49* Sir H. Davy’s further Experiments 
nevertheless exist in the fluid, and be decomposable at a high 
temperature, I attempted to obtain it by acting on the triple 
compound of barium by sulphuric acid, and by evaporating 
the fluid obtained at a gentle heat, and suffering it to cool at 
different periods of the process ; but in this manner of operating 
I gained no better results. 
The triple compound of barium is scarcely soluble in 
water. Water that had been boiled upon it gave only a slight 
cloudiness to sulphuric acid, which possibly might be owing 
to some double compound mixed with it: the fluid when 
evaporated nearly to dryness afforded fumes which had the 
characters of those of sulphuric acid, and by a red heat yielded 
iodine, and left sulphate of baryta. 
When the solid triple compound of baryta was heated in 
very small quantities of diluted sulphuric acid, the fluid sepa- 
rated exhibited acid properties, and when gradually evaporated 
left a substance which congealed by cooling, and formed a 
solid of a yellow colour deliquescent in the air, strongly acid, 
and which reddened vegetable blues, and did not afterwards 
destroy them. When strongly heated, the substance afforded 
the same results as the substance procured from the fluid just 
mentioned. 
The residual solid matter obtained by the action of sulphuric 
acid on the triple compound of barium w'as treated a second 
time w'ith sulphuric acid, yet notwithstanding, when heated to 
redness, it yielded iodine in abundance. 
I have repeated these experiments very often, because M. 
Gay Lussac has stated that an acid compound of oxygene 
and iodine may be procured by dropping sulphuric acid into a 
solution of the triple compound of barium ; but the conclusions 
