USES. 1C>3 
|)iirpose. The prices reported as havin<>' been received for these 
American gems are from $1 to $5 ])er ounce, and they re})resent at 
Hie 2^1'e^^^nt time an important factor in sapphire mining in the 
United States. In regard to the utilization of these stones, Mr. 
Kunz says : 
In Switzerland most of the jewels are cut and sold in boxes of from 500 to 
1,000 per box. Each stone has been given a rounded form and is pierced in the 
(enter, the drill hole being smaller by a minute quantity than the diameter of 
the axle which it is to hold. The bed of the stone in the watch is a small cylin- 
der, apparently of brass, but in reality consisting of a soft-gold alloy. Before 
tlie stone is handed to the watchmaker it is put in a lathe, and by means of a 
liny steel drill, covered with oil and diamond dust, the central opening is en- 
larged sufficiently to enable the steel axle or pin for which it is intended to fit 
into it accurately. The watchmaker first fixes the cylinder in the lathe, then 
])i('ks up the stone with the moistened finger and inserts it in the cylinder 
while the latter is turning with the axis of the lathe. With a pointed tool the' 
workman next presses against the edge of the revolving cylinder and thus 
forces the soft metal to cover and protect the sapphire or ruby to such an ex- 
tent that it appears as if embedded in a metallic cushion. Next a drill is 
inserted in the metallic coat of the cylinder from the opposite side of the lathe, 
and a hole is drilled in this coat exactly of the same size as the hole in the 
stone itself. A great variety of forms have been made recently, not only for 
watches but for electric and other meters. The latter, as compared with 
watches, require a greater and more enduring life in the jewels, which, owing 
to the microscopic inclusions, either of softer minerals or of fluid cavities, is 
often shortened materially. Sapphires, rubies, and even diamonds are used 
with wonderful ingenuity, and with the increasing demand for hard bearings 
in the endless variety of electrical devices, in which the moving points revolve 
rapidly, there is much to be looked for in the way of new devices, and a greatly 
increased demand for jeweled bearings is probable. 
CORUNDUM WHEELS. 
Although an examination of a corundum property may show the 
existence of considerable quantity of the mineral, no mining should 
be imdertaken until satisfactory tests have been made upon the 
corundum to prove that it has those properties that will make it of 
value as an abrasive. 
The value of a corundum deposit as an ore for abrasive purposes 
depends upon that property of the mineral which enables it to retain 
a sharp edge, known as a cutting edge, when it is crushed to grains. 
All corundums do not have this property, and many that exhibit it 
in the first stage of the crushing do not show it in the finer fragments 
and grains. This is more apparent when the corundum has been 
made into a wheel, for when first used the wheel may do good work, 
especially if it is a coarse-grained wheel, but as it wears away the 
grains of corundum become roinided instead of breaking to a cutting- 
edge. In estimating the vahie of a corundum deposit it is therefore 
