274 Statistical IRotes on 



ants by the insatiable demands of the killing labor, and recruits were 

 then drawn from Puebla and other thickly populated Indian centres. 

 Great prison barracks were built on the bare hills, and here all the 

 criminals were sent to enter the work. The ones in charge were in- 

 different with regard to the lives entrusted to their care, and the 

 slaughter, of which scant record remains in the parish burial books, 

 and which resulted from a combination of defects in appliances for 

 both the safety and the comfort of the workmen, was terrific. As the 

 burial trenches were filled with new dead, the depths of the cut were 

 tenanted by new laborers. 



The victims of three years of bondage numbered fully two hundred 

 thousand ere the work was done. Yet the results were but slight, only 

 the excess of water from the highest lakes and streams being carried 

 off. However, the danger from inundations of the city has been very 

 materially decreased by the Nochistongo opening, and no more deluges 

 have occurred since its completion. 



Still the fact that the bottom of the cut was thirty feet higher than 

 the surface of Texcoco, the lowest lying of the lakes, left the city in 

 danger of inundation, as Lake Texcoco is constantly filling up at the 

 rate of one and one-half inches a year and is now but a few feet below 

 the level of the main plaza of the city. 



The drainage works had long been a heavy burden upon the Mexi- 

 can treasury. Up to 1637 Bancroft estimates that $3,000,000 had been 

 expended. Up to the year 1800 the outlay had reached $6,247,670. 

 Up to 1830 the total expenditure was $8,000,000. 



Work done by the Mexican Government. The problem which the 

 Mexican Government had to face was very different from that which 

 confronted Martinez in 1607. The question of preventing submergence 

 is practically solved. The work of Martinez, unsatisfactory as it was, 

 did a great deal to solve it. Since his day the area of the lakes has 

 been gradually diminishing. The rapid evaporation in the rarefied air 

 and under the direct sun of the valley partly accounts for this. Twice 

 the water in Lake Texcoco has almost entirely disappeared, leaving 

 only a sea of mud and a small pool. The great problem which the 

 Mexican Government has now solved is not how to prevent an inflow 

 of water, but how to provide an outlet for sewage. The danger to 

 be averted was not that of drowning, but that of dying from the plague. 



Lake Texcoco more than any other now menaces the security of the 

 capital. The unwise cutting down of forests since the Spanish con- 

 quest permits the waters pouring down into the valley to bring with 

 them annually great quantities of alluvial matter, which have so much' 

 raised the lake bottom and the water level that inundations have been 

 of frequent occurrence. The general level of the City of Mexico is 

 only 6.56 feet above the surface of the lake. The rainy season lasts 



