380 cosmos. 



is on an average, according to Pentland, 12,847 feet above 

 the level of the sea ; the latter, or Thibetian, according to 

 Captain Henry Strachey, Joseph Hooker, and Thomas Thom- 

 son, is upward of 14,996. The wish expressed by me half a 

 century since, in my circumstantial "Analyse de V Atlas Gco- 

 graphique et Physique de Poyaume de laNouvelle Espange (§ xiv.), 

 that my profile of the elevated plain between Mexico and Gu- 

 anaxuato might be continued by measurements over Durango 

 and Chihuahua as far as Santa Fe del Nuevo Mexico, is now 

 completely realized. The length of way, reckoning only one 

 fourth for the inflections, amounts to more than 1200 geo- 

 graphical miles, and the characteristic feature of this so long 

 unobserved configuration of the earth (the soft undulation of 

 the swelling and its breadth in a transverse section, amount- 

 ing sometimes to 240 or 280 geographical miles) is manifest- 

 ed by the fact that the distance (from Mexico to Santa Fe), 

 comprising a difference of parallels of fully 16° 20' about the 

 same as that from Stockholm to Florence, is traveled over in 

 four-wheeled carriages, on the ridge of the table-land, with- 

 out the advantage of artificially prepared roads. The possi- 

 bility of such a medium of intercourse was known to the 

 Spaniards so early as the end of the 16th century, when the 

 viceroy, the Conde de Monterey,* planned the first settlements 

 from Zacatecas. 



In confirmation of what has been stated in a general way 

 respecting the relative heights between the capital of Mexico 

 and Santa Fe del Nuevo Mexico, I here insert the chief ele- 

 ments of the barometrical levelings, which have been com- 

 pleted from 1803 to 1847. I take them in the direction from 

 north to south, so that the most northerly, placed at the top 

 of the list, may correspond more readily with the bearings of 

 our charts \\ 



* By Juan de (Bate, 1594. Memoir of a Tour to Northern Mexico 

 in 1816 and 1817, by Dr. Wislizenus. On the influence of the con- 

 figuration of the soil (the wonderful extent of the table-land) on the 

 internal commerce and the intercourse of the tropical zone -with the 

 north, when once civic order, legal freedom, and industry increase in 

 these parts, see Essai Pol., t. iv., p. 38, and Dana, p. 612. 



t In this survey of tbe elevations of the soil between Mexico and 

 Santa Fe del Neuvo Mexico, as well as in the similar but more imper- 

 fect table which I have given in the Views of Nature, p. 208, the letters 

 Ws, Bt, and Ht, attached to the numerals, denote the names of the 

 observer. Thus, Ws stands for Dr. Wislizenus, editor of the very in- 

 structive and scientific Memoir of a Tour to Northern Mexico, connected 

 with Colonel Doniphan's Expedition in 181G and 1847 (Washington, 

 1848) ; Bt the Chief Counselor of Mines, Bnrkart ; and Ht for my- 



