Evening star., 1926-04-25

built up curious theories out of q very
little knowledge and vast amount OF
mysticism, the outside world. from
king TO qualling peasant, looked on
his workshop with awesome respect
convinced often that it was the open
gateway to the realms of darkness.
Here in Washington we have many
descendants of these maSician-astrolo
gers denS. Every physical and chem
ical laboratory traces back to such
ancestry. But there Us one building
which could, if it wished, lay special
claim to this dubious distinction. 1t is
the beautiful marble palace at Twenty
first and B streets, in the shadow OF
the Lincoln Memorial, built for the
National Academy of Sciences and the
National Research Council.
Not only is this building a national
headquarters knr American science,
serving as an. Office building for scien-
tific organizaJ ions and a meeting place
for scientific bodies. but il is ais" the
open door through which a CuriouS
public may gaze at many OF the mir
acles Of modern magtc-niracleS such
as the minds Of the old-tinle wise men,
with all their lurid ina ginings, never
approached in their farthest flights OF
fancy.
Nearly the whole first floor IS given
over to an array of curious exhibits,
graphically illustrate some of the
most magnificent triumphs of the
modern scientific mind. But they are
not the usual dead exhibits of the
museum case. Most Of them are me-
chanlcal and electrical devices which
the visitor operates for himself. A
card of plain instructions accompanies
each machine. telling how to set ii
going and what principle of science ii
illustrates.
Many of the truths which these de.
vices portray have taken long years
and decades of patient, tOilsome. i'm
mensely painstaking study to discover
Some of them lie at the very basis
of our earthly existence. Yet so sim
pie may a profound truth be, once il
Is established. that a school boy or
girl can understand its demonstration
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INTERESTING, indeed, would it be
If we could summon one of the
medieval sages. the nearest apprOa ch
to the scientist which their times
offered. and take him on a tour of
these strange mechanisms.
Here" we can imagine ourselves
explaining to him. lis what we see
when we look through the huma n
body. Oh, yes. we can see WadayS
right through solid bodies-aslmost as
if we had the invisible cloak which the
romancers of your day were SO fond
Of writing about.
Here is a lamp that would dazzle
your eyes like the sun il it were
lighted. And to light it we do not
even have to wave a magic wand.
We simply press a button.
do YOU see these brilliant color
bands. violet. red. and all the colors
between? We get them by splitting a
sunbeam into its natural parts. Here
is a machine which shows how we
measure the millions of millions of
miles which separate the great suns Of
the sky-the bodies you used to call
fixed stars, which you thought went
round the earth every day. And here,
on the other hand, is a device which
measures the bending of an iron bar
almost to the millionth of an inch
by this bulb we can talk to each
other over continents and oceans.
There by the wall is the modern
Aladdin's lamp in miniature. We. do
not rub its metal sides to summon
our jinni. but we Whirl a bundle Of
metal rods in apparently empty
space, and the electrical demon shat
lives in the air rushes to our help
with terrific power
This is our modern magic Per.
haps. after all. the greatest mistake
which your far-ranging medieval
minds made was that they were not
daring enough in their dreams even
to approach the truth
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WE can imagine how our visitor
from the dark ages would gaze
with all his eyes and listen with
greedy ears as these achievements Of
the human mind were described to
him.
We ourselves. here in Washington.
are too busy with the details of daily
work and play to let our thoughts
wander often to the things shown in
this temple of science, or take the
time to visit a building which many
of our ancestors would have travelled
thousan nds of miles to see
For one thing it is always at our
doors. available whenever we choose
to drive down the Speedway or board
Potomac Park car or bus. And so
like so many other attractions ol
Washington, it must wait until the
out utof-town cousin comes sightseeing
before many OF Us discover its absorb
ing interest.
But eventually the cousin usually
comes. Perhaps a little preliminary
review of some of the most striking
exhibits will be useful IN answering
his curious questions.
No sooner do you enter the door
than YOU see that this is no ordinary
place into which YOU have yentured
For here, before yoUr eye, is some
thing which you can see nowhere else
in the country-Somethir% which
gives at once a quality OF ;strangeneSS
to the whole interior, 8 nd makes yot
appreciate how awestruck were tht
people of old in the FACE Of the al
chemists and astrologer's manifesto
tions of the unknown.
From the dome of the central hall E
brass ball. suspended by a long wire
silently and solemnly swings to ant
fro. passing and repa ssing a dial-likt
plate on standard in the center o.
the room.
It is Foucault pendulum. "Wha
is that" you ask. Simply pendulum
like any other, but one much longel
than usual and hung SO carefully tina
1t has perfectly free play 10 swing il
anv direction. And its sole purpos,
IS, not to move clockwork or othel
mechanism. but TO make visible before
our eyes the rotation of the earth OF
its axis.
One of the laws of the pendulum il
that it invariably tries TO keep swing
ing in the same plane as that il
which 1t was started. No matter wha
happens to it's support it does its hes
to remain loyal to the direction OF it
previous swing.
But this pendulum before your eyes
and all the pendulums you will eve
see are fixed to some support which
Is set into the surface of the rapid,
turning earth. At the end of eacl
swing. therefore. the pendulum bal
finds itself in a different position from
that of moment before In it's stead!
effort to keep to me path it thu
changes direction, very slightly. in re
lation to surrounding objects witt
each successive swing. In the North
ern Hemisphere this change is clock