WASTED FORCES. 293 



tries are quite separate, as you may know the showing would he much 

 more favorable. 



It will be instructive, I think, to trace out the causes of the great 

 waste of power that I have just pointed out, and to see if there are no 

 means of remedying them. And if you will follow me, they will be 

 very apparent. 



The first and greatest source of loss resides in the difficulty I may, 

 I think, safely say the impossibility of burning solid fuel economi- 

 cally in any form of furnace that has yet been devised ; and this prime 

 difficulty is an unanswerable argument in favor of the substitution of 

 liquid or gaseous fuel for steam-making as for other purposes. Let us 

 analyze the matter : The buyer of coal purchases at the outset at least 

 10 to 15 per cent, of non-combustible and useless material with every 

 pound of coal, in the form of ash ; while at least 5 per cent, more of 

 the coal is lost by falling through the grate-bars in the form of the 

 dust or partially burned fragments that find their way into the ash-pit 

 unutilized. If even now, with so much waste as I have just indicated, 

 we could really turn to useful account the whole of the thermal effect 

 of the 85 per cent, or 80 per cent, of the combustible that we have 

 left, we might well be content ; but such is far from being the case. 

 The furnace gases can not, by any possible mode of constructing boil- 

 ers, be retained long enough in contact with the steam-generator to 

 yield up all their heat, and they are thrown out from the chimney fre- 

 quently at a temperature of 800 Fahr. ; and, what is still worse, their 

 combustion is frequently so imperfect that they carry off with them 

 out of the chimney great volumes of unburned carbon in the form of 

 smoke ; the cold air with which the fuel is fed, and which must be- 

 come highly heated before it will begin to combine with the fuel, and 

 which abstracts this heat from the glowing coals through which it 

 passes, is another serious item of loss, which is intensified by the 

 necessity of frequently opening the furnace-doors when large volumes 

 of cold air rush into the fire-space ; and, lastly, the conduction and 

 radiation of heat from the generator to surrounding objects complete 

 the category of losses. Summing up all the items of loss in the steam- 

 generator, it is probable that with the best forms of boilers which it has 

 been possible to construct, not more than 25 per cent, of the theoretical 

 thermal effect of the fuel is utilized in the generation of steam ; and 

 of this 25 per cent., from 5 to 10 per cent, is lost somewhere on the 

 passage of the steam from the boiler to and through the engine by 

 condensation in steam-pipes, and friction of the machinery, leaving us 

 but 15 or 20 per cent, actually realized in practice. I beg that you 

 will not think that I have purposely made the case of the steam-engine 

 worse than it is ; for, so far from doing so, I have actually made out 

 the most favorable possible showing for it, by selecting for my exam- 

 ple the best practice of the best makers. 



Much of this loss, possibly the half of it, I have no hesitation in 



