The Dawson news. (Dawson, Ga.) 1889-current, 1925-01-06
SEA FRICTION Is
MAKING DAY LONGER
STUDY OF ECLIPSES LED TO
FACT EARTH WAS LOSING
TIME IN ITS PASSAGE.

The study of ancient eclipses gave
the first evidence that the day is grad
ually getting longer The change that
is taking place is not sufficiently great
TO cause any trouble--in fact it is so
small that it can only be detected by
the most careful study But it is OF
great scientific interest because it is
hound up with the evolution OF the
earth and moon both in the past and
the future.
In 1903 the English astronomer
HALEY, friend and helper of Isaac
Newton and a man OF great ability,
found that he could not reconcile the
motion of the moon as it was then
known with its motion many centuries
earlier and he suggested that some
thing must have occurred to change it.
Planets to Blame
A century later the great French
mathematician and astronomer Lap
lace proved that the very small at
traction of the planets produced such
a change and the matter seemed set
tied for the time being. Then half a
century later Adams, the discoverer
with Leverrer of the planet Neptune,
stirred everything up again by show
ing that in his calculations Laplace
had made omissions which changed
the amount seriously, so that the an
cient eclipses could not be fully eX-
planned in this way. Many astrono-
mers followed him and finally justified
his criticisms.
Then an era OF speculation started
to explain the difference. The German
philosopher, Emanuel Kant, thought
that the friction OF the tides, as they
continually travelled round the globe,
would act as a brake and tend to slow
down the earth Since the earth is the
clock which we use to measure our
time, this meant that it was the clock
which was losing and not the moon
which was hurrying.
Only a Guess.
Astronomers gradually came round
to this view because it was certainly
true that the friction caused by the
tides must slow down the earth as
well as quicken the motion OF the
moon But after all it was still only
guess because it did not seem posi-
bic to calculate whether the friction
was sufficient to explain the observa-
tons
Many workers, including Simon
Newcomb, who was for many years
head OF the Nautical Almanac office
in Washington, examined the records
OF the ancient eclipses to see wheth
cr HALEY had been right, and found
other eclipses to use, more than 1000
years back, but they did not seriously
change his results.
Friction of the Seas.
The last phase of the story has oc-
Cured since the war. Prof. G. l. Tay-
lor, working in Cambridge, England,
started out to find how much friction
the shallow Irish sea could produce.
He found that it was quite small,
only about one-hftieth OF the amount
required
A colleague of his, Dr. Harold JEFF
fries, calculated the amounts produc-
ed by other shallow seas and found
that there was sufficient friction to
produce what Haley had observed.
Curiously enough, two-thirds of it is
caused by the Boring sea, which lies
between Alaska and Siberia all the
other seas together accounting for the
rest
The whole amount is so small that
the day will only be about one-tenth
OF a second longer 10000 years hence
than it is now But its discovery and
investigation is one OF the big tri-
umphs of mathematical astronomy.