366 INTENDANCY OF PUEBLA. 
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, Ist, On the 
stone dikes which prevent the water of the lake of 
Zumpango from passing into that of San Christo- 
bal, and the latter from flowing into the Tezcuco ; 
2d, On the dikes and sluices which prevent the 
lakes of Chaleo and Xochimilco from overflowing ; 
3d, On the great cut of Enrico Martinez, by which 
the Rio de Guautitlan passes across the hills into 
the valley of Tula; and, 4th, On the canals by which 
the Zumpango and San Christobal may be com- 
pletely drained. These means however, expen- 
sive and numerous as they must appear, are in- 
sufficient to secure it against inundations proceed- 
ing from the north and north-west ; and our author 
asserts, that it will continue exposed 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 the 
cordilleras of Anahuac, and contains the highest 
mountain in New Spain, the voleano of Popo- 
