“ The Tax is, in both form and substance, upon a separate interest in real estate granted by the lessor, and is assessed against the owner of such separate interest. If the university could lease its lands and could also effectually provide that the interest of the lessee in the land so leased should be exempt from taxation, it may readily be seen that the amount of rent which it would receive would be larger than if no such exemption could be obtained, but that is a matter which is wholly immaterial upon the question of the impairment of the contract of exemption that was really made. ”

“ The act repealing the exemption, passed after the sale of the lands by the Indians, was held void because it impaired the obligations of a contract. In the case before us the exemption lasts only so long as the university owns the lands, and, when it conveys a certain interest in them to a third person, it no longer ownes that interest, which at once becomes subject to the right of the state to tax it. When the state exercises that right, as it did under the act of 1903, and taxes the interest in the name of its owner, the state thereby violates no contract, and the tax is valid. ”

“ As long as different interests may exist in the same land, we think it plain that an exemption granted to the owner of the land in fee does not extend to an exemption from taxation of an interest in the same land, granted by the owner of the fee to another person as a lessee for a term of years. ”