Mr. W. R. Browne on Action at a Distance. 443 



particles themselves in contact or not ? If they are not, they 

 cannot keep the bar together ; if they are, they cannot be 

 compressed. Again, if the molecules are spherical, or of any 

 other regular shape whatever, they can not oppose any resist- 

 ance to separation, i. e. there can be no tensional stress. The 

 only way out of this seems to be to conceive them shaped some- 

 thing like burrs, and holding on to each other by hooks. This 

 is altogether contrary to the vortex-atom and all other known 

 theories of molecules. Moreover such burr-like molecules must 

 hold to each other somewhat loosely; and a certain amount of 

 extension would be necessary (as in the case of a slack chain) 

 before any resistance was experienced. But no such slackness 

 has been observed with the most delicate instruments ; and we 

 have seen that an extension of 10 I 00 is sufficient to produce an 

 enormous resistance. For these and the like reasons the hypo- 

 thesis of direct contact is inadmissible. 



(2) Can the facts be explained on the hypothesis of particles 

 projected from the molecules of one section against those of the 

 next ? Now it is clear that any effect due to this cause will be 

 merely an effect of repulsion. Consequently the end section of 

 the bar will be repelled from that next to it, and will fly off; 

 another body brought into contact with the bar will be repelled 

 by it, &c. For these and the like reasons this hypothesis is 

 inadmissible. 



(8) Can the facts be explained on the same hypothesis as 

 that of Le Sage, viz. of independent particles flying through 

 space and intercepted by the molecules of the bar ? In the 

 first place, it is clear that these cannot be the particles of the 

 gravity-gas ; for if these pass through the earth without having 

 more than a small proportion stopped, it is clear that the 

 number intercepted by an inch of iron will be infinitesimal. 

 We should have to conceive, therefore, a separate atmosphere 

 for each solid body, and an atmosphere the effects of which are 

 many thousand times as great as that of the gravity-gas. But, 

 further, let us assume this atmosphere, and consider what will 

 happen when the bar is extended. Anyone section will be 

 removed to a greater distance from the next, and its sheltering 

 influence will be diminished in the inverse ratio of the squares 

 of the distances. Consequently the effect of extension will 

 be to diminish the attraction between the sections: whereas 

 the actual effect is enormously to increase it. For these and 

 the like reasons this third and last hypothesis is also inad- 

 missible. 



The two latter hypotheses, and any combination of them, 

 labour under a further and fatal disadvantage, viz. that the co- 

 hesion of the bar would be different in different parts. Thus 

 in whatever way the flying particles are supposed to move, it 



