THOUGHTS ON THE NATURE AND ORIGIN OF FORCE. 251 



essence they have so swiftly sped without the slightest loss,* we are 

 brought at once to the great problem which has lately been so actively 

 pursued — the origin of the sun's rays. 



Assuming matter originally endowed with molecular attractions and 

 repulsions, (regarding gravitation as resident in the primitive atom, 

 though infinite in range,) and assuming such matter created in a state 

 of power — that is, of extreme diffusion, or with its attractions wholly 

 unsatisfied — we have all that is necessary to explain dynamically the 

 existing order of nature. The great difficulty we have in forming satis- 

 factory theories of the constitution of matter lies in the apparent com- 

 plexity of the forces displayed. Thus we have at least five distinctly 

 marked kinds of molecular attraction, each so characteristic that it can- 

 not be converted into or mistaken for either of the others; and there 

 are probably as many forms of repulsion. But starting with the idea 

 of matter converging or falling together, we see how the encroachment 

 of such a condensation on the repulsive spheres must give rise to a vio- 

 lent agitation ; in short, to a heat vibration far more energetic or intense 

 than any purely chemical action, by as much as the space-potential 

 of gravity exceeds that of affinity ; tar more intense, indeed, than any 

 temperature now' i^robably existing in the sun.t 



Here, then, in molecular gravitative attraction — as the ultimate resort, 

 are we forced to accept the primum mobile — the origin of the power 

 which has not only evolved and molded our solar family of worlds, but 

 which lias sustained our terrestrial economy in all the wondrous changes 

 of its eventful career throughout the geologic ages. Beyond this funda- 

 mental conception of mysterious ''attractions" forever resident in 

 material elements, it does not appear probable that scientific research 

 will be able to carry back the parentage or genesis of force. And yet 

 there have not been wanting numerous hardy attempts to frame explana- 

 tions and hypothetical antecedents of these postulated affections of atoms, 

 or to replace them by dynamical agents or actions ; while really leaving 

 the problem of derivation as unsolved, or more insoluble than ever. 



A laborious and ingenious French-Swiss physicist, Georges Louis 

 Le Sage, about a century ago, devised the hypothesis that all space was 

 occupied with extremely minute bodies, denominated by him " ultra- 

 mundane corpuscles,''^ moving in continuous right lines in all possible 

 directions, with inconceivable but uniform velocity, and without collision 



* The question is sometimes raised whether the lij^ht and heat of the sun and other 

 stars may not be somewhat enfeebled or absorbed in passing throngli the celestial 

 spaces. The doctrine of conservation of force teaches ns that any absorption of either 

 light or heat implies a proportionate amount of work being done, the consequenceof 

 v.'hich would be a heating oi space itself! 



fA pound of coal falling to the sun from the distance of Neptune (which planet must 

 be regarded as an ancient landmark of equatorial drift) would reach it with a velocity 

 not very far short of four hundred miles per second ; and the arrest of this motion 

 would generate a heat vibration many thonsand times greater than could be obtained 

 from the combustion of the same pound of coal. 



