394. §C. M. Warren on Organic Elementary Analysis. 
which is movable in the cork—turned up.’ The joint at ¢ is 
then disconnected; the end leading to the receiver C tightly 
closed with a piece of glass rod; and a communication estab- 
containing water,—not shown in the figure,—for collecting the 
use, would hardly be compensated for. So that, while I wo 
not, therefore, recommend the use of an additional quantity of 
oxyd of copper, I would also discard the other expedient of col- 
lecting the gas over mercury, or water, etc., unless the saving of 
the surplus oxygen, together with the additional security af 
forded, should be considered of sufficient importance to recom- 
mend it. As the passing through of the gas the second time 
requires no attention after it is once started, and occupies but @ 
short time, during which the operator may attend to anything 
else, I much prefer, for myself, to retain in use that part of the 
Pp 
: t 
operation; especially in the case of volatile liquids. In the 
latter case, the neck of the bulb—which has previously been 
‘provided with one or more scratches on its side near the end— 
3 * That this tube may not e as a siphon, the outer limb is formed by at- 
_taching, near the bend, a flexible tube, of larger bore than that of the alase tube. 
xible tube is preferable to glass, on account of the readiness with which 
> any change of position of the ylass tube, by which it may always 
the receiver underneath; and prevent waste of mercury. 
apts itself to 
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