After
enough material had been separated by him, on September 11, 1893, Dr.
Huntington and the writer were enabled, through the courtesy of
Messrs. Tiffany & Company, to try the desired experiment in their
diamond-cutting pavilion in the Mining Building of the World's
Columbian Exposition, (a) They had prepared a new skaif or
wheel, 10-1/2 inches in diameter, which was placed in position after
having been specially planed down and prepared with the radiating
scratches so as to be easily charged with diamond powder. A diamond was
then soldered in a metal dop and placed on the clean wheel, which made
2,500 revolutions per minute. This diamond was tried for more than five
minutes by itself without the slightest polish resulting, and no
markings other than such as would be produced by the minute shattering
of the diamond at extreme edges, due to the friction, as when a diamond
is placed on an uncharged wheel. A cleavage weighing five
thirty-seconds of a carat was set with solder in the metal dop, ready
to be placed on the wheel, the diameter of which where the stone was to
be placed was 4 inches. The wheel was then charged with the residue
from the meteorite (the powder mixed, as usual, with oil).
The
moment that the diamond was placed on the wheel a hissing noise was
apparent, showing to an expert that the material was really cutting the
diamond. In three minutes a flat surface measuring 3 mm. by 1 mm. had
been ground down and polished. A small crystal with a natural face up
was then set in the metal dop, the crystal being a complex twin,
weighing four thirty-seconds of a carat. It was first tried on a
projecting angle. The cutting was very slow for about seven minutes as
the natural face of a diamond is always exceedingly hard. The position
of the stone was then slightly changed, and a face measuring 2 mm. by
1 mm. was ground on the stone and cut. Three minutes later the surface
had been cut down somewhat and a decided polish was produced on the
triangular face, which was 3 mm. by 1.25 mm. The fragment used was one
of the octahedral faces of a crystal. The face ground down was at the
angle of 45 degrees with the octahedral face-The entire time of this
experiment was fifteen minutes. The two experiments having been made
with great .care with both of us. present, we can not hesitate to
pronounce the material diamond, or a substance with the same hardness,
color, luster, and brilliancy, (b)
The diamond industry.—The
great interest manifested in the diamond-cutting industry at the
present time makes a statement of the condition of this, and the allied
industries abroad, opportune.
At
Amsterdam, which is the chief diamond-cutting center at present, there
are 52 large factories and about 20 small ones, using steam as a motive
power, where the rough diamonds are cut into brilliants and roses. The
largest of these is the establishment of Messrs. Boas
a This was announced in the American Journal of Science, Vol. XLVI, December, 1893, pp. 469-472. b Paper read by G. F. Kunz before Chicago Academy of Science, September 15,1893.
