TRUE VOLCANOES. 231 



in direction with that of the Cordillera. Upon the ridge of 

 the wall, the three domes, set up like castles, follow from 

 S.W. to N.E. : Cuntur-guachana, Guagua-Pichincha (the 

 child of the old volcano), and el Picacho de los Ladrillos. 

 The true volcano is called the Father, or the Old Man, Rucu- 

 Pichincha. It is the only part of the long mountain ridge 

 that reaches into the region of perpetual snow, and therefore 

 rises to an elevation which exceeds the dome of Guagua- 

 Pichincha, the child, by about 190 feet. Three tower-like 

 rocks surround the oval crater, which lie somewhat to the 

 southwest, and therefore beyond the axial direction of a wall 

 which is on the average 15,406 feet in height. In the spring 

 of 1802 I reached the eastern rocky tower accompanied only 

 by the Indian, Felipe Aldas. We stood there upon the ex- 

 treme margin of the crater, about 2451 feet above the bot- 

 torn of the ignited chasm. Sebastian Wisse, to whom the 

 physical sciences are indebted for so many interesting observ- 

 ations during his long residence in Quito, had the courage 

 to pass several nights in the year 1845 in a part of the cra- 

 ter where the thermometer fell toward sunrise to 28°. The 

 crater is divided into two portions by a rocky ridge, covered 

 with vitrified scoria?. The eastern portion lies more than a 

 thousand feet deeper than the western, and is now the real 

 seat of volcanic activity. Here a cone of eruption rises to a 

 height of 266 feet. It is surrounded by more than seventy 

 ignited fumaroles, emitting sulphurous vapors.* From this 

 circular eastern crater, the cooler parts of which are now 

 covered with tufts of rushy grasses, and a Pourretia with 

 Bromelia-like leaves, it is probable that the eruptions of fiery 

 scoria?, pumice, and ashes of Rucu-Pichincha took place in 

 1539, 1560, 1566, 1577, 1580, and 1660. The city of 

 Quito was then frequently enveloped in darkness for days to- 

 gether by the falling, dust-like rapilli. 



To the rarer class of volcanic forms which constitute elon- 

 gated ridges belong, in the Old World, the Galungung, with 

 a large crater, in the western part of Java ;f the doleritic 

 mass of the Schiwelutsch, in Kamtschatka, a mountain 

 chain upon the ridge of which single domes rise to a height 

 of 10,170 feet; J Hecla, seen from the northwest side, in the 

 normal direction upon the principal and longitudinal fissure 



* Kkinere Schriften, bd. i., s. 61, 81, 83, and 88. 

 t Junghuhn, Reise durchJava, 1845, s. 215, Tafel xx. 

 t See^Adolf Erman's Reise urn die Erde, which is also very import- 

 ant in a geognostic point of new, bd. iii., s. 271 and 207. 



