82 MISCELLANY. 
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Action of Sulphurous Acid on Hyponitrous Acid — Crystals in the Cham- 
bers of Lead — Theory of the formation of Sulphuric Acid. By M. F. de la 
Provostaye. Translated by same. — Notwithstanding the repeated at- 
tempts of chemists to determine the nature of the crystals in the chambers 
of lead, their composition is yet uncertain; some look upon them as a 
combination of nitrous and sulphuric acid and water; whilst M. Dumas, 
guided by numerous analogies, supposes that for their existence there is 
a direct combination of sulphuric and hyponitrous acids. M. de la Pro- 
vostaye undertook to decide this important question; he has observed that 
sulphuric and hyponitrous acids (which have only now been made to re- 
act upon each other) combine together in producing a new compound, the 
more interesting, since it throws great light upon the crystals of the leaden 
chambers, and upon the theory of the formation of sulphuric acid. 
This new substance dissolves in all proportions in hydrated sulphuric 
acid, and gives in very extended limits, crystallizable combinations. 
The crystals of the chambers of lead, which had been hitherto looked up- 
on as identical, are really nothing but mixtures, in variable proportions, 
of this substance with anhydr and hydrated sulphuric acid, which explains 
the difference of the results of their analyses. Finally, the author admits 
that these crystals are never formed but under the influence of anhydrous or 
hydrated sulphuric acid ; and that water, when it is free, always tends to 
decompose them. 
New Method of Analysing Sulphurous Waters, and the re-action of Iodine 
with Sulphydric Acid— The Sulphydrometre. By M. Alphonse Dupas- 
quier, Professor of Chemistry at Lyons. Extracted from the Annals of 
Chemistry and Physic. By A. D. Chaloner, M. D Having un- 
dertaken to write a full account of the fine institution which has been 
founded near the Allevard Spring, (Isere,) in the midst of the magnificent 
landscapes of the valley of Graisivandan, M. Dupasquier has occupied 
himself, carefully, with the analysis of the sulphurous waters which these 
springs abundantly supply. He has studied it thoroughly, and his inves- 
tigations have led him to the discovery of a process as simple as curious ; 
to recognise and prescribe the exact quantity of/ree or combined sulphydric 
acid in mineral waters. The tincture of iodine being poured into a fluid 
mixed with sulphydric acid, decomposes this acid entirely, and so instan- 
taneously that it is very easy to ascertain the point where its decomposi- 
tion is finished, and where the iodine combines no longer. Consequently, 
from this observation, which is peculiar to him, M. Dupasquier thought 
that in making use of a Tincture of Iodine, carefully prepared, he could 
from the quantity of Iodine employed to saturate a litre of sulphurous wa- 
ter, subtract the proportion of sulphydric acid, either free or combined, 
which it contains. This foreknowledge was confirmed by experience, 
