92 Mr. C. Davison. 



four seconds, followed by tremulous motion for about eight seconds ; 

 the beginning of the sound coincided with that of the shock, the end 

 followed that of the shock by about two seconds, the principal vibra- 

 tions felt when the sound was loudest. Both of these places are at 

 considerable distances from the fault-line, and on opposite sides of 

 it. Consequently, from these and similar observations, we may 

 conclude that in the direction of the minor axis there is no sign of 

 the sound outracing the shock. 



Time-Relations of the Sound and Shock. The beginning of the 

 sound preceded that of the shock at 59 places, coincided with it at 11, 

 and followed it at 3, places. The latter are, however, close to places 

 where the sound was heard before the shock. Hence, in all parts of 

 the disturbed area, the beginning of the sound as a rule preceded 

 that of the shock. 



The end of the sound preceded that of the shock at 16 places, 

 coincided with it at 6, and followed it at 16, places. In the majority 

 of cases, the end of the sound preceded that of the shock at places 

 near the major axis, and especially close to the ends of it ; and it 

 followed the end of the shock at places chiefly within the isoseismal 5 

 and in the neighbourhood of the minor axis. 



The epoch of maximum intensity of the sound preceded that of the 

 shock at 19 places, which are as a rule near the ends of the major 

 axis, coincided with it at 18 places, which are not far distant from 

 the epicentrum or minor axis, and followed it at 3 places, namely, 

 Rothley, Woodhouse Eaves and Wymondham. 



Lastly, the sound appeared to precede the shock entirely at seven 

 places, Ashley, Barton Segrave, Bretby, Farndon, Hazelbeach Hill, 

 Quarndon and Wartnaby. Six of these are close to the ends of the 

 major axis, and still closer to the continuation of the anticlinal fault- 

 line. 



Thus, the more detailed evidence here summarised supports the 

 conclusion previously stated, that the sound apparently outraced the 

 shock in the direction of the major axis of the disturbed area, but not 

 in the direction of the minor axis. 



Space-Relations of the Sound and Shock. In the absence of any 

 scale of seismic sound-intensity, it has not been possible to indicate 

 the position of any isacoustic lines. It is clear, however, that they 

 would not be concentric with the isoseismal lines. For instance, the 

 shock was felt, while no sound was heard, by the observers at 

 Burton-on-Trent, Castle Donington, Cole Orton, Long Eaton and 

 Staunton. The sound was heard, while no shock was felt, by the 

 observers at Aldwincle, East Haddon, Finedon, Holme, Loddington, 

 Ragdale Hall and Thorpe Underwood. In one or two cases this may 

 have been due merely to defective observation ; but, on the whole, it 

 is evident that the shock was a more prominent feature than the 



