"From the northern extremity of this tunnel called la boca de San Gregorio, an open cut of eight thousand six hundred metres conducted the waters to the salto or fall of the river Tula, where, quitting the valley of Mexico, they precipitate themselves into that of Tula, from a natural terrace of twenty Mexican varas in height, and take their course towards the bar of Tampico where they enter the gulf of Mexico. An enterprise of such magnitude could hardly be free from defects, and Martinez soon discovered that the unbaked bricks, of which the interior of the tunnel was composed, were unable to resist the action of water, which, being confined within narrow limits, was at times impelled through the tunnel with irresistible violence. A facing of wood proved equally ineffectual, and masonry was at last resorted to; but even this, though successful for a time, did not answer permanently, because the engineer, instead of an elliptical arch, constructed nothing but a sort of vault, the sides of which rested upon a foundation of no solidity. The consequence was that the walls were gradually undermined by the water, and that the vault itself in many parts fell in.
"This accident rendered the government indifferent to the fate of the gallery which was neglected, and finally abandoned in the
year 1623, when a Dutch engineer, named Adrian Boot, induced the viceroy to resume the old system of dyke and embankments, and to give orders for closing the tunnel of Nochistongo. A sudden rise in the lake of Tezcoco caused these orders to be revoked, and Martinez was again allowed to proceed with his works which he continued until the 20th of June, 1629, when an event took place, the real causes of which have never been ascertained."
"The rainy season having set in with unusual violence, Martinez, either desirous to convince the inhabitants of the capital of the utility of his gallery, or fearful, as he himself stated, that the fruits of his labor would be destroyed by the entrance of too great a volume of water, closed the