Yol. 6 3 .~] 



OCHIL EAETHQUAKES OE 1900 10 1907. 



365 



At places within the isoseismal 5, the shock consisted of one or 

 more prominent vibrations followed by a series of tremors. It 

 seemed as if a very heavy dead weight had suddenly fallen on the 

 floor, the house quivering after the fall. The mean duration of the 

 shock was 3 seconds. 



The sound-area coincided with the disturbed area in all direc- 

 tions, except perhaps towards the east. The sound was heard by 

 89 per cent, of the observers, 17 per cent, of whom compared it 

 with passing waggons, etc. ; 10 per cent., with thunder ; 27, with 

 wind ; 40, with the fall of a heavy body ; 3, with explosions ; and 

 3, with miscellaneous sounds. The large number of references to 

 the fall of a heavy body is evidently to the ' thud ' or sound which 

 attended the prominent vibration at the beginning, the subsequent 



l-i°0' ~ l3°50'long.W. l3°40' 



Fig. 2. Earthquake or Julx 23*?1905. 



Scale of Miles. 

 12 3 4 



sound being variously described. The beginning of the sound 

 preceded that of the shock in 37 per cent, of the records, coincided 

 with it in 26, and followed it in 37 per cent. ; while the end of 

 the sound preceded that of the shock in 18 per cent, of the records, 

 coincided with it in 18, and followed it in 64 per cent. In every 

 case, the duration of the sound was either equal to, or greater than, 

 that of the shock. 



(8) 1905, July 26th, 6.3 p.m. 



Intensity, 4. Number of records, 9, from 7 places. 



All the records of this shock come from places in the Hillsfoot 

 district — from Alva, Gogar, Logie, Menstrie, Sauchie, Tillicoultry, 

 and Tullibody. The disturbed area was much smaller than that of 

 the preceding shock, and probably did not extend so far as Dun- 

 blane, Greenloaning, Blackford, and Glendevon, so that it must 

 have contained less than 80 square miles. 



The shock was similar in its nature to that of July 23rd. The 



