Page:Popular Mechanics 1928 11.pdf/5

 

Vol. 50

 

wo men recently spent a quiet afternoon diving into a great tank at the navy yard, Washington. They wore bathing suits and on their heads was a curious-looking device not unlike an ordinary gunny sack with a rubber tube attached to the wearer's mouth.

First one man would disappear slowly beneath the surface. His every move was visible to the few spectators above, for the water was absolutely clear. Treading water, he would find the bottom and then, by means of some magic powers attached to the head device, he would remain down there, may be half an hour, possibly longer. Safe on the surface once more, he would watch similar maneuvers of his companion diver.

Since the apparatus is so built as to work efficiently only from the bottom up, rather than from the surface down, it was necessary to inclose the diver's head into a device looking like an inverted half of a barrel. It served the purpose of entrapping a substantial quantity of air, thus permitting quick descent.

Extremely simple as those diving operations appeared to be, they meant much to 