4.4.4 PROF. ROSE ON A NEW COMBINATION OF THE 
tact with the air it very soon evaporates, and then occasionally leaves 
behind an exceedingly small portion of hydrous sulphuric acid. This 
great volatility, as also the easy decomposability, of the compound, en- 
tirely prevented my bringing it into a small glass bulb with a long neck 
drawn to a point, as is done with other less volatile and decomposable 
fluids, by warming the ball and then dipping the point in the fluid. 
When the bulb is quite cooled, the compound does not rise in the 
stem, less on account of its own vapour preventing it, than because it is 
decomposed in the rarified space in the bulb, and sulphurous acid gas is 
evolved. This is also the reason why it is not possible to ascertain the 
specific gravity of the vapour of this compound. If ever so small a por- 
tion of water be brought in contact with this fluid, a strong effervescence 
and evolution of sulphurous acid gas immediately ensues. The com- 
pound is entirely decomposed by a small quantity of water. If it be 
brought into a glass vessel, so nearly dry that not the slightest moisture 
is perceptible on its sides, even then a slight effervescence and decom- 
position occur; this is the reason of the necessity for the great care to 
avoid the slightest trace of moisture in the formation of this com- 
pound, which would otherwise be entirely prevented. Ifa large quantity 
of water be added to it, it boils fiercely, through the sudden evolution 
of sulphurous acid. 
If dry ammoniacal gas be passed into the fluid, anhydrous sulphate 
and sulphite of ammonia are formed. The product thus obtained is of 
a yellowish colour, and soluble in water; if the solution be saturated 
with muriatic acid, sulphurous acid is evolved, but no precipitate of 
sulphur falls until -the fluid is boiled. A solution of nitrate of silver 
causes a precipitate in it, which is at first white, then yellow, brown, and 
at last (very quickly if boiled) black. These are the properties of a 
combination of dry sulphurous acid and ammonia, which I have before 
described*. A solution of chloride of strontium causes a precipitate of 
sulphate of strontia, occasioned by the sulphuric acid, which is formed 
by the action of the chloride of strontium upon the solution of the an- 
hydrous sulphite of ammonia ; if this precipitate be removed, and the 
supernatant liquid boiled, a fresh precipitate of sulphate of strontia 
falls, which is one of the properties of the solution of the anhydrous sul- 
phite of ammoniat. 
In analysing this substance, I have only succeeded in estimating ex- 
actly the quantity of sulphuric acid, not of sulphurous, though I at- 
tempted it in several ways. A weighed portion of the compound, in a 
very small bottle, which had been weighed previously with the glass 
stopper, was oxidized by fuming nitric acid, in such a way that no loss 
could be sustained by the violent action. The nitric acid was in a large 
* Poggendorff’s Annalen, vol. xxxiii, p. 235. + Ibid. vol. xxxii. p. 81. 
