With regard to the species of fish common to the Atlantic and the Mediterranean, the giddy speed of the Nautilus prevented me from observing them with any degree of accuracy.
As to marine mammals, I thought, in passing the entrance of the Adriatic, that I saw two or three cachalots, furnished with one dorsal fin, of the genus physetera, some dolphins of the genus globicephala, peculiar to the Mediterranean, the back part of the head being marked like a zebra with small lines; also, a dozen of seals, with white bellies and black hair, known by the name of monks, and which really have the air of a Dominican; they are about three yards in length.
As to zoöphytes, for some instants I was able to admire a beautiful orange galeolaria, which had fastened itself to the port panel; it held on by a long filament, and was divided into an infinity of branches, terminated by the finest lace which could ever have been woven by the rivals of Arachne herself. Unfortunately, I could not take this admirable specimen; and doubtless no other Mediterranean zoöphyte would have offered itself to my observation, if, on the night of the 16th, the Nautilus had not, singularly enough, slackened its speed, under the following circumstances.
We were then passing between Sicily and the coast of Tunis. In the narrow space between Cape Bon and the Straits of Messina the bottom of the sea rose almost suddenly. There was a perfect bank, on which there was not more than nine fathoms of water, while on either side the depth was ninety fathoms.
The Nautilus had to maneuver very carefully so as not to strike against this submarine barrier.
I showed Conseil on the map of the Mediterranean the spot occupied by this reef.
“But if you please, sir,” observed Conseil, “it is like a real isthmus joining Europe to Africa.”
“Yes, my boy; it forms a perfect bar to the Straits of Lybia, and the soundings of Smith have proved that in former times the continents between Cape Boco and Cape Furina were joined.”
“I can well believe it,” said Conseil.
“I will add,” I continued, “that a similar barrier exists between Gibraltar and Ceuta, which in geological times formed the entire Mediterranean.”
“What if some volcanic burst should one day raise these two barriers above the waves?”
“It is not probable, Conseil.”
“Well, but allow me to finish, please, sir; if this phenomenon should take place, it will be troublesome for M. Lesseps, who has taken so much pains to pierce the isthmus.”
“I agree with you; but I repeat, Conseil, this phenomenon will never happen. The violence of subterranean force is ever diminishing. Volcanoes, so plentiful in the first days of the world, are being extinguished by degrees; the internal heat is weakened; the temperature of the lower strata of the globe is lowered by a perceptible quantity every century to the detriment of our globe, for its heat is its life.”
“But the sun?”
“The sun is not sufficient, Conseil. Can it give heat to a dead body?”
“Not that I know of.”
“Well, my friend, this earth will one day be that cold corpse; it will become uninhabitable and uninhabited like the moon, which has long since lost all its vital heat.”
“In how many centuries?”
“In some hundreds of thousands of years, my boy.”
“Then,” said Conseil, “we shall have time to finish our journey, that is, if Ned Land does not interfere with it.”
And Conseil, reassured, returned to the study of the bank, which the Nautilus was skirting at a moderate speed.
There, beneath the rocky and volcanic bottom, lay outspread a living flora of sponges and reddish cydippes, which emitted a slight phosphorescent light, commonly known by the name of sea-cucumbers; and walking comatulæ more than a yard long, the purple of which completely colored the water around.
The Nautilus having now passed the high bank in the Lybian Straits returned to the deep waters and its accustomed speed.
From that time no more mollusks, no more articulates, no more zoöphytes; barely a few large fish passing like shadows.
During the night of the 16th and 17th of February, we had entered the second Mediterranean basin, the greatest depth of which was 1,450 fathoms. The Nautilus, by the action of its screw, slid down the inclined planes, and buried itself in the lowest depths of the sea.