8 An Account of some Experiments on the 



Heated slowly in a bent luted glass tube, connected with 

 merury, the native muriat affords water and oxygen gas, 

 and the residue is an agglutinated brownish mass, which 

 dissolves in nmriatic acid and gives a greenish precipitate 

 with p<iiash, and is apparently a mixture" of brown oxide of 

 copper and cuprane. When the heat is raised rapidly to 

 redness, the water expelled is impregnated with muriatic 

 acid and nuiriat of copper. I have obtained from 25 grains 

 of the mineral heated to redness till gas ceased to be pro- 

 duced, just two cubic inches of oxygen". This expulsion (jf 

 oxygen seems to be owing to the action of chlorine on the 

 brown oxide to form cuprane; and there is, I have ascer- 

 tained, a similar production of oxygen when heat is applied 

 to a mixture of the deliquescent muriat and brown oxide 

 of c<ipper. 



From these results, which perfectly agree with those ob- 

 tained by eminent chemists on the contment, who have ex- 

 amined diflerent speciujens of this mineral, it appears to be 

 a submuriat of copper, diflering in a chemical point of 

 view from the deliquescent salt, merely in containing a 

 smaller proportion of acid. 



The following exnerimmts were made with the desiorn of 

 ascertainmg (he proportions of its constituent parts. 



Fifty grams of the crystals in powdtr, boiled in a solution 

 of 5'» grains of pota>h. afforded dQ-b grams of brown oxide 

 of copper heated to dull redness. 



And !20 grains disso'ved in nitric acid, and precipitated 

 bv means of niirai of silver, afforded I2-<J grains of dry 

 horn silver. 



Hence, considering the deficiency of weiaht, as indicat- 

 it^g the quantity oi combined water, 100 of ^he native sub- 

 muriat of copper seem to consist of 



73'0 brown oxide ri5'S023 chlorine 



16'2 muriatic acid = < 

 JO-8 water (. '47 hydrogen. 



This analysis, allowance being made for difference of 

 theorv, nearly agrees with that of Klaproth. 



M. Proust, I he'ieve, first discovered an artificial com- 

 pound similar to the native bub-muriat of copper. He ob- 

 tained it, in the preparation of the nitro-muriat of copper, 

 and also by a |)artia' abstrnciio:» of the acid of the deli- 

 quescent muriat, by means of an alkali. I have found 

 that it niHv be procured in several other ways. It 

 may be made directly by adding the hydraied blue oxide of 

 copper t<i a solution of muriat of copper; and it may be 

 very readily and CECononiically prepared, by exposing to 



the 



