82 Professor Alex. B. W. Kennedy [April 21, 



WEEKLY EVENING MEETING, 

 Friday, April 21, 1893. 



David Edward Hughes, Esq. F.E.S. Vice-President, in the 



Chair. 



Professor Alex. B. W. Kennedy, F.E.S. M.B.I. 



Possible and Impossible Economies in the Utilisation of Energy. 



The importance of the subject is not difficult to understand if you 

 realise the enormous results — so large as to be even of national 

 interest — which depend upon what can and what can not be done in 

 the way of utilising energy. Economy in energy may mean wealth 

 and prosperity to a nation ; waste in energy may mean diminished 

 commerce and general depression. 



As an engineer, I am bound to take my stand at once on the firm 

 basis that practically nothing is impossible except perpetual motion. 

 In essence all the things which I shall have to characterise as impos- 

 sible are really perpetual motions, or what is the same thing, attempts 

 to get more out of something than there is in it. 



It is familiar to even the least mechanical in this room that there 

 are, in Nature, vast — I dare not say inexhaustible — sources from 

 which we can obtain energy by certain more or less familiar processes. 

 I say " obtain " energy, using the most familiar expression, but per- 

 haps the word is not a very happy one. We require energy to light 

 lamps, to smelt metals, to drive factories, to pull trains, but in no case 

 do we obtain it ready made as we draw water from a well. There is 

 plenty of it in existence, plenty to be had, but to get it in the form 

 in which we want it we have always to transform it from some other 

 form to the required one. 



There is in every electric lighting station in this city, for instance, 

 first a transformation of the natural energy of chemical combination 

 into heat, then the transformation of heat energy into mechanical 

 energy in a steam engine, then the transformation of the mechanical 

 energy into electrical energy in the dynamo, and lastly the trans- 

 formation of electrical energy into light, and also very largely back 

 again into heat, in the lamp. 



Often the transformations are not so numerous as in this case, but 

 they always exist to some extent, and all the possibilities and impos- 

 sibilities of which I have to speak are practically related to some or 



