SCIENCE AND ITS APPLICATION TO MARINE PROBLEMS. 
Science and its Application to Marine 
Problems.- 
By PROFESSOR J. C. McLENNAN, F.R.S. 
(Scientific Adviser to the British Admiralty.) 
1. Inrropucrion. 
In the great struggle which has now been brought to its close, the 
introduction and use of the submarine as an agent of unrestricted war- 
fare by our former enemies constituted a menace of paramount and 
vital importance to the safety and welfare of the British Commonwealth 
and its allied uations. 
As early as 1915 a Board of Inventions and Research was established 
for the purpose of developing anti-submarine devices and systems capable 
of coping with the menace. In the autumn of 1917, after exhaustive 
researches had been carried out by this Board, it was finally realized 
by all that the submarine problem was one of the most difficult ever 
presented to science for solution. It became clear that it was necessary 
to introduce into service practically a new system of physical science 
and engineering, and it was, therefore, decided to set up with the 
Admiralty a Department of Research and Experiment, under the direc- 
tion of Mr. Charles H. Merz. In the Naval Service, too, a special Anti- 
Submarine Division was organized, and in the Department of Torpedoes 
and Mines provision was made for greatly extending, by research, experi- 
ment, and trial, the capabilities and use of improvements in mines and 
torpedoes as aids to naval warfare. 
As a result of this great effort, it may be stated that by the late 
summer of 1918 it became clear to those associated. with the movement 
that the submarine problem was well in hand from a scientific point 
of view, that the character of the means of coping with the menace in 
an effective manner was clearly defined, and that the elimination of 
the pest was only a matter of a few months’ time. 
In the following paper a brief survey is given of some of the most 
notable advances made in dealing -with certain naval and marine 
problems presented to us on the naval side during the war. 
9. Anti-SupmMariIngE Measures and Drvicus. 
(a) Listening Devices.—As the power of the submarine in its attack 
is due to invisibility, it is clear that, in countering it, methods 
must be employed which will reveal its presence and give definite infor- 
‘mation regarding its movements. Of all the physical disturbances 
emitted or produced by a moving submarine, the pressure waves set up 
in water by vibrations having their source in the vessel are the ones 
which are propagated to and are detectable at the greatest distance. 
Efforts were, therefore, directed from the first to_the development of 
listening devices. The investigations in this field were exceedingly 
ramified, and were pressed with great vigour. 
As a result, great improvements were made in hydrophones. In 
the development of these devices, microphones and magnetophones of 
——$—$— 
* Condensed from a paper read before the North-East Coast Institution of Engineers and Shipbuilders. 
4II 
