Arrowrock dam, in Idaho, is probably the most spectacular structure to the credit of the Service. Completed on October 4, 1915, it ranks all other dams in the world in its height, 350 feet above bedrock. It is of rubble concrete, arch gravity type, and contains 585,130 cubic yards of material. It was built by Government forces, and not by contract, and its completion in two years less than the estimated time and at a saving of more than two million dollars in the estimated cost, furnishes a striking example of Federal efficiency and economy. In connection with this important work the engineers built and operated a standard gauge railway 14 miles long, which carried more than 80,000 passengers, and 14,000,000 tons of freight. A unique camp, containing 4,000 people, was established, with sewerage, water works, and electric lights. Schools for the children of employees, a hospital, postal savings bank, churches, and Y. M. C. A., a large general store and commissary, blacksmith and machine shops, sand-grinding and cement-mixing plants, all under the engineer’s direction, gave to the camp the aspect of an enterprising and busy community. It was a camp in which, for four years, there was no night. Throughout the greater part of this period the work proceeded without interruption, night and day, with three eight-hour shifts. Profiting by the experience gained on other large works of the Service, and with labor-saving devices of their own invention, the engineers on Arrowrock worked with extraordinary swiftness and sureness, and established a most enviable record for economy and time. The total cost of the Arrowrock is approximately $5,000,000, and its principal purpose is to conserve the floods of Boise River for the irrigation of 240,000 acres of land embraced in the Boise project. WRITTEN ESPECIALLY FOR THE MENTOR BY C. J. BLANCHARD ILLUSTRATION FOR THE MENTOR, VOL. 6, No. 17, SERIAL No. 165 COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC. [Illustration: SUBURB OF PHOENIX, ARIZONA--RECLAIMED FROM DESERT LAND] _RECLAIMING THE DESERT_ _The Romance of the Desert_ SIX A vein of romance runs through every form of human endeavor. No life so sordid, prosaic, or wretched, but has felt sometime its light and gladsome touch. In the desert, romance finds its chief essentials in adventure, courage, daring and self-sacrifice. For more than half a century man has been writing a romance of compelling interest upon the face of the dusty earth. Irrigation, with Midas’ touch, has changed the desert’s frown to smiling vistas of verdure. Its solemn silence has been broken by the voices of countless happy people.