“Our negro guide now informed us that we must make haste to re‐cross our narrow bridge, as the sea would get up as the tide rose. We lost no time, and got back dry enough; and I was obliged to make my sketches from the mainland. “In about three‐quarters of an hour the sight was truly magnificent. I do not exaggerate in the least when I say the waves rolled in, long and unbroken, full twenty‐five feet high, till, meeting the headland, they broke clear over it, sending the spray flying over to the mainland; while, from the centre of this mass of foam, the Souffleur shot up with a noise which we afterwards heard distinctly between two and three miles. Standing on the main cliff, more than a hundred feet above the sea, we were quite wet.” [Illustration: “THE SOUFFLEUR,” ISLAND OF MAURITIUS.] To the combined influences of tides and waves may also be attributed the monsoon hurricanes which so often visit the Indian Ocean. The air may have been just previously without a breath, when immense waves, accompanied by whirlwinds, come rolling in. “At the period of the changing monsoons, the winds, breaking loose from their controlling forces, seem to rage with a fury capable of breaking up the very foundations of the deep,” and ships are often literally whirled round, or bodily lifted up, their crews being utterly impotent. Turning to another subject, partially discussed before—the colour of the sea—it may be remarked that by itself as sea water it is really colourless. Its varying colours are caused by reflection, by the varied bottoms it covers, or by the presence of actual animal, vegetable, and mineral bodies. The ocean, “When winds breathe soft along the silent deep,” is azure blue or ultramarine, becoming greener in‐shore. There are some days when it is generally green, others sombre and grey. A bottom of white sand will give a greyish or apple‐coloured green; of chalk, a pure clear green; if the bottom is brownish‐yellow sand, the green is naturally duller in character. In the Bay of Loango the waters appear of a deep red, from the red bottom. The Red Sea owes its colour to actual floating microscopic algæ and to red coral bottoms. Sea water, concentrated in the salt marshes of the south of France by the heat of the sun, is also red: this is due to the presence of a red‐shelled animal of microscopic size. These minute creatures do not appear till the salt water has attained a certain concentration, while they die when it has reached a further density. Navigators often traverse patches of green, red, white, or yellow‐coloured water, their coloration being due to the presence of microscopic crustaceans, medusæ, zoophytes, and marine plants. [Illustration: A SHIP SAILING IN PHOSPHORESCENT SEA.]