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heavy lava, which alfo has for its bafe the ' 

 horn-ftone, is of an iron-bl;ick, compad:, but 

 not fufficiently hard to give fparks with 

 fteel. The garnets, which are of a yellow- 

 iih white colour, and fome of them four 

 lines in diameter, for the moft part have 

 clefts or fiflures, but in fuch a manner that 

 in the recent fradlures the furface refembles 

 around polypetalous flower. 



The furnace melted the lava, but not the 

 garnets, which only acquired the red colour 

 of copper. 



The garnets of the fourth and laft fpecies 

 have four-and-twenty facets, and are femi- 

 tranfparent, white, and vitreous. Their ma- 

 trix is a compadl lava of a horn-ftone bafe, 

 which emits an argillaceous odour. In the 

 the furnace it changes into a black ena- 

 mellar product, but the garnets remain un- 

 touched. 



On comparing thefe refults with others 

 before detailed, we fhall find that the ftruc- 



ture 



