12 pkesident's addbess. 



Engineering and the War. 



With regard to the many important engineering developments made 

 during the war, several papers by authorities are announced in the 

 syllabus of papers constituting the sectional proceedings of this year's 

 Meeting. Among them are ' Tanks, ' by Sir Eustace d'Eyncourt; ' Scien- 

 tific Progress of Aviation during the War, ' by Dr. Bairstow ; * Airships, ' 

 by Lieut. -Col. Cave-Brown-Cave; 'Directional Wireless, with Special 

 Eeference to Aircraft,' by Capt. Robinson; 'Wireless in Aircraft,', by 

 Major Erskine Murray; 'Wireless Telegraphy during the First Three 

 Years of the War,' by Major Vincent Smith; ' Submarine Mining,' by 

 Com. Gwynne; 'Emergency Bridge Construction,' by Prof. Ingles; 

 and ' The Paravane,' by Com. Burney. Accordingly, it is quite un- 

 necessary here to particularise further except in the few following 

 instances : — 



Sound-ranging and Listening Devices. — Probably the most inter- 

 esting development during the war has been the extensive application 

 of sound-listening devices for detecting and localising the enemy. The 

 Indian hunter puts his ear to the ground to listen for the sound of the 

 footsteps of his enemy. So in modern warfare science has placed in 

 the hands of the sailor and soldier elaborate instruments to aid the 

 ear in the detection of noises transmitt€d through earth, water, air, or 

 ether, and also in some cases to record these sounds graphically or 

 photographically, so that their character and the time of their oocuirence 

 may be tabulated. 



The sound-ranging apparatus by which the position of an enemy 

 gun can be detemiined from electrically recorded times at which the 

 sound wave from the gun passes over a number of receiving stations, 

 has enabled our artillery to concentrate their fire on the enemy's guns, 

 and often to destroy them. 



The French began experimenting in September 1914 with methods 

 of locating enemy guns by sound. The English section began work 

 in October 1915, adopting the French methods in the first instance. 

 By the end of 1916 the whole Front was covered, and sound-ranging 

 began to play an important part in the location of. enemy batteries. 

 During 1917 locations by sound-ranging reached about 30,000 for the 

 whole army, this number being greater than that given by any other 

 means of location. A single good set of observations could be relied 

 upon to give the position of an enemy gun to about 50 yards at 7,000 

 yards' range. It could also be carried on during considerable artillery 

 activity. 



The apparatus for localising noises transmitted through the ground 

 has been much used for the detection of enemv mining and counter- 



