TRUE VOLCANOES. 309 



my American travels, the most celebrated phenomenon is 

 the elevation of the newly produced Jorullo, and its effusion 

 of lava. This volcano, the topography of which, founded 

 on measurements, I was the first to make known 3 , by its 

 position between the two volcanoes of Toluca and Colima, 

 and by its eruption on the great fissure of volcanic activity*, 

 which extends from the Atlantic Ocean to the Pacific, pre- 

 sents an important geognostic phenomenon, which has con- 

 sequently been all the more the subject of dispute. Fol- 

 lowing the vast lava-stream which the new volcano poured 

 out, I succeeded in getting far into the interior of the 

 crater, and in establishing instruments there. The eruption 

 in a broad and long-peaceful plain in the former province of 

 Michuacan, in the ni<jht from the 28th to the 29th of Sep- 

 tember, 1759, at a distance of more than 120 miles from 

 any other volcano, was preceded for fully two (?) months, 

 namely, from the 29th June in the same year, by an unin- 

 terrupted subterranean noise. This differed from the won- 

 derful bramidos of Guanaxuato, which I have elsewhere 

 described 5 by the circumstance that it was, as is usually 

 the case, accompanied by earthquakes, which were not 

 felt in the mountain city in January, 1784. The erup- 

 tion of the new volcano, about 3 o'clock in the morning, 

 was foretold the day before by a phenomenon which, in 

 other eruptions, does not indicate their commencement but 

 their conclusion. At the point where the great volcano now 

 stands, there was formerly a thick wood of the Guayava 

 (Psidium pyriferum), so much valued by the natives on ac- 

 count of its excellent fruit. Labourers from the sugar-cane 

 fields (cafiaverales) of the Hacienda de San Pedro Jorullo, 

 belonging to the rich Don Andres Pimentel, who was then 

 living in Mexico, had gone out to collect the fruit of the 

 guayava. When they returned to the farm (hacienda) it 

 was remarked with astonishment that their large straw hats 

 were covered with volcanic ashes. .Fissures had, conse- 

 quently, already opened in what is now called the Malpais, 

 probably at the foot of the high basaltic dome el Cuiche. 



3 Atlas Gfeographique et Physique, accompanying the Relation His- 

 torique, 1814, pi. 28 and 29. 



4 Cosmos, vol. v. pp. 279 280. 



* Cosmos, vol. i. p. 205, and vol. v. p. 179. 



