The Secretary of the Army is authorized to set aside, for use in the establishment of normal and industrial training schools for Indian youth from the nomadic tribes having educational treaty claims upon the United States, any vacant posts or barracks, so long as they may not be required for military occupation, and to detail one or more officers of the Army for duty in connection with Indian education, under the direction of the Secretary of the Interior, at each such school so established: Provided, That moneys appropriated or to be appropriated for general purposes of education among the Indians may be expended, under the direction of the Secretary of the Interior, for the education of Indian youth at such posts, institutions, and schools as he may consider advantageous, or as Congress from time to time may authorize and provide.