Marston was the first to make a careful inspection of every article intended for the operation.
"Do you consider these buoys powerful enough to lift the Projectile, Captain?" he asked next morning, as the vessel was briskly heading southward, at a distance of ten or twelve miles from the coast on their left.
"You can easily calculate that problem yourself, Mr. Marston," replied the Captain. "It presents no difficulty. The Projectile weighs about 20 thousand pounds, or 10 tons?"
"Correct!"
"Well, a pair of these buoys when inflated can raise a weight of 30 tons."
"So far so good. But how do you propose attaching them to the Projectile?"
"We simply let them descend in a state of collapse; the diver, going down with them, will have no difficulty in making a fast connection. As soon as t
