390 Description of an Eudiometer. 
exclude mercury, some small globules of 
which always remain in the globe when filled 
over that fluid, a metal cap may be cemented 
upon the neck of the vessel (fig. 1.) which, 
after exhausting it by the air pump, may be 
filled with gas from a receiver furnished with 
a proper stop-cock. An apparatus of this 
kind was used in the experiments on muviatic 
and oxymuriatic acids, which I have de- 
scribed in the Philosophical Transactions for 
1812; and may be advantageously applied to 
other purposes. 
