%68 Dr. Wollaston on the cutting diamond . 
circumstance this supposed superiority of the natural diamond 
over that which has been cut by art, could depend, I was not 
able to gain any information. 
Having procured a common glazier’s diamond ready set, 
and such a quantity of glass as I thought would be sufficient 
for learning by experiment the art of cutting, I endeavoured 
first by forcible pressure on the point in different directions 
to effect my purpose. But although I could thus tear the 
surface to a considerable depth, I could by no means com- 
mand the direction of the fracture. 
When I placed the diamond more inclined to the surface, I 
could occasionally, and in part, obtain what I thought to be a 
proper cut; but I was unable to continue the stroke with 
steadiness, and so incapable of repeating it a second time with 
a similar effect, that I was convinced the precise direction 
necessary for cutting was confined within very narrow limits. 
Having found that the diamond required to be moved in the 
direction of one of its edges, and having by repeated trials 
formed a judgment of the requisite inclination of its handle, 
I mounted it in a frame, in which I could fix it at any angle 
of elevation that appeared suitable, and could turn it round its 
axis to adjust the direction of its edge. By this arrangement 
I had no difficulty in repeating any successful trial, or of vary- 
ing it according to hints derived from such imperfections as 
were observable ; and I soon discovered that difference in the 
form of the natural diamond, from that of diamonds cut by 
art, on which I believe the power of cutting to depend. 
■ When a diamond is formed and polished by the lapidary, 
all the surfaces are plain surfaces, as far as it is in his power 
to make them so, and consequently the edge or line in which 
