286 COSMOS. 



volcanoes of a series all stand over one focus, the net of fis- 

 sures through which they communicate is, nevertheless, cer- 

 tainly so constituted that the obstruction of old vapor chan- 

 nels, or the temporary opening of new ones, in the course of 

 ages, render simultaneous eruption at very distant points 

 quite 'conceivable. I may again advert to the sudden dis- 

 appearance of the column of smoke which ascended from 

 the volcano of Pasto, when, on the morning of the 4th of 

 February, 1797, the fearful earthquake of Riobamba con- 

 vulsed the plateau of Quito between Tunguragua and Coto- 

 paxi.* 



To the volcanoes of the island of Java generally a charac- 

 ter of ribbed formation is ascribed, to which I have seen noth- 

 ing similar in the Canary Islands, in Mexico, or in the Cor- 

 dilleras of Quito. The most recent traveler, to whom we 

 are indebted for such admirable observations upon the struc- 

 ture of the volcanoes, the geography of plants, and the psy- 

 chrometric conditions of moisture, has described the phenome- 

 non to which I here allude with such decided clearness that 

 I must not omit to call attention to this regularity of form, 

 in order to furnish an inducement to new investigations. 

 "Although," says Junghuhn, "the surface of a volcano 

 10,974 feet in height, the Gunung Sumbing, when seen from 

 some distance, appears as an uninterruptedly smooth and 

 sloping face of the conical mountain, still on a closer exam- 

 ination, we find that it consists entirely of separate longi- 

 tudinal ridges or ribs, which gradually subdivide and become 

 broader as they advance downward. They run from the 

 summit of the volcano, or more frequently from an elevation 

 several hundred feet below the summit, down to the foot of 

 the mountain, diverging like the ribs of an umbrella." These 

 rib-like longitudinal ridges have sometimes a tortuous course 

 for a short distance, but are all formed by approximated 

 clefts of three or four hundred feet in depth, all directed in 

 the same way, and becoming broader as they descend. They 

 are furrows of the surface " which occur on the lateral slopes 

 of all the volcanoes of the island of Java, but differ consider- 

 ably from each other upon the various conical mountains, in 



vicinity of the mountain, consisting of detritus intermingled with nu- 

 merous angular, erupted blocks of lava, and compared it with the 

 earliest reports, regards the statement, which has been disseminated 

 by so many valuable works, that a portion of the mountain and an 

 area of several square miles sank during the eruption of 1772, as 

 greatly exaggerated (Junghuhn, bd. ii., s. 98 and 100). 



* Cosmos, vol. v., p. 183, and Voyage aux Regions Equinox, t. ii., p. 16. 



