Page 253 - Lokmanya Tilak Samagra (khand 2)

40 SAMAGRA TILAK - 2 • THE ARCTIC HOME

beams of the dawn, when the sun is about 16° below the horizon.
But it is said that in higher latitudes the light of the sun is dis-
cernible when he is from 18° to 20° below the horizon. Probably
this latter limit may prove to be the correct one for the North
Pole, and in that case the dawn there will last continuously
for two months. Captain Pim, quoted by Dr. Warren, thus
describes the Polar year :-
" On the 16th of March the sun rises, preceded by a long dawn
of forty-seven days, namely, from the 29th January, when the
first glimmer of light appears. On the 25th of September the sun
sets, and after a twilight of forty-eight days, namely, on the 13th
November, darkness reigns supreme, so far as the sun is con-
cerned, for seventy-six days followed by one long period of
light, the sun remaining above the horizon one hundred and
ninety-four days. The year, therefore, is thus divided at the
Pole :-194 days sun; 76 darkness, 47 days dawn, 48 twilight."*
But other authorities assign a longer duration to the morning
and evening twilight, and reduce the period of total darkness
from 76 to 60 days, or only to two months. Which of these calcula-
tions is correct can be settled only by actual observation at the
North Pole. It has been ascertained that this duration depends
upon the powers of refraction and reflection of the atmosphere,
and these are found to vary according to the temperature and
other circumstances of the place. The Polar climate is at present
extremely cold; but in the Inter-Glacial epoch it was different,
and this, by itself, would alter the duration of the Polar dawn in
Inter-Glacial times. But whatever the cause may be, so much is
beyond doubt that at the Pole the twilight of the yearly morning
and evening lingers on for several days. For even taking the lowest
limit of 16?, the sun, in his course through the ecliptic, would
take more than a month to reach the horizon from this point;
and during all this time a perpetual twilight will prevail at the
Pole. Long dawn and long evening twilight are, therefore, the
principal factors in shortening the darkness of the Polar night
and if we deduct these days from the duration of the night, the
period of darkness is reduced from six to two, or at the most,
to two-and-half-months. It is, therefore, erroneous to suppose
that the half yearly Polar night is such a continuous period of

• See Paradise Found, JOth Ed., p. 6~.