PHILOSOPHICAL SOCIETY OF WASHINGTON. 167 



by no construction, by no combination, by no involution or evolu- 

 tion of any purely " mechanical " process can he possibly obtain, or 

 explain, or even conceive his postulate — a rigid body. The attempt 

 is indeed more hopeless than to demonstrate an axiom by mathe- 

 matical deduction. That which is the necessary basis and starting- 

 point of any intelligible mechanics, can scarcely be supposed to be 

 the product or derivative of such mechauics. A truly mechauical 

 theory cannot dispense with an extraneous foundation. Those who 

 would exclude potential causes from the field of mechauical science, 

 but betray the hopeless — helpless nakedness and imbecility of their 

 hypothetic fictions. "Later philosophers" says Isaac Newton, 

 " banish the consideration of such a cause out of natural philosophy, 

 feigning hypotheses for explaining all things mechanically, and re- 

 ferring other causes to ' metaphysics ; ' whereas the main business 

 of natural philosophy is to argue from phenomena without feigning 

 hypotheses, and to deduce causes from effects, till we come to the 

 very first cause, — which certainly is not mechanical." * 



Give to the ambitious kinematic artist his cloud of sand, — or if 

 he prefer the outfit, let him be furnished with an indefinite quantity 

 of a perfectly continuous frictionless and incompressible fluid — 

 bound up if you please in a chain of " vortex rings," — by no 

 motions or composition of motions — continued through the seons of 

 eternity — could he ever manufacture therefrom either a lever, or a 

 rope. The kinematic gospel of a mechanical theory of primeval 

 motion is therefore a sophism and illusion. It is founded on a mis- 

 conception of the very essence of a true mechanics. And the sys- 

 tem that would proudly aspire to an architecture of a kosmos from 

 the elements of matter disrobed and denuded of every quality but 

 motion, would achieve as its highest triumph and product — a uni- 

 verse of dust and ashes. 



Without inertia there could be neither transmission of motion, 

 nor even continuity of motion. Without inertia, kinematics itself 

 would be but an empty name. And with inertia, kinematics would 

 be a science of purely rectilinear movement ; for by no artifice 

 could any other be producible. No curvature of motion — no re- 

 silience of motion — is possible without the domination and con- 

 straint of occult forces. Without " dynamics " there could be no 

 such thing as a science of " kinetics." Without the ceaseless pres- 

 ence and action of occult forces there could be no such thing as the 



* Ovtics. Second edition, 1717 : book III, query 28. 



