SUNSPOT MINIMA AND VOLCANIC ERUPTIONS. 49 



turbecl. Geologists of the last thirty years have paid 

 special attention to this matter, and the result is that a 

 vast stock of information on the subject is available, form- 

 ing a solid basis for the science of seismology of the future. 



(2) The second factor in point of importance seems to be 

 "absence of sunspots," — the actual relations of a sunspot 

 minimum to an earthquake maximum will need to be 

 studied for several decades yet, before properly understood. 

 Sunspot minima seem however to fix the periods in which 

 great eruptions may be expected. 



(3) To fix the season or month also falls within the realms 

 of astronomy, as here the position of the earth with regard 

 to the sun, and of the moon with regard to the earth must 

 be considered, as well as the attractions of the nearer 

 planets Venus and Mars. 



(4) Lastly to fix the exact days, if it ever becomes pos- 

 sible, is likely to become an adjunct to the science of 

 meteorology, as here cyclones and pressure changes are to 

 be considered. 



The Possible causes of Interdependence of Seismic activity 

 and Sunspots. 



Assuming that there is such an interdependency, what 

 may be the possible cause or causes? Here it is only 

 possible for me to enunciate some facts and to suggest a 

 few theories for consideration. 



Prof. Hazen, the American meteorologist, Dr. Koppen, 

 Dr. Halm (of the Sonnblick Observatory, Austria), the 

 English meteorologist Alexander B. McDowall, and many 

 others, working on similar lines, have noticed a decided 

 connection between climate and sunspots. McDowall's 

 researches are given in a paper read on April 21st 1897. 1 



Most German and Indian meteorologists have noticed a 

 a similar connection ; they are of the opinion that rainfall 



1 Quart. Journ. Roy. Met. Soc, Vol. xxiii., p. 243 - 250. 

 D— June 4, 1902. 



