

VULCANISM 163 



were hurled 4,000 feet or more into the air, with a noise which could 

 be heard for miles. The discharges continued with great violence 

 for four days, and at the same time earthquakes were felt through- 

 out the entire region. After the eruption was over, two craters 750 

 feet deep, with nearly vertical sides, were found at the top. An 

 enormous amount of loose material had accumulated on the sides 

 of the mountain. 



Vesuvius was again disastrously active in the spring of 1906. 

 The history of this eruption is summed up by Professor Jaggar as 

 follows: "In 1904 there was a lava-flow which stopped in Sep- 

 tember of that year. In May, lava flowed from a split in the north- 

 west side of the cone and continued in active motion throughout 

 the year. It ceased flowing at the time when the present [1906] 

 eruption opened a new vent on the south side of the cone. 



"On April 4, 1906, a splendid black ' cauliflower' cloud rose 

 from the crater (Fig. 1, PI. XLI, p. 145). On April 4th, 5th, 

 6th, and 7th, lava mouths opened, . . . first 500 feet below the 

 summit, then 1,300 feet lower, and finally 600 feet lower still, all in 

 the same radial line. The lowest mouth was more than half way 

 down the mountain, and from this orifice came the destructive 

 streams. It should be borne in mind that these flows are not floods 

 of lava which cover the whole slope of the mountain, but relatively 

 narrow snake-like trickles, none the less deadly when they push 

 their way through a closely built town. The molten rock crusted 

 over and cracked, making a tumble of porous boulders at its front. 



"At 8 P. M., April 7th, a column of dust-laden steam shot up 

 four miles from the crater vertically. The cloud snapped with 

 incessant lightnings. New lava mouths opened, and the flows 

 moved forward, crushing and burning and swallowing parts of 

 Boscotrecase, the stream forking so as to spare some portions of 

 the town. 



"Boscotrecase was ruined wholly by lava; Ottajano by falling 

 gravel. Boscotrecase is traversed in two places by the clinkery 

 lava stream, and in some cases houses were literally cut in two. 

 The stream of lava had forked about a spur of the mountain, leav- 

 ing the higher land with its vineyards untouched. The lower land 

 with its town was invaded. There is so little timber in the Italian 



