KINETIC THEORIES OF GRAVHATION. 245 



the distance is infinite, the integral is negatively infinite. But how it 

 is a Innetion of " space" in any more general sense, is certainly not ob- 

 vious. As Professor Briicke, of Vienna, has forcibly said iji bis response 

 to Faraday : " So far as my consciousness reaches, so far as 1 am capa- 

 ble of distinguishing true from f;ilse, and like from unlike, all known 

 facts are brought into complete harmony wiih our laws of thought, 

 when we suppose forces as the causes of phenomena to reside in the 

 masses, the spaces between these masses being traversed by the forces. 

 If the forces could be imagined as existing in space, it must also be 

 conceivable that matter may be auuihilated without changing the sum 

 of the forces, and this, at least by me, is not conceivable/'* 



" Section 2, The force-generating faculty exists in space, and is di- 

 rected centripetally. [?] This is proved by the following consid<^.rations. 

 The integral Ibrceproduciug power of any body, however small, subject 

 to the law of universal gravitation, is illinjitable as space. It is impos- 

 sible to imagine an infinite attribute belonging to a finite entity.! It is 

 therefore in space that the energy that contributes the power of gravi- 

 tation exists, and the element of matter merely gives to it a centripetal 

 direction. This, as a consequent of the law of gravitation, seems note- 

 worthy from it probably being applicable to molecular forces generally. 

 It favors the idea that the function of the material element is to give 

 (lireetloii to a living force that p<'rvades space.'*| The first part of this 

 proposition, (as an iteration of the previous one,) that gravitative force 

 "exists in space," is derived as an inference from a metaphysical postu- 

 late, — " It is impossible to imagine" it as belonging to a finite body. 

 But our powers of " imagining" can hardly be accepted as the measure 

 of scientific verity. "It is impossible to imagine" the nature of elec- 

 trical action, chemical affinity, lumini^erous vibration, aether, atom, 

 ibrce, or space ! Who is able to formulate in thought the co-existence 

 of an equal repulsive and attractive energy in either pole of a bar 

 magnet, simultaneously discriminating by opposite action between the 

 reversed etids of two magnetic needles? But when it is said that the 

 sole function of the mateiial element is to give centripetal direction to 

 the circumambient ocean of force, wonderful indeed is the conception of 

 virtue in the " finite entity" thus drawing to itself the centripetal ten- 

 dency in all directions throughout illimitable space, and instantaneously 

 readjusting these infinite lines of ibrce with every momentary change 

 of position! If difficulty of "imagining" were a criterion of error, 

 surely it might be well applied to this hypothesis. 



" Section 3. The law of gravitation with respect to the element of 

 radial space, is usually defined with reference to a constant element of 

 time; the increment of velocity generated being proportional to the 

 increment of time, whatever the direction or velocity of the motion, and 



" L. E. D. Phil. Mas., February, 18.58, vol. xv, pp. 87, 88, 



t Is it impossible to iuiagiue an atom having an eternal duration ? 



t Phil Mag., 1858, vol. xv. pp. 331,332. 



