144 Jounsron-Lavis—The Eruption of Vesuvius in April, 1906. 
ERvupPtive PornoMena or Aprin, 1906.* 
April 2nd.—On this day the vapour-plume above Vesuvius was larger, and 
from time to time was darkened by the ejection of dust and sand. This, no doubt, 
was an indication of the formation of a new, or the extension of an old, lateral 
rift. In consequence of the withdrawal of magma necessary to fill this, the level of 
the lava fell in the chimney; and, as always occurs, the edges of the cone of 
eruption began to fall in, and to be re-ejected in a partially pulverized condition, 
mixed with fresh lava-cakes. The latter fact shows that the top of the lava 
column had not fallen very low. ‘The fumaroles appeared more active; the seismic 
apparatus, such as it was, at the Vesuvian Observatory exhibited a state of agitation 
of the ground ; and the telephone poles, Torre to Naples, from Ongino onwards 
‘“‘gave out a noise comparable to that of a cauldron of pitch boiling violently.” 
April 3rd.—Seems to have passed without any very extraordinary or special 
manifestation, except that the explosions at the central crater were well marked. 
The boati were distinctly audible at the lower station of the funicular railway and 
even at a greater distance. 
April 4th.{—Karly in the morning, at about 5.30 a.m. according to Mercalli, an 
opening occurred on the south slope of the cone near a spot marked Casotto delle 
Guide on the Carta Topografica Militare of 1903.§ This was on a radial fissure, 
as shown by clefts and fumaroles above the outlet. The outpour was of small 
importance, destroying the west bends of the Fiorenza path (see Pl. XXII.). The 
ejecta from the summit principally consisted of lava-cakes, showing that the lava 
was high in the chimney, and that there was little disintegration of the sides of 
the sinall inner crater. Professor Mercalli and others who were on the mountain 
observed a marked increase in the violence of the explosions near midday. All 
the morning the mountain was in a tremulous state, with of course more agitation 
at this time. Between 2 and 3 p.m. the lava-top must have sunk, probably filling 
the repeated extensions of the dyke or dykes. At the same time, the crumbling 
* There are many discrepancies even in the written records of scientific men, not to speak of casual 
observers. From careful inquiries and by the comparison of different chronicles of the events, I have 
endeavoured to construct what I hope to be a fairly accurate history of the successive incidents. My 
very detailed knowledge of the locality, and my intimate acquaintance with many of the observers, will, 
I hope, have assisted the correctness of this diary. 
| Gargiulo, Gaspare, ‘‘ I] Vesuvio e le sue eruzioni in Rapporto a Torre Annunziata” in ‘Il tributo 
di Riconocenza torrese a Maria T. T. della Neve.’”’—Torre Annunziata, 1906, in 8°, p. 13. 
} Prof. Lacroix has apparently confounded the 3rd and 4th of April. Op, cvt., p. 12. 
§ That is, at an altitude of 1200 m. 
