SULPHUROUS ACID ON HYPONITRIC ACID. rw 
proportions to constitute nitrous acid (or a mixture of hyponitric 
acid and nitric oxide) be placed in contact with sulphuric acid, 
erystals may be obtained. This method, and all others which 
I can describe, repose on this fact, that the elements of sulphuric 
acid and nitrous acids, being placed in contact, determine the 
formation of white crystals. Now, how can the existence of 
sulphurous acid in a body thus formed be admitted? Is it pos- 
sible that the nitrous acid deoxidizes the sulphuric acid? There 
is, however, a radical identity between these crystals and those 
which have been particularly described in this paper; for the 
first dissolve without decomposition in sulphuric acid in the 
cold, and when heated the crystals become coloured precisely as 
the anhydrous compound. This last, dissolved in the proper 
quantity of sulphuric acid, crystallizes on cooling. The crystals 
offer very diversified forms, but the arrangement represented in 
fig. 2. can always be distinguished. Now, in preparing crystals 
by all the various processes, and fusing them, they affect pre- 
cisely the same form on crystallizing. 
To these arguments it may be replied, in the first place, that 
the body under consideration is the most stable compound which 
ean be produced in the reaction. Indeed, the substance SO, 
+ N O,, which cannot be exhibited except in combination with 
SO, O, reminds us of a combination, the discovery of which is 
due to M. Henry Rose, and which he has designated by the 
name of sulphate of perchloride of sulphur; representing its 
composition by the formula S Cl,+ 5SO,. The analogy of 
these two combinations will be rendered more apparent by wri- 
ting this last formula in the manner S, Cl, O,,, or S, Cl, O,, or 
lastly, 
S$ O,, Cl 
SO. ©. 
which exactly corresponds with 
SO,, N O, 
S O,, O. 
_ It might be expected, according to this manner of viewing 
it, that under the influence of anhydrous sulphuric acid, dry 
sulphurous and hyponitric acids should unite without mutual 
decomposition ; this has, in fact, been verified in the following 
manner :— 
In one of the double bent tubes employed in the preparation 
of the substance (fig. 1.), the vapour of anhydrous sulphuric 
acid was condensed. Liquid sulphurous and hyponitric acids 
