C 169 3 
X. On the fallacy of the experiments in which • water is said to 
have been formed by the decomposition of Chlorine . By Sir 
H. Davy, LL.D.F.R.S. 
Read February 12, 1818. 
Some experiments have been lately communicated to the 
Royal Society of Edinburgh, from which it has been inferred, 
that water is formed during the action of muriatic acid gas on 
certain metals, and consequently, that chlorine is decomposed 
in this operation. 
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 theore- 
tical speculations on such an occasion, will be unnecessary; 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 
action 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 being one of double affinity , the hydrogen of the mu- 
riatic acid unites to the oxygen of the oxide, and the chlorine 
combines with the metals. 
A copious dew was formed by passing muriatic add gas 
through flint glass tubes red hot, and a less copious dew, by 
passing it through green glass tubes. In the first instance, 
mdcccxviii. Z 
