1842.] on the North-Western Frontier. 247 



it may be taken at 10 a. m., while at Delhi it was 10 minutes past 11 

 a. m., hence then 530 miles were traversed in 1 hour and 10 minutes, or 

 the shock travelled at a rate of 7.571 miles per minute, or 454.26 

 miles per hour. This, it is to be observed, is an average rate, and the 

 velocity at Jellalabad and Peshawur was doubtless much greater, but 

 a much more multiplied series of intermediate observations than we 

 now have, would be necessary to enable us to form even an approxi- 

 mative idea of the law of decrement of rate of progress with re- 

 ference to distance travelled. From Delhi to Poojnah is about 50 miles, 

 and the times consumed in travelling from the one place to the other 

 was 20 minutes, consequently the velocity of the shock was 150 miles 

 per hour. Again, the distance from Poojnah to Kulsea is very nearly 

 36 miles, and the time 30 minutes, so that the velocity had diminished 

 to 72 miles per hour, supposing the times to have been correctly 

 observed, which, within a small limit, was probably the case. Hence 

 then we have, Miles. 



Rate of progress of shock from Peshawur to Delhi, 454.26 per hour. 

 „ „ from Delhi to Poojnah, 150 ditto. 



„ from Poojnah to Kulsea, 72 ditto. 



We may next attempt to form some estimate of the breadth of the 

 undulations, of which there appear to have been several, although 

 no data are furnished, from which we can learn either their number or 

 individual extent. We must therefore content ourselves with estima- 

 ting the total breadth of the zone of disturbance, as it may be called, 

 at different points. 



The duration of the shock at Kawulsur is said to have been 5 minutes, 

 and supposing the velocity to have been there twice the average between 

 Peshawur and Delhi, or 15.142 miles per minute, the breadth of the 

 disturbed zone would be 75.71 miles, or in five minutes, a series of 

 terrestrial waves, whose united breadth was this number of miles swept 

 past Kawulsur. This is a horizontal measurement ; but of the vertical 

 height of the waves, on which their destructive influence chiefly 

 depends, we can form no estimate, yet it must have been considerable, 

 if we may judge from the ruin caused. 



At Poojnah, the duration of the shock was considered to be three 

 minutes, the velocity 2.5 miles per minute, and therefore the breadth 

 of the disturbed zone was here 7 miles. While again at Kulsea, where 



