50 AMERICAN HUSBANDRY. 



tion is considered equal to one degree of latitude in 

 its influence upon temperature. Hence it does not 

 follow, that because a crop will thrive and ripen in 

 a given latitude upon tide-water, it will thrive and 

 ripen equally well in the same latitude at a higher 

 elevation. On the contrary, to be better understood, 

 we say that, other tilings being alike, the climate on 

 tide-water, in latitude 42, is similar to that of a 

 place elevated three hundred feet above tide-water 

 in latitude 41, or of a place nine hundred feet above 

 tide-water in latitude 39 ; so that the table-land of 

 Mexico, in latitude 16, at an elevation of seven 

 thousand and eight hundred feet above the ocean, 

 should possess about the same mean temperature, 

 and produce the same natural and artificial growth, 

 as Kingston upon the Hudson, though the extremes, 

 both of heat and cold, are probably greater at the 

 northern than they are at the southern point.* 



* " All the western part of the inlendancy of Vera Cruz," 

 says Humboldt, in his New Spain, " forms the declivity of the 

 Cordilleras of Anahuac. In the space of a day, the inhabitants 

 descend from the regions of eternal snow to the plains in the vi- 

 cinity of the sea, where the most suffocating heat prevails. The 

 admirable order with which different tribes of vegetables rise 

 one above another, by strata, as it were, is nowhere more per- 

 ceptible than in ascending from the port of Vera Cruz to the ta- 

 ole-land of Perote. We see there the physiognomy of the coun- 

 try, the aspect of the sky, the form of plants, the figures of ani- 

 mals, the manners of the inhabitants, and the kind of cultivation 

 followed by them, assume a different appearance at every step 

 of our progress. 



" As we ascend, nature appears gradually less animated, the 

 beauty of the vegetable forms diminishes, the shoots become 

 less succulent, and the flowers less coloured. The aspect of 

 the Mexican oak quiets the alarms of travellers newly landed at 

 Vera Cruz. Its presence demonstrates to him that he has left 

 behind him the zone, so justly dreaded by the people of the 

 North, under which the yellow fever exercises its ravages in 

 New Spain. This inferior limit of oaks warns the colonise 

 who inhabits the central table-land how far he n ay descend to- 

 wards the coast, without dread of the mortal disease of the twit 

 ito. Forests of liquid amber, near Xalapa, announce, by the 

 freshness of their verdure, that this is the elevation at which 



