CORRESPONDENCE OF RAY. 169 



tides ; as when a man, with the forcible stroke of a ham- 

 mer, breaks, for example, a brick, it flies into innu- 

 merable parts, of different figures, perhaps scarce any two 

 like? 



How come there to be such great aggregates of bodies 

 of the same kind, as water, earth, air ? 



Whereas you say the same particles, by various trans- 

 positions, divisions, motions, &c. may put on different 

 faces, and stir up in us various perceptions, I answer, 

 that I cannot imagine any other difference of bodies but 

 what proceeds from the motions of figures of then* com- 

 ponent particles. 



From the motions of them can come nothing but a 

 greater^ less measure of fluidity; therefore all other 

 varieties must arise from their figures. From the figures 

 of homogeneous particles, or such as are of the same 

 shape, no considerable varieties can proceed ; for, from 

 suppose a bag of shot, perfectly spherical and solid, 

 should 1 shake or move them to the world's end, I should 

 get a body of no other texture than I had at first ; though 

 in bodies of other figured particles there might possibly 

 be variety of textures, from the situs of the component 

 particles in respect of each other. Yet this is not likely, 

 because it is very difficult to set the particles, all or most 

 of them, in one and the same situs one to another, and 

 scarce possible to be done but by an intelligent agent, 

 which yet must be done to produce like and homogeneous 

 textures ; therefore the most of these differences must 

 arise from the admixture of heterogeneous particles. The 

 fire is not such an analyst but that it doth communicate 

 particles to the bodies it divides or transforms, as we see 

 in minium made of lead, in which, that some parts out of 

 the fire adhering to the lead do so transform it, appears 

 probable by the increase of weight ; and many other like 

 instances there are. 



That fixed salts are all alike (whether they be com- 

 pound or simple bodies), I gather from the impressions 

 they make on our senses, and from their operations. 



