THOUGHTS ON THE NATURE AND ORIGIN OF FORCE. 253 



one atom touclies the matter of its neighbors. Hence matter will be 

 continuous throughout ; and in considering a mass of it, we have not to 

 suppose a distinction between its atoms and any intervening space. 

 The powers around the centers give these centers the proi^erties of atoms 

 of matter; and these powers again, when many centers by their con- 

 joint forces are grouped into a mass, give to every part of that mass 

 the properties of matter."'* And yet, in his earlier speculations, he 

 says in regard to electrical action in a vacuum, " Suppose it possible 

 for a ijositively electrified particle to be in the center of a vacuum an 

 inch in diameter, nothing in my present views forbids that the i:)article 

 should act at the distance of half an inch on all the particles forming 

 the inner superficies of the bounding sphere."t This, as Dr. Miiller has 

 remarked, is certainly an admission of the dreaded actio indistans ; but 

 whether this view was subsequently modified is not very clear. Nor is 

 it clear that Faraday, in afiirming the presence of matter wherever it 

 acts, had any other concei)tion than that usually entertained by those 

 who accept the atomic theory. To assert that our moon " touches" the 

 earth, nay, that it embraces I^eptune, notwithstanding its perfectly 

 determinate boundary of material surface, is only to employ words in a 

 wholly unintelligible sense. To affirm an infinitude of material interpen- 

 etrations is simply to ask the adoption of a new term instead of " mat- 

 ter," to represent that bounded something, or congeries of somethings, 

 which all experimental research attests to be impenetrable. 



Professor J. Challis, of the University of Cambridge, England, has 

 proposed "A Theory of Molecular Forces," which he has presented 

 in a refined mathematical exposition, in a series of essays published 

 in the FhiJosophical 2Ia(jazine, from 1859 to 1S71,-| and which, assuming 

 the molecules of matter to be surrounded by a continuous ethereal 

 medium of uniform elasticity pervading all space, resolves all forms 

 of force into the pressure of this ether ; each atom being the center 

 of vibrations propagated from it equally in all directions. 



Dr. Balfour Stewart, in an essay on " The Dynamical Theory of Heat," 

 appears inclined to favor a somewhat similar view. He remarks : "Till 

 we know what the ultimate nature of matter is, it will bo premature to 

 speculate as to the ultimate nature of force ; though we have reason to 

 believe that it depends upon the diffusion of highly attenuated matter 

 throughout space."§ 



Professor Frederick Guthi-ie, in a paper read before the Eoyal Society 

 of London, in 1870, " On Approach caused by Vibration," detailing some 

 very interesting experiments showing small converging aerial currents 

 resulting from tuning-fork vibrations, (in perfect accordance with the 



* L. E. D. Phil Mag., February, 1844, third series, Vol. XXIV, p. 142. ~ 



i Experimental Sesearchcs in Electricity. Reprinted from the Pliil. Trans., 1831-1838. 

 Series xiii, sec. 161G, Vol. I, p. 514. 



1 L. E. V. Fhil. Mag., fourth series, Vols. XYIII, pp. 321 and 442 ; XIX, 88 ; XX, 280, 

 431 ; XXI, 65, 92 ; XXIIl, 313 ; XXVI, 230 ; XXXI, 459 ; and XLI, 280. 



§ North Briti-^h Eeview, February, 1864 ; (Vol. XL, page 22, American edition.) 



