4o8 



THE POPULAR SCIENCE MONTHLY 



CORRESPONDENCE. 



"WASTED FORCES." 

 Messrs. Editors. 



A RECENT issue of your " Monthly " con- 

 tained a criticism, by Mr. J. W. Cloud, 

 of some points in my paper on " Wasted 

 Forces " published in yours of July, in which 

 it is alleged I am in error. I had intended 

 replying at once to this criticism, but have 

 been prevented until now by circumstances. 

 My critic makes the point that, in my at- 

 tempt to account for the low duty of the 

 steam-engine, I have ignored one of the 

 chief elements of the problem, namely, " the 

 low efficiency of the medium." 



To this criticism I beg to reply that for 

 the purpose of showing the margin for pos- 

 sible improvement in engines, whether de- 

 riving their motive power from steam or any 

 other medium, the only elements entering 

 into the problem are those I have named in 

 my article, to wit: 1. The amount of work 

 that should be given out, and which is the 

 equivalent of the number of heat-units im- 

 parted to the medium by the combustion of 

 the fuel ; and, 2. The amount of work ac- 

 tually realized. The difference is the loss, 

 and this loss is due not to " the low efficiency 

 of the medium," but to the low efficiency of 

 the machine. 



To make myself quite plain, I will add 

 my understanding of what a perfect engine 

 should be. The perfect engine, hypothcti- 

 cally stated, is an apparatus that will utilize 

 all the heat-units evolved by the complete 

 combustion of fuel in the generator in the 

 generation of steam ; that will use all the 

 steam that the generator supplies, convert- 

 ing it into water in so doing ; that will put 

 that water back again into the generator 

 whence it came ; and that will give out dur- 



ing a given time an amount of work that 

 shall be the equivalent of the number of 

 heat -units that have disappeared during 

 that time. 



I confess my inability to perceive what 

 the question of latent or sensible heat has 

 to do with the problem ; and, in view of the 

 fact that my critic has taken the pains to 

 warn the readers of the " Monthly " that my 

 statements might give false impressions, I 

 wish to reaffirm the strict correctness of the 

 theoretical view I have advanced ; and to 

 assert, my critic to the contrary notwith- 

 standing, that the difficulties in the way of 

 increasing the duty of the steam-engine to 

 a very close approximation to that which 

 theory calls for are purely of a mechanical 

 nature, and therefore not beyond the power of 

 mechanical science to overcome. 



This is the gist of the matter, and Itake 

 direct issue with my critic in denying that 

 the element of the high latent as compared 

 with the low sensible heat of the medium, 

 whether it be steam or any other, that is 

 used, is the impassable barrier to future im- 

 provement that he would make it appear. 



On another point that my critic makes, 

 namely, that I throw too much of the re- 

 sponsibility of the low duty of the steam- 

 engine on the generator, I have no hesita- 

 tion, after further inquiry into the subject, 

 to yield to him, and to admit that fifty per 

 cent, would have been nearer the truth than 

 twenty-five per cent., which I gave in my pa- 

 per. I gave that figure simply as an opin- 

 ion derived from a practice that is exceed- 

 ingly variable and complex, and therefore 

 liable to wide differences of result. 

 Very truly, 



William H. Wahl. 



EDITOR'S TABLE. 



RECEPTION OF THE "^ DATA OF ETHICSr 



THE science of morals is as legiti- 

 mate as the science of rocks, and 

 far more important. When, therefore, 

 a new step has been taken in its de- 

 velopment and exposition, we are inter- 

 ested in all the indications of its rec- 

 ognition. The reception of Spencer's 

 " Data of Ethics" shows on the whole 



a very marked progress of religious 

 liberality. There is much protest but 

 large concession, while the expressions 

 of intelligent appreciation and cordial 

 sympathy are many and emphatic. We 

 give some illustrations, with comments, 

 of the manner in which his position is 

 now regarded. 



We certainly never expected to live 



