089 gramme. Similarly,
the 68.83 pounds which constitute the weight of 1000 cubic feet of moist
acetylene, as measured under British standard conditions, are composed of
almost exactly 68 pounds of dry acetylene and 0.83 pound of water vapour.
The data required in calculating the mass of vapour in a known volume of
a saturated gas at any observed temperature and pressure, _i.e._, in
reducing the figures to those which represent the dry gas at any other
(standard) temperature and pressure, will be found in the text-books of
physical chemistry. It is necessary to recollect that since coal-gas is
measured wet, the factors given in the table quoted in Chapter XIV. from
the "Notification of the Gas Referees" simply serve to convert the volume
of a wet gas observed under stated conditions to the equivalent volume of
the same wet gas at the standard conditions mentioned.
HEAT OF COMBUSTION, &C--Based on Berthelot and Matignon's value for the
heat of combustion which is given on a subsequent page, viz., 315.7 large
calories per molecular weight of 26.016 grammes, the calorific power of
acetylene under different conditions is shown in the following table:
Dry.
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