was 60 deg. and the room at 70 deg., gives 13.7 deg. rise of temperature with the
water at 40 deg. and the room at 50 deg.. Conversely, when the water is at 70 deg.
and the room at 80 deg., a lower result is obtained. The explanation appears
to be this: The gas which escapes from the water was not in existence in
the gaseous form previous to the experiment, and the heat communicated
to the gas being a definite quantity it follows that the more the gas
is cooled the greater the proportion of chemical energy in the shape of
heat will be utilized and recorded as calorific power.

In order, therefore, to make the experiment more simple and workable
at all temperatures, a sample of coal was selected, which should be
perfectly manageable and readily consumed. Appended is an analysis of
the coal employed (from Ebbw Vale, Monmouthshire):

Composition per cent.

Carbon...............................88.33
Hydrogen............................. 5.08
Oxygen............................... 3.28
Nitrogen............................. 0.55
Sulphur.............................. 0.70
Ash.................................. 1.26
Water (moisture)..................... 0.80
-----
100.00

In the following experiments the standard temperature of the water was
taken as 60 deg. F., and as the coal gave 13.4 deg. of rise of temperature, 67 deg.
F. was selected as the standard room temperature. The reason for this
room temperature is obvious, for, whatever heating effect the higher