During the next six months National Park Service officials, aided by the army officers, gathered data which proved the inadvisability of continuing the use of troops. It should be noted that the attitude of the officers throughout was cogently expressed by Captain Harris: And it is believed that to the extent in which the present method of government and protection is an improvement upon former methods it is due to the visible power and force of the National Government as represented by the military garrison in the Park. It is not to be inferred that the claim is made that a military government is the only one practicable for the Park, or even that it is the best adapted or most suitable. It is believed, however, that no efficient protection can be given to the Park without the support of a well-organized and disciplined police force of some description.[336] In this spirit, the cost of a military garrison and its lack of opportunities to drill were reviewed. It was clearly demonstrated that a ranger force of a chief ranger, four assistants, twenty-five permanent Park rangers of the first class, and twenty-five seasonal rangers would constitute a “well-organized and disciplined police force” and something else besides. It was also pointed out that the cost would be considerably less. This effort resulted in a second withdrawal of the troops in 1918. At the same time another ranger force was effected with substantially the same personnel as developed in 1916.[337] In due time the members of this new corps acquired a modest attitude of confidence in their own capacity which still abides. Mr. Mather assumed office as the first National Park Director on May 16, 1917. In a short time the fruits of his vision were disclosed. Under his inspiring leadership the National Park program was steadily expanded. Peace was made with, and a degree of cooperation obtained from, the natural antagonists of the National Park Service. Several wealthy citizens who had acquired vast private estates were induced to donate portions thereof for the general public. Sportsmen who had observed the diminution in numbers of wild creatures were converted to the idea of refuges through self-interest. The positions of the lumber, grazing, irrigation, and water-power interests were less yielding on this all-out conservation issue. They would evidently favor a compromise. The general public gradually responded to the suggestion that the country beautiful was even more alluring than beautiful cities.[338] In Secretary Lane’s third annual report in 1919 the National Park Service policy was announced under three broad principles: