May 17, 4894] 



NA TURE 



67 



and incredible superstitions. This remark applies with still 

 greater force to vulcanology, for the study of which it is neces- 

 sary to possess an extensive knowledge of physics, chemistry, 

 and a well developed faculty of observation. For a century 

 or tivo previous to the nineteenth, however, there were acute 

 i-bservers, and we in Nfaples well know such names as those of 

 Sorrentino, Duca e Padre della Torre. 



Towards the end of the last century the active and extinct 

 volcanic regions of Italy attracted the attention of four great 

 men of science, each of a diliferent nationality. I allude to 

 SpalUnzani, -Sir William llamilmn, Dolomieu, and Breislak. 

 Although their nationality wasdiftcrent, they had two merits in 

 common — that of scientific truth and that of Baconian methods 

 of reasoning. In other words, they were pure men of science, 

 since by that term we understand one who observes carefully, 

 records neither more nor less than he observes, and draws from 

 these facts, and those collected by others, his conclusions, 

 without disregard to a clear knowledge of the principles in- 

 volved, and without flights of imagination. It is, therefore, more 

 to these four men that we owe the advance of human knowledge 

 concerning volcanoes than to all the writers who preceded 

 them. 



In the first years of the nineteenth century, vulcanological 

 literature was enriched by many workers, because, as the allie<l 

 sciences were then inaking great strides, they were able to ofif,;r 

 to vulcanologists much more powerful and accurate means of 

 investigation. Thus we had Humboldt, Scrope, Daubeny, Pi 11a, 

 and Gemmellaro. 



Following these came a phalanx of illustrious students of 

 geology, some of whom are still among us, while others, 

 though dead in person, are living and immortal in the memory 

 of man as heroes of science and of human knowledge. Amongst 

 these we may enumerate Lyell, Dana, Scacchi, Palmieri, 

 Silveslri, and Phillips, whilst at present many younger and 

 gifted investigators are not wanting. 



No other branch of science has been so heavily burdened by 

 extravagant hypotheses, which have so much retarded its pro- 

 gress, as that of vulcanology. It is not only in the first half of the 

 present century but even still that we find an extensive literature 

 produced by men who advertised themselves as scientific investi- 

 gators, when in truth they did little else but write memoirs 

 and books to promulgate and sustain fantastic, extravagan*, 

 imiginary, and impossible hypotheses. Nevertheless, amongst 

 this chaff we not only meet with grain, but very good grain. 



As a subject of study, Vesuvius holds the first place in all 

 vulcanological investigations of this and the last century. A lew 

 figures will make this fact more evident. Some four years since, 

 my wife and myself collected the titles of books, memoirs, and 

 other writings referring to the South Italian volcanoes, for the 

 purpo<e of publishing a bibliographical list. We found the 

 following numbers : — 



Graham's Island, or Isola Ferdinandea 



Roccamonfina 



Lipari Islands 



Alban Hills 



Campi Phlegriei ... 



Etna 



Vesuvius 



28 



33 



... 119 



210 



- 539 

 ... 880 

 ... 1552 



From this table it will be seen how much has been written 

 concerning Vesuvius ; in fact, its literature constitutes nearly half 

 o( what has been written about all the volcanic regions south of 

 Rome. If we add to these the titles referring to the Campi 

 Phlegroei, we then find that in a total of 3361 not less than 

 2ogi concerns the volcanic district around Naples. Let me, 

 however, give you a still more striking fact. The Naples branch 

 of the Italim .VIpine Club possesses the richest vulcanological 

 library in existence. The catalogue contains more than 7000 

 entries of papers, books, and manuscripts. In this number, 

 however, are included books that not only treat of vulcanology, 

 but in large part refer to seismology and, to a smaller extent, 

 to geology. It will be seen, therefore, that the Neapolitan 

 volcanic district represents more than a quarter of all vulcano- 

 logical literature. 



It is true that the history of Etna and the.'E)lian Islands 

 reach farther l)ack than that of Vesuvius, but on the other hand 

 the history of this latter is by far the mo>t complete. From a 

 chronological point of view, Vesuvius and also the Campi 

 Phlegrxi hold a more important place in history than any ol 

 their rivals. Even if the Fompeians, the Ilerculaneans and the 



NO. 128 I, VOL. 50] 



Slabians did lose all their pnpsrty eighteen centuries since, 

 the modern world has recovered it as archceological treasures, 

 whose value represents, from the point of view of culture, many 

 times the original and the compound interest on the same for 

 the whole interval ; and this we owe to our Vesuvius. The 

 Phlegrrcn region around Naples is so enchained with the poetry 

 of the heroic and classic periods, that without it the legends of 

 Cuma, of I'ilhecusa, of Sparctacus, .)f Parlen jpe, of Baja, and 

 so many others, which fill pages and pages of ancient history, 

 would not exist. 



