Xll. ABSTRACT OF PROCEEDINGS. 



THE FOLLOWING PAPERS WERE READ : 



1. " Possible Relation between Sunspots and Volcanic and 

 Seismic Phenomena and Climate," by H. I. Jensen, b.sc, 

 Junior Demonstrator in Chemistry and Geology, Uni- 

 versity of Sydney. (Communicated by Professor T. W. 

 E. David, b.a., f.g.s., f.r.s.) 

 This paper is a sequel to the author's note communicated 

 to the Royal Society of New South Wales, on June 4th, 

 1902. The paper is divided into two parts. In the first part 

 it is shown that while there has been a marked rise in solar 

 activity since the middle of 1902, seismic and volcanic dis- 

 turbs nees have fallen oil' on the earth, both in violence and 

 frequency almost to a minimum. The causes to which 

 Dr. J. Milne ascribes seismic disturbances in his " Earth- 

 quakes/' arc reviewed, and it is concluded that most earth- 

 quakes are primarily due to gain or loss of heat by a portion 

 of the earth's crust, to gain in regions undergoing rise of 

 isogeotherms alter heavy sedimentation, to loss in regions 

 of rapid secular contract ion. In both cases it is shown that 

 solar activity will exert a considerable influence if it be 

 granted that more heat is received from the sun in years 

 of sunspot maximum than in years of sunspot minimum. 

 In areas undergoing heating and folding like Japan, Java, 

 and Argentina, an increase in our annual supply of solar 

 heat, such as is experienced at sunspot maxima, may exert 

 a disturbing influence ; but in areas undergoing cooling 

 comprising the gre iter part of the earth's land surface, a 

 falling oil of solar heat leads to seismic disturbances, by 

 hastening secular cooling, hence earthquakes are more 

 numerous at sunspot minima than at maxima. It is freely 

 admitted that various secondary causes or liberating forces, 

 may have considerable influence in locating the time for 

 earthquake outbreaks. Volcanoes are similarly shown to 

 be in the main divisible into two classes (1) those which 



