chap, xv DIAMOND POLISHING 45
and
do not spare diamond dust, although it is expensive, in order to make
the stone run faster, and they weight it much more heavily than we do.
I
have known them to weight a stone with 150 livres of lead. It is true
that it was a large stone, which weighed 130 carats after it had been
cut, and that the mill was like ours, the large wheel of which was
turned by four blacks. The Indians do hot agree with us in believing
that weighting them causes flaws in the stones. If theirs do not
receive any it is because they always have a small boy who holds in his
hand a very thin wooden spoon, with which he anoints the wheel
incessantly with oil and diamond powder. Besides this their wheel does
not go so fast as ours, because the wooden wheel which causes the steel
one to revolve is seldom more than 3 feet in diameter.
The
Indians are unable to give the stones such a lively polish as we give
them in Europe ; this, I believe, is due to the fact that their wheels
do not run so smoothly as ours. For, being made of steel, in order to
grind it on the emery, of which it has need every twenty-four hours, it
has to be taken off the tree, and it cannot be replaced so as to run as
evenly as it should do. If they possessed the iron wheel like ours, for
which not emery but the file is required, it is not necessary to remove
it from the tree in order to file it, and they could give the stones a
better polish than they do. I have stated that it is necessary to rub
the wheel with emery or to file it every twenty-four hours, and it is
desirable that this should be done every twelve hours if the workman is
not lazy. For when the stone has run a certain time, the part of the
wheel where it has pressed becomes polished like a mirror, and if the
place be not roughened by emery or the file, the powder does not stick
to it. When it does adhere more work can be done in one hour than in
two when there is none on the wheel. Although a particular diamond may
be by nature hard,
details of the methods of Indian lapidaries see Mukharji, Art Manufactures of India, 267 ff. ; Baden Powell, Handbook of Manufactures and Arts of tlie Punjab, 193 f.; on the European methods, Ency. Brit., xvi. 198 f.
