A rhythmic regularity was there all right, but, strangely enough, it required the careful observation of the casual scientist to discover a fact which entirely escaped the more permanent, but less observant, soldiers. In 1926 the Geophysical Laboratory of the Carnegie Institution directed Dr. Eugene T. Allen and Dr. Arthur L. Day to make an exhaustive study of Yellowstone’s thermal features. After seven seasons of research, in cooperation with the National Park Service, they were able to publish a monumental treatise on this subject.[334] Later observations by such naturalists as George Marler, W. Verde Watson, and Herbert Lystrup not only confirmed the principle of rhythmic recurrence in many cases but discovered behavior patterns that enabled rangers to forecast a given eruption with uncanny accuracy. Factors of this character were in the mind of Secretary of the Interior Franklin K. Lane in 1915 when he appointed Stephen T. Mather as his assistant. Mr. Mather’s portfolio particularly related to the formulation of an integrated National Park policy. Chapter XV THE NATIONAL PARK SERVICE Although there were thirteen national parks in 1912, each received a separate appropriation and had separate management. The business of these playgrounds was scattered among three departments, and nowhere in Washington was there a single official or desk wholly devoted to their interest.[335] To this problem Stephen Tyng Mather brought high intelligence, sound philosophy, and supreme endeavor. By 1915 he had achieved administrative experience that ripened into wisdom equal to undertake the preservation of America’s scenic and recreational heritage. With this general proposition in mind, Mr. Mather made two visits to Yellowstone during the season of 1915. There he carefully analyzed the administrative policies and personnel. While it is only fair to state that other federal officials were also planning a new national park organization and procedure it was largely Mr. Mather’s Yellowstone report that provided the needed impetus. From then on he supplied the energy, foresight, and devotion to effect a transition. On August 25, 1916 the National Park Service Bill received President Wilson’s signature. This measure placed the control and general supervision of the entire national park activity squarely into the hands of a Director of National Parks. The bill was sponsored by Senator Reed Smoot of Utah and Representative William Kent of California. Thereafter, on October 1, 1916, the troops of U.S. Cavalry left Fort Yellowstone for duty along the Mexican border. With C. A. Lindsley as Acting Superintendent a fine ranger corps was organized of mountain scouts and released soldiers. Shortly afterwards Congress reversed its action and voted to deny the use of Department of the Interior funds for protective purposes. This forced the return of the soldiers, and the army resumed control on June 30, 1917.