RISE OF MOLTEN ROCK TO THE EARTH'S SURFACE 129 



plosions were resumed. On May 25, 1905, a small stream of lava 

 began to issue from a fissure high up upon the central cone, and 

 from this time on the lava continued to flow down to the valley or 

 atrio, separating the inner cone from the caldera remnant of Monte 

 Somma. Seen in the night, this stream of lava appeared from 



FIG. 130. Night view of Vesuvius from Naples before 

 the outbreak of 1906. A small lava stream is seen 

 descending from a high point upon the central cone 

 (after Mercalli). 



Naples like a red hot wire laid against the mountain's side (Fig. 

 130). With gradual augmentation of Strombolian explosions 

 and increase in volume of the flowing lava stream, the same condi- 

 tion continued until the first days of April in 1906. The flowing 

 lava had then overrun the tracks of the mountain railway and 

 accumulated in considerable quantity within the atrio (Fig. 131). 

 On the morning of April 4, a preliminary stage of the eruption 

 was inaugurated by the opening of a new radial fissure about 500 



