342 REPORT— 1892. 



but on Marcli 17 and 18 sligtt reflection from the crater was visible for 

 the first time for nearly a year, showing the rise of the lava in the 

 chimney, due certainly in part from blocking of the lateral channel, as the 

 outflow of lava below was markedly diminished. On the 21st. the activity 

 at the crater was distinctly at the first degree, but on the 22nd the second 

 degree was attained. On that evening, however, a. gush of lava showed 

 the removal of the lateral obstruction to its outflow, and the central 

 activity so diminished that the following night no reflection was visible. 

 On March 29 and 31 the crater again showed the first degree of activity. 



This was followed during the first week of April by a fresh outflow of 

 lava, which still more increased during the next week. During the first 

 four days of the month feeble reflection was from time to time visible 

 from the crater. On the 12th, black dusty smoke was puffed out from 

 time to time. On visiting the Atrio, I found the lava that flowed had 

 formed the mound above spoken of, surmounted by fumaroles. 



During the night of May 3-4 fresh portions of the crater wall 

 collapsed and blocked the vent, so that during the following day hai'dly 

 any vapour crowned the summit of the volcano. By the next day the 

 increased tension of the vapour was suflBcient for it to force its way 

 through the obstruction, and much black sandy smoke escaped during 

 the 5th, 6th, 7th, and 8th. Obstructing masses that had detached them- 

 selves from the crater sides again plugged the vent on the 27th and 28th ; 

 the next day dark, sandy, and dusty smoke was emitted. 



The flowing lava showed few new phenomena, with the exception of 

 the fine examples of conical and tubular spiracles formed above the lava 

 exit at the same locality, being above one set figured in the last report, 

 now buried. 



One is unique on account of its curved overhanging form. As was 

 seen in the photograph exhibited, it was ejected at the highest point of 

 the new lava, and quite at the foot of the great Vesuvian cone. I can 

 only explain its inclination at the lower part, by supposing that the 

 vapour and lava fragments were projected upwards and outwards in a 

 plane radial to the volcanic chimney which corresponds with tlie orienta- 

 tion of the fumarole. This lateral projection seems to have gone on for 

 some time, so that many of the blobs of lava blown out fell, and formed a 

 support for the inclined tube. As the blasts escaped more feebly the 

 edges of the mouth became more solid, and so the lower lip diverted the 

 column more in an upright direction, until the growth became almost 

 vertical. The whole efl'ect is to produce a large mass somewhat re- 

 sembling a recumbent animal with its neck and head erect. 



About twenty yards more distant from the foot of the cone was another 

 large, obtuse, conical-shaped fumarole, which had been broken away on 

 one side, and well exhibited the dome-like interior covered by stalactitic 

 lava, as shown in a photograph exhibited. These two specimens con- 

 stitute very fine examples of the spiracles which may be built up on 

 the surface of a coarsely crystalline lava, such as that now issuing from 

 Vesuvius. They differ very considerably from those described and illus- 

 trated by Dana and others from Hawaii, and from those formed on acid 

 lavas at Reunion, of which one or two figures have been published. 



At the summit of the great cone few changes have occurred beyond the 

 further enlargement of the crater. Wlien slips took place from the edges, 

 dark dust-laden vapour was puffed out from time to time. On one or 

 two occasions the lava rose sufficiently high in the chimney, combined 



