24 THE POPULAR SCIENCE MONTHLY. 



Mohammedanism are distinguished for their high moral quality, and 

 by this won their glorious victories ; and their crystallization in the 

 heart of a noble-minded prophet and reformer was in each case pre- 

 ceded by a great social and moral quickening throughout the commu- 

 nity in which they arose. When the depths of the human heart are 

 moved and the imperative claims of justice, truth, and purity once 

 perceived, then the death -knell of mere nature-worship has. been 

 rung in that land. As the pagan god, Wainamoinen, in the Finnish 

 epic of the Kalevala, when he hears of the birth of Christ, enters his 

 canoe and paddles away to the northern wastes of snow and silence, 

 so must the worship of force give way to the more majestic divinity 

 of conscience. The varied influences of man's environment conspire 

 with the aspiring instincts of his in most soul to conduct him con- 

 stantly out of the imperfect toward the perfect. Whether or not he 

 reach it, it is that that must be the goal of his striving. 



---- 



ISCHIA AND ITS EAETHQUAKES. 



By M. CH. V&LAIN. 



THE island of Ischia, which has recently been so terribly rent by an 

 earthquake, is situated in the northwestern part of the Bay of 

 Naples, and near the Phlegrean fields, with which the little island of 

 Procida, likewise volcanic, constitutes a connecting link. It forms a 

 part of the Neapolitan volcanic region, which may be considered as 

 still in a state of solfatarian activity, which is exemplified by the 

 well known solfatara of Puzzuoli, where the sulphur is re-deposited, as 

 far as it is mined, by numerous gaseous emanations, and by the escape 

 of carbonic acid in the Grotto del Cane near Lake Agnano. All of 

 these exhalations, which are the mark of a declining volcanic activity, 

 attest that this region, situated on a great line of fracture running 

 northwest and southeast from Vesuvius to Vultura, is still in direct 

 communication with the subterranean sources. The ancients fully 

 recognized this, and regarded all those explosive craters, now trans- 

 formed into a chain of remarkably picturesque lakes across the Phle- 

 grean fields, as so many doors of Tartarus through which the infernal 

 divinities took souls to the banks of the Acheron. The most celebrated 

 of them, Lake Avernus, " Atri Janua Ditis " (the gate of black hell), 

 now smiling and salubrious, then exhaled torrents of suffocating gases 

 which well justified its name, and rendered a stay there mortal to the 

 birds that ventured into its neighborhood. 



The Neapolitan volcanic region extends from Vesuvius to Vultura, 

 on the eastern edge of the Apennines, and includes the Phlegrean fields 

 and the connected islands of Ischia and Procida. The volcanic activity 



