arger ones, whose business consisted chiefly in repairing chipped or
imperfectly cut stones or in recutting stones previously cut abroad,
which, owing to the superior workmanship in command here, could be
recut at a profit, or in recutting very valuable diamonds when it was
desired, with the certainty that the work could be done under their
own supervision, thus guarding against any possible loss by exchange
for inferior stones.

The industry employed 236 persons, of whom 69 were under age, who
received $148,114 in wages. Of the 19 establishments, 16 used steam
power. The power is usually rented. Foot power is only used in one
establishment. Three of the firms are engaged in shaping black
diamonds for mechanical purposes, for glass cutters and engravers, or
in the manufacture of watch jewels.

The diamonds used in this industry are all imported, for, as already
stated, diamonds are only occasionally found in the United States.

The importation of rough and uncut diamonds in 1880 amounted to
$129,207, in 1889 to $250,187, and the total for the decade was
$3,133,529, while in 1883 there were imported $443,996 worth, showing
that there was 94 per cent. more cutting done in 1889 than 1880, but
markedly more in 1882 and 1883. This large increase of importation is
due to the fact that in the years 1882 to 1885 a number of our
jewelers opened diamond cutting establishments, but the cutting has
not been profitably carried on in this country on a scale large enough
to justify branch houses in London, the great market for rough
diamonds, where advantage can be taken of every fluctuation in the
market and large parcels purchased, which can be cut immediately and
converted into cash; for nothing is bought and sold on a closer margin
than rough diamonds.

There has been a remarkable increase in the importation of precious
stones in this country in the last ten years. The imports from 1870 to
1879, inclusive, amounted to $26,698,203, whereas from 1880 to 1889,
inclusive, the imports amounted to $87,198,114, more than three times
as much as were imported the previous decade.

* * * * *

SOME EXPERIMENTS ON THE ELECTRIC DISCHARGE IN VACUUM TUBES.[1]

[Footnote 1: From a recent communication made to the Physical
Society, London.]

By Prof. J.J. THOMSON, M.A., F.R.S.

[Illustration: FIG. 1.--Coil of Glass Tube for Vacuum Discharge
Experiments. The primary coils are filled with mercury