gaseous mixtures, and its application to their analysis. 27$ 
quantity to enable me to submit it to a more minute exami- 
nation ; but its characters appeared to resemble those of a 
product, obtained by M. Gay Lussac, by mixing cyanogen 
with ammoniacal gas.* 
If oxygen be added to a mixture of hydrogen and cyanogen, 
in quantity sufficient to saturate both the gases, it is still ne- 
cessary, in order that an immediate effect should be produced 
by the sponge, that the hydrogen should exceed the cyano- 
gen in volume. A decided action then takes place ; an im- 
mediate absorption ensues ; fumes of nitrous acid vapour 
appear, which act on the surface of the mercury ; and, after 
removing the nitrous acid by a drop or two of water, and 
transfering the gas into a dry tube, carbonic acid is found to 
have been produced, equivalent in volume to double that of 
the cyanogen. 
V. Effect of adding various other Gases to an Explosive 
Mixture of Hydrogen and Oxygen. 
It had been already ascertained by Professor Dobereiner, 
that one volume of oxygen, diluted with 99 volumes of nitro- 
gen, is still sensible, when mixed with a due proportion of 
hydrogen, to the action of the sponge. -f Carbonic acid, also, 
even I find when it exceeds the explosive mixture ten times, 
retards only in a slight degree the energy of the sponge. 
Oxygen, hydrogen, and nitrous oxide gases, when employed 
* Annales de Chimie, XCV. 196. 
f In analyzing atmospheric air by adding hydrogen to it, and acting on the 
mixture by a platinum ball, I have generally obtained a diminution indicating more 
than 21 per cent, of oxygen. This I find to be owing to the absorption of a small 
quantity of nitrogen by the ball, especially when, ^fter being heated, it has been 
rapidly passed hot through the mercury. 
MDCCCXXIV. N n 
