2 1 o r Elements of Mineralogy. 



folution, in the temperature of 60, and more 

 if hotter. Pure air alfo decompofes hepa- 

 tic air. 



It is (found in many mineral waters, and 

 particularly in the hot baths of Aix la Chapelle. 

 The caufe and manner of their containing 

 fulphur, which was long a problem, has at 

 laft been happily explained by Mr. Bergman. 

 It plentifully occurs in the neighbourhood of 

 volcanos, and in feveral mines. 



SPECIES HI. 



Naphtha. 



A fine thin fragrant colourlefs oil, which 

 iflues out of white, yellow, or black clays in 

 Perfia and Media^ is known by this name. 

 It burns with a bluifli yellow flame, and is as 

 inflammable as aether, and like it, extracts 

 gold from Aqua Regia. It is not decompo- 

 fed by diftillation, and yet if long expofed to 

 the air, it changes colour, thickens, and de- 

 generates into petrol. Its fmell is very dif- 

 ferent from that of vegetable oils ; it diflblves 

 refins and balfams, but not gum refins, nor 

 claftic gum. It diflblves the eflential oils of 

 thyme and lavender, but is infoluble in fpirit 

 of wine andaether. Its fpecific gravity is 0,708. 



SPECIES 



