ACCOUNT OF A MINERAL SUBSTANCE. 179 



this is very evident ; for, from the experiment there defcribed, 

 it appears, that when the metallic acid or oxide was digefted 

 with lixivium of potafh, only a part was diffolved ; and that the 

 remainder was infoluble in the fame lixivium, till it had received 

 an additional portion of oxigen, by being treated with nitric 

 acid ; alfo that feveral of thefe alternate operations were re- 

 quired, before any given quantity of the metallic oxide could 

 be completely combined with the alkali. Now there is much 

 reafon to believe, that in this cafe, when the metallic oxide or 

 acid was digefted with potalh, the portion which was diffolved 

 received an acceffion of oxigen at the expence of the other 

 part, which of courfe was thus reduced to the ftate of an info- 

 luble oxide, and therefore required to be again oxidated by 

 nitric acid, before it could combine with the alkaline folution ; 

 but ftill it appeared, that an adequate proportion of oxigen 

 could never be fuperinduced, fo as to render the oxide totally 

 and immediately foluble in the alkalies by one operation, or 

 even by two. 



We may, therefore, regard this as an inftance of the effects 

 refill ting from difpofing affinity, and as very fimilar to thofe 

 obferved in refpecl to copper, which have been noticed by my 

 ingenioits friend Mr. Chenevix, in his valuable analyfis of the 

 arfeniates of copper and of iron *; 



My refearches into the properties of this metal, have of From the limited 



courfe been much limited by the fmallnefs of the quantity "Marches on the 



1-ttii i /-i/>i fmall quantity or 



which I had to operate upon ; but I flatter myfelf that more re, the only de- 



of the ore may foon be procured from the Maffachufet mines, du &»°n as to 



particularly as a gentleman now in England (Mr. Smith, Se- utility is, that 



cretary to the American Philofophical Society), has obligingly the precipitates 



offered his affiftance on this occafion. We (hall then be able * re fine colours ' 



more fully to inveftigate the nature of this fubftance ; and (hall 



be more capable of judging how far it may be applicable to 



ufeful purpofes. At prefent, all that can be faid is, that the 



olive-green pruiliate and the orange-coloured gallate are fine 



colours ; and, as they do not appear to fade when expofed to 



light and air, they might probably be employed' with advantage 



as pigments. 



I am much inclined to believe, that the time is perhaps not The new metals 



very di/tant, when fome of the newly difcovered metals, and are probably 



compounds. 



* Phil, Tranf. for 1801, p. 2o3, 



N 2 other. 



