ERUPTION OF STBOMBOLI— PERRET. 287 



followed by along period of almost complote repose, this constituting 

 quite a radical change from the foregoing habit of Stromboli and 

 imitatmg the modus operandi of other volcanoes, such as Vesuvius 

 and Etna. During this period not the least glimmer of light was 

 to be seen at the crater and when I agaui visited the volcano in 

 1909 it was still in a state of quiescence. In this connection a fact 

 of general interest may be mentioned. Some years previous to this 

 time a project was on foot to erect a lighthouse upon "Strombolic- 

 chio." This is a monolith of lava (pi. 3^ fig. 1) rising 50 meters 

 above the sea at a short distance from the island. In my opinion 

 it is a volcanic "neck;" that is, the solidilied lava which existed in 

 the conduit of a small volcano formerly active on this spot, the 

 cone of which, formed, of fragmentary materials, has been desti'oyed 

 by centuries of weathering, leaving the solid core as a monument to 

 its former existence. A flight of steps was cut from the sea level 

 to the top and the top itself was leveled, but the project was aban- 

 doned, as I am informed, precisely because the illumination from 

 Stromboli formed a better lighthouse than any which could be 

 constructed by man. Upon the failure of the volcano a light was 

 needed and a lighthouse is now to be erected upon Strombolicchio. 



The eruption of July-August, 1912, was, on the whole, greater 

 than its predecessor and was initiated by a continuous series of 

 violent local earthquake shocks. These undoubtedly were due to 

 a conduit partly obstructed by lava which had consolidated therein. 

 This was ejected in solidified form, as contradistinguished from that 

 of 1907, in irregular blocks of all sizes up to two meters in diameter. 

 One of these, shown in plate 3, figure 2, fell 500 meters distant from 

 the crater. The rock is a compact, basaltic lava containmg a con- 

 siderable proportion of olivine. 



Besides this rock the chief product of this eruption was the enor- 

 mous quantity (for Stromboli) of ash. This reached a depth of over 

 2 meters on the upper parts of the mountain, as shown by the photo- 

 graph (pi. 4) of a stone shelter built near the sumndt to shelter 

 observers of the target practice of the fleet. In the towns the Hat 

 roofs were covered to a depth of 6 to 8 centimeters and, in contrast 

 to that of 1907, this ash was alkaline but no less fatal to green vegeta- 

 tion. As long as the fallen ash remains dry it is harmless and a heavy 

 rain is innocuous, as it washes the ash from the leaves, but if the ash 

 on the leaf is moistened by the dew or a few drops of rain the soluble 

 materials are extracted and attack the leaf, generally affectmg one 

 or more sectors, as shown in plate 5. 



From the standpoint of the volcanologist, the most interesting 

 feature of this ash is the fact that it is constituted almost entirely of 

 new material — i. e., it was formed directly from liquid lava by inter- 



