THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. II. 



No. IV.— APRIL, 1875. 



OZR-ia-IZCT^LXj ARTICLES. 



I. — Contributions to the Study of Volcanos. 1 



By J. W. Judd, F.G.S. 



The Lipaki Islands. — Stromboli. 



(PLATE VIII.) 



Presenting as it does the only example of a volcano in the phase 

 of permanent moderate activity to be found in Europe, Stromboli 

 must always have the strongest claims on the attention of geologists. 

 Here may at all times be witnessed, in perfect security, those explo- 

 sions produced by the disengagement of vapour in the midst of 

 masses of liquefied rock, which, following one another at longer 

 or shorter intervals, and taking place with greater or less violence, 

 constitute a most striking feature in nearly all volcanic eruptions ; 

 and the causes, sequence and attendant phenomena of these outbursts 

 can in the case of this volcano be most conveniently studied. 



As might be anticipated from the less striking character of its 

 action, Stromboli is less frequently mentioned by ancient writers 

 than Vulcano ; yet, as early as the fourth century before Christ, it 

 is spoken of as being in a state of eruption, and references to it 

 occur in the writings of Aristotle, Callias, Diodorus Siculus, Strabo 

 and Cornelius Severus. Most interesting to the geologist, however, 

 is the notice of the mountain by Pliny, who in the first century 

 of our era describes it in terms which are still applicable to it at 

 the present day. 



But if the ancient accounts of this volcano are somewhat meagre, 

 we are nevertheless fortunate in possessing the means of tracing 

 very completely its history in modern times ; during the last one 

 hundred years numerous sagacious and trustworthy observers have 

 visited the volcano, and given clear and accurate accounts of its 

 condition. Their descriptions enable us to define the true character 

 of the operations going on within its crater, to determine how far 

 these operations are constant in their action, and to ascertain the 

 limits of variation in the intensity, succession and results of its 

 outbursts. 



The general characters of the phenomena presented by Stromboli 

 — "the lighthouse of the Mediterranean "—are well known to be as 

 follows. The mountain, which is of conical form, rises directly 

 from the deep waters of the Mediterranean to the height of more than 

 3000 feet above its surface ; as the sea between the Liparis affords 



1 Continued from page 115. 



DECADE II. — TOL. II. — NO. IV. 10 



