But a prolonged search failed to reveal any trace of the man of science.
Where could he be?
A scrutiny of his cabin, even looking under the bunk, failed to reveal him. The boys began to fear he might have been swept overboard, when suddenly Frank exclaimed:
"Perhaps he is in his laboratory."
"Hiding there?" asked Billy.
"No, I don't think so. The professor, whatever his oddities may be, is no coward," rejoined Frank.
"No, his search for the Patagonian dog-flea proved that," agreed
Harry.
Frank lost no time in opening the trap-door in the floor of the main cabin, which led into what had formerly been the "valuables room" of the Southern Cross, but which had been fitted up now as a laboratory for the professor.
"There's a light burning in it," announced Frank, as he peered down.
"Oh, professor—Professor Sandburr, are you there?" he shouted the next moment.