Page:Mexico as it was and as it is.djvu/361



M, lying in the lap of a valley, with mountains around it continually pouring their streams into the sandy soil, has been frequently in danger of returning to the "slime from whence she rose." Since the trees have been cut from the plains and the surface exposed to the direct action of the sun, the valley has become drier and the lake has shrunk; but Mexico has, nevertheless, been several times threatened with inundations.

In estimating the dangerous situation of the Metropolis, it is necessary for you to recollect the position and levels of the adjacent lakes. Southeastwardly is the lake of Chalco; northwestwardly the lake of Tezcoco; and north of that again, in a continuous chain, are the lakes of San Cristoval and Zumpango. The latter sheet of water is about eighteen feet higher than San Cristoval,—San Cristoval is twelve feet higher than Tezcoco,—and the level of the great Square of Mexico is not more than three feet above that of Tezcoco. Thus, the head of water which could be easily poured over the Capital is immense, especially as the river Cuautitian pours an additional stream constantly into the northern link of the chain at Zumpango. In 1629 the whole city of Mexico, with the exception of the Plaza, was laid waste by inundation. In most of the streets the water continued for upward of three years, and, until 1634, portions of the town were still traversed by canoes.

So great was the misery and want caused by this misfortune, that the Court of Spain had issued orders to abandon the Capital and build a new one, between Tacuba and Tacubaya, on upland levels, that had never been reached by the lakes before the conquest. An earthquake, however, rent the earth and freed the city of the accumulated waters; and the result of this warning was the completion of an immense Desagua or sewer, which thoroughly empties the ordinary contents of the valley. But urgent as was the necessity for this work, it was procrastinated by the dilatoriness of Mexican laborers, until the year 1789. "The whole length of the cut," is said by Mr. Ward, "to be, from the sluice called Vertideros, to the salto of the river Tula, 67,537 feet; where the waters are discharged at a spot about 300 feet beneath the level of the lake of