the Water of Kilburn Wells. 
117 
EXPERIMENT IV. 
On adding 42 drops of the purest concentrated vitriolic acid 
to two pounds of the Kilburn water, it became perfectly clear, 
and some air was disengaged ; this air rendered lime-water 
turbid . 
Experiment. — A few drops of pure and nitrous acid were 
dropped into a tumbler full of the water ; the smell of hepatic 
air was diminished, and hardly any precipitate formed. From 
this experiment it becomes probable, that the water contains 
no liver of sulphur, but only hepatic air : from the appear- 
ances on adding the vitriolic acid, may be inferred, that this 
water contains little calcareous earth, and no terra ponder os a. 
EXPERIMENT V. 
In order to ascertain whether the hepatic air really existed 
in the water, or whether the appearances which made this pro- 
bable might not arise from the air of marshes, which will oc- 
casionally imitate the other, I filled three quart bottles with 
distilled water, and nearly emptied them just over and al- 
most in contact with the spring. The air, which of course took 
the place of the water I had emptied, was subjected to the 
following experiments : 
(a) Apiece of white arsenic being immersed in it, its sur- 
face soon became yellow. 
(h) A solution of lead being put into one of these bottles, 
the precipitate which was formed soon became of a blackish 
brown colour. 
( c ) A solution of silver being put into the third bottle, the 
precipitate formed was blackish. All these are proofs of the 
existence of the hepatic air. 
