256 
Selected Articles. 
action of the air; the oxide of iodine being dissipated in the 
same way as nitrous acid gas loses its colour by the volatili- 
zation of the oxide of azote. 
This combination does not take place in all proportions, 
but in definite quantities ; for, if oxide of iodine in excess be 
added, it is decomposed, and the iodine precipitates. The 
author thinks that this phenomenon can only be explained, by 
admitting, that when the dose of oxide of iodine is sufficient, 
the iodous acid which forms immediately, decomposes the ox- 
ide, by depriving it of its oxygen, and is itself again convert- 
ed into iodic acid ; and, in fact, during the precipitation of the 
iodine, the yellow colour of the liquid disappears. This M. 
Sementini thinks is a strong proof, of the intimate union 
which takes place between the two compound substances, 
each of which, evidently acts on the other. He has prepar- 
ed iodous acid by combining one hundred parts of solid iodic 
acid dissolved in water with three parts of oxide of iodine of 
the greatest density. 
Although the analogy which exists between nitrous and 
iodous acid appears to intimate that this latter would not form 
iodites, as nitrous acid forms nitrates and not nitrites, he has 
combined iodous acid with ammonia; the union took place 
without the disengagement or precipitation of iodine, although 
the yellow colour disappeared at the moment of the combina- 
tion of the acid with the alkali. The solution on evaporation, 
furnished a salt differing from the iodate of ammonia in many 
particulars. 
The iodite of ammonia is less efflorescent, its taste is less 
saline, it detonates when heated in an open vessel, disengag- 
ing vapours of iodine for a long time ; its colour is of slight 
green. The solubility of the two salts is very different, the 
iodite being soluble in one half less water than is required to 
dissolve the iodate. M. Sementini has not given an exact 
analysis of these two salts, but having detonated equal quan- 
tities of each in a proper apparatus, he observed the follow- 
ing results : a production of a much greater quantity of aque- 
ous vapour from the iodite, and also a greater residuum of 
iodine. — Journ. de Pharm. 
