6 Element of Mineralogy. 



Magnejia or Muriatic Earth 



i rt * Its fpecific gravity when perfectly pure 

 is about 2,33. 



2 a * It requires about feven thoufand fix 

 hundred and ninety-two times its weight of 

 water to diffolve it in the common tempera- 

 ture of the air. 



3 d * It is combinable with acids, and though 

 the vitriolic eafily feparates it from the ni- 

 trous and marine, yet it does not precipitate 

 it, as it does calcareous Earth and barytes, 

 but forms Epfom fait which is bitter and 

 foluble in its own weight of water \ whereas 

 with the former Earths it forms infipid and 

 very difficultly fojuble tompounds. 



4 th - Expofed to the ftrongeft heat, it will 

 neither burn to lime, nor melt per fe, butlofes 

 much of its weight, partly by evaporation, 

 and partly by the lofs of a certain proportion of 

 water, which it naturally retains. Neither will 

 it vitrify in company with any other fimple 

 Earth, except the calcareous, of which, accord- 

 ing to Mr. Achard ioo s " will promote the fu- 

 fion of from twenty-five to fifty of magnefia, 

 it will alfo melt with argillaceous and filiceous 

 Earths together, and much more readily if 

 calcareous Earth be added to them. Like 



lime 



