RECENT DEVELOPMENTS IN SUBMARINE SIGNALING. 

 By J. B. Millet, Esq., Visitor. 



[Read at the twenty-second general meeting of the Society of Naval Architects and Marine Engineers, held in 



New York, December 10 and 11, 1914.] 



In order that the present state of the art of submarine signaling may be 

 better appreciated, it is necessary to review briefly its origin and growth. 



Something over thirty years ago, Professor Tyndall on behalf of the Trinity 

 House, England, supported by a liberal grant from the Government, undertook 

 a very careful, scientific investigation to ascertain why fog signals in the air could 

 not always be heard even at short distances, or, when heard, could not be located 

 with any accuracy. The strandings of vessels on the coast of Great Britain each 

 year amounted to an appalling number, and in a very great majority of cases the 

 officers reported that they had mistaken the direction from which the fog signals 

 came, although they could be heard clearly. There seemed to be something mys- 

 terious about the action of sound in the air, more especially when the air was filled 

 with fog. About the same time, Professor Henry was authorized by the United 

 States Government to make a similar study of the problem in America. At the 

 end of their researches these two pre-eminent authorities agreed entirely upon one 

 conclusion, viz., that fog signals in the air were absolutely untrustworthy. There 

 was little satisfaction in this, and navigators as a rule were very loath to accept 

 this conclusion as a definite fact. They were dependent absolutely upon fog bells 

 and fog whistles to guide them when in danger of stranding or colliding, and there 

 was nothing else to do but to continue to trust them as best they could. Trinity 

 House, however, which controls the lighthouse establishments of Great Britain, as 

 is well known, from that time on has warned all navigators not to place implicit 

 confidence upon any air signal that they could not actually see. 



It would appear from this that the navigators and the shipping concerns would 

 all gladly accept and investigate any invention which might tend to be a source 

 of relief, but the natural conservatism of those who pass their lives upon the water 

 has prevented them from taking up submarine signaling with anything like the 

 interest which ought naturally to be expected. 



It may be a surprise to many to know that, as early as 1883, Prof. Lucian I. 

 Blake, of Kansas, conducted elaborate experiments with sound in water in search 

 of an aid to navigation. He used bells rung under water to create sound, and 

 microphones with which to receive it. He was assisted by the United States light- 

 house authorities. In the Lighthouse Board report of 1889 compiled by Arnold 

 Burges Johnson, Chief Clerk of the Board, a complete description of Professor 

 Blake's experiments is given. This was the first attempt made in this country to 



