competent to manage such a gigantic engineering scheme, and the passage was stopped up. The canal had been opened and walled in a few years, but it required two centuries to complete the cut in a loose earth, in sections of from 262 to 328 feet in breadth, and from 131 to 164 feet in perpendicular depth. The work was neglected in years of drought, but renewed with extraordinary energy after a season of heavy rains.
In 1762 there were still at the northern extremity of the tunnel of Martinez 6,356 feet which had never been converted into an open trench (tajo abierto). At length, in 1767, the Flemish viceroy, the Marquis de Croix, undertook to finish the desague. The cut was enlarged, but, in fact, the great canal was never entirely completed. Millions had been expended, and the Government, hesitating between the Indian system of dikes and the modern scheme of a canal and open cut through the hill, never had the courage to adhere to the same plan.
The gallery was allowed to be choked up, because a wider and deeper one was required; and the cut of Nochistongo was not to be finished, while the officials were disputing about the project of the canal of Tezcuco, which was never executed.
In the beginning of the present century the entire length of the desague from south to north was 20,585 metres, or about 12¾ miles. This is reckoning from the sluice of Vertideros, about 2½ miles south of Huehuetoca, to El Salto del Rio de Tula.
For farther particulars about this great canal, the reader is referred to Humboldt's Political Essay on the Kingdom of New Spain, Black's translation, vol. ii, pp. 75-112, from which the above abstract is taken. Humboldt also discusses the scheme of extending the canal from El Salto to Tampico, on the Gulf of Mexico. For many years this plan, although never undertaken, was considered practicable by the Mexicans.
It may be remarked that a canal of such length could be used for irrigation in the dry season, as well as for the transportation of merchandise by small craft. Of course a great many locks would be necessary, as the difference of level between Huehuetoca and Tampico is 7,400 feet. The tourist can obtain a hasty view of this great hydraulic work from the car-window, as the track is now laid through the cut (tajo) of Nochistongo. But, to examine the desague
