but there are particular cases where the nature of the ground will not admit in hydraulical operations of all the advantages which theory may prescribe.

When we take into consideration the expense of the excavations required in the Rio del Desague, from the sluice of Vertideros or that of Valderas to the Boveda Real, we are tempted to believe that it would be, perhaps, easier to secure the capital from the dangers with which it is still threatened by the lake of Tezcuco, by recurring to the project attempted to be carried into execution by Simon Mendez during the great inundation from 1629 to 1634. M. Velasquez examined this project in 1774. After surveying the ground, that geometrician affirmed that 28 pits of ventilation, and a subterraneous gallery of 13,000 metres in length, for bringing the water of Tezcuco across the mountain of Citlaltepec towards the river of Tequixquiac, could be sooner finished, and at less expense, than the enlarging the bed of the desague, deepening it for a course of more than 9000 metres†, and cutting a canal from the lake of Tezcuco to the sluice of Vertideros near Huehuetoca. was present at the consultations which took place in 1804 before deciding that the water of Tezcuco should pass through the old cut of

I

* 42,650 feet. Trans.

29,527 feet. Trans.

Nochistongo. The advantages and disadvantages of Mendez's project were never discussed in these conferences.

It is to be hoped that in digging the new canal of Tezcuco more attention will be paid to the situation of the Indians than has hitherto been done, even so late as 1796 and 1798, when the courses of Zumpango and San Christobal were executed. The Indians entertain the most bitter hatred against the desague of Huehuetoca. A hydraulical operation is looked upon by them in the light of a public calamity, not only because a great number of individuals have perished by unfortunate accidents in Martinez's operations, but especially because they were compelled to labour to the neglect of their own domestic affairs, so that they fell into the greatest indigence while the desiccation was going on. Many thousands of Indian labourers have been almost constantly occupied in the desague for two centuries; and it may be considered as a principal cause of the poverty of the Indians in the valley of Mexico. The great humidity to which they were exposed in the trench of Nochistongo gave rise to the most fatal maladies among them. Only a very few years ago the Indians were cruelly bound with ropes, and forced to work like galley slaves, even when sick, till they expired on the spot. From an abuse of law, and especially from an abuse of the principles,

introduced since the organization of intendancies, the work at the desague of Huehuetoca is looked upon as an extraordinary corvée. It is a personal service exigible from the Indian, a remain of the mita*, which we should not expect in a country where the working of the mines is perfectly voluntary, and where the Indian enjoys more personal liberty than in the north-east part of Europe. In turning the attention of the viceroy to these important considerations, I could have referred to the numerous testimonies contained in the Informe de Zepeda. In every passage of it we read "that the desague has diminished the population and prosperity of the Indians, and that such or such a hydraulical project dare not be carried into execution, because the engineers have no longer so great a number of engineers at their disposal as in the time of the viceroy Don Luis de Velasco the Second." It is consoling, however, to observe, as we have already endeavoured to explain in the beginning of the fourth chapter, that this progressive depopulation has only taken place in the central part of the old Anahuac.

See above, chap. V. The Indian is paid at the desague at the rate of two reals of plata, or 25 sous per day (=1s. Old.). In Martinez's time, in the 17th century, the Indians were only paid at the rate of 5 reals or 3 francs per week (= 2s. 6d.), but they also received a certain quantity of maize for their maintenance.

In all the hydraulical operations of the valley of Mexico, water has been always regarded as an enemy, against which it was necessary to be defended either by dikes or drains. We have already proved that this mode of proceeding, especially the European method of artificial desiccation, has destroyed the germ of fertility in a great part of the plain of Tenochtitlan. Efflorescences of carbonate of soda (tequesquite) have increased in proportion as the masses of running water have diminished. Fine savannas have gradually assumed the appearance of arid steppes. For great spaces the soil of the valley appears merely a crust of hardened clay (tepetate), destitute of vegetation, and cracked by contact with the air. It would have been easy, however, to profit by the natural advantages of the ground, in applying the same canals for the drawing of water from the lakes for watering of the arid plains, and for interior navigation. Large basins of water ranged as it were in stages above one another facilitate the execution of canals of irrigation. To the south-east of Huehuetoca are three sluices, called los Vertideros, which are opened when the Rio de Guautitlan is wished to be discharged into the lake of Zumpango, and the Rio del Desague to be thrown dry for the sake of cleaning or deepening the course. The channel of the old mouth of the Rio de Guautitlan, that which existed in

1607, having become gradually obliterated, a new canal has been cut from Vertideros to the lake of Zumpango. In place of continually drawing the water from this lake, and from San Christobal, out of the valley towards the Atlantic Ocean, in the interval of 18 or 20 years, during which no extraordinary rise takes place, the water of the desague might have been distributed to the great advantage of agriculture in the lower parts of the valley. Reservoirs of water might have been constructed for seasons of drought. It was thought preferable, however, blindly to follow the order issued from Madrid, which bears," that not a drop of water ought to enter into the lake of Tezcuco from the lake of San Christobal, unless once a year, when the sluices (las compuertas de la Calzada) are opened for the sake of fishing* in the basin of San Christobal." The trade of the Indians of Tezcuco languishes for whole months from the want of water in the salt lake which separates them from the capital; and districts of ground lie below the mean level of the water of Guautitlan

* This fishing is a grand rural festival for the inhabitants of the capital. The Indians construct huts on the banks of the lake of San Christobal, which is thrown almost dry during the fishing. This bears some resemblance to the fishing which Herodotus relates the Egyptians carried on twice a year in the lake Moeris, on opening the sluices of irrigation.