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Proceedings of the British Association. AT 
Account of a new compound of arsenious and sulphuric acids ; 
by Dr. Schaffaeutl. This was obtained from the escaping 
smoke of copper calcining furnaces near Swansea, in South 
Wales. ‘The new compound was another singular instance 
where an anhydrous crystallized body was deposited under the 
presence of water only, and was a remarkable proof of the un- 
limited number of different forms of combination which might 
be produced even in inorganic substances in contact under vary- 
ing circumstances. 'The copper ores smelted in South Wales 
were chiefly copper pyrites, mixed with iron pyrites, gray copper 
ore, &c.; in fact, a mixture in which the sulphurets of copper, 
iron, arsenic, antimony, cobalt, nickel, zinc and tin were invaria- 
bly found together. The sulphur and arsenic escape from these 
ores during the calcining process, as sulphurous and arsenious 
acids, and have been found to destroy all vegetation for miles 
around the copper works, without affecting animal life in the 
slightest degree. By bringing the escaping fumes in contact 
with steam, and forcing it through burning charcoal, or subject- 
ing it only to a great pressure in ‘contact with steam, the new 
solid compound was deposited on the cool surfaces of the cham- 
bers connected with the calcining furnace. It was deposited in 
beautiful crystallized leaves or tables, perhaps belonging to the 
same class as Wohler’s dimorphic modification of the crystalliza- 
tion of arsenious acid, the regular form of which belongs to the 
octahedron. It was found to consist of 
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Arsenious acid, - - - - - 68.250 
Sulphuric acid, - - - - - 27.643 
Protoxide of iron, - . . - 3.029 
Oxide of copper, - - - - 0.420 
Oxide of nickel, - - - = 0,656 
99.998 
These crystals attracted moisture from the air with great ra- 
pidity and with evolution of heat, corroding animal and vegeta- 
ble substances as powerfully as concentrated sulphuric acid. One 
of the remarkable changes during the formation of this com- 
pound, was the conversion of sulphurous acid into sulphuric acid, 
as well as the presence of iron, copper, and nickel, in a deposit 
from gaseous matter. No other definite compound of arsenic 
acid with another acid seems to be known, except those with the 
organic tartaric and paratartaric acids. 
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