Page:Popular Science Monthly Volume 90.djvu/599

 Popular Science Monthly

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��A lens system is so arranged as to form a clearly defined aiming mark

��The Acetylene Life-Preserver. It Blows Itself Up with Gas

VERY efficient is the lite-preserver pic- tured in the illustration below. All that it asks of the person to be saved is that it be strapped securely around his body. It will do the rest. As soon as it strikes the water it will inflate itself with gas and will become so buoyant that it will keep its wearer afloat until he is rescued. Kurt Nebel, of Chicago, III., is the inventor.

An inflatable tube lies flat against the body when fastened around it. To this tube is attached a gas bag, with a container for carbide at its lower end. The gas bag is also pro\'ided with inlet-valves through which the water enters, finding its way eventually to the carbide and generating gas instantly from the contact. This gas rises and fills the tube around the wearer's body.

Before the gas bag is inflated it is held flat by a gelatin cord which is looped around its center and which dissolves when immersed in water, so that the bag can round out. This disten- sion, together with the pressure of the water on the outside, tends to open the inlet valves so that the water may find entrance to the carbide. The device is also used as a buoy for those learning to swim.

If thrown out into the water to a "man overboard," the water will dissolve the gelatin cord and the gas bag will become inflated just as pre- viously described, so that all the person to whom it is thrown will have to do will be to slip his head and shoulders through it and adjust the strap to fit snugly around his body. The device will continue to gen- erate its own

, . WHEN GELATIN ,

eas for an in- loop dissolves

^<ia HJI ail 111 CAS BAG EXPA.NOS

definite length of time. The wearer's ^^^^ movements are unimpeded by it.

�����UFE PRESERVER

���An upward snap of the muzzle of the revol- ver closes the circuit which lights the lamp

��A New Flash-Light for the Gun

MANY and astonish- ing are the varia- tions of the schemes to attach a flash-lamp to a firearm and so make shooting in the dark as nearly infallible as possible.

The latest improvement in that line is a self-lighting lamp attached to a pistol, the light staying out until the pistol is leveled at the mark, then lighting automatically.

The lamp circuit is completed by a tube of mercury" and air, with the mercun.- so arranged in conjunc- tion with the air that it will move readily. A quick upward snap of the muzzle of the gun moves the mercury in the tube, closing the circuit and light- ing the lamp. A downward snap of the muzzle of the gun drives the mer- cury forv\ard and breaks the circuit again. A lens sj's- tem in the lamp is so arranged as to form a clear and easily defined aiming mark, which is read- ily adjustable.

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��Above: The acety- lene life-preserver in operation. It will keep the wearer afloat for an indefi- nite length of time

��At left: Device in detail. When water makes its way into the gas bag it gen- crates sufficient gas to inflate the tube

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