444 PROF. nosK 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 brouglit 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 sligJit 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. If a 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 ammoniaf . 



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. f Ibid. vol. xxxii. p. 81. 



