SUN-SPOT MINIMA AND VOLCANIC ERUPTIONS. 43 



At the time of the Baku and Transcaucasian earthquakes 

 I read up some facts about European volcanoes and earth- 

 quake areas, and in connection with Vesuvius I noticed 

 that it was in violent eruption approximately every eleventh 

 year. This being the well known sunspot period I started 

 on a further enquiry. Late in the fifties of last century, 

 four distinguished scientists Julius Schmidt, Wolf, Kluge, 

 and Poey had discussed a probable relation between volcanic 

 and sunspot phenomena. 



Schmidt came to the conclusion that there was no marked 

 coincidence between the appearance of sunspot s and earth- 

 quakes, though, as far as can be gathered, he did not inves- 

 tigate the converse, namely, whether there is any connec- 

 tion between the phenomena of absence of sunspots and 

 the occurrence of violent shakings on the earth. 



M. R. Wolf, a distinguished authority on sunspots and 

 earth magnetism, considered that earthquakes and volcanic 

 eruptions were coincident ivith sunspots. 1 He apparently 

 only theorised on the subject instead of investigating facts, 

 which, if studied, would speedily have disillusioned him. 



Kluge, a noted authority on earthquakes, after a careful 

 study of seismic disturbances in various parts of the world 

 between 1850 and 1857, came to the conclusion that when 

 there are few sunspots, earthquakes, volcanic eruptions 

 and magnetic disturbances have been at a maximum. 

 Though later researches have proved him to be wrong as 

 far as magnetic disturbances are concerned, 1 hope to-night 

 to prove him right in regard to volcanic and seismic 

 phenomena. 



M. H. Poey, who examined a catalogue of West Indian 

 and Mexican earthquakes between 1634 and 1870, shows 2 

 that earthquakes have come in groups, first at -maxima, 



1 Bern. Naturf. Gesellschaft, 1852. 2 Comptes Eendus, 1874. 



