Evening star., 1941-12-25
Of Sturs, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas r. Henry.

By Thomas r. Henry.
Afraid shelters have saved thousands
| of British lives.
The idea that it is just as safe to stay
at home, which has spread widely in the
United States of late, Is entirely false
according to the testimony of high
ranking British military officer, who has
been closely associated with home de-
| fense and now is on duty here.
Since the start of the war the British
press service has arranged interviews
with its foremost experts on home de
fense problems, with the restriction that
the men remain anonymous.
Probably the most efficient device that
can be produced quickly according to
this expert. Is the "slit trench" 1t is
merely slit in the ground, six feet deep
and two feet wide. A man can just
squeeze into it, with his head Just below
the surface.
The slit trenches are built in zig-zag-
ging sections, and one section will hold
three or four persons. There is no
cover.
When home military camp is set up
the first detail is to dig slit trenches
Their efficiency was illustrated by the
British expert with the example of the
bombing of camp near Glasgow last
winter. The camp was completely de-
molished. Because of the slit trenches
dug in the immediate vicinity not a
single man was injured.
At first glance the slit trench seems
almost too simple, but, the British ex-
pert explains, it has sound scientific
basis.
First, only hit ION the line" can do
very much damage. The probability Of
such hit Is very unlikely.
The person in the trench is almost
completely protected from flying debris.
The shock waves of an explosion are alb
sorbed in the earth. There is no danger
of being buried alive from a cave-in.
The trench, it was explained, probably
Is about as efficient as the more elaborate
Anderson shelter, thousands of which
were distributed early in the war to be
set up by individual families Neither,
Of course, affords any protection what
soever from direct hit, the mathemat-
tcal chances of which are extremely
small. Both give nearly perfect protec-
ton against debris.
The slit trench is simplification of
the type Of shelters which were con-
structed in most of the parks of London
during the few weeks preceding the war.
These were much larger, concrete lined,
and covered trenches which could accom-
modate several hundred persons and in
which two could stand side by side with
elbow room between them.
These required an appreciable time to
build. Their only advantage was that
the top of the head was protected from
debris OF explosions. They had the dis
advantage of the sensation of confine-
ment in a narrow space, with no way of
knowing what was going on outside.
England long ago gave up the idea,
the expert explained, that any extended
warning could be expected before a raid.
Even If approaching planes could be de-
tected half hour or more in advance,
there would be no means of knowing
where they would strike and the normal
life Of large section of the country
would be disrupted while folks scampered
to central AFRAID shelters.
Schools especially, he warned, should
have shelters, even if they must be of the
simplest sort, so close at hand that they
can be occupied within minute or so.
Certain animals have solved the prob
lem of living essentially without water.
This is the contention of DR.. Ernest
P. Walker. assistant director OF the Ma
tional Geological Park, in the annual
report of the Smithsonian Institution.
Through long periods of evolution, he
says, they have developed means of sur
viving with maximum of moisture, so
that today water seems abhorrent to
them.
The most specialized of these animals,
he points out, are some of the rodents,
such as the pocket and kangaroo rats
of the Southwestern United States and
the Jerboas of Asia and Northern Africa.
These animals" Mr.. Walker explains
"live in regions where the rainfall is very
scant over much of their range and
where water is practically unobtainable
They have, therefore, become adapted to
living with almost no water to drink.
During the very short time when there
is green vegetation they may eat some
of it. At other times they obtain no
moisture except, perhaps, an occasional
drop of dew. But their needs are
adequately supplied by chemical proc
esses that take place within their own
bodies, where the constituents of dried
| seeds and other vegetable foods are
converted into moisture by oxidation.
81 have often offered water to pocket
mice, kangaroo rats, grasshopper mice
| and other desert animals to make certain
they did not suffer from lack of moisture.
Almost invariably they refuse it, although
occasionally they may sip little and
then not touch moisture again for
months.
| "One pocket mouse, very old male,
took to using water rather regularly. He
lived in captivity for eight years and was
apparently adult when captured. 1t may
be that as he became older his normal
ability of converting dry food into moist
ure became impaired. Another animal
of the same kind seemed greatly offended
when I offered her water On a few
occasions I dropped single drop of
water on her and was much amused at
her violent antics of rolling in the sand
to remove the offending substance from