250 REPORTS ON THE STATE OF SCIENCE, ETC. 



But this valuable series of Philippine records does not begin with 1918 ; it extends 

 back at least to 1890, and it was clearly desirable to examine the earlier years to see 

 how far they support the evidence of 1918-26. This examination has been made, 

 and the results are nearly ready for presentation, though owing to various circum- 

 stances the amount of work has been considerable. 



Briefly, the earlier years show the periodicity indicated by 1918-26, with a slight 

 change of period which is only reasonable ; but it has been necessary to examine 

 another sensibly different periodicity. Further, the years 1890-1903, though not so 

 valuable as those which follow, still contribute to the testimony, but require special 

 treatment. 



The Interchange of Seismological Information. 



At the beginning of 1929 as the result of negotiations opened by the Director of 

 the Meteorological Office, there was an important extension of the system of 

 exchange of seismological information by wireless telegraphy. When large earth- 

 quakes occur, data collected by the Coast and Geodetic Survey of the United States 

 are now added to the meteorological messages broadcast from Arlington. These 

 messages are re-broadcast from the Eiffel Tower. To begin -n-ith, the broadcast 

 data referred only to the seismograms at two selected stations. Since May the 

 positions of the epicentres as determined by the Coast and Geodetic Survey have 

 been given as well. 



During the half year, January to June 1929, there were seventeen occasions on 

 which details of earthquakes were broadcast from Arlington and picked up at the 

 Air Ministry, London. 



Particulars of the code used for the seismological reports can be obtained from 

 the Superintendent of Kew Observatory, Richmond, Surrey. 



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