fall and partly upon irrigation. North of the twentieth parallel, irrigation is necessary on the table-land. In the southern States the rains are generally limited to one continuous season, which varies from five to seven months in the year. As in other tropical latitudes, a deluging rain oftentimes does more harm than good to the growing crops.
Referring to this important subject, Humboldt has remarked in his work on New Spain, vol. ii, page 455: “Were the soil of Mexico watered by more frequent rains, it would be one of the most fertile countries cultivated by man in either hemisphere." The prosperity of New Spain depends upon the proportion of dry and wet season. The farmer, of course, takes advantage of the rainy season, and in the northern and central States he sows in May and reaps in October. Two crops of wheat and Indian corn are grown annually in various sections of the tierra templada and on the central table-land. The second crop is, however, sometimes destroyed by a premature frost. In the States of Vera Cruz, Oaxaca, Guerrero, Tabasco, Mexico, and Jalisco, three crops of maize are cultivated in a single year! They are called respectively the riego, temporal, and tonalmile.
As irrigation (riego) is necessary for more than one half of the surface of the country, let us now consider this subject. In the Aztec Empire acequias, or irrigating ditches, were used. The Spaniards were agreeably surprised to find a system equal to that which the Moors had established in the Iberian Peninsula. The plan of watering the soil by artificial channels, however, is at present limited to a comparatively small portion of the arable land in the country. In order to increase the annual yield of grain and vegetables, the Mexicans should adopt the system of tanks which has been in use so long in British India.
Water-companies should be organized for this purpose, and the huge ravines, or barrancas, of the sierra should be
