360 



Dr. C. Damson — British Earthquakes, 1900. 



accompanied the principal shaking, while the rumble which died 

 away with the tremor was unnoticed or undescribed. 



The beginning of the sound preceded that of the shock in 

 10 cases and coincided with it in 19 ; while the end of the sound 

 preceded that of the shock in 2 cases, coincided with it in. 17, and 

 followed it in 3 cases. The time-relations of both initial and final 

 epochs are given by 22 observers, and these show that the sound 

 was of greater duration than the shock in 8 cases, and of equal 

 duration in 12, while in 2 others the relative duration is doubtful. 



EartliquaTce of Sept. 22, at 4.30 p.m. — This shock was weaker and 

 less widely observed than the preceding, and I have not moi"e than 

 20 accounts from 13 places, together with negative records from 

 15 places. The intensity of the shock was 4, and probably was not 

 much greater even near the epicentre. 



The boundary of the disturbed area is an isoseismal of the same 

 intensity as that of the earlier shock, that is, slightly less than 4. 

 In the north-east quarter, the boundary is indicated by a broken 

 line, being doubtful owing to the absence of observations in this 

 part of the disturbed area. It is 11 miles long and 7 miles wide, 

 and contains an area of 60 square miles. The longer axis is 

 parallel to that of the other shock, and its centre is 2| miles N. 

 37° W. of Alva. 



Though slighter, the shock closely resembled that of the 17th 

 inst., one observer (at Bridge of Allan) describing it as a sudden 

 abrupt loud shock, as if some extremely heavy body had fallen 

 outside the house, followed immediately by a tremor. 



The earthquake-sound was recorded by 13 out of 15 observers 

 who enter into details, that is, the audibility-percentage, as in the 

 first earthquake, was 87. Of the few observers who describe the 



