PROCEEDINGS FOR 1920 XV 



pertinent to these subjects, resolutions and plans embodying the 

 views of the Royal Society of Canada subject to the approval of the 

 Society as expressed by it in general meeting assembled or through its 

 Council, the members of such committee to consist of representatives 

 selected by Sections III, IV and V. — Carried. 



The members of the committee selected by the sections and 

 appointed by the Society were : 



Section III — J. C. Fields, J. C. McLennan. 



Section IV— D. B. Dowling, T. L. Walker. 



Section V — F. E. Lloyd, Andrew Hunter. 



The Popular Lecture — -{Thursday evening, May 20) 



Some Great War Inventions 



The annual popular lecture on the above subject was given in 

 the ballroom of the Chateau Laurier at Ottawa before the Fellows 

 and guests of the Royal Society of Canada by Professor A. S. Eve. 



In 1902, Dr. R. B. Owens, Professor of Electrical Engineering at 

 McGill University, took out a patent for guiding a ship by means of 

 coils placed upon it. These coils received a current by induction due 

 to an alternating current in an insulated cable placed beneath the 

 sea or river. This experiment was successfully tested by Dr. Herdt in 

 the River St. Lawrence. During the war this plan was revived partly 

 due to information received as to German activity, and partly to the 

 initiative of a young Canadian, Captain Manson, who had on the 

 western front employed a similar method for locating breaks in land 

 lines used for signalling. Owing to recent developments and im- 

 provements in electronic valves this method became of practical 

 service in guiding ships of the Royal Navy along swept channels 

 through minefields. The scheme was for a time kept secret, but has 

 recently been released by the British Admiralty. 



Various methods of locating submarines by hydrophones and 

 hydrophone fish were described. Some account was given of ex- 

 periments on the West Coast of Scotland to test the pressures exerted 

 by exploding mines. 



The remainder of the lecture was devoted to a description of 

 developments occurring in Wireless Telegraphy and Telephony. A 

 comparison was made between efïects obtained by sound and those 

 in Wireless Telegraphy. In particular, resonance, beats and damping 

 were shown with tuning forks, and the analogy to Radio work was 

 pointed out. Two one-quarter kilowatt generators, of frequency 240, 

 were employed to illuminate tungsten filament lamps. As the phase 



