“I’ve been thinking about that,” said Phil. “And I’m pretty sure that we’ll never be able to carry on diving operations from the dory. It seems to me we’d do better to build a big raft, and mount the apparatus on that. We could tow it out through the passage in the reef easily enough.”
“That sounds like a crackerjack idea to me,” said Dick, enthusiastically, and the others agreed with him. So it was decided to try out this plan as soon as they got all the supplies off the Fleeting that they would be likely to require.
The construction of the raft was a difficult operation, but at last they had it finished, and Phil and Benton embarked in the dory to go on a hunt for the wreck, while the others attended to mounting the windlass on the raft.
CHAPTER XIII
UNDER THE SEA
In the boat they had installed the radio apparatus necessary for locating submerged objects, together with a log to be used as a buoy attached to a long length of cord. The purpose of this was to mark the site of the wreck if they should be so fortunate as to locate it.
Benton, who was rowing the boat, was skeptical over Phil’s radio outfit, and did not hesitate to express his doubts.
“I know you’ve tried to explain the business to me, Phil,” he said, “but I’m blest if I understand it yet. How do you figure to locate that wreck with radio waves?”
“It’s not so complicated as it seems,” said Phil. “This set is equipped with unusually sensitive vacuum tubes, and with certain condenser arrangements, radio waves affected by metal deposits are received through the water. Now, in the receivers of this set I can hear the incoming radio waves, and the second that they vary in strength I know that we are near some large quantity of metal. That’s simple enough, isn’t it?”
“Well, yes, but this was a wooden ship, remember,” objected Benton.
“Yes, but if it’s the one we are after, there is plenty of metal aboard,” said Phil. “Yellow metal—gold, in other words, as well as anchors, windlass and other metals.”