The cock _q_ is then shut, _p_ is
opened, and the analytical examination proper is begun by discharging the
several carbide receptacles by turning the winch _i_. After the
first receptacle has been discharged, five or ten minutes are allowed to
elapse for the main evolution of gas to occur, and the cock _p_ is
then shut. Weights are added to the gasholder until the manometer
_n_ gives the zero reading; the position of the gasholder C is then
read off, and readings of the barometer and of the thermometer _o_
are made. The gasholder is then emptied down to the zero mark by closing
the cock _p_ and opening _q_. When this is done _q_ is
closed and _p_ is opened, and the winch _i_ is turned until the
contents of the next carbide receptacle are discharged. This procedure is
followed until the carbide from the last receptacle has been gasified;
then, after waiting until all the carbide has been decomposed, but in any
case not less than two hours, the position of the gasholder is read, and
readings of the barometer and thermometer are again taken. The total of
the values obtained represents the yield of gas from the sample
examined."
The following example is quoted:
Weight of the tin received, with its contained |
carbide .
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