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ON SEISMOLOGICAL INVESTIGATIONS, 55 
Earthquake No. 1362, April 18, 1907, origin 124° BK. 13° N, 
Per sec. 
Bombay, _ time to travel 31m., distance 49°, velocity 2:92 km. 
East-West Kodaikanal, 3 40 m., Chl ed Hite a 2°08 km. 
Honolulu, “ 43 m., a 74°, - 3°19 km. 
Average . : - 2°73 km. 
Irkutsk, time to travel 28 m., distance 42°, velocity 2°77 km. 
Shide, “A 65 m., aa OZ. 4 2°90 km. 
Kew, a 65 m., 3 LOZ? % 2°90 km 
Seek South + pidston, ; 64m, 5 99 ., 3:39km 
Edinburgh, 5 59 m., Bs 99°, ves 3°07 km. 
Tokio, AS 14 m., ee P Atte. 5 3°56 km. 
Average . F a 3 09 km. 
Earthquake No. 1632, October 13, 1908, origin 102° W. 18° N, 
Eaxt-West Honolulu, time to travel 28 m., distance 52°, velocity 3°43 km. 
Victoria, time to travel 23 m., distance 35°, velocity 2°81 km. 
Irkutsk, 3 60 m., 3; LOSS, i 3°23 km. 
Tashkend, on 60 m., en 2285 i 3°76 km. 
North-South ~ Victoria, Re 23 m., ne aii Ss 2°81 km. 
Beirut, aa 82 m., sane lds. A 2°56 km. 
Edinburgh, a bi i en amar S12 3 2°77 km. 
Bidston, ~ 54 m., a3 (ES ss 2°70 km. 
Average . a - 2°95 km. 
When we look at the averages at the end of the above nine tables, 
it appears that in seven instances the velocity for East-West motion 
has been greater than that given for North-South motion. In two 
instances—viz., those for Karthquakes Nos. 884 and 1362—the reverse 
has been the case. 
If we combine the results for all nine earthquakes we get 35 
observations for East-West motion, which give an average velocity of 
2°96 km. per second, and 58 observations for North- South motion, the 
average velocity for which is 2°88 km. per second. 
VI. Comparison of the Amplitudes of East-West and North-South 
Motion at a given Station. 
At Eskdalemuir during the year 1910 two Milne pendulums, one 
of which recorded North-South motion and the other East-West motion, 
_had periods which did not differ from each other more than one second. 
At times they had the same period, but usually the former had a 
period of 17 seconds and the latter 18 seconds. From this we should 
expect that, if the displacement of the booms was due to tilting, the 
amount of this as measured in millimetres would be slightly greater 
in the East-West direction than in the North-South direction. For 
40 earthquakes recorded during this year this was the case, but there 
are 16 instances in which the boom recording North-South motion 
showed the greatest displacement. In nine instances the amount of 
displacement was the same on both pendulums. It may be added 
that for a short period—viz., from January 1 to February 12—the 
