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archaeologist to determine who these aboriginal irrigators were and the probable antiquity of their work. The Pueblo Indians say that these ditches were made by the Yuma Indians, who were driven gradually westward by the Comanches and Apaches, finally settling in their present home on the Colorado River. On the Rio Grande below El Paso are several ditches, which are probably the oldest now in use in the United States. They were built by the Pueblo Indians, who, according to their traditions, migrated to this place from New Mexico at a very early date, certainly before the advent of the Spaniards under Coronado. This explorer mentions finding well-established systems of irrigation among the Indians in this vicinity in 1540, when he passed on his expedition northward. The old Spanish mission ditches around San Antonio, mentioned on later pages, are also worthy of note as among the oldest in the United States.

RETARDATION OF DEVELOPMENT.

Taking into consideration the climatic conditions and the object lesson furnished by the old ditches, it is somewhat remarkable that irrigation has not been more generally developed in Texas. The causes for the slow growth of this method of agriculture in the State as a whole are found in the persistent attempts of the settlers to extend methods of farming applicable in the humid East, and in the existing laws modeled on those of the well-watered region. There has been in Texas, as well as throughout the whole of the Great Plains region of the United States, a belief, founded upon hope and the representations of interested land agents, that the rainfall would increase as settlement progressed and tracts were brought under cultivation. In the sub-humid region the annual fluctuations of water supply are always relatively large, but no permanent increase is shown by official records. The average distribution of rainfall in the western part of the State is favorable for agriculture, 19 per cent of it coming in the spring and 36 per cent in the summer, but in spite of this the crops are often either a total or a partial failure. In the country near the arid line this is the case about three years out of every four, because of the fact that a drought almost invariably occurs during the growing season, rendering useless all of the rain that falls afterwards.

Another cause of delay in irrigation development has inhered in the customs of the people. Their chief interests have been in cattle, and the results of so many years of nothing but stock raising have left them with neither the knowledge nor the inclination for the laborious occupation of the farmer.

But the principal bar to the spread of the industry has been the unsatisfactory condition of the laws relating to it. So long as the common-law doctrine of riparian rights was recognized as the only one having any force in the State, irrigation 6n a large scale was out of the question. At common law the riparian proprietor is entitled