74 PROVOSTAYE ON THE ACTION OF 
contain 4 cubic centimetres of nitrogen, arising from the air of 
the small retort. 
A quantity of this gas, which occupied 168 measures of a 
small graduated tube, was treated with potassium in excess ; 
the residue occupied 72 measures. About one-thirtieth of this 
gas is excess of nitrogen, we shall therefore have for 162-4 mea- 
sures, a residue of 66°4; or of 47°83 cubic centimetres of nitro- 
gen for 117 cubic centimetres of the mixed gases. This number 
affords 
Nitrogen . . . 12°02 per cent. 
According to the same experiment, 0°501 gramme furnished 
95°66 cubic centimetres of nitric oxide, and consequently 21°34 
of sulphurous acid. Calculated according to the formula above 
given, 23°3 should have been obtained. But this accordance is 
as satisfactory as can be expected. 
Properties.—This substance produces a deep red colour when 
applied to the skin, or rather the part touched appears as if 
deeply bruised. The tint quickly becomes yellow, and disap- 
pears in a few moments, leaving only a faint black shade. Ex- 
posed to the air, it gradually decomposes, absorbing water, and 
evolving hyponitric acid. In contact with a quantity of water, 
it immediately causes an abundant evolution of pure nitric oxide. 
The solution of sulphuric acid which remains, continually evolves 
the odour of this gas, and must consequently retain a consider- 
able portion. Indeed, 0°662 gramme of the substance gave no 
more than 32 or 33 cubic centimetres of nitric oxide; while, 
assuming that all the nitrous acid formed from the compound 
(S O, O, S O, N O,) is decomposed into nitric acid and nitric 
oxide, 83 cubic centimetres ought to have been collected. The 
hydrated bases also decompose this substance. Anhydrous 
baryta has no action while cold, but at an elevated temperature 
it suddenly becomes incandescent. Red vapours appear in the 
tube, and sulphate of barytes remains. 
The action of dry ammoniacal gas has not been sufficiently 
studied. I have merely ascertained that a very hard white crust | 
is formed on the surface of the substance, which prevents fur- 
ther absorption. 
The body produced appears to be a species of sulphamide : 
no trace of decomposition is perceptible, 
If a current of dry ammoniacal gas be passed through the 
melted substance, a large quantity of nitrogen is disengaged ; 
