ON SEISMOLOGICAL INVESTIGATIONS. 



95 



culminated in the violent eruptions at Vesuvius in April 1906 is a matter 

 of conjecture. The largest earthquakes, eclipsing either of these, or the 

 one of April 18, 1906, which devastated Central California, were numbers 

 1036 and 1052. They originated in Central Asia, one on July 9, and 



Fig. 1. 



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the other on July 23, 1905. As accounts of destruction do not appear to 

 have reached Europe, it may;be assumed that the epifocal areas were 

 only sparsely populated. The latter disturbance was felt in Tomsk, 

 Kiachta, and other places. 



IV. Large Earthqtiakes in relation to Time and Space. 



Megaseismic motion has been automatically recorded since 1884.' 

 Maps showing the origins of world-shaking earthquakes have been pub- 

 lished in ' British Association Reports ' since 1899. The last refers to the 

 earthquakes of 1 905, and is contained in this report. When, therefore, we 

 are considering the time-relationship between earthquakes originating in 

 different localities, the records at our disposal only extend over seven 

 years. The material is admittedly as yet far too meagre to give satisfactory 

 results, but, nevertheless, it is interesting to note the direction in which 

 it points. 



' Sets. Soc. Trans., vol. x., p. 6. 



