ON SEISMOLOGICAL INVESTIGATIONS. 



77 



These figures, whetlier taken collectively or as entries for any pair of 

 stations, apparently indicate that earthquake motion is propagated more 

 freely towards the west than it is to the east. 



Comparison of Records obtained from Stations in the Koi'thern Hemisphere un'tJi 

 those obtained in the Souther?! Hemisphere. All Stations which arc comiiared 

 are at approximately the same distance from the Origins considered. 



District No. 1. 



Stations in Southern Hcmhjjheje. 



Stations ill Xortlicrii Hemisphere. 



Station 



Cape Town . 

 Australia 

 Cordova 

 Nev/ Zealai d 



Average . 



Mauritius . 

 Australia 

 Cape Town . 

 New Zealand 



Average . 



Australia 

 Mauritius . 

 New Zealand 

 Cape Town , 

 Average . 

 If we take 



Dis- Percentage 

 tance of Records 



75 

 98 



125 

 135 



108 



70 . 



85 

 105 



79 • 



60 

 75 



82 

 120 



30 

 20 

 20 

 £0 



22 



Station 



Toronto 



Victoria 



Victoria 



Honolulu 



Honolulu 



Average 



97 



3t 



District No. 2. 



45 

 42 

 41 

 14 



35 



Average 



86 



57 



District No. 3 

 54 

 29 



88 



17 

 29 

 33 



Honolulu 



Victoria 

 Victoria 

 Beirut . 

 Beirut . 

 British stations! 

 San Fernando 



Averajje . 



68 



an average for the above three districts we get for the 

 Southern Hemisphere an average distance of 90°, with an average per- 

 centage of records of 29 per cent. For the Northern Hemisphere the 

 corresponding figures are 87° and 53 per cent. 



General Conclusions. 



The General Conclusions are^ ^rsf, that a greater percentage of earth- 

 quakes travel farther west, or against the motion of the earth, than they 

 do towards the east ; and second, that the range of recorded motion across 

 the Equator to the south is shorter than it is towards the east or west. 



In any hypothesis to explain these observations we should bear in 

 mind that the direction in which a given earthquake travels farthest will 

 Involve, amongst others, the following considerations : — 



1. What wag the direction in which a given initial impulse was 

 delivered 1 If the seventy-five carthauakes wc have discussed all 



