74 REPORTS ON INVESTIGATIONS AND PROJECTS. 



tempted primarily in the hope of obtaining some Hght on the cause of such 

 changes. The synchronism of two apparently independent sets of phe- 

 nomena suggests a possible relationship; the two may be related as cause 

 and effect, or they may be due to some common outside cause. When Mr. 

 H. W. Pearson, of Duluth, pointed out an apparent synchronism between 

 his supposed changes in the level of the sea and the changes in climate in- 

 ferred by Mr. Huntington, it appeared advisable to investigate the matter. 

 Mr. Pearson kindly put his notes at the disposal of the Institution. An 

 examination of them brought out the interesting fact that most of the sup- 

 posed evidences of changes in sea-level w^as in reality evidence of changes in 

 the land. Rapid filling of river mouths took place at the supposed times of 

 a falling of sea-level, which were times of aridity according to the inferred 

 climatic changes ; while the flooding of swamps and the cutting of embank- 

 ments took place in the times of supposed rising of sea-level, which were 

 also times of moisture. The rapid deposition of silt by rivers is character- 

 istic of arid periods, while severe storms are characteristic of wet periods. 

 Hence the supposed synchronism of changes of sea-level and changes of cli- 

 mate does not seem to exist, but in its stead we have a new type of evidence 

 of changes of climate. 



Another similar line of research has yielded results of much more im- 

 portance. Meteorologists have concluded that the climate of the earth is 

 characterized by an eleven-year cycle which has a relation of some sort to 

 the sunspot cycle of similar length. Several authors have concluded that 

 earthquakes and volcanoes also occur in eleven-year cycles synchronizing 

 with that of the sun. U climatic and seismic cycles synchronize with those 

 of sunspots, it is probable that they synchronize with one another. To test 

 this a list of all known earthquakes since the beginning of the Christian era 

 was prepared by Miss Ethel B. Kirkton. From this a curve of seismic 

 activity has been plotted for comparison with the curves of climate derived 

 from the Big Trees and other sources. The degree of agreement is such as 

 to afford ground for most interesting speculations as to the possible relation 

 of climatic changes, earthquakes, and volcanoes to one another and to the sun. 



Inasmuch as the investigation of changes of sea-level yielded only a nega- 

 tive result, the funds intended for it were turned toward the preliminary 

 steps of another line of research. This was a mathematical study of the 

 effect of diverse conditions of climate and weather upon human efficiency 

 and activity. Statistics were gathered as to the rate of piece-work in fac- 

 tories day by day under varying conditions of weather. The long process of 

 tabulating and computing these has only been begun. Nevertheless indica- 

 tions have already been found that changes of weather produce effects hith- 

 erto unsuspected. For example, it appears that absolute temperatures are 

 less important than variations of temperature. Change of almost any kind 

 seems to be stimulatory. Further investigations in various parts of the 

 country are needed in order to test the matter. I\Iany other relationships 



