INTENDANCY OF TUEBLA. 317 



large the gallery ; but the operations were conducted 

 with very little energy, and in the end it was deter- 

 mined to abandon the plan, to remove the top of the 

 vault, and to convert it into an open passage by cut- 

 ting through the hill. A lawyer, named Martin de 

 Solis, undertook the management of this enterprise ; 

 though it required nearly two centuries to complete 

 the work ; the canal not being opened in its whole 

 length until 1789. As it now appears, it is stated by 

 Humboldt to be one of the most gigantic hydraulic 

 operations executed by man. Its length is 67,537 feet, 

 its greatest depth 197, and its greatest breadth 361. 



The safety of the capital depends, 1st, On the 

 stone dikes, which prevent the water of the lake of 

 Zumpango from passing into that of San Christobal, 

 and the latter from flowing into the Tezcuco ; 2d, 

 On the dikes and sluices which prevent the lakes of 

 Chalco and Xochimilco from overflowing; 3d, On 

 the great cut of Enrico Martinez, by which the Rio 

 de Guautitlan passes across the hills in the valley 

 of Tula ; and, 4th, On the canals by which the Zum- 

 pango and San Christobal may be completely drained. 

 These means, however expensive and numerous as 

 they must appear, are insufficient to secure it against 

 inundations proceeding from the north and north- 

 west ; and our author asserts, that it will continue ex- 

 posed to great risks until a canal shall be directly 

 opened from the lake of Tezcuco. 



The intendancy of Mexico contains, besides the 

 capital, several towns of considerable size, of which 

 the more important are, Tezcuco, Acapulco, Tolucca, 

 and Queretaro, the latter having a population of 

 thirty-five thousand. 



2. The government of Puebla is wholly situated 

 in the torrid zone, and is bounded on the north-east 

 by that of Vera Cruz, on the south by the ocean, on 

 the east by the province of Oaxaca, and on the west 

 by that of Mexico. It is traversed by v the cordille- 

 ras of Anahuacj and contains the highest mountain 



