PHILOSOPHICAL SOCIETY OF WASHINGTON. 129 



It is very certain, however, that the hypothetical fluid of cohe- 

 sion-pressure must be something entirely different in constitution 

 from the luminiferous aether, since any mode of action which could 

 be imagined for compressing together the elements of matter, would 

 necessarily be incompatible with the transmission of solar radiation 

 having the quality and propertied of the vibrations actually ob- 

 served. The fantastic scheme of Le Sage (in which cohesion is 

 effected by the quaquaversal impacts of infinitesimal corpuscles 

 flyiug swiftly in all directions, and whose various sizes determine 

 the differing collocations of chemical unions,) — notwithstanding the 

 approval of Prof. Tait,* — scarcely requires a " serious considera- 

 tion."^" Nor has any form of impact, of pressure, or of undula- 

 tion, yet been proffered by the ingenuity of the kinematist — either 

 at all adequate to the maintenance of the known conditions of 

 matter, or indeed in itself at all conformable with any known 

 modes of action. 



The dynamist having searched in vain for any plausible co- 

 ordination of the indisputable facts of cohesion with an intelligible 

 mechanical agency, simply acquiesces in the result, and without in- 

 voking the unknown or the irrelevant, accepts this established 

 property as ultimate and inexplicable. 



kinds of energy as ultimately kinetic." [Nature. Sept. 21, 1876: vol. 

 xiv, pp. 459, 463.) 



The climax of kinematism however has been reached by the inventor 

 and apostle of the "fourth state of matter," — William Crookes, who is 

 disposed to dismiss matter itself to the same limbo — of changing position : 

 " From this point of view then matter is but a ?node of motion ; at the 

 absolute zero of temperature the inter-molecular movement would stop, and 

 although something [?] retaining the properties of inertia and weight would 

 remain, matter — as we know it — would cease to exist." (Nature. June 

 17, 1880: vol. xxn, p. 153.) This seems to touch the sublime "secret" 

 of George William Frederick Hegel, in which "nought is everything, 

 and everything is nought." — Seyn und Nichts ist d.asselbe. 



* Lectures on some recent advances in Physical Science. By P. G. Tait. 

 12mo. London, 1876: lect. xn, p. 299. 



f " The hypothesis of Le Sage - - - is too grotesque to need serious 

 consideration ; and besides will render no account of the phenomenon of 

 elasticity." Sir John F. W. Herschel, "On the Origin of Force." 

 (Fortnightly Review. July 1,1865: vol. I, p. 438. Also, Familiar Lectures 

 on Scientific Subjects. 12mo. London, 1866: art. XII. pp. 466, 467.) 



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