Adjustable 

 water irxlets 



/Cover ddjvjster 



Cover 



ater inlets 



Terminals short- 

 circyited by the 

 salt water 



Sattery 



Detor^atof 



Explosive 



Popular Science Monthly 



At left: Another Hallock 

 depth-bomb. This one 

 explodes through the ac- 

 tion of salt water entering 

 through the sides and top 

 of the upper end and 

 short-circuiting a pair of 

 terminals. Depth of ex- 

 plosion is regulated by 

 adjusting the openings 

 at which the water enters 



At right: Dunlop bomb, which is set off 

 through the driving in of a pair of wings upon 

 striking the water. Wings release a clock- 

 work, which runs for a time (meanwhile 

 bomb is sinking), then a firing-pin is dis- 

 engaged, a primer set off, and the bomb fired 



when the bomb and its 

 attachments descend 

 from the airplane. Just 

 beneath the parachute 

 is an aluminum disk on 

 the lower 

 side of which 

 is mounted a flexible diaphragm. 

 When the diaphragm strikes 

 the water in trailing along after 

 the bomb at the end of the 

 cable, it is driven inward, and 

 causes an electric contact to be 

 made between the ends of the 

 wires coming up through the 

 cable, which, in turn, causes the 

 bomb's explosion at a depth 

 below the surface determined by 

 the cable's length. Should this 

 impact contactor at the dia- 

 phragm fail to set off the bomb, 

 other pairs of contacts are pro- 

 vided at intervals along the ca- 

 ble's length. These are separated 

 by pieces of calcium carbide, or 

 starch, and are suitably pro- 

 tected from mechanical injury. 

 The carbide or starch dissolves, 

 allowing the contacts to come 

 together and explode the bomb. 



Another of Mr. Hal- 

 lock's inventions is shown 

 above. This one is with- 

 out a parachute and ex- 

 plodes by the action of 

 saltwater entering at the 

 sides and top of the up- 

 per end, and complet- 

 ing an electric circuit 

 through the pair of elec- 



ReqMlatinq 

 rr,ect\an.ism 



The Leon depth-bomb — one type. 

 U. S. Government has experi- 

 mented with these considerably 

 during past year. Here regulating 

 mechanism for keeping bomb at 

 a predetermined depth is shown. 

 Pressure of water actuates a bel- 

 lows. This opens and closes a com- 

 pressed air supply just enough 

 to keep bomb at depth desired. 

 Firing meclianism not shown 



trodes shown. The depth at which 

 the bomb is to explode is regulated by 

 adjusting the size of the openings ad- 

 mitting water. The smaller the opening 

 the longer the bomb can descend as a result 

 of its initial velocity be- 

 fore flying into atoms. 



It is a curious fact, dis- 

 covered sinct? the war be- 

 gan, that an airplane when 

 high in the air, can fre- 

 quently see a submarine 

 plainly, even though it be 

 submerged as much as one 

 hundred feet. Naturally 

 the depth varies with the 

 clearness of the water 

 in any given region, but 

 surprising results have 

 been attained. A sub- 

 marine is visible under 

 water from a height for 

 the same reason that a 

 nickel is visible in a pan of 

 water when your eye is 

 directly over it. Should 

 you get your eye off to one 

 side and almost to the level 

 of the water in the pan, 

 refraction i light-bending) 

 effects would enter in, 

 as well as reflection of 

 other objects to your eye 

 from the water's surface. 

 Inconsequence you could 

 not see the nickel. It is 

 for the same reason that 

 one can rarely see the 

 bulk of a submarine un- 

 der water from t he deck of a 



xplosive 



566 



