472 PELOUZE ON CERTAIN COMBINATIONS OF A NEW ACID, 
combinations, and furnishes at the same time a means of preparing them 
with facility. After several attempts, which it is useless to recount 
here, I arrived at the following process, in which I have best suc- 
ceeded. 
A concentrated solution is made of sulphite of ammonia, which is 
mixed with five or six times its volume of liquid ammonia; and into 
this is passed, during several hours, deutoxide of azote: the experiment 
may be conveniently made in Woolff’s apparatus. The gas which is not 
absorbed by the liquid contained in the first flask, is taken up by that in 
the second or third. A number of beautiful crystals are seen gradually 
to deposit themselves, in the same manner as those obtained at a low 
temperature with the neutral sulphite of ammonia; these are to be 
washed with ammonia previously cooled, which, beside the advan- 
tage of retarding their decomposition, offers that of dissolving less of 
them than pure water. When the crystals are desiccated, they should 
be introduced into a well-closed bottle ; in this state they undergo no 
alteration. The same process is applicable to the corresponding salts 
of potash and soda. 
Before passing to the examination of this new class of bodies, I shall 
detail an experiment which throws the clearest light upon their com- 
position. Ifa strong solution of caustic potash be passed into a gra- 
duated tube, containing a mixture of two volumes of deutoxide of 
azote and one volume of sulphurous acid, all the gas after some hours 
disappears. If the deutoxide of azote be in a proportion greater than 
2:1 to the sulphurous acid, the excess remains free and unabsorbed 
above the liquor; and if, again, we employ less nitrous gas than the 
quantity indicated, the new salt will be found always mixed with sul- 
phite of potash: in a word, the two gases, deutoxide of azote and sul- 
phurous acid, never react except in the proportion in volumes of 2 : 1. 
It is easy to convince ourselves that the sulphite disappears, and that 
the salt which replaces it is formed by a new acid. In fact, the red 
sulphate of manganese, introduced into the tube in which the action 
takes place, is not discoloured ; whilst the sulphuric solution of indigo 
shows plainly, by the permanence of colour, the absence of nitrates and 
nitrites; and if, after pouring a salt of baryta into the liquor, we 
gather the precipitate which is there formed, wash it several times with 
a diluted solution of potash, and treat it afterwards with nitric acid, it 
dissolves entirely, and we may thus be assured that there has been no 
production of sulphate. 
These experiments, added to the complete absorption of the deut- 
oxide of azote by a neutral sulphite, at a temperature of —15°, left no 
doubt in my mind as to the composition of these new salts. Two 
volumes of sulphurous acid, in acting upon four volumes of deutoxide of 
azote and one atom of alkali (potash, soda, or ammonia), should pro- 
