Telegraphing Through the Ocean 



So that ships may avoid one another in a fog, 

 Christian Berger converts them into huge 

 vioHns which send out sound-wave signals 



THE small-town American bo\' has a 

 noise-making io\', which for sim- 

 plicity, cheapness, and, above all, 

 effectiveness, can hardly be surpassed. 

 The principal components of the con- 

 trivance are: one tomato- 

 can, one string, one lump 

 of resin, and plenty of 

 muscle in the small boy's 

 right forearm. 



Into a hole in the bottom 

 of the tomato-can the 

 string is run, a lumpy knot 

 on its inner end pre\enting 

 it from slipping completely 

 through. This leaves a 

 long, dangling cord 

 when the ex-tomato-con- 

 tainer is held outward in 

 the boy's left hand. With 

 his right he grasps the 

 lump of resin and com- 

 mences to stroke the string. 



A responsive "ee-ee-eek" 

 emerges from the mouth of the can at 

 the beginning of the stroking process. 

 Shrieks, cat-calls and strident, earsplit- 

 ting wails can be made to follow the 

 "ee-ee-eek." 



In a sense the contrivance is not 

 unlike a violin. The can is a resonator; 

 so is the violin body. The string is 

 rubbed to make a sound ; so is the 



The harder he pulls the 

 more distracting the noise 



The 

 the 



fundamental 

 same. 



catgut of a violin, 

 principle invoK'ed 

 C u r i o u s 1 \' 

 enough, a contri- 

 vance operating 

 very much on the 

 same principle 

 has been found to 

 be one of the most 

 effective submarine 

 signaling devices 

 yet brought out. 

 The machine in 



question is the invention of Mr. H. 

 Christian Berger, a New York physicist. 

 It has been put in successful service on 



a number of American vessels, some of 

 them warships — despite its resemblance 

 in principle to the tomato-can toy or 

 the violin. It is the result that counts. 

 Mr. Berger's device employs either a 

 narrow steel strip or 

 else a piano wire as 

 the vibrating member, 

 this serving the same 

 purpose as the string in 

 the case of the can-toy 

 or violin. One end of 

 the wire is attached to a 

 I^late in the steel hull of a 

 \essel, the other end being 

 fastened to a similar plate 

 on the opposite side, or 

 else terminating in a frame- 

 work affixed to a conven- 

 ient beam. The steel plate 

 in the side of the vessel acts 

 as a sounding-board to send 

 sound-waves out into the 

 water, just as the bottom 

 of the tin can sends waves into the air. 

 Instead of a lump of resin in the hands 

 of a small boy as the exciting agency for 

 the vibrating strip, this contri\-ance 

 employs a motor-driven rubbing-wheel, 

 the felt-covered rim of which is the 

 equivalent of a violin bow and is 

 moistened with alcohol in order to 

 proxide an efficient rubbing medium. 

 Although the motor which dri\cs this 

 wheel runs continuousK-, the wheel itself 

 mav be started and 



SKETCH SHOWINO 

 DIFf[R[NC[ BE 

 TWEfN AIR BELl 

 4ND 5U5MARINE 



Btll 



stopped at will by 

 means of a telc- 

 graph-key control- 

 ling an electromag- 

 netic clutch moun- 

 ted on the motor- 

 shaft. Thus a 

 telegraph-ke\- 

 governs the send- 

 ing of x-ibrations 



just as in wireless telegraphy. 



The question naturally arises: Ot 



what use is a submarine signaling 



few feet under water a bell's sound 

 loses its characteristic bell-like tone 



711 



