Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1910-11-25

All scientific progress is due to the
ability of the inventor to produce appa-
ratus of exquisite delicacy and refine
ment, and while Americans have Jagged
behind somewhat in this direction in
past generations. they have been max
ing up lost time in these latter days
1--e late Professor Langley wanted to
learn something about the heat of the
stars, so he devised the bolometer, that
wonderful little instrument of such mary
elous sensitiveness to heat. Others had
perfected various kinds of heat-gneasur-
ing instruments, but none Of them was
sensitive enough to tell Professor Lang
ley what he wanted to know. AT another
time he was trying to make the birds
tell him their secret of flight; but there
was no means of communication between
them. So he fitted up a pair of shot
gun cameras" electrically connected to-
gether. He had two Of his assistants
watch a bird and at an agreed time to
point their camera guns at the bird
from different angles. When one or the
operators got good view. he pulled the
trigger and both cameras snapped Sd
simultaneously The result was that the
birds picture was secured at different
angles at precisely the same moment
. When Prof. A. A. Nicholson, Of Chi
cago, sought an extremely accurate meas
ure of length, he found that the most
delicate measure in existence was not
accurate enough to suit his purposes. So
he determined to solve the problem or
accurate linear measurement. He devised
an instrument called the interferometer
When he had perfected 1t. he found ne
had produced a machine that would tel
the length of anything, even down TO the
'one-tlfth millionth part of an inch. Pro-
fessor Nicholson found that light waves
were almost exactly like the water
waves when two stones are cast stimuli
taneously into a still pond. If the two
circles interfere they quickly wear each
other down; but II they coincide, the
height of the little waves Is increased
Humanitys debt to delicate SCIENTIFIC
instruments is we'll illustrated by three
things used by the scientlst-the micro
scope the telescope. and the spectro-
scope none of which was invented by an
American, but all of which have been
used by Americans to make some won
derful discovery in the realm of science.
With the microscope man has been able
to invade the regions of the infnitisemal;
while the telescope has carried him into
the realms of the infinite. The marVels
of modern surgery came from knowledge
gained with the microscope, ana lhe
whole germ tribe was discovered by It's
use. For thousands of years men llVed
all unconscious that such things as germs
existed Then a doctor held a microscope
10 a drop of blood and a new world OF
living creatures was discovered. Num-
berless inventions and discoveries have
been based on this instrument. In the
case OF the telescope, our time. our MOD
ern methods of surveying and our mas
terv of the laws of gravity and motion
are practical things which may be traced
to II. g.
with the spectroscope the arusan 10
able 20 determine the properties OF sucn
mundane stuff as common sugar; wnlle
tbs astronomer Is able to go trilions of
miles into space and catch rays of light
which tell him what kinds of matter are
found inn the star which he Is studying.
The old-fashioned prism. through winch
a raw of light looked like rainbow. Is
the simplest form of the spectroscope
With this instrument, minerals nave oeeh
found in the stars before they were dis
covered in the earth. In the arts. the
snectroscope IS used in the analysis OF
sugar. II ia used to show the exact mo-
rnent when iron is converted into steel
when in the converter and is great AID
in the detection of adulterants In foods
II Is in these fields that the Americans
have made the best use Of the spectre
SCOPE It will also inform its owner
whether the thOuSandth part or a gram o.
dried blood is Of human or animal origin
When the chemist goes into court ana
swears positively that a certain red
splotch in the evidence Is human blood.
he predicates his oath upon his spectro-
scopic analysis.
The accuracy Of weighing instruments
is no less remarkable than those which
measure length, heat or other qualities
Scales of such extreme sensitiveness have
been devised in America that they will
register n difference of one-five-hundredth
of a mi'Iigram. We get an idea of what
this means by the following illustration;
If two weights of common shape. each
Weighing two pounds. were placed on
one side of the scales. and two others
exactly like trem were placed in identical
positions on the other side. there would
he a perfect balance. But If on one side.
ore weight should be put on top Of the
other, the bare two inches Of difference
in the distance of that weight from the
center of the earth would cause the
scales to register the difference in weight
In Other words. so refined are these bal
ances that they will tell the difference in
weight OF a two-pound block of steel
when moved two inches farther from, or
nearer to. the center Of the earth.
Even in the machine shon one comes
across Instruments OF remarkable pre-
cision. There are many machines made
in which the difference Of a thousandth
part of an inch would be the difference