1815, ] On Iodine. 131 
ish, and had a strong odour of chlorine, which it lost when heated. 
I observed that during this process a little oxygen was disengaged, 
and the liquid became alkaline. Having evaporated it to dryness, 
I put a certain quantity of the residual saline mass into a small glass 
retort, to the beak of which was fitted a syphon-shaped tube, rising 
to the upper part of the vessel in which the oxygen gas was collected. 
I heated the retort gradually nearly to redness. When no more 
oxygen was disengaged, and when the apparatus had sunk to its 
original temperature, I brought the water in the jar to a level with 
that in the cistern, and withdrew the tube which had conducted the 
gas into the jar. By this method, the oxygen which remained in 
the tube and retort was replaced by an equal»quantity of common 
air. Knowing the quantity of oxygen disengaged, and of chloruret 
remaining in the retort, it was easy, on the supposition that 100 
parts of chlorate contain 38-88 of oxygen, to determine the quan- 
tity of chlorate of potash mixed at first with the chloruret of potas- 
sium, and to calculate the ratio of the one to the other. By this 
method I found that 100 of chlorate corresponded in this mixture 
to 356°5 of chloruret. On suturating with chlorine a solution of 
potash more concentrated than the preceding, the proportion of 
chlorate to chloruret was still found sensibly the same. But when 
the potash was dissolved in about 30 times its weight of water, the 
ratio of the chlorate to the chloruret was then i00 to 512.. It 
results then from these experiments, that the more concentrated 
the potash is, the more chlorate do we obtain relatively to the 
chloruret ; but that the ratio always differs from that of 1 to 3, 
which calculation gives us. As I remarked that the solution. of 
potash, though super-saturated with chlorine, is alkaline, when 
the excess of chlorine is disengaged by heat, I determined the 
quantity of alkali in excess, by saturating it with hydrochloric acid 
of a given strength. By this means I reduced the ratio of 100 
chlorate to 356°5 chloruret, to that of 100 to 349. I observe 
further, that oxygen is disengaged when we heat a solution of 
potash saturated with chlorine, and even during the saturation of 
the potash, according to the observation of M. Berthollet. But as 
I have not determined the quantity, I cannot say what modification 
it will introduce into the ratio. However, as it is evident that on 
decomposing by heat the saline mass produced by the saturation of 
potash with chlorine, we must obtain a quantity of oxygen equal 
to that contained in the alkali, whether chloric acid be formed, or 
any other combination of chlorine and oxygen, we cannot ascribe 
to any other causes than those of which I have just spoken, the 
easily decomposed by heat, and of burning most combustible bodies, depends on 
the chlorine preserving all its caloric when it combines with potash. As a proof, 
it was stated, that during the combination of these two bodies, the temperature 
of the solution did not sensibly vary. This cause cannot be true, for in the ex- 
periment of which I have just spoken, the temperature at the commencement of 
the saturation rose from 64° to 174°. 
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