ON THE VOLCANIC PHENOMENA OF VESUVIUS. 471 



The Volcanic Phenomena of Vesttvius and its Neighbourhood. — 

 Report of the Committee, consisting of Mr. H. Bauerman, 

 Mr. F. W. RuDLER, Mr. J. J. H. Teall, and Professor H. J. 

 Johnston-Lavis. (Draivn up by Professor H. J. Johnston- 

 La vis.) 



Vesuvius. — Daring the first week of June 1892 mucli dnst-bearing 

 vapour escaped from the crater, but on the seventh of the month incan- 

 descent lava- cakes were being ejected, and a greater flow of lava was 

 visible in the Atrio del Cavallo. The central crater increased in activity 

 during the 8th and 9th, but on the 10th much dusty smoke issued during 

 the day, but at night no reflection was visible. The following day less 

 vapour was emitted, which only occasionally was darkened by dust. 

 During the 12th, 13th. 14th, and 15th very little vapour was visible 

 about the crater ; a little more, sometimes white and sometimes dark 

 from dust, issued from the last date till the evening of the 22nd, when a 

 fresh gush of lava came forth in the Atrio del Cavallo, and a few incan- 

 descent cakes were ejected from the crater. On the 23rd more lava and 

 high jets of incandescent lava-cakes were thrown out from the crater. 

 The volcano was much quieter the next day, followed by marked repose 

 during the rest of the month.' 



During the next two months little of note occurred. The lava some- 

 times increased, and at other times it diminished, but it practically never 

 stopped flowing. The central crater also varied within narrow limits, 

 the vapour being occasionally charged with dust when a bit of crater 

 edge collapsed and partly choked the main vent. 



During September much the same state persisted. No reflection was 

 ever visible from the central crater, though the usual column of vapour 

 escaped freely, and was accompanied from time to time by dust and sand. 



The month of October was a most unfavourable one, as for more than 

 half of the month the cone was enveloped in cloud ; but neither during this 

 month nor during November and December did any marked change occur 

 at the central crater. Occasionally a faint but uncertain glimmer was visible 

 on some evenings over the main vent. Lava, as usual, continued to pour 

 forth, flowing first to one side and then to the other of the Atrio, so that 

 the point of its exit described in the former report has been raised, and a 

 hill sloping away to the W., N., and B. continues to rise and to obliterate 

 part of the space between the great cone of Vesuvius and the escarpment 

 of Monte Somma. 



During November the highest point of this boss, in the Atrio del 

 Cavallo, piled up as it had been by the constant guttering forth of lava, 

 was crusted over and surmounted by some ruined spiracles formed in 

 June of the same year (1892). At certain points of this crust most 

 beautiful sublimations of aphthitalite were deposited at a low red heat. In 

 removing these deposits they were found to be of a dull red incandescence, 

 but digging a few centimetres deeper amongst the scoria, of a bright red 



' For much of the daily record I am indebted to Signer Aw. Bartolo Longo, pro- 

 prietor of the observatory of the Valle di Pompei, and to Signers C. M. Tosti and 

 Professor V. Capaccio, the observers. Unfortunately the record is not continuous, 

 but what I have been able to obtain has been carefully checked and much extended 

 by my closer observations on the volcano. 



