RECENT DEVELOPMENTS IN SUBMARINE SIGNALING. 113 



using the granular transmitter properly installed. Pumps, or dynamos, or some 

 machinery which makes a very considerable noise, are always operating on big 

 ships, and, if it is possible to hear them, an observer on a submarine boat could 

 quickly locate them. I have often heard sounds of this sort many miles through an 

 ordinary granular transmitter, and on one occasion on the Baltic, running at half 

 speed, detected and located a passing steamer several miles off in fog by listening to 

 the sound of her screws. Provided with ears of this sort, a submarine boat could 

 get its orders by under-water signal from its mother ship, could be recalled if de- 

 sired, or warned, and, by using the oscillator as a signaling apparatus, could also 

 give signals of her own. She could call for help, locate her position, or state any- 

 thing she wanted to state by using the Morse system. 



Since I know all this to be true, I am convinced that this new invention will 

 bring to the submarine boat these tremendously important additional new features 

 of efficiency, and it seems to me that one of the most important duties of the Navy 

 Department of the United States now is to take charge of experiments with this 

 oscillator, to conduct them themselves at the expense of the government, and to 

 find out, before any other country does, how far this new invention can be made an 

 important factor in our navy. 



DISCUSSION. 



In connection with the presentation of his paper, Mr. Millet said : — 



"The apparatus calls for no particular scientific knowledge and no great experience. One 

 of the things that has impressed me most about it in many years' experience with it and in 

 developing its use, is the fact that after it was used by people who were not navigators, who 

 had no knowledge of navigation, but who had been told all they had to do was to listen to 

 the receiver on one side of the ship and compare the sound with that on the other side of 

 the ship, they could then determine with considerable accuracy the location of the sound. 

 I remember the case of a ship going into Boston Harbor in fog. They were trying to pick 

 up the lightship. The captain was on the bridge, it was quite a thick fog, and his wife went 

 to the apparatus and used it and told him where the lightship was. It would seem that one 

 of the great features of an apparatus of this sort is that it does not require any special 

 experience to use it with efficiency. The more one uses it and becomes acquainted with the 

 sounds on his own ship the more expert he becomes in the use of the apparatus. It can be 

 compared to the wireless telegraph system. The first time you put a wireless apparatus to 

 your head you do not recognize all the sounds, if any of them, but sooner or later you do 

 pick out what you want to hear. With the submarine bell, if you are within a reasonable 

 range of the bell, you will hear something that sounds like a bell; and, as a rule, unless the 

 sound of the bell passes through some portion of the structure of the ship, you will hear a 

 musical note. If it is aft, for example, whereas the apparatus is well forward, you might 

 not get any musical vibration. 



