XX President's Address for the year 1887. 



direction did not commence until some years had elapsed 

 after Queen Victoria's coronation. Similarly other forms of 

 energy, such as electricity in motion, sound, &c., can be 

 obtained in return for so much mechanical work. Energy, 

 including all these various powers as special manifestations, 

 is constant in quantity. It may be called the currency of the 

 universe, capable of being translated into various forms, but 

 capable as a whole of neither increase or decrease. This 

 doctrine is fatal to the hopes of that race of enthusiasts, even 

 now by no means extinct, who endeavour to discover what 

 is popularly called perpetual motion, but which really means 

 an inexhaustible source of mechanical power. The proper 

 appreciation of the doctrine of the conservation of energy at 

 once shows that to hope to create or increase mechanical 

 work by the use of complex arrangements of levers, springs, 

 and w^ieels, is just as unreasonable as to hope to create or 

 increase the quantity say of a fluid like water by simply 

 passing it through a complex arrangement of pipes or 

 passages— a project which, as far as I am aware, no one has 

 yet been insane enough to expend his time and labour upon. 



This great law is expressed thus by the eminent physicist, 

 Clerk Maxwell : — '' The total energy of any body, or system 

 of bodies, is a quantity which can neither be increased or 

 diminished by any mutual action of such bodies, though it 

 maybe transformed into any one of the forms of which energy 

 is susceptible," and its utility in guiding both the scientific 

 investigator and the practical mechanician is beyond all 

 expression. 



And, lastly, evolution — the grand doctrine that every thing 

 is passing steadily through regular and orderly stages of 

 growth and development — first dimly hinted at by early 

 Greek thinkers, touched now and then by the scientists of 

 the seventeenth and following centuries, but never worked 

 out until the present half century, in which the united labours 

 of astronomers, geologists, and biologists have impressed it 

 so deeply upon the public mind, that whether it be in news- 

 paper, sermon, lecture, or ordinary conversation, our thoughts 

 und words are tinged and flavoured with it. 



