NOTES. Ixxvii 



an apparently perfect regularity and uninterrupted horizontally, which astonish 

 the observer accustomed to all the irregularity in the extent of the snowy cover- 

 ing which belongs to our variable temperate zone. This uniformity in the height 

 of the snow-line, and the knowledge of its maximum variation, in the region 

 round Quito, furnish an observer with vertical base-lines of 15,800 English feet 

 above the sea, and 6400 above the high plain ; of which, combined with very 

 exact measurements of angles of altitude, he can avail himself in the determina- 

 tion of distances, and the rapid solution of other topographical questions. The 

 second of the level lines above spoken of, i. e. the horizontal line which marks 

 the lowest limit to which the snow of a single casual fall descends, decides as 

 to the relative height of lower mountains, whose summits do not enter the region 

 of perpetual snow. Of a long chain of such summits, which had been erroneously 

 regarded as of equal elevation, many are seen to remain below the temporary fall 

 of snow while the rest are above it ; and thus the estimation as to their relative 

 height is corrected. In the mountain region of Quito, where the Sierras Nevadas 

 often approach each other, but without their perpetual snow-coverings being con- 

 tinuously connected, I have often heard, from the lips of uneducated country 

 people and herdsmen, such considerations and inferences from the lines of perpe- 

 tual snow and of casual snow showers. The grandeur of nature stimulates the 

 intellectual susceptibility of individuals among the coloured inhabitants, even 

 where they are in the lowest stage of civilisation. 



( 331 ) p. 239. Abich, in the Bulletin de la Socie'te' de Ge'ographie, 4 e se'rie, 

 t. i. (1851) p. 517; with a fine representation of the form of the ancient vol- 

 cano. 



C 02 ) p. 239. Humboldt, Vues des Cord. p. 295, PI. LXL, and Atlas de 

 la Relat. hist, du Voyage, PI. XXVII. 



( 333 ) p. 240. Kleinere Schriften, Bd. i. S. 61, 81, 83 and 88. 



( 33 ) p. 241. Junghuhn, Eeise durch Java, 1845, S. 215, Tafel XX. 



C 335 ) p. 241. See Adolf Erman's Eeise urn die Erde (a work of great geo- 

 logical importance, as well as valuable in so many other ways), Bd. iii. S. 271 

 'and 207. 



( 33G ) p. 241. Sartorius von Waltershausen, Physisch-geographische Skizze 

 von Island, 1847, S. 107; and his Geognostischer Atlas von Island, 1853, Taf. 

 XV. and XVI. 



( 337 ) p. 242. Otto von Kotzebue, Entdeckungs-Eeise in die Siidsee und in die 

 Berings-Strasse, 18151818, Bd. iii. S. 68; Eeise- Atlas by Choris, 1820, Taf. V.; 

 Vicomte d'Archiac, Hist. desProgres de la Ge'ologie, 1847, t. i. p. 544 ; and Buzeta 

 Diccionario geogr. estad. historico de las Islas Filipinas, t. ii. (Madr. 1851), p. 436 

 and 470 471 : where, however, there is no mention of the double circle (of a second 



