|
UNITED STATES, CANADA AND MEXICO
|
319
|
||
|
|
|||
|
tions,
and here is continued the sand quartzite feed, in order to wear down
any irregularity of resetting upon the car. This operation usually
lasts for two days, when the bed is cleansed, and diminutive globules
of chilled shot-iron are rolled under the rings. Then follows treatment
with emery, beginning with the coarser grade and ending with the finer.
After a week of this work, the bed is thoroughly washed, the rings
removed, and large wheels, made from blocks of bass-wood clamped
together, presenting a rough surface by being set across the grain of
the wood, are placed in position. The speed, both in the movement of
the car and of the wheel, is now increased, and tin oxide is used to
burnish the surface, which is brought to a mirror-like finish by means
of trip-oli, fed to felt-covered wheels, that are revolved at the rate
of 300 revolutions a minute.
The
cutting and carving of rock crystal now done in the United States, even
the cutting of crystal balls, vases, cups, and vials; is equal to work
produced anywhere, as the vials, bonbon boxes, and clock exhibited at
the Paris Exposition in 1889 by Messrs. Tiffany & Co. fully
demonstrated. Much of the cutting of precious stones, such as ruby,
sapphire, emerald, and garnet, is of the highest order. Sards,
bloodstones, and other cheap agates are often cut abroad to a uniform
size for mounting, because it costs less to fit the stone to the
mounting than the mounting to the stone, and such stones as are found
here are generally cut in this country.
/Watch Jewels.—About
1,200,000 watches with jeweled works are annually manufactured in the
United States, requiring about 12,-000,000 jewels, seven to twenty-one
for each watch ; of these 5,000,-1,000,000 are ruby and sapphire, and
7,000,000 are garnet jewels, valued at over $300,000. Most of them are
imported, but the Waltham Company does its own cutting, employing about
200 hands. About 15,000 carats of diamond in the form of bort, are used
annually in slitting and drilling these jewels. Nearly all the ruby,
sapphire, and garnet used for jewels are imported, but it is hoped that
American materials will soon be used. To be of value for this purpose,
the material must not only be flawless, but also be of some decided
shade of red or blue, and of a hardness greater than that of quartz.
|
|||
|
|
|||