under the same boiler, but with a different furnace, and taking 1 lb. of
gas to be 2.35 cubic feet, the water evaporated was found to be 20.31
lb., or 83.4 per cent. of the theoretical heat units were utilized. The
steam was under the atmospheric pressure, there being a large enough
opening to prevent any back pressure, the combustion of both gas and coal
was not hurried. It was found that the lower row of tubes could be
plugged and the same amount of water could be evaporated with the coal;
but with gas, by closing all the tubes--on the end next the stack--except
enough to get rid of the products of combustion, when the pressure on the
walls of the furnace was three ounces, and the fire forced to its best,
it was found that very nearly the same results could be obtained. Hence
it was concluded that the most of the work was done on the shell of the
boiler."

In no other way can I give the members of the Iron and Steel Institute so
much information in regard to this new fuel as by including in this paper
a very able communication from the chief chemist at our Edgar Thomson
Steel Works, Mr. S.A. Ford, who is to-day the highest authority upon the
subject:

"So much has been claimed for natural gas as regards the superiority of
its heating properties as compared with coal, that some analyses of this
gas, together with calculations showing the comparison between its
heating power and that of coal, may be of interest. These calculations
are, of course, theoretical in both cases, and it must not be imagined
that the total amount of heat, either in a ton of coal or 1,000 cubic
feet of natural gas, can ever be fully utilized. In making these
calculations I employed as a basis what in my estimation was a gas of an
average chemical composition, as I have found that gas from the same well
varies continually in its composition. Thus, samples of gas from the same