RECENTLY DISCOVERED MINERALS. 169 



Copper together, combined with Arsenic Acid. The following is 

 the formula which Mr. Church has given it : 



PbO+3 (CuO, AsO«) + 2 HO. 



The Minerals which I have in this Paper very briefly noticed, 

 have been fully described, both chemically and physically, by 

 Professor Church, in the Journal of the Chemical Society. The 

 specimens were found in Cornwall by Mr. Tailing, who has been 

 very energetic in collecting the various species ; it is to him that 

 we mainly owe these discoveries. 



