70 PHILOSOPHY OF STORMS. 



Trieste, but if to the force of the wind, we add the dimin- 

 ished pressure of the air along the northern shore of the 

 Mediterranean and the Adriatic, and the increase of the 

 pressure of the air on the outside of the storm, by the rush of 

 the air outwards above ; the rise of waters, there might be 

 quite sufficient to produce the disastrous effects which 

 spread consternation over so much of the southern part of 

 Europe. 



Was the remarkably warm winter of 1821 and 1822, in 

 all the north of Europe, caused by the immense quantity of 

 latent caloric given out during these great rains, together 

 with the southern winds which prevailed in consequence of 

 the upward vortex of air over Iceland during this whole 

 winter ? At St. Petersburg, dreadful floods of rain repeat- 

 edly occurred during the winter, and the snow had entirely 

 disappeared by the first of February; and even beyond 

 Tobolsk, warm winds prevailed, and generally in the inte- 

 rior there was no snow. And on the 2d of March, the 

 Dwina was free from ice at Riga. 1 



If this were the only fact on record, of rain accompany- 

 ing volcanoes, it ought in this case, to be considered acci- 

 dental and unconnected, but nothing is better established 

 than the connexion of volcanoes with rains, from their very 

 frequent concomitancy. Indeed, Baron Humboldt speaks 

 of the mysterious connexion of volcanoes with rains, and 

 adds, that they sometimes on breaking out change dry sea- 

 sons into rainy in South America. This connexion will be 

 considered mysterious no longer. It may here be added as 

 a reason why volcanoes do not always produce rains, that 

 in the most unfavorable state of the dew point, rains cannot 

 be produced. 



M. Lyell, in his Principles of Geology, vol. 2, page 94, 



1 See the Phil. Journals of 1822, which all seem to acknowledge that there 

 was some connexion between the bursting out of this volcano and the rains 

 which ensued. 



