THEORY OF THE STEAM ENGINE. CXLV. 
The work on this engine has since been carried on by others, 
and it is hoped that in the near future sufficient experimental 
results will be available for a complete investigation of the mode 
of variation of the thermal losses in this particular type of engine. 
Meanwhile from the results already obtained, Mr. A. L. Rice has 
deduced the formula for cylinder condensation already quoted 
C (r-1)™ 
See Be 
where “(C,” ‘m” and “k” are functions of the pressure. 
Sufficient information is not yet available to allow of a thorough 
criticism of this formula, but in the account published by its 
author, the statement is made that it has been found to closely 
accord with the results of tests ona large variety of engines work- 
ing under widely differing conditions, and undoubtedly the 
Principle adopted in the construction of the formula, of using 
variable functions of the different working conditions, is the 
correct one. 
Probably sufficient has now been said to show that a consider- 
able amount of experimental work will still be necessary before 
the conditions affecting the heat wastes in a cylinder are 
thoroughly investigated. When this investigation is complete 
the material will be at hand for an exhaustive theory of the 
steam engine. 
Discussion. 
Mr. Hoventon said that Mr. Barraclough’s paper, although a 
- Most valuable contribution, was not one which could be readily 
discussed. The statement made in the paper that only about 10 
per cent of the heat supplied to the cylinder could be turned into 
useful work was generally true—in some engines 15 per cent, is 
utilised—but the reason of this arose from no fault of the engine 
but of the medium used to convey the heat of the coal to the 
cylinder. In converting water into steam, that is into gas, a large 
amount of heat is expended in overcoming the internal resistance 
to evaporation and this is responsible for the loss as it is impossible 
