"How?"
"I'll show you. Washington, bring out the diving suits."
The colored man, his eyes growing bigger every minute, went to a locker and brought out what seemed quite a complicated bit of apparatus.
"With the aid of these," said the professor, "I will be able to go out, walk along the ocean bed, and investigate the mystery. Do you boys want to come along?"
"Is it safe?" asked Mark, who was inclined to be cautious.
"As safe as any part of this under-sea voyage," replied the professor. "These diving suits are something I have not told you about," he went on. "They are my own invention. Besides the regular rubber suits there is an interlining of steel,—something like the ancient suits of chain mail—to withstand the great pressure of water. Then, instead of being dependent on a supply of air, pumped into the helmet from an apparatus in a boat on the surface, each person carries his own air supply with him."
"How is that?" asked Jack, and Mark also asked the question.
"Simply by attaching a little tank of the compressed gas to the shoulder piece of the suit," said the inventor. "There is enough air in the tank to last for nearly a day. It is admitted to the helmet as needed by means of automatic valves. In other respects the diving suit is the same as the ordinary kind, except that there is a small searchlight, fed by a storage battery, on top of the helmet."
In spite of their fears at venturing out under the great ocean, the two boys were anxious to try the suits. So, after some hesitation, they donned them.
"Here, take these with you," said the professor, before their helmets were screwed on. He held out what looked like long sticks.