184 , On Iodine. {Serr 
the arrival of our English philosopher there.” It is Sir H. Davy of 
whom they speak. Soon after showing iodine to Davy, and com- 
municating to him the result of his experiments, M. Clement read 
his note to the Institute, and concluded by announcing that I was 
going to continue the subject. On the 6th of December I read a 
note to the Institute on the subject, which was printed in the Mo- 
niteur of the 12th of December, and afterwards in the Annales de 
Chimie, Ixxxviii. 311. Jt is needless to say here that the results 
which it contained determined the nature of iodine, and that I 
there established that it is a simple body analogous to chlorine. 
Nobody hitherto has disputed that I was the first who discovered the 
nature of iodine: and it is certain that Davy did not publish his 
results till more than eight days after having known mine. 
—<— 
Nore A. 
When we make iodine, an alkaline oxide, and water, act upon . 
each other at once, there is formed in general an iodate and 
hydriodate, or, if you choose, an ioduret. The oxygen which 
acidifies the iodine may be furnished either by the alkaline oxide or 
by the water. Let us examine which of these two in all probability 
furnishes it. When we employ potash, we may admit that it is it 
which furnishes the oxygen to the iodine ; for as iodine disengages 
oxygen from the potash at a red heat, we may conceive that the 
same thing takes place at the ordinary temperature by means of 
water ; especially if we consider that here two products are formed, 
iodate and ioduret, and that there are of consequence two forces 
which tend to decompose a portion of the potash. The same thing 
may be said of soda, from which iodine likewise separates the 
oxygen at a red heat; and of all the oxides in which the oxygen is 
but weakly condensed. But is this necessarily the case also with all 
the other oxides? JTodine does not disengage the oxygen from 
barytes, strontian, lime, and magnesia, even at a very high tem- 
perature ; and this circumstance, while it renders it more difficult 
to conceive the decomposition of a part of these alkalies by means 
of water, although there is then the concurrence of two affinities, 
renders very probable the existence of a limit beyond which the 
united affinities of the iodine for the metal, and the iodic acid for 
the metallic oxide, cannot overcome the affinity of the metal for 
oxygen. In this case the water may be decomposed ; and J have no 
doubt that this is the fact. On the supposition that there exist only 
iodurets in solution in water, and no hydriodates, it is a necessary 
consequence that the oxygen is furnished to the iodine by the me- 
tallic oxide. But if there exist hydriodates, then the oxygen will 
be furnished by the water in all the cases in which they are formed. 
The question then reduces itself to this—do hydriodates exist ? We 
shall examine it. But as it is the same with the hydro-chlorates, 
which are better known, we shall turn our more particular attention 
to them. 
