CONTRIBUTIONS OF PHYSICAL SCIENCE 41 



suggested and largely developed by Mason. It consisted of 

 a row of from thirty to sixty sound receivers strung along 

 in two rows one on either side of the keel of the ship, well for- 

 ward ; the sound pulses coming in to all of the receivers on one 

 side were arranged to travel in tubes of just such length as to 

 cause them all to unite in the same phase at the mouth of a 

 tube leading to one ear of the observer, while all the sound 

 pulses received by the other row are brought together in a 

 similar way at the other ear. By now using the binaural sense 

 to equate exactly the sound paths to the two ears, it is possible 

 to locate the direction of the source of sound to within one or 

 two degrees. This instrument could pick up submarines from 

 one to ten miles away depending upon their speed and the 

 weather conditions. A variant of the multiple receiver de- 

 vice, using microphones and electrical compensators to equate 

 phases in place of ordinary sound receivers and sound compen- 

 sators, was even more effective. Many of our submarines 

 and destroyers which went across during the summer of 1918 

 were equipped with the acoustical form of this device, and 

 now the electrical form is being still further developed for 

 peace use, rather than for war, for it is possible through it to 

 eliminate the chief terror of the sea, namely, collision in fog. 

 And, when it is remembered that the preventing of a single dis- 

 aster like the sinking of the Tltantic or of the Empress of Ire- 

 land more than pays, without any reference to the value of hu- 

 man lives, for all the time and money spent by England, France 

 and the United States combined in developing detecting devices, 

 it will be seen how shortsighted a thing it is for any country 

 to fail to find in some way the funds necessary for carrying on 

 research and development work in underwater detection. For 

 decades and for centuries we have allowed ships to go down 

 year by year needlessly, simply because we have not realized 

 the possibilities of prevention through properly organized scien- 

 tific research in this field. 



Another device capable of detecting a lurking submarine half 

 a mile or more away by the use of a beam of sound waves of 



