180 



HISTORY OF THE DESAGUE OF HUEHUETOCA. 



stupendous canal now known under the name of the Desague de 



HUEHUETOCA. 



" The plan of Martinez appears to have embraced two distinct 

 objects, the first of which extended to the lakes of Tezcoco and San 

 Cristoval, while the second was confined to the lake of Zumpango 

 whose superfluous waters were to be carried into the valley of Tula 

 by a subterraneous canal into which the river Guautitlan was like- 

 wise compelled to flow. The second of these projects only was 

 approved by the government ; and the line of the canal having been 

 traced by Martinez between the Cerro or hill of Sincoque and the 

 hill of Nochistongo to the north-west of Huehuetoca, where the 

 mountains that surrounded the valley are less elevated than in any 

 other spot, — the great subterraneous gallery of Nochistongo was 

 commenced on the 28th of November, 1607. Fifteen thousand 

 Indians were employed in this work, and as a number of air shafts 

 were sunk, in order to enable them to work upon the different 

 points at once, in eleven months a tunnel of six thousand six hun- 

 dred metres 1 in length, three metres five in breadth and four metres 

 two in height, was concluded. 



"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 un- 

 baked 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 un- 

 dermined 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 



1 The metre is equal to thirty-nine thousand three hundred and seventy-one 

 English inches. 



