314 Hare’s Eudiometers, &c. 
transferred to the interior of any other recipient, the gas 
which had entered, or any part of it, may be made to go in- 
to any such recipient by reversing the motion of the wire. 
As the hands are, during this operation, remote from the 
part of the tube which contains the aeriform matter, no ex- 
pansion can arise from this source, and the operation is so. 
much expedited, that there is much less chance of variation 
from any other cause. By taking care to have the surface 
of the gas in the bell glasses below that of the fluid in the 
cistern, the density of the former will be somewhat too 
great, but on bringing the orifice of the gas measurer on a 
level, with the surtace of the fluid in the cistern, the gas, no 
longer subject to any extra pressure, will assutne its proper 
volume, the excess being seen to escape in bubbles. Should 
the tube in lieu of water, be filled with any solution, calcu- 
lated to absorb any gas, of which the proportion, in any 
mixture, is to be ascertained, and if the quantity of absorp- 
tion which can take place while the wire is drawing out, is 
deemed unworthy of attention, we have only to introduce 
the shorter leg of the tube into the containing vessel, as 
above described, and draw out the wire to two hundred on 
its scale, then depressing the point below the surface of the 
fluid in the pneumatic cistern in the usual time with due ag- 
itation, all the gas which the fluid can take up, will disap- 
-pear. The quantity will be represented by the number of 
divisions which remain without the tube, after pushing in 
the wire just so far, as to exclude the residual gas. 
Should it be deemed an object to avoid the possibility of 
any absorption during the time occupied in the retraction of 
the sliding wire, or should it be desired to expose the gas to 
a larger quantity of the absorbing fluid, an additional vessel 
is used, which is of an oblate spheroidal form, with a large 
neck, ground to fit on the shorter leg of a gas measurer, and 
furnished at the opposite apex with a tube, of which the 
bore converges to a capillary opening, surmounted by a 
screw, as already described, on the point of the gas measurer 
simply. This vessel (in shape not unlike a turnip) is filled 
with the absorbing fluid, and the gas measurer being duly 
charged with gas as above described, inserted into it. By 
the action of the sliding wire, the gas is propelled into the 
spheroid, where, by agitation and time the absorption is 
eompleted. Meanwhile the orifice of the spheroid should 
