rado and adjacent portions of Utah, Arizona and New M where the cliff dwellings are found, as well as across th der valleys through which are scattered numerous ru community dwellings. Their knowledge of engineering dent, and remarkable. Careful levels have been run several miles of their canals. The grade was found fairly uniform and suited to a canal of such dimensio well as in accord with present day knowledge of hydr safe velocities and coefficients of friction. While thes defined remains of ancient irrigation works have long lived the civilization to which they belonged, there are where they have been utilized in modern works. The ditc Las Cruces, New Mexico, have been used uninterrupted over 300 years. Some 70 years before the settlement of J town, the Spaniards irrigated on the Rio Grande. Advent mission fathers pushed on to California, carrying the irrigation with them.

The beginnings of irrigation by English-speaking peo this country were in the Salt Lake valley of Utah, in 1847. The Mormon pioneers, driven out from Illinois and souri, stopped from necessity on the shores of the Grea Lake. They diverted the waters of the little canyon st upon the present site of Salt Lake City, so that they raise a crop from the very last of their stock of potatoe save the band from starvation. At about the same time for irrigation was drawn from the ditches used for mining by the gold miners of California. After the sto of hydraulic mining by the passage of anti-débris laws ditches were either abandoned or used exclusively for irrig Many were enlarged and are still used.

While considerable wheat is irrigated in some s cally all that is grown in them, yet the average irrigated wheat in all the irrigating states is rela only 14 per cent. Excluding California and Washi much wheat is raised and little irrigated, this rise cent; 17.7 per cent of the wheat produced is ir pared to 14.1 per cent of the acreage. On this however, takes no account of differences in soil, climate, the yield in these states would be incre per cent if all the wheat were irrigated.

The Problems of Irrigation in our country are, a along two general lines: Agricultural and eng legal and social. Of these two lines, the latter the greatest difficulties. Litigation and controver a menace and a source of loss to many communiti institutions existed for adequately defining, limi tecting water rights. The claims of navigatio conflict with those of irrigation. When streams f more than one state, interstate difficulties arose. are the basis of a suit by the state of Kansas aga of Colorado.

Work at the solution of either class of probl immensely handicapped by a most lamentable lack

1 12th U. S. Census, 6:825-870.

gation as could easily be accomplished with simple means pendent of co-operative institutions has largely been ef As the work extended, greater problems arose, claims b hopelessly conflicting and united effort under institution ministration became an imperative condition of advanta development.

Water Supply.-There are two sources of water for i tion: Surface waters, such as streams and lakes, and s ranean waters. The former supply over 90 per cent c irrigated land. There are three ways of obtaining underg waters: By pumping from wells; by driving tunnels int sides of hills and mountains; and by using flowing wells. tesian areas are widely scattered, and individually they small size, except in the Dakotas and California. In 51,896 acres, or 1.4 per cent of the irrigated land, were irri from wells. In 14 irrigating states there were 8,097 wells, ly half of which were used in irrigation. Each well sup on an average 13 acres, had a depth of 210 feet and disch 54 gallons per minute; 169,644 acres were irrigated from in 1899. Underground waters seem to be present very g ally. It is claimed that there is not a farm of 160 acres the great plains region without the requisite moisture absol needed for from 10 to 30 acres of tillable ground.' The age depth of water applied to crops in 1899 was 4.35 feet in 1900, 4.13 feet.

Application to Crops.-The two principal methods of in tion are by flooding and through furrows. The former is erally used in growing grain. There are two method flooding, the check system and by wild flooding. By the 1 process a level field is completely submerged. When the g is not level enough for this, the field is divided into com 1 Hinton, Rept. on Irriga., Cong. serial No. 2899, part I,

THE FURRCT VEZED OF BRIGAMING

conposition of rocks in regions where the rainfal to wash out the scible elements as in humid soluble salts are naturally distributed throughout are not harmful until the application of irrigation are then leached out of the higher grounds and in the lower lands. Evaporation tends to bring surface. Many irrigation waters also contain mu lution, which results in a further deposition of salt of these factors is often ruinous to vegetation. sands of acres have been thus rendered unfit for the United States, and the agricultural industrie Inges in India were wholly or partly destroyed b

The Cost of Irrigation in the United States as shown b eleventh and twelfth census is as follows:

A rise in values would be expected, instead of a fall, as lands with water supply were scarce in 1899, and those were first irrigated which required least labor and capital has been estimated that a perpetual water right in a country is worth from $25 to $50 per acre. The cost of gation from many of the original ditches was as low as $5 per acre.2

The Semi-Arid Region of the United States.-There are still living who knew the Mississippi valley as a wilder For several generations a popular American slogan has "westward the course of empire takes its way,' " and the r ity with which the fertile lands of the great river valleys brought under cultivation has been almost incredible. As huge wave of immigration swept across the prairie to the g plains, it encountered the subhumid belt as a buffer between humid and the arid regions. Gradually the settlements ceeded westward from the abundantly watered Mississippi lower Missouri valleys, and pushed into the well defined humid slope which rises progressively toward the Roc These virgin lands, bordering upon the greatest wheat ra region of the world, and fully as fertile, since they were washed by frequent rains, were a continual temptation

1 Mon. U. S. Geol. Sur., 25:546-547.

2 Indus. Com., 10:xxxii.