EARTHQUAKE MOTION TO GREAT DISTANCES. 



1 51) 



Here there are evidently very great divergences, which can only be attributed to 

 differences in the sensitiveness of the instruments to this phase. There is no visible 

 relation tat ween distance and rate of travel, while the apparent rates vary from 3 '2 to 

 :> - 8 kiloms. per second.* In view of these divergences it becomes a question whether 

 some of the records rejected as giving times much too early should not be included, 

 ;md for this reason they have been tabulated here. 



From this, if the data are accepted, it seems that the first waves of this phase may 

 travel at rates that rise to near 5 kiloms. per second, though those which are ordi- 

 narily registered at the commencement of this phase have not a greater apparent rate 

 of travel than about 3 '5 kiloms. per second.! 



If, instead of the very indeterminate commencement of this phase, we tnke the 

 more easily determinable time of the maximum movement, we find, as shown in the 

 table below, that greater uniformity of result which might be expected to follow 

 i'rom the fact that the recorded times are less influenced by variations in the sensi- 

 tiveness of the different instruments. 



* The minimum values may be neglected, as they are evidently due to a tardiness in action of the 

 instruments. 



t The Sacramento earthquake of April 19, 1892, recorded at Strassburg, gives a rate of 3'8 kiloms. per 

 second over an arc of 82-5. The Vency.ucla shock of April 28, 1894, recorded in Russia, gives 3-5 and 

 1-0 kiloms. per second over arcs of 93'8 and 93-6 respectively. The earlier phases of these shocks were 

 not recorded. 



