Popular Science Monthly 



583 



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. 



JS*^" 



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 



