no RECENT DEVELOPMENTS IN SUBMARINE SIGNALING. 



in the last thirty years, scientists and those who are using the apparatus daily 

 would have found an opportunity to have extended its field, and have analyzed 

 every factor in it, and would have demonstrated to the entire world, with abso- 

 lute conviction, that safety in the navigator lies in using sound in water; but in 

 developing a system of this sort it is necessary to have ships, and large ones, 

 which can be used at the will of the investigator. It is also necessary to oper- 

 ate bells or other sounding apparatus in the water, and it is clearly to be seen 

 that these are conditions which no private company can possibly meet, and no 

 shipping company is willing to go to the expense of allowing any vessel to be used 

 for this purpose for any length of time. It appears, therefore, as if it will be neces- 

 sary for some government to conduct exhaustive experiments in order to ascertain 

 how far sound in water can be used, or it never will be done. 



To say that collisions between ships at sea in fog need never occur, to say that 

 collisions with icebergs can be avoided by means of submarine signals, to say that 

 the efficiency of submarine boats can be enormously increased by the same appa- 

 ratus, would of course be to excite comment and to create more or less disbelief 

 that the efficiency of this system extends so far. Nevertheless the above is all 

 true, and has been so frequently demonstrated, that it would seem unnecessary to 

 have to assert its truthfulness were it not for the fact that the possibilities of this 

 art are so little understood. 



In order that two vessels approaching each other in fog may be kept apart, 

 it is necessary that they either see or hear each other. It is known that their air 

 signals cannot be trusted. It is also known that sound that comes through the 

 water can be trusted. Consequently, that ships may avoid collision it is only neces- 

 sary that one should make a sound in the water which the other can hear, or that 

 both should be able to exchange signals under the water. 



An early experiment made by the writer in 1895, in Long Island Sound, 

 between two ships approaching each other at full speed, showed conclusively that 

 if a heavy bell were rung in a tank built into the forepeak below the waterline 

 of a moving vessel, other vessels which were approaching it forward of its beam 

 could, if supplied with receiving apparatus, hear this bell and locate the approach- 

 ing steamer at distances from two to three miles. The bell operated in this experi- 

 ment was comparatively inefficient, but the principle was demonstrated by this 

 experiment. It was witnessed by the Minister of Marine for Canada and several 

 of the directors of the Allan Line at Montreal. There, however, like other im- 

 portant demonstrations that this art has provided, the subject dropped. A few 

 demonstrations were conducted by the writer for the British Government a year 

 later, but that was all. It was recognized that some sort of a sound producer which 

 would create a sound strong enough to carry a great many miles above all other 

 noises in the water was necessary in order to make this particular feature of the 

 invention practical. A large number of experiments have been tried with various 

 kinds of apparatus, and large sums have been spent in the last ten years or more, 

 but nothing practical was found until Prof. Reginald A. Fessenden invented 



