320 EEPORT — 1891. 



that magnificent view of VesuTius and the Atrio del Cavallo, one sees 

 below the new lava-stream in the form of the letter La, the horizontal 

 portion of which is still being prolonged down the Atrio towards the 

 Fossa della Vetrana. In the middle of the rilge we found a thin coating 

 of fine red dust which had reached thus far from the crater. Much of 

 the Atrio was also covered by the same material. Scaling the cliff face 

 just beyond the Cognulo di Ottajano to the Atrio del Cavallo, we again 

 visited the lower point of the outburst. Most of the beautiful fumaroles 

 ■were in a state of ruin, and lined by good-sized crystals of liEeraatite and 

 mixed chloride crusts. Here the lava was quite solid, though at one 

 point was a hole, some 50 m. from the base of the great cone, where we 

 could see the molten rock flowing lazily along about a metre beneath our 

 feet. The lava at the end of the flow was making considerable progress 

 to the westwards, and stood opposite dyke 13. 



During the month of July few changes took place in the mountain ; 

 the crater still got larger, dust was thrown out, and the lava descended. 

 These phenomena are capable of continuing for months if the drainage 

 opening does not enlarge. 



After an interval of a month, during which by the kindness of Messrs. 

 Treiber and Ferber I was kept continuously informed of any change, I 

 again visited the volcano. The crater had considerably enlarged, but 

 chiefly in a south-easterly direction, in the line of the fi.ssures that have 

 existed for a long time at the edge of the crater plain and the top of the 

 great cone. These fissures had also increased in size and number since 

 my last visit, so that altogether this seems to be, at present, the most 

 favoured direction for the next disruption of the great cone. The crater 

 has therefore an irregular oval form, with the major axis directed 

 N.W.-S.E. Ou this occasion I could not see the bottom of the crater, 

 but on its walls were several dykes, which may be enumerated according 

 to their orientation: — N.E. ; N. ; N.N.E., probably the dyke of the last 

 eruption ; N.W. ; S.W., probably the upper part of the fissure i below 

 which emits hydrochloric acid ; the hollow dyke that has supplied the 

 eastern rift; the hollow dyke that supplied the eruption of May 2, 1885 ; 

 and a little solid dyke close to it. There may have been others, but the 

 perilous nature of the crater edge requiring great care, even in the only 

 two places one could approach, together with the abundant irritating 

 vapour, prevented a careful examination. 



The lava, which had at one time extended down to nearly opposite 

 Messrs. Cook's gate-lodge in the Fossa Vetrana, was now flowing very 

 slowly at the junction of the Fossa and the Atrio del Cavallo. 



A few days previously four shocks of earthquake occurred, limited to 

 the great cone and felt at the lower railway station. These, combined 

 with the other phenomena above mentioned, show that the cone is in an 

 exti'emely un>;table state, and want of confidence must be felt until some 

 time fui'ther has elapsed. 



In conclusion, the reporter must thank Mr. G. M. Cook, of Messrs. 

 Cook, Son & Co., for granting free passage over the Vesuvian Railway, 

 thus greatly facilitating the investigation of the volcanic phenomena. 



