Evening star. [volume] (Washington, D.C.) 1854-1972, 1926-07-25
Science Has Solved
Curious Measurement Problems
Guarded
f cion n
BY GEORGE H. DACY.


from a scientific standpoint than its
worth would suggest, for
it Is our cherished standard meter,
unit of length.
This meter bar was made many
years ago when the international
metric system came into being at
Sevres, near Paris, where the Inter
national Bureau of Weights and
Measures has it's laboratories. It's
home in Washington. since the in
ception Of the Bureau of Standards,
has been a special flreproof vault in
which the kilogram. standard unit OF
mass. is also painstakingly protected.
Director G.. X. Burgess of the Blu
reau of Standards is custodian of
these indices Of length and weight.
Only the technically trained scientists
who study and solve the enigmas of
length are allowed to work with this
metal rod, which Is 1887
inches In length.
During practically every moment
of every hour in the day length in
one form or another is Of critical Inn
portance to 117.000, 900 American cit
liens. The complicated working
parts of the motor car in which you
ride to your Office must be Of accurate
length or diameter or else they will
not function. The length of one car
rail--if you travel by steam or cleo
trio train--must be intimately cor
related with it's mate IL the joint is
to occur at the proper point in the
track. The length Of your billfofder
must be exactly right or 1t will not
accommodate the silver certificates,
national bank notes or greenbacks
which It was made to hold. The
length of the trousers you wear must
be correct, or some critical eye will
appraise you as lily CARRIED. Length
In a million and one different ways
greets us In as many different forms.
Some years ago, when the Inter
national Bureau of Weights and
Measures designated the scientific
length of the meter as the arbitrary
distance between two points and
when the metric system was estab-
lished, several meter bars Of length
were distributed among the various
countries, including England, France.
italy. Russia, Germany and the
United States. No two of these meter
bars were exactly alike. All of them
have to be sent back to Paris oc-
casionally for standardization and
correction.
For example, the treasured Amer
lean meter bar is returned to Paris
for comparison and correction once
every four or Ave years. This trip
teens with interest, for the bar Of
platinum and iridium is treated as
royalty as a king and Is guarded as
carefully as our Chief Executive
when he travels. Although the
metallic meter bar seems to be
armored against normal wear and
tear, and looks as IL 1t would last as
long as science. It's technical guard
ians say that it would be damaged
seriously If it suffered a fall or was
otherwise misused. Furthermore,
the value of the precious metals
which compose 1t Is sufficient to en-
gender uncommon care.
The scientist who takes the meter
to Europe sleeps in his stateroom on
railroad and ship with one of his
arms "handcuffed" to the valuable
yardstick of science. He guards the
metal rod as cautiously as though
it were a priceless gem. The travel
ing dress of the meter is built for
service. 1t consists Of a felt-lined.
hardwood case, in which the metal
bar is placed. This wooden box fits
tightly into a steel tube. The tube,
in turn, is packed carefully in Il
special crate. The package is sealed
securely. 1t is addressed to the In.
ternational Bureau of Weights and
Measures. On its return trip to
Washington, 1t is sent in care of our
Secretary of State. 1t always travels
under the guardianship of a trusted
expert of the Bureau of Standards.
The meter Isl suspended in a special
hammock which protects It from Jolt
and Jar during it's railroad and ocean
trips.
X y * +
T Usually, our standard meter re-
- mains abroad for eight or ten
months. The actual comparison with
the worlds unit of the metric system
at Sevres consumes two to three
months of daily research. The Amer
lean standard is tested and corrected
to enthusiastically small amounts.
Such painstaking work is necessary
because the meter is used so fire.
quertly in important scientific work.
When the worlds best scientific tai
ent met in France to define the
meter, the first idea was to make it
equivalent in length to one ten-nil-
lioneth Of the eaIth's quadrant at a
certain meridian. This plan, how
ever, did not prove practical. It was
then that the scheme of q meter by
definition was born. Science estab-
lisl1ed the length as certain arbi
trary distance between two points.
The only absolutely correct and &C
curate measure of length now in use
under the metric system is this meter
by definition. All the other meter
bars are either plus or minus meas
ures. That is to say, allowance has
to be made for their slight scientific
errors when extremely delicate meas
urements are made.
These errors are usually as small
as one to two hundred thousands OF
an inch.
If our basic meter bar were used
at the Bureau of Standards for the
ordinary scientific measurements
which have to be made almost daily
in one form or another, there would
be extreme danger of the carefully
corrected standard being damaged.
In order to protect against such pos
sibilities, several working standard
meter bars have been made. They
are frequently compared for accuracy
with the meter which enjoys foreign
travel every once in so often. The
ultimate technical results are salts
factory. The unit meter out Cleve-
land Park way is standard at zero
degrees Centigrade. Hence the cor.
rections for the working standards
are made according to room tempera-
ture and their powers of expansion.
standardized microscopes and Their
nometers are employed in the proc
ess of this delicate work OF COM
parison and correction.
You can gain some idea OF the ex-
IRENE delicacy and accuracy OF the
work when you understand that the
thermometers are very carefully
standardized. Even the delicate mi
crometer screws which. control the
Alice Cooinhe married Edward But