408 



Proceedings of the Royal Irish Academy. 



I propose to examine the lists published of the eruptions of the 

 following Yolcanoes — Hecla, Katla, and TroUadyngia ; also those of 

 Etna and Yesuvius. The three first I take from a Paper having 

 appeared in the " Smithsonian. Report" of 1885 ("Washington, 1886), 

 under the title — " Ohservations on Yolcanic Eruptions and Earth- 

 quakes in Iceland within Historic Times, translated and condensed from 

 a History of Iceland by Thomas Thoroddsen, hy George H. Eoshmer." 



One reason for selecting these Icelandic eruptions, is that the 

 intervals between the eruptions are generally long, and rarely re- 

 present a close succession of years which would favour a chance 

 coinLcidence between the year of occurrence of the eruption and one of 

 the sun-spot period years. Another reason for the selection is, that 

 generally the Smithsonian Papers are carefully prepared, and the 

 data carefully checked. 



In this list, Hecla appears with 17 eruptions as follows : — • 



No. 



Date. 



Remarks. 



1 



1104. 





2 



1157. 





3 



1206, December 4, 



Lasted till follo\\'ing spring. 



4 



1222. 





5 



1294, 



With violent earthquakes and formation 



6 



1300, July 10, 



of crevices. 

 One of the most- violent of the volcano. 



7 

 8 



1341, May 19, 



1389-90, 



Enormous fall of cinders accompanied by 



an earthquake. 

 Lasted to middle of 1390. 



9 



1436. 





10 



1510, July 25. 





11 

 12 

 13 



1554, May (end of), 



1578, 



1597, Januaiy 3, lillMarcli, 



Accompanied by frequent shocks of earth- 

 quake. 



Accompanied by frequent shocks of earth- 

 quake. 



Great projection of cinders. 



U 

 15 



1619, July (end of), 

 1636, May 8, 



The ashes carried northward produced 



intense darkness. 

 Lasted until following winter. 



16 



1693, Feby. 13, till August, 



Very violent. 



17 



1766, April 5, 



Lasted until autumn. 



