The commonwealth. (Greenwood, Miss.) 1896-1923, 1905-11-17
JEWELS IN METERS.
DIAMONDS FIGURE IN REGIS
TERING ELECTRIC SUPPLY.
They Are Used as Bearings Much
the Same as Pivot Cups in
the Movements Of
a. Watches.

the Same as Pivot Cups in
the Movements Of
A. Watches.
There are over $50, 900 of jewels, sap
phires and diamonds, hidden away
within the bounds of. the Greater New
York where few people know anything
about them. They are in the meters
registering the supply OF electricity
wherever that element is use-a jewel
in each meter, and upon the jewel de-
ponds largely the accuracy of the work
Of the meter, says the New York Times.
No m in need of a new tiara, how
ever, or politician looking for an il
Eliminating shirt stud need hunt them
up, for they are very tiny, IA or 20 10
the carat, and not beautiful wen when
seen with the aid of the magnifying
glass.
But they are interesting. and the
diamonds in their most approved form
particularly so. They are c~up-shaped,
and the inner surface of each is high
ly polished. The polishing of anything
but the fiat surface of a diamond has
hitherto been considered an impossi-
bility. Every facet of a diamond cut
for an ornament is fiat, polished by
being held to a big lap revolving at a
high rate of speed and with the use of
oil and diamond dust. The most ex-
pert lapidary in this country said,
when the diamond cup was proposed,
that the polishing of the concave sur
face of a diamond was an impossibility.
OLher experts in Holland-Rotterdam
and Amsterdam-the home of diamond
cutting, made the same statement.
But with the need came the invention,
and now a machine with a ball at
tachment gives the inside of the tiny
cup as high a polish as is found on
the most beautiful jewel in a ring.
The correct registering of the supply
of electricity by the meter depends
largely upon the revolution of a tiny
pivot upon a smooth surface. These
are the bearings of the meter. The
pivot is of brass, with a center of
hardened piano wire, which is nearly
as smooth and brilliant as a diamond.
The jewels form the polished surface
upon which the pivot revolves, and
here is where the diamond cup ap-
pears. 1t is set In the top of a hollow
screw of brass, and beneath it is a
brass plug, with a spring to minimize
the effect of vibration. If the jewel
used becomes roughened or defective
in the slightest degree the revolutions
will decrease in member and the meter
fall short in its measurements, a re-
suit which, while it may be satisfac-
tory to the consumer, will not please
the electrical company furnishing the
supply, There are few meters, it is
said, which do not fall a triie short
in their registering, and the consumer
as a rule gets his supply of electricity
at a discount which is more or less
material.
1t is owing to this fact that from
the beginning the electrical companies
been making experiments to find
the best material for use in the meter,
]. e., the hardest and smoothest sur
face upon which the pivot of the meter
may revolve. Agate was tried first,
but r~oughened Immediately, and steel
was found to be little better. Then the
sapphire came into use, the tiny cups
being formed of it. But the life of a
sapphire is barely a year, with the con-
slant mechanical action upon it, and
IS necessary to renew 1t at the end
every IL months, and often in less
time, and a new pivot is put in each
time the Jewel is renewed. A diamond
Is harder than a sapphire, and expert
ments have proved them to be more
satisfactory, the only difficulty being
mat, In the first place, they could not
be made in cup shape because it was
aid that a concave diamond could not
be polished.
Before this was done successfully
a cup was improvised, a fiat diamond
4
1t the bottom and the sides formed
by a ring Of sapphire set over it. There
are several different kinds of sapphires
which have been tried. The best come
rom Ceylon and Siberia, the latter
having but a small output. There is
also a Montana sapphire, which is
by its greenish shade. but
which Ia softer than the others, having
,nly half the life of a Ceylon stone,
Inc sapphires made in cup shape were
lsed almost from the first, being re.
placed by the diamond with the san.
'hire ring. which is still used.
Diamonds have been used for onlv
'oout two years, and until the last six
months have been almost p~rohibitory
n price. The diamond cups as they
ome from the stone cutters cost 81
while the rough diamond would be
worth only about 40 cents. The san
phires cost only about 20 cents a Gun.
Inc diamond cups are not vet in
general use. Only three firms are
them. and n toLo,