The Washington times., 1910-09-04
VELOCITY DEVICES
FALSE, SAYS EXPERT
Snatton Says SpeedometerS
and thermometers Regis
ter Inaceurately.

That magnetic thermometers. used b.
the navy 10 measure the velocity OF the
wind in firing during target practice,
and magnetic speedometsrs.- used Dy
automobiles to register speed. are so in
accurate as 10 make them practically
useless. is demonstrated by an investi-
cation Just completed by the Bureau Of.
Standards
The Bureau of Standards. after a
thorough Investigation. reports that the
magnetic Instruments show a variation
during hot and cold weather OF = per
cent
As a result Of these tests that have
been made on thermometers and speed
oIneTers. DIT. StTaJGOn. OF the Bureau Of
Standards. has determined to wage a
war on the manufacturers Of magnetic
Instruments generally
This does not mean that the director
VIII publish names and make the facts
public IN such way as 10 ruin those
who have heavily invested il the manu-
lecture Of thermometers and speed
onlereTS. He does not move IN that way
Thermometers Corrected.
Some time ago he discovered, after an
investigation covering many months,
that thermometers made in the United
States were q huge joke, 50 far as &C
curacy in recording temperature was
concerned Some of them varied -
much as One-third from the truth. The
director did not publish the facts He
simply wrote 10 each OF the ul1DJtTaC-
tuners advising them Of the errors in
their instruments and setting before
them 2 correct standard and methods
OF attaining IT,
The manufactures acted upon the
suggestions made. with the result thai
today as good thermometers are made
in this country rs anywhere IN the
world, with the exception Of those made
by one firm in Paris
p 10 r.#
Standards are Of wide significance" said
Director StratrCu. just before he left for
the Pacific coast 10 spend his vacation
Eliminating al technical DhraseoIoEy
known 10 experts IN mechanic they
amount 10 this a magnetic aDemom-
eter or speed0meler u III record an error
OF / per cent FOR every four ceEeeS
Fahrenheit IN temperature during hot o.
cold weather That is If a battle were
IN progress during a temperature Of 100
degrees, which would be aCcentuated IN
effect by the sun beating directly upon
the instrument. and an a0emometer
should be used 10 ascertain the velocity
OF the wind blowing at fifty miles per
hour, the error would be ABOUT % per
cent
Makes Them Useless.
This, in my opinion. would certainly
De enough to make the magnetic instrU-
rncnts now used practically valueless- ]
sneak from nv own experience as an
officer in the naval militia As these
Instruments are shipped To the Navy
Department IN carloads, and used on al
ships of the navy. the Importance OF the
tests can easily be seen
'fThe inaCcuracy Is the same as If
clock which. one depends upon TO keep
an appointment at Z O'clocS varied 70
such an extent that at that hour u
would give the time aS or . o clock,
depending upon whether the tenpera-
ture was hot or cold In long range n--
ing IN target practice the velocity OF
wind Il Is recognized IS an important
factor. II the Instrument which Is used
in measuring the wind Is Inaccurate, II
Is misleading. and cannot but result IN
making accurate firing more difficult -
Army and Navy Journal.