TRUE VOLCANOES. 265 



mountains and volcanoes in the interior of Mexico (the old 

 Anahuac) led me, after my return to Europe, while inserting 

 the maxima of elevations in my chart of New Spain, to the 

 exceedingly remarkable result that there is in this place, from 

 sea to sea, a parallel of the volcanoes and greatest elevations 

 which oscillates by only a few minutes to and from the paral- 

 lel of 19°. The only volcanoes, and, at the same time, the 

 only mountains, covered with perpetual snow in the country, 

 and consequently elevations varying from 12,000 to 3000 

 feet — the volcanoes of Orizaba, Popocatepetl, Toluca, and 

 Colima — lie between the latitudes of 18° 59' and 19° 20', 

 and thus indicate the direction of a fissure of volcanic activity 

 of 360 geographical miles in length.* In the same direction 

 ^lat. 19° 9 / )> between the volcanoes of Toluca and Colima, at 

 a distance of 116 and 128 geographical miles from them, the 

 new volcano of Jorullo (4265 feet) rose on the 14th Septem- 

 ber, 1759, in a broad plain, having an elevation of 2583 feet. 

 The local position of this phenomenon in relation to the sit- 

 uation of the other Mexican volcanoes, and the circumstance 

 that the fissure from east to west, which I here indicate, in- 

 tersects the direction of the great mountain chain striking from 



* See all the bases of these Mexican local determinations, and their 

 comparison with the observations of Don Joaquin Ferrer, in my Recueil 

 d? Observations Astron., vol. ii., p. 521, 529, and 536-550; and Essai 

 Politique sur la Nouvelle Espagne, t. i., p. 55-59, and 176, t. ii., p. 173. 

 I had myself early raised doubts with regard to the astronomical de- 

 termination of the position of the volcano of Colima, near the coast 

 •of the Pacific (Essai Polity t. i., p. 6§; t. ii., p. 180). According to 

 angles of altitude taken by Captain Basil Hall while under sail, the 

 volcano is situated in lat. 19° 36', and consequently half a degree far- 

 ther north than I concluded to be its position from itineraries ; cer- 

 tainly without absolute determinations for Selagua and Petatlan, upon 

 which I depended. The latitude, 19° 25', which I have given in the 

 text, is, like the determination of altitude (12,005 feet), from Captain 

 Beechey {Voyage, pt. ii., p. 587). The most recent map by Laurie 

 (The Mexican and Central States of America, 1853) gives 19° 20' for 

 the latitude. The latitude of Jorullo may also be wrong by 2 — 3 

 minutes, as I was then occupied entirely with geological and topo- 

 graphical investigations, and neither the sun nor stars were visible for 

 determinations of latitude. (See Basil Hall, Journal written on the 

 Coast of Chili, Peru, and Mexico, 1821, vol. ii., p. 379 ; Beechey, Voy- 

 age, pt. ii., p. 587; and Humboldt, Essai Polit., t. i., p. 68; t. ii., p. 

 180). In the true and exceedingly artistic views of the volcano of 

 Colima, drawn by Moritz Rugendas, which are preserved in the Ber- 

 lin Museum, we distinguish two adjacent mountains — the true volcano, 

 which constantly emits smoke, and is covered with but little snow, and 

 the more elevated Nevada, which rises far into the region of perpetual 

 snow. 



Vol. V.—M 



