220 PROF. G. MACLOSKIE, D.SC., LL.D., ON 



energy are changing into light or heat, and Hght and heat 

 are being dissipated into space, with a tendency in the end to 

 equalize tlie temperature of the universe. While energy is 

 changing from one form to another, as while heat is passing 

 between objects of unequal temperature, it may be made to 

 do work which is measurable in units. A machine is a con- 

 trivance for getting some kind of motion or work out of it 

 in the course of its transformations ; and the mechanical con- 

 ception of nature signifies that aJl the physical movements 

 and phenomena of the universe have been derived from the 

 interaction of the matter and energy which are its constituent 

 factors. 



This theory may be held in a theistic or an atheistical 

 sense. The atheist may hold that the physical world is the 

 only world, and that nothing else exists. The theist may 

 hold that even admitting all that the mechanical theory 

 asserts, there are ethical and orderly phenomena in nature, 

 not coming under the measurable categories of matter or 

 energy, yet proving that there is close to us an extra- 

 physical world, with extra-physical beings, and that there is 

 a God before all and over all. 



Though energy is indestructible, its constant dissipation 

 is a continual loss for all practical purposes. Fifty years ago 

 scientific men supposed that the Avorld had been going on at 

 the present rate from everlasting. Lyell admired the 

 " sublime " view of the past history of our globe being an 

 eternal round of similar cj^cles of geological formations, 

 never beginning and never to end; and this was the 

 scientific view of cosmogony taught in the text-books and 

 encyclopedias. But it is now omitted as belonging to 

 exploded science ; since it was shown by Thomson that our 

 universe probably had a beginning, and with equal probability 

 is moving towards its conclusion. This depends on the 

 puzzling fact that whilst many processes in nature can be 

 reversed, by calling in new energy from the environment, 

 the mechanism of nature as a Avhole is not reversible. If a 

 plant has its starch converted into sugar which is dissipated 

 through the sap, it is able to reconvert the sugar and collect 

 it again as starch. But why the cosmos is not a reversible 

 machine we cannot tell. Clerk Maxwell somewhere suggests 

 that as heat is only the general or average result of molecular 

 movements, an inability to controvert the individual molecules 

 puts the recovery of the general result beyond our reach. 

 But how does it come that the process is never reversed 



