558 POPULAR SCIENCE MONTHLY 



VESUVIUS DURING THE EARLY MIDDLE AGES 



BY Dr. CHARLES R. EASTMAN 



HARVARD UNIVERSITY 



TT is certain that Vesuvius, prior to the Plinian eruption of 79 A. D., 

 -*- by far the most tragic, and one of the three most violent in Italian 

 history, was regarded as an entirely extinct volcano. The details of 

 this eruption, the sequence of its phenomena, and its peculiarly de- 

 structive effects, are familiar to us from contemporary sources, and 

 from the memorials written in large characters by the mountain itself 

 over the ruined cities at its base. From the date cf this catastrophe 

 onward for over fifteen hundred years, when the period of modern 

 investigation begins, our knowledge of Vesuvian history depends upon 

 more or less casual mention, and upon brief notices of eruptions in 

 monastic chronicles. 



Owing to the scantiness of our information, little attention has been 

 paid by students to the long interval separating the two most violent 

 paroxysms known to have shaken the mountain. Yet, inadequate as 

 the records are, their importance is of the first order. They register 

 for us the dates of major disturbances, at least, extending over a period 

 of sixteen centuries, and afford some means for estimating the intensity 

 of volcanic action in the Naples district for a still longer period. More- 

 over, they furnish data for reconstructing the probable form of the 

 mountain in antiquity, and for detecting the amount of change it has 

 undergone since Plinian times. Nor should it be forgotten that the 

 early topographic descriptions that have come down to us offer in- 

 teresting points of comparison with the present condition of the stately 

 guardian of the Bay of Naples. 



Thus it appears that the original sources of information, which are 

 all that need concern us in the present article, acquaint us not only 

 with the actual history of Vesuvius since the first century of our era, 

 but, taken in connection with other facts, throw a fresh coloring upon 

 the accounts of the ' burnt mountain ' that have survived from classic 

 times. Two of the points just enumerated will repay further inquiry : 

 first, the chronology of eruptions during the early middle ages; and 

 secondly, the probable form of Somma-Vesuvius in antiquity. One 

 reason why a review of the chronology seems desirable is because the 

 dates of medieval eruptions are often confused, and the authorities for 

 them incorrectly given, or more frequently omitted. It will be profit- 

 able, therefore, to take a brief survey of the original sources, but without 



