The proceeds of all certificates of indebtedness due the seminary fund, the net proceeds of all sales of lands granted to the state for the benefit of the state university with its several divisions, as provided by law, and all gifts, grants, bequests, or devises to said seminary fund for the benefit of the university, and not otherwise appropriated by the terms of any such gift, grant, bequest or devise, shall be paid into the state treasury, and securely invested by the board of curators of the state university and sacredly preserved as a seminary fund, the annual income of which shall be faithfully appropriated for maintenance of the state university, and for no other uses or purposes whatsoever.