Polytechnic Association. 585 



" I think that I may say, first, that the theory at present accepted, 

 and which it would be considered somewhat heretical to deny, is this, 

 that a certain amount of chemical change corresponds and is inter- 

 changeable with a certain amount of heat and electric force ; and that 

 this heat again corresponds and is interchangeable with a certain 

 amount of work or mechanical energy. This is, no doubt, a very 

 pretty, plausible and apparently philosophical theory ; but is it true ; 

 or how far is it true ? This is the question I now propose to consider, 

 with a special view to the further question of the economy of electro- 

 dynamic engines." 



Ii there is any one feature peculiar to modern science, it is that it is 

 cumulative. Plato, Pythagoras or Socrates were men as capable as 

 any of the present day ; but our knowledge vastly exceeds theirs, 

 because standing upon their shoulders we can see further than they 

 did. It becomes important, therefore, if a single stone in the foun- 

 dation of our great system of science is suspected of being unsound, 

 that we should determine whether it is so or not. And I propose to- 

 night to show you the errors which Mr. Highton has made, and that 

 we have, therefore, no rea'son to abandon the laws from which we have 

 come to the conclusion that in the present state of our knowledge 

 electro-magnetic engines are not and cannot be made economical. 



The experiment of Mr. Highton is this : With a certain battery, 

 connected with a certain electro-magnet, he supports a certain weight. 

 He then connects the same battery with four similar magnets, the wire 

 dividing and each section passing around two magnets, and it supports 

 double the weight. He concludes that that series can be multiplied 

 to any extent, and thus that the power can be increased ad infinitum. 

 Lest I should be thought to be caricaturing his argument, I will quote 

 his exact words from the Chemical News of October 28. He says : 



" In trying experiments on this subject the author found that the 

 magnetic power evolved by a given battery could be increased without 

 limit. This was the case both in theory and practice. * * * By 

 simply increasing the length and section of the wire, the magnetic 

 power may be increased without limit. * * * Enough has been 

 said to set aside the a priori argument against electro-dynamic engines 

 — namely, that as a pound of zinc can only produce a certain amount 

 of heat, and a pound of carbon, which is much cheaper, can produce 

 more heat, therefore electro-dynamic engines can never compete with 

 steam engines. In fact, it is a question of prime cost of machinery 

 and skill in construction, and not of cost of working." 



Now, if you examine the conditions of Mr. Ilighton's experi- 



