Recent Researches at Vesuvius

Abstract

PROF. ALESSANDRO MALLADRA, the successor of Mercalli at the Royal Vesuvian observa tory, has published a number of papers, from 1912 onwards, on the volcanic manifestations and progres sive changes in the great crater farmed in 1906. It has been possible in recent years to descend, by hazard ous paths, to the edge of the central funnel, 250 metres below the crater-edge, and valuable observations have been made on the gases emitted from the fumaroles. Prof. Malladra furnishes a well-illustrated summary of the conditions in 1914 in “Nel cratere del Vesuvio” (Boll, reale Soc. Geografica, 1914, p. 753). The gradual widening of the crater by the falling in of its cliffs is shown in plan in a paper, “Sulle modificazioni del Vesuvio dopo il 1906” (ibid., p. 1237). The small aperture of 1900 is also here indicated, almost imme diately over the pit that is now active. The volcano remained quiet, in a solfataric stage, for seven years after the enormous outburst of 1906; but a glowing funnel opened in the floor of the crater of explosion on July 5, 1913. Prof. Malladra was en gaged in a hypsometrical survey on the cone a few hours after this outbreak (“Sui fenomeni consecutivi all apertura della bocca 5 Luglio, 1913,” Rend. R. Accad. Sci. Fis. e Mat. di Napoli, fasc. 11 and 12, 1914), and has recorded a true incandescence, accom panied by the emission of fresh scoria;, specimens of which were collected on one of many later visits. The “yellow fumarole” in the crater gave a temperature-reading of 128° C. in 1911. In September, 1913, this had risen to 330°, and in October to 347°. During the collection of gases from this fumarole for analysis, water condensed, containing hydrochloric acid in the proportion of 9-21 grams per 100 c.c., and smell ing strongly of sulphuretted hydrogen. The author points out that, following the arguments of Brun as to the possibility of the permeation of water into a heated mass from without, this water must be truly magmatic. He thus provides further evidence, in addition to that of Day and Shepherd, against Brun's main contention.