49^ *S/r H. Dayy*s further Experwients 
potassamey or \ode of potassium, is fused with boracic 
acid, there is a perfect mixture of the two bodies. In my first 
researches on this mixture, I conceived that they entered into 
chemical union, apd formed a violet coloured glass, and that 
the acid property of the boracic acid was neutralized by the 
new compound ; but I since find that the violet colour of the 
glass is owing to the developement of iodine, and when the 
application of heat is long continued, much iodine is disengaged, 
and the colour of the glass changes to olive, and borate of 
potassa is formed. When the glass is dissolved in warm water, 
an olive coloured powder separates, soluble when boiled in the 
caustic alkalies, so that there is great reason to suppose that it 
is boron, and that the boracic acid is decomposed by the attrac- 
tion of the potassium combined with the iodine for oxygene, 
assisted by the tendency of iodine to assume the elastic state. 
I fused the neutral compound of iodine with silica ; no change 
was effected when the experiment was made in close vessels, 
but when the mixture was exposed to air, and intensely heated, 
a little iodine was evolved, some potassa formed, and some 
silica dissolved by it. 
3. On other acid compounds of Iodine. 
1. I have made several experiments on the combination of 
iodine and chlorine, obtained by admitting chlorine in excess 
to known quantities of iodine in vessels exhausted of air, and 
repeatedly heating the sublimate. 
Operating in this way, I find that iodine absorbs less than 
one third of its weight of chlorine. 
The compound of iodine and chlorine is a very volatile sub- 
stance, and in consequence of its action upon mercury, I have 
