“That’s dandy,” replied Benton, “and when we get down to San Domingo we’ll do a lot of cruising just off shore so that you can get thoroughly familiar with your work before cutting loose for the big adventure. That removes a lot of worry from my mind, for I’d hate like thunder to have to ship a crew from the kind of material you find in a West Indian port. They’re smart enough sailors, but as a rule a bad lot to have on any trip, let alone an expedition that’s looking for treasure.
“Now as to supplies. We’ve got to take along guns, revolvers and plenty of ammunition. Then we’ll need dynamite and blasting powder—”
“I don’t see exactly where that comes in,” remarked Tom.
“For use in getting to the treasure,” explained Benton. “Granted that we locate the ship, it’s altogether unlikely that we’d be able to get through the hatches. They’d in all likelihood be crusted with barnacles or covered with silt and sea growths that would make it impossible for the diver to get into the hold unaided. But he could plant a charge of dynamite, and then after he’d been drawn up the charge could be fired by means of an electric spark from a battery in the boat above. That would tear a big hole in the deck and give the diver a chance to get in.
“Speaking of the diver,” Benton went on, “brings us to one of the most important things of all, and that is the diving suit. We can’t afford to get any but the best, for the man that goes down in it literally takes his life in his hands. The work though is less dangerous than it used to be because of the improvements that have been made.
“For instance, in the old-fashioned suits the fresh air was served to the diver from the surface of the water through a tube and the pressure within the suit was increased to equal the pressure outside of it. But the more modern suit that I have in mind eliminates the necessity of the air tube. The diver carries his own oxygen with him in a tank that is fitted into a steel shell that is a part of the suit. Beside the oxygen tank is another tank containing caustic soda which absorbs the carbon dioxide given out by the expelled breath of the diver. A valve operates to deliver a certain amount every hour of oxygen properly mixed with nitrogen.
“You see how much safer the diver is under these conditions. Most of the danger used to lie in accidents to the air tube. It might get entangled, or cut or bitten by a shark and then it was all up with the diver. Now he’s independent of that. He can work longer at a time and with much greater peace of mind.
“Then too he can see under water much better than he did in the old days. The head piece of this suit I’m talking of has four openings which are fitted with heavy glass, so that he can look out in front or on either side without shifting his position. And as the diver goes down, three blazing lights of many hundred candle power each, in glass especially made to resist pressure, are let down with him so that instead of groping around he can work at his ease in a great zone of light that floods the water and the ocean bed for many yards on all sides of him.
“Moreover they’re using manganese bronze nowadays for the trunk and headpiece of the diving suit and that is a good many times stronger than steel. Take it altogether, the work of the diver isn’t nearly as hard and perilous as it used to be.”
“No cinch though under the best of conditions, I should think,” put in Dick.