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- Scarcely had a part of the water of the valley of Mexico begun to flow towards the Atlantic océan, when Enrico Martinez was reproached with having dug a gallery neither broad nor durable, nor deep enough to admit the water of the great swellings. The chief engineer (Maestro del Desague) replied, that he had presented several plans, but that the government had chosen the remedy of most prompt execution. In fact, the filtrations and erosions occasioned by the alternate states of humidity and aridity caused the loose earth frequently to crumble down.
They were soon compelled to support the roof, which was only composed of alternate strata of marle, and a stiff clay called tepetate. They made use at first of wood, by throwing planks across, which rested on pillars ; but as resinous wood was not very plentiful in that part of the valley, Martinez substituted masonry in its place. This masonry, if we judge of it from the remains discovered in the obra del consulado, was very well executed; but it was conducted on an erroneous principle. The engineer, in place of fortifying the gallery from top to bottom with a complete vault of an elliptical form (as is done in mines whenever a gallery is cut through loose sand), merely constructed arches, which had no sufficient foundation to rest on. The water, to which too great a fall was given, gradually undermined the lateral walls, and deposited an enor
mous quantity of earth and gravel in the water. course of the gallery, because no means were taken to filtrate it, by making it previously pass, for example, through reticulations of petate, executed by the Indians with filaments of the shoots of palm trees. To obviate these inconveniences, Martinez constructed in the gallery at intervals a species of small sluices, which, in opening rapidly, were to clear the passage. This means, however, proved insufficient, and the gallery was stopt up by the perpetual falling in of earth.
From the year 1608 the Mexican engineers began to dispute whether it was proper to ena Jarge the socabon of Nochistongo, or to finish the walling, or to make an uncovered aperture by taking off the upper part of the vault, or to commence á new gallery farther down, capable of also receiving, besides the waters of the Rio de Guautitlan, and the lake of Zumpango, those of the lake of Tezcuco. The archbishop Don Garcia Guerra, a Dominican, then viceroy, ordered new surveys to be made in 1611 by Alonso de Arias, superintendant of the royal arsenal (armero mayor), and inspector of fortifications (maestro mayor de fortificaciones) a man of probity, who then enjoyed great reputation. Arias seemed to approve of the operations of Martinez, but the viceroy could not fix on any definitive resolution. The court of Madrid, wearied out with these disputes of the engineers, sent to Mexico in 1614 Adrian Boot, a Dutchman, whose knowledge of hydraulic architecture is extolled in the memoirs of those times preserved in the archives of the viceroyalty. This stranger, rea commended to Philip III. by his ambassador at the court of France, held forth again in favour of the Indian system; and he advised the con struction of great dikes and well protected mounds of earth around the capital. He was unable, however, to bring about the entire relinquishment of the gallery of Nochistongo till the year .1623. A new viceroy, the Marquis de Guelves, had recently arrived at Mexico; and he had consequently never witnessed the inundations produced by the overflow of the river of Guaútitlan. He had the temerity, however, to oro der Martinez to stop up the subterraneous pasa sage, and make the water of Zumpango and San Christobal return to the lake of Tezcuco, that he might see if the danger was, in fact, so great as it had been represented to him. This last lake swelled in an extraordinary manner; and the orders were recalled. Martinez recommen.ced his operations in the gallery, which he continued till the 20th June* 1629, when an event occurred, the true causes of which have ever remained secret.
The rains had been very abundant; and the eń. gineer stopt up the subterraneous passage. The city of Mexico was in the morning inundated to the height of a metre*. The Plaza Mayor, la Plaza del Volador, and the suburb of Tlatelolco, alone remained dry. Boats went up and down the other streets. Martinez was committed to prison. It was pretended that he had shut up the gallery to give the incredulous a manifest and negative proof of the utility of his work; but the engineer declared that, seeing the mass of water was too considerable to be received into hiš narrow gallery, he preferred exposing the capital to the temporary danger of an inundation, to seeing destroyed in one day, by the impetuosity of the water, the labours of so many years. Contrary to every expectation, Mexico remained inundated for five years, from 1629 to 1634ti The streets were passed in boats, as had been done before the conquest in the old Tenochtitlan. Wooden bridges were constructed along the sides of the houses for the convenience of foot passengers.
In this interval four different projects were presented and discussed by the Marquis de Ceralvo, the viceroy. An inhabitant of Valladolid, Simon Mendez, affirmed in a memoir, that the
* 34 feet. Trans.
+ Several memoirs bear that the inundation only lasted till 1631, but that it broke out afresh towards the end of the year 1633.
ground of the valley of Tenochtitlan rose consi. derably on the N. W. side towards Huehuetoca, and the hill of Nochistongo; that the point where Martinez had opened the chain of mountains which circularly shuts in the valley corresponds to the mean level of the most elevated lake (Zumpango), and not to the level of the lowest (Tezcuco); and that the ground of the valley falls considerably to the north of the village of Carpio, east from the lakes of Zumpango and San Christobal. Mendez proposed to draw off the water of the lake of Tezcuco by a gallery which should pass between Xaltocan and Santa Lucia, and open into the brook (arroyo) of Tequisquiac, which, as has been already observed, falls into the Rio de Moctesu ina or Tula. Mendez began this desague, projected at the lowest point; and four pits of ventilation (lumbreras) were already completed, when the government, perpetually irresolute and vacillating, abandoned the undertaking as being too long and too expensive. . Another desiccation of the valley was projected in 1630 by Antonio Roman, and Juan Alvarez de Toledo, at an intermediate point, by the lake of San Christobal, the waters of which were proposed to be conducted to the ravin (barranca) of Huiputztla, north of the village of San Mateo, and four leagues west from the small town of Pachuca. The viceroy and audiencia paid as little attention to this project