EDITORIAL 



In the L5ulletin of the Seismological Society of America, 

 Volume V, page 30, March, 1915, appeared an article entitled 

 "Seasonal Periodicity in Earthquakes," by William A. Spalding. 

 By permission of the Editor of that publication, we re-produce 

 that article in this Bulletin. 



Several years prior to the organization of this Academy of 

 Sciences, Mr. Spalding, who was one of its Founders and who 

 has served five terms as its President, became interested in the 

 observations of Heinrich Samuel Schwabe, — an amateur Astron- 

 omer of Dessau, Germany, — from which was deduced a period- 

 ity in sun-spot phenomena. These labors of Schwabe were in 

 vestigated by Prof. R. Wolf of Zurich, Stewart, De La Rue, J. 

 H. Kedzie, and others, who published monographs upon the 

 subject, but it was not until after a careful study of the theory 

 of Equinoctial perturbation proceeding from the various planets 

 of the Solar system, enunciated in 1875 by Prof. John H. Tice 

 of St. Louis, Mo., that Mr. Spalding became so intensely ab- 

 sorbed in investigating the causes of seismological disturbances. 



On December 22, 1892, five years before he first became 

 President of this Academy, he read a paper before The Teach- 

 ers' Institute in Los Angeles, in which he presented the con- 

 clusions to which he had arrived. His prediction of the tune 

 for a seismic convulsion was so positive, and the date of its 

 occurrence was so exact, that, had these transpired during the 

 darkness and superstition of the mediaeval periods, his voice 

 would have been acclaimed one of prophecy ; but, as has Ijeen 



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