MINERALOGY. iSr 



corroded into a white powder by the ipirit 

 of nitre. 



The vegetable acid, foaps, and pure alca- 

 line falts, alfo corrode this metal by degrees. 



/. Its fpecihc gravity to water is as 7400 to 

 1000, or as 7321 to 1000. 



m. DiiTolved in aqua regia, which for this 

 purpofe ought to confiit of equal parts of 

 the ipirit of nitre and fea-falt, it heightens 

 the colour of the cochineal, and makes it 

 deeper •, for otherwife that dye would be 

 violet. 



SECT. CLXXXL 



Tin is not found naturally in the earth 

 in any other date than, 

 1 . In form of a calx, St annum c aid forme, 

 A. Indurated, or vitrified, Jnduratum. 

 1. Mixed with a little of the calx of 

 arfenic, Minera ftanni vitrea arfe*- 

 nicalis. 



a. Solid tin ore, without any deter- 

 minate figure, Tin-itone". 



It reiembles a garnet of a 

 blackifh brown colour, but is a 

 great deal heavier ± and has been 

 confidered at the Englifh tin- 

 mines as a ftone, containing no 

 metal, until fome years a^o it 

 began to be fmelted to great ad- 

 vantage. 

 b. Criilallifed, Cryft alii fat urn „ Tin- 

 grains. 



Is like the garnets, of a fphe- 

 x rical polygonal figure, but looks 

 more uncluous on the furface. 



N 3 1. In 



