may 

 foe called either falts as technical, or Earths 

 as common language requires. 



Stonn 



