290 COSMOS. 



mat.* On the latter the lava stream, after giving rise to a 

 water-fall, is continued into the tertiary rocks.f From such 

 true effusions of lava, which form coherent masses, Jung- 

 huhn very accurately distinguishes, in the eruption of Gu- 

 nung Lamongan,! on the 6th of July, 1838, what he calls a 

 stone stream, consisting of glowing and usually angular frag- 

 ments, erupted in a row. "The crash was heard of the 

 breaking stones, which rolled down, like fiery points, either 

 in a line or without any order." I purposely direct especial 

 attention to the very various modes in which fiery masses 

 appear on the slopes of a volcano, because in the dispute 

 upon the maximum angle of fall of lava streams glowing 

 streams of stones (masses of scoriae), following each other in 

 rows, are sometimes confounded with continuous lava streams. 

 As the important problem of the rarity or complete defici- 

 ency of lava streams in Java a problem which touches on 

 the internal constitution of volcanoes, and which, I must add, 

 has not been treated with sufficient earnestness has recently 

 been so often spoken of, the present appears a fitting place in 

 which to bring it under a more general point of view. Al- 

 though it is very probable that in a group ro series of volca- 

 noes all the members stand in a certain common relation to 

 the general focus, the molten interior of the earth, still each 

 individual presents peculiar physical and chemical processes 

 as regards strength and frequency of activity, degree and 

 form of fluidity, and material difference of products pecu- 

 liarities which can not be explained by the comparison of the 

 form, and elevation above the present surface of the sea. 

 The gigantic mountain Sangay is as uninterruptedly active 



* The name of G. Idjen, according to Buschmann, may be explained 

 by the Javanese word hidjen, singly, alone, separately a derivative 

 from the substantive hidji or widji, grain, seed, which with sa expresses 

 the number one. With regard to the etymology of G. Tengger, see 

 the important work of my brother upon the connections between Java 

 and India (Kaivi-Sprache, bd. i., s. 188), where there is a reference to 

 the historical importance of the Tengger Mountain, which is inhabit- 

 ed by a small tribe of people, who, opposed to the now general Mo- 

 hammedanism of the island, have retained their ancient Indo-Javanic 

 faith. Junghuhn, who has very industriously explained the names of 

 mountains from the Kawi language, says (th. ii., s. 554), that in the 

 Kawi Tengger signifies hill ; the word also receives the same significa- 

 tion in Geriche's Javanese I)ictiona,Yy(Javaansch-nederdiiitsch Woorden- 

 boek, Amst., 1847). Slamat, the name of the high volcano of Tegal, 

 is the well-known Arabic word selamat, which signifies happiness and 

 safety. 



f Junghuhn, bd. ii., Slamat, s. 153 and 163; Idjen, s. 698; Teng- 

 ger, &. 773. J Bd. ii., s. 760-762. 



