Evening star. [volume] (Washington, D.C.) 1854-1972, 1954-07-23
Seusickness Caused
By 'Heove,' Navy Finds
Doctors Study Six Kinds
OF Errutic Motion at Sea
BY Thomos r. Henry

BY Thomcs K. Henry
The major cause OF seasickness Is the
ships "heave.
\. This is the conclusion Of Navy doc
tors from intensive study Of the amount
Of sickness among Marines and soldiers
on transport ships correlated with six
kinds Of erratic motion.
This has just been reported by Capt.
CHRISTOPHER c. Shaw Of the Naval Hos
pital at Oakland, Calf.
The experiments were carried out on
voyages between the United States and
Europe Of the transports Gen. r. e.
Callan and Gen. Alexander Patch, each
carrying many soldiers with very little
previous sea experience and each
equipped with instruments to measure
six kinds Of motion to which all ships
were subject.
These motions were: Rolling from
side to side. pitching, yawing or throw
ing q ship on course, swaying, surging
and "heaving.n The latter is defined as
AN oscillatory motion much like that
OF cork bobbing on a wave" A GER
tain basic amount of seasickness was
expected. It would have been encoun-
tered on the most quiet seas and pre-
sumably has large mental component.
When this increased markedly it was
reasonable to assume that the cause
was some increase in one or more OF
the six basic cratic motions.
Heaving Blamed.
Ihere was no correlation between
yawing. swaying and surging. Increases
We're noted with accelerated pitching
ana rolling, but they were quite in
conclusive. There was no question. how.
ever, about the correlation with the
corklike motion, heaving. The effect az
was clearly physical and not mental.
and poses considerable problem FOR
marine engineers. The primary effect az
neaving. 1t was concluded. was ac-
centuated by both pitching and rolling,
although neither of these might have
been SUFFICIENT to cause the physical
eHect without the precipitating cause.
Inc problem, Capt. Shaw points out.
Is Tar from academic in both Army and
Navy. In the war period between 1870
ana 1913. for example, more than
$4,000 men were admitted to sick
pays Tor seasickness and were incapaci-
tated an average Of eight days. II was
necessary to discharge 10000 because
OF incurable seasickness. In 1883. dur-
ing the Korean war period, $50 sailors
were invalided out Of the Navy for the
same reason.
1t now is possible to determine time
10 an accuracy Of 2O-billionth of a
second by observations of sun and
moon.
This Is the conclusion of DR.. DIRK
Brouwer. director Of the Yale Obserya-
Tory. who has worked In close Cooper
alton with the United States Naval
observatory. the Nations official time
keeper.
IL Is the elimination, DR.. Brouwer
says. OF the efforts Of mathematician
Tor more than two centuries to prepare
precise tables Of the moons motion
eliminating in the work of the late
DR.. Ernest w. Brown of Yale and the
calculations made possible by new
mathematical machines.
The 20-biNionth of second probabIe
error, however. still worries astrono-
mers since, until it can be eliminated.
i Mere Is no way OF ever telling pre-
] cisely what time II is--or. worse, what
Mme It Will be when certain predicted
event happens thousand years hence.
Efforts Frustrated.
Efforts to measure time precisely bv
the rotation Of the earth long have been
frustrated by variations in the leneth
OF the day, which was about four-hun.
dreths Of second shorter In the 1905
and longer by about the same amount
between 1902 and 1912. DR.. Brouwer
says.
Geophysicists now attribute this var
1ation to turbulent motions Ia the
eartn's liquid core. This turbulence pro-
ouced change in the period Of the
earth's rotation. While the earth as q
whole maintains constant rate, some
times the core turns faster than the
planet as whole and the crust motion
varies accordingly. An observer in outer
space would not see any difference but
an astronomer on the earth's surface
cannot get away from It,
There can be considerable correction
OF the error. however, by observation
OF the moons motion around the earth,
which has been the subject Of intense
mathematical research.
Physicists at the United States Bu-
reau Of Standards are working on
atomic clocks, in which time is meas
ured by the rate of vibration of atoms
in gas molecules. theoretically this
might make it possible to measure time
with an accuracy close to hundred
billionth Of second.
1t is not likely, DR.. Brouwer says, that
the atomic clocks will be sufficiently
practical to compete with the perform
ance Of celestial timekeepers.