550 Mr. PoRRETT on the nature of the Salts 
carbonate of copper or malachite in powder: during the ope- 
ration there was a constant escape of carbonic acid from the 
malachite, and of Prussic acid into which one part of the red 
tinging acid was converted, whilst another part formed the 
white powder containing the protoxide of copper : now as all 
the copper in this ore was in the state of per-oxide, it follows 
that part of this oxide must have relinquished oxygen to some 
principle contained in the red tinging acid ; the principle thus 
oxidated was found to be sulphur, for after the experiment 
on testing the liquid for sulphuric acid, the presence of that 
acid was most unequivocally demonstrated. 
E. Some of the red tinging acid was mixed with diluted 
muriatic acid and’ hyperoxymuriate of potash ; a gentle heat 
was then applied until chemical action took place, when the heat 
was withdrawn and the action moderated by cooling ; by this 
process sulphuric acid was formed in the liquid, and Prussic 
acid also, part of which escaped as gas, and the rest was readily 
discovered in the liquid by neutralizing it and adding a solu- 
tion of iron, with w’hich it formed Prussian blue. 
F. The red tinging acid was electrified negatively in the 
Voltaic circuit, and connected by cotton threads with distilled 
water electrified positively. The result of this experiment was, 
that the acid was carried over to the positive side without de- 
composition, or any separation of sulphur. 
G. The above experiment was repeated, adding to the acid 
in the negative cup potash, and pouring into it mercury, into 
which the copper wire dipped that communicated with the 
battery. The result was the same as in the last experiment; 
the acid was carried over to the positive pole unaltered, and 
neither the potash, the mercury, nor the copper wire had 
