Much the same perplexity has been felt about the blue colour of air, as about the blue colour of the ocean; and much the same course of explanation has been followed. Its blueness was long maintained to be due only or mainly to the “scattering of sunlight” by infinite numbers of floating dust-specks, which also serve to account for the golden and crimson tints of sunset. It now appears that oxygen, an important element in the atmosphere, has a faint blue tint of its own, like water, which at least helps to answer for the blue of the air.
We may therefore say of Water that it is believed to be transparently and intrinsically blue; and that its colour, though not actually due to floating specks of dust and other impurities, is a good deal affected by them. Such materials in the Ocean help to modify its colouring, sometimes deepening it, sometimes adding to its brilliance, sometimes deadening its brightness, sometimes turning it green or yellow. Careful observation has also shown that, when water is especially free from dust-specks, it is of a darker and duller hue than when they are present in large quantities to capture and reflect the sunbeams.
CHAPTER IX.
ICE-NEEDLES TO ICE-MOUNTAINS
“In all time,
Calm or convulsed,—in breeze or gale or storm,
Icing the pole, or in the torrid clime
Dark-heaving;—boundless, endless, and sublime—
The image of Eternity,—the throne
Of the Invisible.”—Byron.
SO far most of our thoughts have been given to Earth’s milder regions; where, indeed, the warm ocean water is at best but a thin slice laid over vast depths of cold water, yet where, so far as man is concerned, heat has the upper hand. In other parts, far to north and south, the Reign of Frost is a dire reality; and that chill monarch “rules the roost” in a masterful fashion, lording it over land and sea for months together, with none to resist his sway.