The canal proved too small, and several schemes were tried for enlarging and strengthening it, with varying and moderate success. The novelty of the enterprise having worn out, people began to think, during a series of dry years, that the peril from the lakes after all was not so great. The engineer Adrian Boot was sent from Spain to visit the canal of Huehuetoca; having done so, he qualified it as insufficient, in which he shared the opinion of those who had not come so far. He failed in making it more efficacious, for, in 1629, came another inundation. In 1614, the rainy season having set in with unusual violence, Martinez, the engineer, himself gave orders to close the mouth of the tunnel, perhaps to rouse the people to its importance, and the importance of not neglecting it. The result was frightful. The whole city was instantly under water, and for five years it was converted into an unwilling Venice, during which the streets were passable only in boats. Martinez, who was put in prison for blocking the tunnel, was released in order to open it again. This he did, and erected a strong dyke which afforded some relief, but inundations were always recurring at intervals, until the whole plan of the work was altered by an open cut to replace the tunnel. This work was undertaken vigorously in 1767, and pressed to a conclusion by 1789. The _tajo_ of Nochistongo, as it is called, can be seen from the Central Railway, whose track runs through it, at an elevation of fifty feet or more above the stream. Owing to such drainage, and the process of evaporation, the large lake of Texcuco has greatly subsided, and the waters which surrounded Tenochtitlan have given place to nothing more than a marsh. The lovely river Lerma, which winds through the valley of Toluca, with fine views of a beautiful mountain, the Nevada de Toluca, bears the name of the worthless favorite of Philip III. This Philip died, and his son, Philip IV., succeeded him, continuing the line of royal favorites, and spending the imported wealth of Mexico and Peru in the extravagances of his court, and the exhausting demands of frequent wars with England, Holland, and France. He left the crown to his son, Charles II., who died without an heir in 1700; and then began the troublous wars of the Succession, which involved the whole of Europe. This ended the reign of the house of Austria. The king whose cause triumphed was a Bourbon, Philip V., and Bourbons continued to reign in Spain until the latter half of the present century. Mexico took no part in the war of succession. When Charles II. died, the ruling viceroy was the Conde de Moctezuma, whose title was from his wife, the great-great-great-granddaughter of the last emperor of the name. Events in Europe caused no disturbance in his mind; he quietly went on ruling, and awaited the result. It has been said that Philip the Bourbon at one time thought of running away from his difficulties at home, and taking refuge in Mexico.