1819.) Mr. Porrett on Sulphuretied Chyazic Acid. 357 
would combine with the metal and convert it to peroxide, and 
the other atom must escape as gas; but as in the process no- 
peroxide is formed, nor any oxygen gas liberated, itis very clear 
that the compound cannot be such as M. Grotthuss conceives 
it to be. 
M. Grotthuss asserts that this compound “ contains a notable 
quantity of water, though Porrett affirms the contrary:” this 
quantity he afterwards states at jth ofits weight. I did certainly 
affirm the contrary; and having since repeated my former expe- 
riments, I now reaffirm it ; however, I by no means intend to 
assert that no water can be formed when it is heated so highly 
as to be decomposed ; for as, according to my experiments, its 
acid contains an atom of hydrogen, and its oxide an atom of 
oxygen, it follows that an atom of water should in that case 
be produced which did not pre-exist as water in it: the weight 
of this water, however, would not exceed +1,th of the sulphuretted 
chyazate, and would only amount to about half the quantity 
which M. Grotthuss procured. { can only account for the 
remaining half on the supposition that he had not sufficiently 
freed by lixiviation the sulphuretted chyazate which he em- 
ployed from adherent salts which would surrender their water of 
crystallization when heated. 
The arguments used by Von Grotthuss to induce a belief that 
the copper exists in this compound in the metallic state are the 
following : 
1. That by the action of heat upon it, a peculiar gaseous body 
separates with a particular smell, which M. Grotthuss, both 
from the analogy of cyanogen and because it is absorbed by 
ammonia, and then strikes a blood-red colour with solutions of 
iron, considers as anthrazothion. 
2. That after the action of heat there remains a sulphuret 
which contains the copper in the metallic state. 
3. That it is nearly insoluble in muriatic acid, whilst, on the 
contrary, the alkaline sulphuretted chyazates are very soluble 
therein. ~ 
4. That during the combination of sulphuretted chyazic acid 
with easily reducible oxides, the former must undoubtedly reduce 
the latter, because its carbon, sulphur, and hydrogen, are each 
capable of reducing such oxides. 
5. That at the instant when it is forming in a mixture of 
acetate of copper and alcohol, a brown colour is perceptible, 
which disappears when it is completely formed. 
. The insufficiency of these arguments for the purpose for 
which they are advanced will appear from the following obser- 
vations : 
1. What M. Grotthuss conceives to be a peculiar gaseous 
body, and which he considers as anthrazothion, I have found to 
be only a mixture of gas and vapours, principally consisting of 
a compound of sulphur with cyanogen, resembling that formed 
