_Agriculture._--The principal source of wealth in Idaho was in 1900 agriculture, but it had long been secondary to mining, and its development had been impeded by certain natural disadvantages. Except for the broad valleys of the Panhandle, where the soils are black in colour and rich in vegetable mould, the surface of the state is arid; the Snake river valley is a vast lava bed, covered with deposits of salt and sand, or soils of volcanic origin. And, apart from this, the farming country was long without transport facilities. The fertile northern plateaus, the Camas and Nez Perce prairies and the Palouse country--a wonderful region for growing the _durum_ or macaroni wheat--until 1898 had no market nearer than Lewiston, 50-70 m. away; and even in 1898, when the railway was built, large parts of the region were not tapped by it, and were as much as 30 m. from any shipping point, for the road had followed the Clearwater. In the arid southern region, also, there was no railway until 1885, when the Oregon Short Line was begun. Like limitations in N. and S. had like effects: for years the country was devoted to live-stock, which could be driven to a distant market. Timothy was grown in the northern, and alfalfa in the southern region as a forage crop. Even at this earliest period, irrigation, simple and individual, had begun in the southern section, the head waters of the few streams in this district being soon surrounded by farms. Co-operation and colonization followed, and more ditching was done, co-operative irrigation canals were constructed with some elaborate and large dams and head gates. The Carey Act (1894) and the Federal Reclamation Act (1902) introduced the most important period of irrigation. Under the Carey Act the Twin Falls project, deriving water from the Snake river near Twin Falls, and irrigating more than 200,000 acres, was completed in 1903-1905. The great projects undertaken with Federal aid were: the Minidoka, in Lincoln and Cassia counties, of which survey began in March 1903 and construction in December 1904, and which was completed in 1907, commanding an irrigable area of 130,000-150,000 acres,[1] and has a diversion dam (rock-fill type) 600 ft. long, and 130 m. of canals and 100 m. of laterals; the larger Payette-Boisé project in Ada, Canyon and Owyhee counties (372,000 acres irrigable; 300,000 now desert; 60% privately owned), whose principal features are the Payette dam (rock-fill), 100 ft. high and 400 ft. long, and the Boisé dam (masonry), 33 ft. high and 400 ft. long, 200 m. of canals, 100 m. of laterals, a tunnel 1100 ft. long and 12,500 h.p. transmitted 29 m., 3000 h.p. being necessary to pump to a height of 50-90 ft. water for the irrigation of 15,000 acres; and the Dubois project, the largest in the state, on which survey and reconnaissance work were done in 1903-1904, which requires storage sites on the North Fork of the