PART II. 
CHAPTER VII. 
(i) TIME OF THE EARTHQUAKE AND RATE OF PROPAGA- 
TION. 
In tlie preliminary report on this earthquake I have already 
gone into the question of the time of the earthquake at its origin, 
and have shown that the locally recorded times are too inaccurate 
to have any reliance placed upon them. I therefore confined my- 
self to the consideration of the records that I had received at that 
time of automatically registering instruments from the various 
Observatories in and around India. On the assumption that the 
large waves of an earthquake travel at something approximating 
to 110 miles per minute I deduced that the time of the earthquake 
centre was approximately 15 hours 50 minutes Indian Standard 
Time (10 hours 20 minutes Greenwich Mean Time). Further con- 
sideration of the Indian seismograms, and especially of foreign 
seismograms, has indicated that this first estimate was too early, 
and that the time at the earthquake centre was approximately 
two minutes later. 
The reports from the various Indian and neighbouring Obser- 
vatories are as follows : — ■ 
Bombay Observatory. 
Plate 6, Fig. 1 shows a reproduction of the Milne Seismogram 
registered at Bombay. 
It will be noticed from the following table that the Director of the 
Bombay Observatory has assumed the value 3"5 km. per second for 
the rate at which the long surface waves travel. If, aS I shall 
show later, this value is too low for the present earthquake, then 
the calculations in which he has used this value will have yielded 
too low results, thus improving the figures in the last column. 
( 3o ) 
