to have been formed by the Decomposition of Chlorine. 327 
In repeating those experiments, I have ascertained, that the 
water is derived from sources not suspected by the authors, and 
that their conclusions are unfounded. To take up the time of 
_ the Society by long experimental details and theoretical specula- 
tions on such an occasion, will be unuecessary; I shall therefore 
only transiently mention the sources of error, and demonstrate 
_ their operation by two or three examples. 
When muriatic acid gas is passed through flint glass tubes 
heated to redness, a small quantity of water is formed by the ac- 
on of the gas on the oxide of lead in the glass, and a smaller 
quantity by its action on the alkali of the glass: the process be- 
ing one of double affinity, the hydrogen of the muriatic acid 
_ unites to the oxygen of the oxide, and the chlorine combines with 
the metals. 
__ A copious dew was formed by passing muriatic acid gas through 
flint glass tubes red hot, and a less copious dew, by passing it 
through green glass tubes. In the first instance, the glass be- 
came opaque, and gained a pearly lustre, and a combination of 
chlorine and lead sublimed from the hotter into the colder part 
_of the tube. In the second, the surface of the tube became 
slightly opaque, but no sublimate was:formed. 
When fine clean iron wire was introduced into such tubes, and 
_ made red rot, and muriatic acid gas passed over it, no particular 
precautions being taken to free the tubes from common air, 
much more water appeared ; but this excess of water principally 
owed its existence to the combination of hydrogen disengaged 
from the muriatic acid gas by the iron with the oxygen of the 
common air. I say, principally, because an inappreciable quan- 
tity must have been deposited from the vapour of hydrated mu- 
riatic acid in the muriatie acid gas. This was proyed by filling 
the whole apparatus with hydrogen in another experiment, and 
_generating the muriatic acid gas in a retort filled with hydrogen, 
when the water produced was no more than might have been 
_ expected from the action of the muriatic acid gas on the oxide 
_of lead and alkali in the glass. I give the details. Above twenty- 
one grains of the first combination of chlorine and iron were 
formed; the quantity of moisture collected by bibulous paper, 
and which was a strong acid solution of the proto-muriate of 
iron, amounted to Jess than half a grain, and of this not more 
than two-thirds could have been water. Now, if chlorine had 
been decomposed in this operation, the quantity of water ought 
to have been at least ten times as great. 
~ Thave shown by numerous experiments, that inthe action of mu- 
riatic acid gas upon metals, hydrogen, equal in bulk to half the vo- 
Tume of the gas, is produced; it is therefore evident, that if water 
had been generated by the action of muriatic acid gas on metals, 
X 4 it 
