“It’s a good thing for us that it does,” Mark answered.
“We must lose no time,” the professor put in. “If the earthquake destroyed the downward shaft, it may effect this one in time. We must escape while we can.”
Then, for the first time, he opened the storeroom and the big cylinder was disclosed to view. It was made of aluminum, and shaped like an immense cigar. The hull was double, and it was strongly braced. Inside were padded berths for the occupants, and there was just room enough for the seven adventurers. Once they had entered they could not move about, but must stay in their little compartment.
Compressed air in strong cylinders furnished a means of breathing, and there were tiny electric lights operated by a storage battery. There was also a chamber to be filled with the lifting gas. The cylinder was so arranged that it would float on it’s long axis if thrown into the water. A trap door hermetically sealed gave access to the interior. A small propellor, worked by compressed air, furnished motive power.
The food supply consisted of compressed capsules on which a man could subsist for several days. There was also some water, but not much, since that can not be compressed and would, therefore, take considerable room.
“The only thing for us to do,” said the professor, “is to get into the cylinder, seal it up, and trust to Providence. This is what I intended to use when we were caught in the draught.”
“How can we get into the column of water after we shut ourselves into the cylinder?” asked Mark.
“The cylinder fits into a sort of improvised cannon,” said Mr. Henderson. “It is fired by electricity and compressed air. We will aim it at the column, press the button and be projected into the midst of the water. Then——” He did not finish the sentence, but the others knew what he meant.
“When are we to start?” asked Mark.
“As soon as possible,” replied the professor. “I must arrange the cylinder, compress the air and lay out the food supply.”