The 'holding cell' was a lavishly appointed 700 square foot room.
The maximum rate of combustion may be as much as so lb of coal per square foot of grate per hour, and in exceptional cases even a greater rate than this has been maintained.
A few experimental results are set forth in Table XX., from which it will be seen that with a relatively low rate of combustion, a rate which denotes very light service, namely lb of coal per square foot of grate per hour, the efficiency of the boiler is %, which is as good a result as can be obtained with the best class of stationary boiler or marine boiler even when using economizers.
This high mean pressure cannot be maintained for long, because as the speed increases the demand for steam per unit of time increases, so that cut-off must take place earlier and earlier in the stroke, the limiting steady speed being attained when the rate at which steam is supplied to the cylinders is adjusted by the cut-off to be equal to the maximum rate at which the boiler can produce steam, which depends upon the maximum rate at which coal can be burnt per square foot of grate.
If C is the number of pounds of coal burnt per square foot of grate per hour, the calorific value of which is c B.Th.U.
