Perth Amboy evening news., 1922-05-23
STANDARD WEIGHTS MOVE
STARTED BY AMERICA
Daily Letter by Frederic j. Haskin

WASHINGTON. May 20.-If you
get short weight on meat or straw
berries at the corner grocery it is
not because Uncle Sam Is unable to
produce accurate weights and scales.
At the United States Bureau of
Standards. government scientists car.
weigh a name written on a sheet o.
paper. They can even add a period
after the signature and weigh that.
And the same precision may be ap-
piled TO weighing an a larger scale.
If it were necessary the apparatus
could be provided to weigh a 49,
000-ton battleship so accurately that
the absence of even a one-pound riv-
ct could be detected.
Back in 1890 the two national
standards, we little kilogram
weights each containing $4,000
worth of platinum and iridium were
brought to this country under sea;
and opened by President Harrison.
They had been made by order OF
the International Weights and Mea-
sures conference at Paris. Each
country represented received two kill
oeram weights, and the two original
weights from which they were made
were deposited at Paris in a vault
guarded by three separate locks.
The presence of all three of the OFF,
Gals who keep the three keys to the
vault Is required whenever these
TWO most valuable weight standards
in the world are consulted.
Since the Bureau of Standards was
established our two national STAN
dards have remained there, locked
in a vault. No one touches them
with his fingers. One has been used
a few times in the past 80 years,
but it is always handled with cham
OILS covered pliers. The other had
never been taken from the vault UNI
til a test was made the other day
because the scientists wanted to find
out whether the standard that had
been used was affected by handling.
They also wished to compare the
secondary standards which are more
generally used about the Laboratories
with the national standards.
The test showed that the national
standards have not changed appre-
ciably during their 80 years exist
ence. Other weights also showed
! changes so slight as TO be unimport-
ant. The largest change in a kilo-
gram weight noted by the delicate
apparatus of the government labora-
tory was one ten-millionth. This
weight had been used for more than
80 years.
This was serious work because the
weight standards of the country are
OF tremendous importance. They
are the best weights made, and they
are the basis of the weighing that
goes on in markets. stockyards'
shipbuilding plants and factories
They are rarely used the
government does not wish to endan-
ger their accuracy by handling them
They are only to be taken out al
long intervals as they were the other
day, to make sure that the country
is operating on a sound weight basis
Precaution Observed
The layman generally thinks that
he is weighing carefully when he
holds his breath and steadies MS
hands as he slides the weights on the
bar. That may be careful enough
work for ordinary purposes. But the
Bureau of Standards sets the recofd
for extreme caution in weighing
tests. Watchmakers, diamond mer
chants, pharmacists and research
workers who use fine and accurate
balances send their weights to ths
bureau to have them proved by Gov
eminent standards. p
The balances in the government
laboratory are in glass cases. Tns
weights are placed on the scale pans
with holders. Some balances ar,
so equipped that a little roune
piece OF the glass case works on I
lever and pushes the scale pan out
side the case. The scientist can ther
place the weights on the scale pal
without opening one whole SIDE o
the ease and letting in dust.
For careful work the weighlnI
expert sometimes stands eight or .ei
feet away from the glass enclose
balance so that the warmth of M
3 body may not affect the reading. IL
reads the figures by use of a tele
scope and mirror.
| In the basement of the building !
, the even temperature room wher
still greater precautions are takei
TO achieve exactness. The room !
built with an extra double wall o
hollow tile. so that when It is KEEP
l closed the temperature remain
constant to within one-tenth of
: degree in many hours. The mos
3 important balance in the buildin
! Is here. It is protected. from vibra
lions by having its mount on a sep
tarate foundation from the floor. Fo