Evening star., 1941-02-01
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas r. Henrg.

By Thomas r. Henry.
Mother earth is growing about l25,o00
tons fatter every year.
She is about 1000, O,O0o,0 900 years old
and up to now, assuming the same rate
of increase from the beginning, she has
gained close to 250,000, 900 900 900 tons.
At present she tips the scales at ap-
approximately 5000, 900, 900 900, 900 900 900
tons, so the annual increment doesn't
worry her much.
These are. the latest computations
reported to the National Research
Councils Committee on the Measure
ment OF Geologic Time by DR.. Fletcher
G. Watson of Harvard University. The
increase Is due to the Shooting stars
perhaps part of the wreckage of some
smashed planet-at least billion of
which hit the outer atmosphere each
year. Only about a thousand a year
actually hit the ground where they can
be picked up and weighed The others
are burned from the heat generated by
their friction with the thin upper air
and eventually come to the earth as
ashes.
Previous estimates of the annual
increment of the planet have been
largely guesses. Dr. Watson reports a
method of actually weighing the shoot
ing stars as they enter the atmosphere.
Harvard astronomers, he says, have
worked out a formula by which the
weight can be computed from the
brightness of the meteor and its velocity.
Both Of these can be measured from
the earth. Thus they have found that
a shooting star of the second magni-
tude-one that can be seen with the
naked eye without dificulty-moving
about so miles second has a mass of
about 10 milligrams. There are close
to 10000 milligrams in an ounce. The
combined weight of these visible meteors
a day, he says, is close to 1000 900 900
milligrams.
Some of these shooting stars are very
large, weighing on the average about
$50 pounds. These actually hit the
earth but there are so few of them that
they add little to the planets weight.
There are others too small to be seen,
even with telescope, but their num-
bers can be estimated with some accu-
racy. The whole adds up to about 125,-
600 tons year. or about three-quarters
OF pound per square klometer of the
earths surface.
In the same report DR.. Watson tells
OF measurements of the approximate
age of meteorites which have hit the
earth. Determinations have been made
on four during the past year by Prof.
F. A. Paneth of the University of Lon
don. The method is essentially the same
as that used to estimate the age of rocks
on earth. The meteorites contain the
radioactive materials-uranium and
thorium. These degenerate into forms
OF lead, throwing off the rare gas helium
in the process. BY determining the
amount of helium in mass OF stone or
iron from the sky one can calculate the
time required for the other elements
to produce it.
admits, few million years out. The
ages range between 1OO,O00,0O0 and a
billion years. The fact that this
material solidified so long," he says,
may require the conclusion that It
originated in some body much smaller
than the earth. Where and how remain
open questions"
The Opaque curtain, ideal for black
outs and boon for modest folks who
undress with the lights on, was pat
ented here today.
1t is fabric only few thousandths
Of an inch thick, as described by the
inventor, Charles c. Quenelle of New
burgh, N. Y, which stops all light. The
patent is assigned to the Dupont COM
pany.
Early In the war In both London and
Paris one of the worst features of the
nightly blackouts was the fact that all
lighted rooms had to be covered with
heavy curtains which, while they shut
OF light effectively, also shut on all air.
Nights were intolerably sultry. II the
curtains were thin they had to be prac-
tically jet black to keep back any fiickers
OF light from the inside.
The new curtains, according to the
patent description, may be of almost any
color and some pleasing shades are
described which would brighten a
blacked-out room and partly offset the
psychology of gloom which has been a
prominent feature of the war. Since no
light can get through these curtains,
shadows thrown against them would be
invisible from the outside.
Opaque curtains in the past, Mr..
Quenelle claims, either have been thick
or have required many coats of q pig
ment composition which rendered them
so stiff as to be almost useless. They
were very difficult to manipulate.
The new curtains either can be made
OF woven cotton fabric or of some of
the cellulose fabrics. The trick, accord
ing to the patent, is first to render them
opaque by treating the cloth with a
composition containing aluminium flakes
They are left impermeable to light and
of an aluminium color, pleasing in itself.
Afterwards they can be dyed to suit the
householder. The thinner they are the
better, he points out, and should not
exceed .013 of an inch in thickness.
They have been tested with photo
electric cell, the most sensitive light
detector known. A few inches away
from the window of q lighted room 1t