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RAPID INCREASE OF LIGHT.

69

day, to state that we could, at noon, read with tolerable ease the smallest type or print by holding the book directly towards the south. The type of the contents of our chapter was that which could be read.

On the 3rd of February the sun was seen from the Hecla's maintop, being the first time since the 11th of November, a period of eighty-four days, being twelve days less than the time of its remaining actually beneath the horizon, independently of atmospherical refraction.

On the 11th of February the sun's meridian altitude was lo. Nothing could excel the beauty of the sky to the S.E. and S.W. at sunrise and sunset about this period—near the horizon a rich bluish purple, and a bright arch of deep red above, the one mingling imperceptibly with the other.

The orange and lake tints painted the sky in the most beautiful manner.

On the 7th of February there was sufficient DayLIGHT from eight o'clock till four, to enable us to perform any work outside the ship with great facility. What a rapid and surprising change! Parhelia or mock suns and halos were frequently observed.

On April the 7th at midnight there was light enough to read the thermometer with great ease, and this continued to be the case of perpetual light until the 2nd of September, or a period of 150 days.

And from the 4th of May to the 7th of August, a period of 96 days—the sun never set, but wheeled round day by day—a perpetual sun.

We cannot fail to perceive the evidences of the

70

DURATION OF LIGHT IN THE POLAR REGIONS.

universal law of Divine beneficence in the preponderance of the light over the dark. The sun never set for 96 days, but he was absent only 84, giving the majority of twelve days.

It would almost seem a senseless paradox to assert that the polar regions had a larger portion of light than the tropics. But such is not so remote from the truth as a casual thought might suggest; at any rate, there is a peculiar distribution of light in the polar regions.

The tropics enjoy the full blaze of light and heat in their intensity, but each of these elements undergo some modifications as they approach the polar regions. The light suffers great refraction, and produces some remarkable effects; the sun is seen when he is much below the horizon, and the same cause gives rise to the amazing length of twilight, so characteristic of these regions.

“When the sun loves to pause,
With so fond a delay;
That the night only draws
A thin veil o'er the day.”

MOORE.

As these effects increase rapidly as we approach the pole, it is possible that absolute darkness is unknown there, and that there prevails a continuous twilight during the short time even that it is absolutely beyond the assigned limits of twilight declination or depression, but without even assuming this, or a single point beyond the demonstrated fact, we may consider the polar regions as the realms of light. Such being the apparent ordination of this agent, we may well suppose some specific purpose to be effected by the presence of such

THE AURORA, OR ELECTRIC LIGHT.

71

a flood of light. The subject receives considerable interest from Professor Faraday's important researches on the relations of light and magnetism, and the great fact he established of the rotation of a ray of light by magnetic force, and his own conclusions that it did not seem impossible to him that the sun's rays might be found to originate the magnetic force of the earth, and that the atmosphere was the medium through which it was eliminated. Here we have the light, the magnetism, and the needle, and the electric lights.

AURORA BOREALIS AT

LONDON.
Throughout the valuable work

of Mr. Howard on the Climate
of London, there are very
few remarks, or notices even,
of the appearance of the
aurora borealis-in fact, they
are only very casually ad-
verted to. But in the winter
of 1819-20 they are
tioned frequently.

AURORA AT MELVILLE

ISLAND.
Captain Parry remarks that in

no instance whatever, at
Melville Island, did the
aurora produce the slightest
effect either on the gold leaf
electrometer or on the mag-
netic needle. The most
diligent and unwearied at-
tention was given to this
subject throughout the whole
season, and many opportu-
nities were afforded them
of making the most delicate

men

observations—but no effect. 1819. Oct. 13th.-Aurora borealis

seen, consisting of stationary
white light, S.W.

1819.
Oct. 13th.—The aurora borealis

is said to have appeared at

night. Oct. 17th.-Fine aurora bore

alis in the evening-observed at Tottenham by my friend William Philips.

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These instances of the aurora are given at London and Melville Island, because they evidently seem to denote something like a monthly recurrence about the same period. Mr. Howard's observations are most laconic; they are among the very few entries in his work. October 13th, 17th; November 18th ; December 14th ; January 14th. And when we consider their coinci

SIMULTANEOUS APPEARANCE OF AURORA.

73

dence with simultaneous exhibitions of the aurora at Melville Island, and allowing eight hours for the difference of time between the two places, some connection appears to exist between them, and that the aurora is often of considerable extent and of wide-spread action.

In respect to its assumed periodicity, why should we exclude the subtle spirit of electricity, when we perceive and note the obedience of its allied agent, heat, to the law of order? At any rate the examples I have given are, as far as a few instances go, in favour of such an idea. It may be objected that on the 18th November I have introduced a brilliant meteor instead of an aurora. But yet it may be well to advert to such a subject, as I am inclined to believe that some of the meteors, and especially those falling stars, whether in showers or singly, belong to the province of atmospheric electricity, and are connected and associated, in some degree, with the aurora, as far as electricity is concerned, for during the displays of the aurora, falling or shooting stars and meteors are very frequently mentioned as being

seen.

And Mr. Howard's brilliant meteor was the periodic return of the auroral principle which took this form. Such, however, may be only a meteoric thought, and have no abiding power, and be excluded from the list. With even this excluded there remains the vestige of a fact and the presence of truth in the others.

The polar atmosphere is one of extreme interest in respect to its important properties of light, and the

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