Sometimes poetic ecstacy attacks the mind of the scientist ; 

 for, contrary to what the general public believe, science rather 

 than abolish poetic sentiment further develops it, but in a more 

 serious and refined form. 



When, as we wander around Naples, we reach the hill of 

 Cuma, and we encounter a few ruined walls and a few pot- 

 sherds that peep out through the rich vegetation of that spot, 

 where now the only inhabitants are the goats and the lizards, 

 our imaginations speed back for nearly three millenniums, when 

 this same rock, almost as in its present state, was chosen by the 

 daring Greek navigators as the site of their new colonial towii. 

 All of us know the history of Cuma, all of us know that this 

 little bit of Italy for one half of historic time held a very im- 

 portant place. We are deeply impressed when we make an 

 effort to conceive clearly what 3000 years really is, how many 

 generations lived and died during that time and in that place ; 

 but far greater are we impressed when we think that 3000 

 years is but a fraction in the .firtf/c^/Vfl/ history of that hill, and 

 finally our mind fails to grasp the value of time when we con- 

 sider that the physical record of this hill is not more than a 

 minute fraction of the geological chronology of our globe. 



Without going very far back in the geological history of our 

 region, I will ask you to follow me to the first part of the 

 Pliocene epoch, an epoch, as all know, to be considered quite 

 near our own time. All of us now admire the beauty of the 

 Gulf of Naples, which has few rivals in the entire world, but 

 at that time its conformation was very dilTcrent to what it is 

 now. It then lormed a very much larger gulf, represented 

 today by the plain we call the Campania Felice, with a large 

 part of the Terra di Lavoro. We must figure to ourselves a 

 broad gulf limited on the north by the promontory of Gaela, 

 where its confines were limited by high limestone cliffs. Its 

 coast had roughly the following trend. From Gaeta it corre- 

 sponded with the present provincial road to close under Castel- 

 forte, and from there was almost represented by the valley of 

 the Garigliano as far as the gjrge between Monte Faito and 

 Monte Cammino, by which narrow strait it was in communica- 

 tion with the sea covering the plain of Cassino. Winding 

 round the south of Monte Cammino it .again extended north- 

 wards to Mignano. The eastern coast of this strait corre- 

 sponded with the present line of railway from Mignano to 

 Taverna St. Felice, which coast, turning eastwards, passed 

 under Presenzano to extend into the niouniains by the valley of 

 the Volturno. From this point the coast, winding round several 

 islands, represented to-day by hills and mountains separated 

 from the main mass of the Appennines, it extended into these 

 latter, forming so many fiords. The sea then covered all the 

 plain, and its waves beat the foot of the mountains behind 

 Pietramelara, Pignataro Miggiore, Capua, Caserta, Nola, 

 Palma, Sarno, .Vngri, and Castellamare, and then corresponded 

 roughly with the present coast of the peninsula of Sorrento. In 

 the middle of this great gulf roe two important isles— Capri 

 and Monte Massico, besides a quantity of small ones. 

 Numerous fiords penetrated the Appennines. where to-day we 

 have the Garigliano, the Volturno, Valle di Maddaloni, Valle 

 Caudina, and" the Valle di .\vella. In fact, this part of the 

 coast of Italy in those pliocene times was very similar in con- 

 figuration to that of the Istrian coast of to-day. 



The rivers bringing down to the sea sand and mud, which, 

 settling at the bottom of the gulf, prepared an almost fiat marine 

 floor, which later was to form the foundation of theCamp.anian 

 Plain. At that period the Campania Felice was only sea, and 

 where today flourishes vines, or.ingcs, lemons, and gardens of 

 flowers, then only gre^v marine algx. 



The great fissure in the earth's crust which corresponds with 

 the western coast of Italy, and along which were foimed the 

 Italian volcanoes, opened a way for the igneous magma to the 

 bottom of this gulf. Numerous eruptive centres were formed, 

 giving rise to the volcanoes of Ischia, Roccamonfini, Campi 

 PhlegKvi, and Vesuvius. The order in which these different 



