COPPER. 149 



When 11*875 grains of this salt are exposed to 

 a temperature of between 400 and 500, or in- 

 deed to a lower temperature, there is a diminu- 

 tion of weight amounting to exactly S'SJS grains, 

 the green colour disappears, and an orange 

 brown matter remains, weighing exactly 8*5 

 grains. Now, the 3-3J5 grains of matter driven 

 off consist of pure water, as may be ascertained 

 by performing the experiment in a retort, to 

 which a receiver is luted. The water will come 

 over into the receiver quite pure, unless too 

 much heat has been applied. In that case some 

 chlorine is apt to pass off, owing I presume to 

 the agency of the common air in the retort. 



3*375 grains of water is the equivalent for 3 

 atoms of that liquid ; yet the salt contained only 

 2 atoms. The other atom of water was formed 

 by the union of the atom of oxygen in the oxide 

 with the atom of hydrogen in the muriatic acid. 

 Thus the salt is changed into chloride of copper, 

 which, as is obvious from the facts just stated, is 

 a compound of 



1 atom copper . 4 

 1 atom chlorine 4'5 



8-5 



8. The subchloride of copper was noticed by 



. 11 -i-ii ride of cop- 



Boyle ; and it has been minutely described by per. 



Prout, Chenevix, and Dr. John Davy. I have 



Dd2 



