IN THE INTERIOR OF TRANSPARENT BODIES. 405 



forces exercised on them by the material particles. Hence, if there be a 

 number of etherial particles surrounding each material particle, it is impos- 

 sible, in general, that both sets of particles can be symmetrically arranged. 



But let us suppose that there are not so many, or at most, as many 

 etherial particles as there are material, then it is evident that if the 

 material particles be symmetrically arranged, so also will the etherial. 

 The following figures will make this evident. Figure (4) represents 

 what we may conceive to be the arrangement of the particles when 

 each material particle is surrounded by several etherial; the large dots 

 representing the former, and the small dots the latter. Figure (3) represents 

 what may be the arrangement when there are fewer particles of ether 

 than of matter ; and Figure (2) when there are just the same number 

 of both. Figure (1) represents what, I think, is not at all an improbable 

 arrangement in the case of very transparent bodies, where, though there 

 are more particles of ether than of matter, yet the arrangement is 

 symmetrical, in consequence of the etherial particles being repelled so 

 strongly by the material that they form themselves into globules, which 

 may be regarded each as one particle: I shall hereafter explain on what 

 grounds I conceive this to be a very probable arrangement in the case 

 of very transparent bodies. 



Fig. (1.) Fig. (2.) 



Fig. (3.) Fig. (4.) 



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Vol. VII. Part III. Zz 



