xviii 



these different materials in a work devoted 

 wholly to the descriptions of the volcanoes 

 of Peru and New Spain. Had I given the 

 physical description of a single province, I 

 could have treated separately what relates 

 to geography? mineralogy, and botany ; but 

 how could I interrupt either the narrative, 

 a disquisition on the manners, the aspect 

 of nature, or the great phenomena of 

 general physics, by the fatiguing enumera- 

 tion of the productions of the country, the 

 description of new species of animals and 

 plants, or by the dry detail of astronomical 

 observations ? Had I adopted a mode of 

 composition, which should have contained 

 in the same chapter all that has been ob- 

 served on the same point of the globe, I 

 should have composed a work of cumbrous 

 length, and devoid of that clearness, which 

 arises in a great measure from the methodi- 

 cal distribution of the matter. Notwith- 

 standing the efforts which I have made to 

 avoid, in this narration of my journey, the 

 errors I had to dread, I feel conscious, that 

 I have not always succeeded in separating 

 the observations of detail from those gene- 

 ral consequences, which interest every en- 



