VOL. XXIV.] PHILOSOPHICAL TRANSACTIONS. QQ 



small, and as all of them were not so smooth as polished glass, and had several 

 small scratches or slits in them, 1 suppose that might happen hy the breaking 

 or dividing of these sandy particles from each other. 



That piece of the red stone still remaining entire, was about the size of a 

 pea ; and when I beat it in pieces^ a spark of fire flew out of it. I made a 

 small bit of it glowing hot, and so let it drop into water, supposing that not 

 only the particles of sand would thus be separated, but that the red matter also 

 which consolidated the sand would be divided from it ; but I found that the sands 

 only were separated from each other, and each particle of sand was as strong as 

 if it had never been in the fire, and was also surrounded with the red matter ; 

 but in some of them, which had assumed a greater transparency than before, I 

 could plainly discover that each particular grain consisted, or rather was a con- 

 geries of several small particles, of which could be seen in some sands, 50 such 

 projecting like pointed pyramids, all transparent, and some of them had the 

 same figure as the grain of sand itself had. By these observations I was fully 

 satisfied, that the sands of which the above-mentioned red stone was composed, 

 had for the most part preserved their original figure, and that they were so hard 

 and solid, that their falling one upon another could not produce any adhesion, 

 otherwise than by the intervention of that red matter, which was interspersed 

 and mixed with them. 



From these observations I was naturally led to consider diamonds ; and my 

 hypothesis is, that all the diamonds that have been, or shall be discovered, do 

 not grow, nor are made in any series of time, but were formed like other sands, 

 in the beginning of the world ; for how is it possible that such a pellucid body 

 can be produced in the bowels of the earth, by a congealing or coagulated 

 succus or moisture; and if it were so, why do we not meet with very large 

 diamonds ? for when a small diamond is once formed, there would be a more 

 than ordinary conflux of the same plastic matter to it, as we find in other things, 

 that they have always a strong tendency or inclination to substances of a homo- 

 geneous nature with themselves. I have been assured that in some places, 

 water filtrates through the rocks into the subterraneous caverns, and coagulates 

 at the top of those vaults into icicles, like nine-pins, and at last are really pe- 

 trified. And yet I believed that these petrifactions, viewed by the microscope, 

 would be found to differ from the rock itself. To be satisfied in my observa- 

 tions, I took a piece of white marble brought from Italy, which was of two 

 sorts, the one strong, the other light and very brittle. I broke the brittle 

 marble gently, that the configuration of the small particles might not be much 

 altered ; and having viewed several of them with my glass, I saw abundance of 



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