414 Experiments on the variable « stion of the Electric Column. 
precipitated the liquor by lime ater in a long and narrow 
bottle. There was an abundant and flaky precipitate. The 
bottle was corked and luted, and next day the water was de- 
canted. The precipitate was in a heap, and adhering to the 
bottom of the bottle: it was filled with mereury, and turned up- 
side down in the trough; acetie acid was introduced, diluted with 
about an equal part of water. A brisk effervescence took place. 
The gas disengaged was passed into a smaller bottle, and it was 
several times passed from one bottle to another through water, in 
order te wash it, and free it from the little acetic acid with which 
it might have been mixed. ‘This gas was without any sensible 
- smell: it extinguished combustion, reddened turnsole tincture, 
and precipitated lime water. It was not very soluble in water, 
but nevertheless entirely absorbable by it: it was carbonic acid. 
There was charcoal, therefore, in the ethereated liquor. We 
cannot suppose that this carbonic acid was owing to carbon 
foreign to the liquor: every precaution had been taken to re- 
move every cause of error. In short, we shall see other proofs 
of this in the course of this paper. The liquor from which the 
carbonic acid had been precipitated by the lime water was pre- 
cipitated by the water of barytes. The precipitate formed was 
sulphate of barytes. 
The blackish matter found in the tube after the operation 
was therefore sulphuret of copper mixed with charcoal. At 
least it is not probable that these three bodies are united: and 
if we may be permitted to refer it to the appearance, we might 
even affirm that the carbon was deposited on the surface of the 
sulphuret of copper, which seemed really to have been strewed 
with it. 
[To be continued. ] 
LXXXIX. Experiments on the variable Action of the Electric 
Column. 
London, June 13, 1814. 
Sirs, oa HAVE the pleasure to inclose you an account of some 
experiments on the action of the electric column, communicated 
to me by an electrician of great promise, whose scrupulous at- 
tention to the essentials .of accurate experimental inquiry it has 
frequently afforded me pleasure to observe. 
' It will be seen that these experiments render the conclusion 
drawa by Mr. Howldy, from the ingenious experiments related 
at page 241, vol. xlili. of your Magazine, rather exceptionable ; 
and that they tend to confirm the opinion I have advanced in the 
** Elements of Electricity,” page 478, that variations of tem- 
perature have the most evident influence of any known cause on 
the action of the electric column. 
T have 
