TAB. XXXI. 



CUPRUM arseniatum. 

 Arseniate of Copper. 



Class 3. Metals. Order 1. Homogeneous. 

 Gen. 4. Copper. Spec. g. Arseniate of Copper, 



Div. 1. Crystallized, 



Spec. Char. Arsenic acid combined with copper. 

 Syn. Philos. Trans, for 1801, p. 169. 



We are obliged to Mr. Chenevix and Count Bournon for 

 the best account of the arseniates of copper. They are 

 found at Huel Gorland mine in Cornwall. The simplest 

 variety, according to Count Bournon, is the obtuse octa- 

 edron. He observes that this octaedron has, in each of its 

 pyramids, two opposite planes more inclined than the other 

 two; which gives a parallelogrammic form to their com- 

 mon base. The two planes which are most inclined meet 

 at the apex of each of the pyramids, in an angle of. 130°, 

 and at the common base in one of 50°. The two planes 

 which are less inclined meet at the apex in an angle of 115°, 

 and at the base in one of 65°. 



