respecting the Nature of Light. 201 



Yjodiea do not touch each other in any state hitherto known; 

 which, though a very singular conchision, is yet impossible to be 

 denied." And Newton in his Optics, part iii. book ii. prop. 8, 

 appears to have entertained a similar idea; for he says, " A con- 

 cave S))here of gold filled with water, and soldered up, has, 

 upon pressing the sphere with great force, let water squeeze 

 through it, and stand on all its outside in multitudes of small 

 drops, like dew, without bursting or cracking the gold, as I have 

 been informed from an eye witness. From all which we may 

 conclude, that gold has more pores than solid parts, and by 

 consequence that water has above forty times more pores than 

 parts." And he further adds, " that he who shall find oUt an 

 hypothesis by which water may be so rare, and yet not capable 

 of compression by force, may doubtless by the same hypothesis 

 make gold and water, and all other bodies, as much rarer as he 

 pleases, so that liglit may find a ready passage through trans- 

 parent substances." Hence, as it appears that even the most 

 sohd body is porous, it is not, I think, too hypothetical to sup- 

 pose that the particles of matter may be differently arranged in 

 diifereiit bodies; and that those bodies which are transparent, or 

 transmit light freely, may have their atoms so arranged as to 

 form an indefinite series of right-lined canals; which is effected 

 by these atoms having for each other a certain degree of po- 

 larity. 



Crystallization, which affords the most transparent bodies, is 

 a strong argument in favour of this supposition. If it were not 

 for some peculiar arrangement of the particles of a crystal, how 

 can we account for the same substance always assuming a de- 

 terminate form upon going from a fluid to a solid state ? So 

 correctly does this take place, that we are able in many in- 

 stances to determine the composition, by knowing the form of 

 the crystal of the subject under examination. The only means 

 of accounting for this regularity is by supposing that the parti- 

 cles of matter composing the crystal, have with respect to each 

 other a certain polarity. It is only upon this principle that 

 many of the phaenomena of magnetism can be at all explained. 

 For how otherwise can the fragments of a magnet instantly 

 observe a polarity; and magnets, which have been struck by 

 lightning, or by having the electric shock passed through them, 

 have their poles changed ? An instance is recorded of a ship's 

 compass being struck by lightning, ever afterwards turning east 

 and west. Pciliaps in this case the poles of the atoms forming 

 the needle were turned so as to lie transversely instead of longi- 

 tudinally. 



To account for bodies being opaque, according to this hypo- 

 thesis, we have only to observe^ that in such bodies the particles 



are 



