148 Jounston-Lavis— The Eruption of Vesuvius in April, 1906. 
narrow tongue poured down the slope past the Casa Bianca, and stopped at about 
the 375 contour-line.* The flow itself did not reach this point till about 3 a.m. 
the following morning; but as I shall show later on, this must have been the 
stock of fluid rock already without the mountain, or in the lateral rift. About 
an hour before midnight, a slight calm appeared to have occurred, due, no doubt, 
to a rapid fall in the lava-level, in consequence of an abundant outpour at the 
different lateral rents. 
April 8th.— Twenty minutes after midnight, with a loud report, a great rift, 
3 kilometres in length, split the mountain parallel to the lava of Terzigno. Near 
the middle of this rift, a crater was formed, ejecting scoria, etc., with such 
force as to equal in volume that of the central crater. Half an hour after 
midnight, explosion after explosion occurred from the great crater with terrific 
violence, shaking the whole region, so that houses were in a constant state of 
tremor, and people were awakened. The column of ejecta was enormous, and 
the electric discharges were continuous, so that, in addition to the explosions of 
the mountain, was added the constant noise accompanying these lightnings. 
There seem to have been two violent convulsions, one at 31 minutes after mid- 
night, and one at about 2.40 a.m. Many witnesses assert that during these early 
hours the ejecta were somewhat luminous, and appeared more especially so towards 
Ottajano. The essential ejecta of the nature of that described later on no doubt 
did issue with sufficient heat to be luminous; nevertheless the brushwood buried 
in it, at the Punta del Nasone, was not burned, so that as the volcanic material 
spread through the air and vesicularized, its heat was no doubt rapidly used up 
in this process. As the night advanced, all was one vast dark mass of stone- 
laden atmosphere. It was during these early hours that the ejecta were chiefly 
essential, which, carried in a north-easterly direction, spread over Somma, Ottajano, 
S. Giuseppe, and away over the Campanian plain to Nola, Palma, Sarno, 
damaging also Terzigno, Piazzollo, Cinquevie, and S. Gennaro di Palma. 
Crossing the Apennines and the Adriatic, the finer dust reached as far as 
Montenegro. ‘Towards dawn, the ejecta were chiefly supplementary, or accessory, 
being derived from funnel-like paring of the walls of the upper part of the chimney 
by the evolution and escape of vapour from gradually increasing depths, and 
formed the dark mass in the atmosphere, as mentioned above. The edges of 
this growing crater were of course constantly falling in, only to meet the uprushing 
column of vapour by which the materials that had composed them were carried 
to very great heights. It is estimated that during the day the column of 
fragmentary materials attained over 7,000 metres. Prof. Matteucci and A. 
* All localities, heights, and contour-lines refer to my geological map. Geological Map of Monte Somma 
and Vesuvius, with a short and concise account, &c.1:10,000. London; Geo. Philip & Son, 1891, in 
6 sheets, 
