WORKS FOR PREVENTING INUNDATIONS. 311 



to flow through this artificial channel, it gradually oc- CHAP.xxiv 

 casioned depositions and erosions, so that it became qv^ — 7. 

 necessary to support the roof, which was composed of of the canal 

 marl and clay. For this purpose wood was at first em- 

 ployed, and afterwards masonry ; but the arches being 

 soon undermined, the passage at length was obstructed. 



Several plans were now proposed, and in 1614 the 

 court of Madrid sent to Mexico a Dutcli engineer, Adrian 

 Boot, who advised tlie construction of great dikes after Adrian Boot 

 the Indian plan. A new viceroy, however, having re- 

 cently arrived, who had never witnessed the effects of 

 an inundation, ordered Martinez to stop up the subter- 

 raneous passage, and make the water of the upper lakes 

 return to the bed of the Tezcuco, that he might see if the 

 danger were really so great as it had been represented. 

 Being convinced that it was so, he ordered the German 

 to recommence his operations in the gallery. The 

 engineer accordingly proceeded to clear it, and continued 

 working until the 20th June 1629, when finding the 

 mass of water too great to be received by this narrow 

 outlet, he closed it in order to prevent its destruction. 

 In the morning the city of Mexico was flooded to the 

 depth of three feet, and, contraiy to expectation, re- 

 mained in that state for five years. In this interval 

 vai'ious plans were proposed for draining the neighliour- 

 ing lake, although none of them w^as carried into effect ; 

 but the inundation at length subsided in consequence 

 of a succession of earthquakes. 



Martinez, who had been imprisoned from a belief that Cliange of 

 he had closed the gallery for the purpose of affording ^^^""^ 

 the incredulous a proof of the utility of his work, was 

 now set at liberty, and constructed the dike of San 

 Christobal. He was ordered to enlarge the gallery ; but 

 the operations were conducted with very little energy, 

 and in the end it was determined to abandon the plan, 

 to remove the top of the vault, and to convert it into an 

 open passage by cutting through the hill. A lawyer, 

 named Martin de Solis, undertook the management of 

 this enterprise ; though it required nearly two centuries 



