166 BULLETIN OF THE 



The Import of a " Mechanical" System. — It has been a fond as- 

 sumption of the kiuematist that his all-embracing system of motion 

 as the origin and essence of phenomena, is pre-eminently the " me- 

 chanical " theory of nature as contrasted with a " mystical " or 

 " transcendental " theory. It may be well therefore to consider 

 what is really signified by the term " mechanical." 



Underlying every possible conception of the simplest element of 

 a " machine " are two essential postulates : — first, the necessity of a 

 frame-work invested with the inherent qualities giving it structural 

 consistence and endurance, — and secondly, the necessity of a store 

 of potential energy by which it may be actuated and made opera- 

 tive: since it is an elementary truism that no machine can originate 

 energy. 



The geometrician who ambitious of placing his science on a more 

 rational basis should announce a new system rejecting all assump- 

 tions and establishing its theorems by no propositions which had 

 not first been mathematically demonstrated, might possibly receive 

 the applause of the inexpert, but would not be likely to meet with 

 approbation or encouragement from the great jury of his brother 

 geometers. The physicist who proclaims that he undertakes to 

 build up a system of mechanical laws on a foundation exclusively 

 mechanical, acts in no sense and in no degree less irrationally. 

 Probably his first requirement will be — " given a rigid body." But 



act of our minds." Isaac Newton. [PHncipia. 1687: book in, — con- 

 cluding "scholium.") 



" In fact the causes of all phenomena are at last occult. There has how- 

 ever obtained a not unnatural presumption against such causes ; and this 

 presumption though often salutarj' has sometimes operated most disadvan- 

 tageously to science. " Sir William Hamilton. [Discussions on Philoso- 

 ])hy and Literature. 8vo. London, 1852: appendix i, p. 611.) 



" The first causes of phenomena lie beyond the limited scope of our per- 

 ceptive and reasoning faculties. - - - Their intimate nature and prime 

 origin are for us inscrutable mysteries." Dr. A. W. Hoffman. [Intro- 

 duction to Modern Chemistry. 1865: lee. IX, p. 138.) 



" Ultimate scientific ideas then are all representative of realities that 

 cannot be comprehended. - - - Alike in the external and the internal 

 worlds, the man of science sees himself in the midst of perpetual changes — 

 of which he can discover neither the beginning nor the end. * - - In 

 all directions his investigations eventually bring him face to face with an 

 insoluble enigma ; and he ever more clearly perceives it to be an insoluble 

 enigma." Herbert Spencer. [First Principles. 2d ed. 1869: parti, 

 chap, in: sect. 21, pp. 66, 67.) 



