FIG. 100–U. S. SUBMARINE "SHARK" READY FOR A DIVE
Photo by Pictorial News Co.
FIG. 101–FIRST SUBMARINE CONSTRUCTED IN UNITED STATES. IT WENT TO THE BOTTOM WITH SEVEN MEN, WHO WERE DROWNED
Photo by Pictorial News Co.
There is one kind of submarine built for peaceful pursuits which deserves mention. It is the Argonaut, invented by Simon Lake. This remarkable boat crawls along the bottom of the sea, but not at a very great depth. It is equipped with divers' appliances, and is used in saving wreckage. Divers can go out through the bottom of the boat, walk about on the sea bottom, and when through with their work re-enter the boat; all the while boat and men are, perhaps, a hundred feet below the surface. The divers' compartment, from which the divers go out into the water, is separated by an air-tight partition from the rest of the boat. Compressed air is forced into this compartment until the pressure of the air equals the pressure of the water outside. Then the door in the bottom is opened, and the air keeps the water out. The men in their diving-suits can then go out and in as they please.
For every boat there is a depth beyond which it must not go. The penalty for going beyond this depth is a battered-in vessel, for the pressure increases with the depth. Every time the depth is increased thirty-two feet the pressure is increased fifteen pounds on every square inch. Beyond a certain depth the vessel cannot resist the pressure. Submarines have been made strong enough to withstand the pressure at a depth of five thousand feet, or nearly a mile. Most submarines, however, cannot go deeper than a hundred and fifty feet.