Page:Popular Mechanics 1928 11.pdf/6

 humanity—the possibility of avoiding loss of life in submarine disasters.

First Stage in Descent with the Diving Bell; Diver Climbing Inside for Lowering Close View of the Bell That Aided in Rapid Descents during Breathing-Mask Tests by the Navy; Note Air Hose and Connection

The two divers are counted among America's best-known experts on submarine life-saving devices—Lieut. C. B. Momsen and Chief Gunner C. L. Tibbals. For six months they had been working night and day on the breathing device they had invented in conjunction with F. M. Hobson, civilian engineer in the naval bureau of construction.

Following the tank tests in sixty feet of water, the experts took their apparatus a few miles down the historic Potomac, recently choked with mud through flood. Instead of the inverted barrel, an especially rigged up diving bell, weighing about 1,500 pounds, was employed to convey the diver to the bottom. During the descent, he was located within the bell in such fashion that, while standing on a platform, his head was inside a bubble of air. Slowly he was lowered, his system meantime becoming gradually accustomed to the steadily increasing pressure until he reached the bottom, 110 feet below the surface.

Fundamentally, the apparatus has all the essential characteristics of standard European life-saving apparatus, but the new navy device weighs only two pounds—many times lighter than others of its kind, which range around twenty-one pounds. Then, too, the rebreather is small, about eight by ten inches.

Lieutenant Momsen, one of the inventors of the newcomer, gives a graphic description of its operation on the scene of actual disaster. "There are two ways," he explains, "whereby it may be used to advantage. First of all, when no help seems to be at hand and the crew of 