"Because you must travel with the speed of lightning almost to East Africa and round the Cape of Good Hope."
"I did not say I was going to do so," replied the captain.
"You can't go overland, since there is no canal through the Isthmus of Suez——"
"But one can go under land," interrupted the captain.
"Under land," answered the professor, holding up his hand.
"Undoubtedly," said Captain Vindex calmly. "For a long while nature has made underneath this tongue of land what men are trying to do now on the surface."
"Does there exist a passage?"
"Yes, a passage or tunnel, which at fifty feet depth touches a solid rock."
"How did you discover it—by chance?"
"No," said the captain. "I guessed that such a tunnel existed, and I have been through it several times."