Evening star. [volume] (Washington, D.C.) 1854-1972, 1905-04-09
body win no, afrectfthe accuracy of the

body win not afrectfthe accuracy OF the
work.
The machine that does the finest work
now undertaken by the bureau Is OF Ger
man make. American manufacturers are
not yet equipped to turn out the finest OF
these mathematical instruments. They al
so explain TO the bureau that the cost CT
labor in this country is so much greater ID
this line of work that they cannot COM
pete with the foreign manufacturer. one
instrument maker said that IL would cost
him 500 to turn out n machine that
German or Austrian firm could make and
sell in this country al a profit for $50. How
much of this is manufacturers talk II IL
impossible just now to say But the facs
remains that most OF the highly refined
machines and instruments have 70 be
bought abroad. The measuring room Is
now in position TO verify and graduate
scales to 1850 o0Oth of an inch. When
It Is remembered that a cigarette paper is
Just a thousandth OF an inch thick II VIII
be seen that this measurement is tolerably
small.
The Polariscope Test.
The light and optical instruments are
under the personal charge Of the director
of the bureau. DIR. w. S. Stratton. assisted
by DR.. P. @. Nutting. University OF Cali
fornia: Mr. F. ]. Bates and DR.. Blake. 1t
is in this work that the much discussed and
little understood polariscopic- work is car
ried on. The bureau is expected to pass on
every sample OF imported sugar that is
subjected to the polariscope test on coming
into the United States. When It is seen
that difference of tenth of one per cent
in the reading on this test would amount
to 10000 a year in duty on the sugar
brought to this country. Il Will be realized
that there is some need for accuracy. The
sugar importers are constantly going into
court and challenging the determinations
of the port collectors on the fneness of the
sugar imported. So now all the tests are
checked by the bureau. and the polariscopes
of the various collectors are being care
fully standardized to eliminate much OF
the dispute possible. The bureau has
polariscopes that will read to a thousandth
of one per cent. but this is finer than the
limit of error in making up the sugar solu-
ton that they test, SO this extreme re-
finement is not used in the actual test.
The electrical work OF the bureau is very
interesting, but much of il Is too compli-
Gated for the average outsider to UNDER
stand. The standardtzing Of incandescent
| lamps is one of the things that would APP
| peal to almost every one, however. The
work is done in a black-walled room with
| dead black screens to prevent reflection
and disturbance. The standard lamp is
| connected up with series OF resistance
| coils and delicate devices for controlling the
| actual current used. The lamp to be tested
is clipped into its standard and rapidly re-
volved. and the comparative brilliancy OF
| the two accurately read off through glass
! against a scale on the opposite wall. This
| is only for what is known as the 'hori-
| zontal lighting capacity of the lamp. There
| IL another machine, just being installed,
| which is lined with mirrors set in the seq
| ment of a circle that Will give the dtstribu-
| tive power Of lamp at all points of the
| compass and angles TO the zenith.
Director of the Bureau.
The general electric work is under DR..
! Wolff OF Johns Hopkins. assisted by Mr..
F. E. Cady. Massachusetts Institute OF
| Technology, and Dr. G. w. MIddlekauf, also
of Johns Hopkins. Magnetism and abso-
lutte measurement of current are under DIR.
X. f. Guthe, University OF Marburg. Mich.
Work on induction and capacity is handled
by DIR. n. L. Dorsey of Johns Hopkins. as
sisted by Mr.. F. w Grover of Wesleyan
University. All electrical measuring In
struments are under the personal charge
| of the physicist. assisted by DR.. NJ. q.
Lloyd, University of Pennsylvania; II. Il.
Brooks, Ohio State University; c. Z. Reid,
photometric work is in charge of Mr.. L. p.
Hyde of Johns Hopkins.
The office of the bureau which has TO
do with the immense amount of CORE
| spondence involved and much of the interi-
or economy of the place is under the Sec
rotary of the bureau. Mr.. Henry d. Hub
bard of the University of Chicago.
| The director of the bureau and its moving
| spirit since its Inception is Prof w. s.
| Stratton of the University of Chicago. The
| force under him numbers altogether about
| seventy-fiye. and represents graduates of
| all the big technical colleges OF the country.
Il The force may be increased in the future.
Il but at present, though hard worked, II Is
fully up to its requirements.