Transactions of the Royal Society of Canada 



SECTION III 

 Series III DECEMBER 1917 and MARCH 1918 Vol. XI 



" Ow the Transmission of Sound Through Earth and Rock.'' 



By Louis Vessot King, M.A., (Cantab.), D.Sc, F.R.S.C., and A. 

 Norman Shaw, B.A., (Cantab.), D.Sc. 



The object of these notes is to call attention to a problem which 

 is apparently capable of considerable development, and to record 

 a number of experiments which throw further light on the subject. 

 The data have been abstracted from one of the reports sent in to the 

 British Inventions Board by one of the writers (L.V.K.), after kind 

 permission to publish a short account of the matter had been obtained 

 from the Ministry of Munitions through Sir Richard Paget, Secretary 

 of the British Board of Invention and Research. The contents are 

 as follows: 



TABLE OF CONTENTS 

 Section 1. Introduction and Historical Survey. 



'' 2. Notes on the Means Available for Generating Elastic Waves in Rock 



Media. 

 " 3. Experiments Carried on at Macdonald College, Ste. Anne de Bellevue, on 

 the Transmission of Sound through Earth and Rock. 

 (i) Sound Generating Apparatus. 

 (ii) Receiving Microphones. 

 " 4. Experiments on the Magnification of Telephonic Currents. 



Section 1. — Introduction and Historical Survey. 



That vibrations set up on the earth's surface, whether through 

 soil or bed rock, are capable of travelling considerable distances, has 

 long been known. In particular, tremors associated with earthquakes 

 are capable of travelling many hundreds of miles. Among the first 

 systematic experiments carried out on the transmission of vibrations 

 through the earth's surface may be mentioned those of Robert Mallet^ 

 who devised a means of detecting minute tremors at considerable 

 distances from their source, by observing the agitation of a mercury 



'Mallet, Robert, Irish Acad. Proc. V., 1850-53, pp. 143-44; Brit. Ass. Report. 

 1851, pp. 272-320; Roy. Soc. Proc. XI., 1860-62, pp. 352-356; Brit. Ass. Report, 1861. 

 pp. 201-236; Phil. Trans., 1862, pp. 655-679, Vol. 151; Phil. Trans., 1862, pp. 

 663-676. 



Sec. III. Sig. 6 



