594 HARVARD LAW REVIEW kind was taxable to the corporation.^^ On the other hand, the predominant owner, for instance the mortgagor, may be taxed not on the value of his interest, but on the entire value of the land;^^ the person to whom the land is taxed is immaterial, so far as the vahdity of the tax Uen is concemed.^^ A franchise appurtenant to land may be taxed as an interest in the land, and is taxable where the land lies to which it is appurte- nant. Thus a franchise to construct a bridge may be taxed as appurtenant to the shore from which the bridge is allowed to be extended.^^ A ferry franchise is taxable by the state from whose shore the ferry is allowed to nm,^^ and cannot be taxed by another state, for instance, the state which controls the opposite bank but has not granted the franchise.^^ It follows that in the case of an interstate bridge or ferry, which is in fact attached to two opposite shores, the sovereign of either shore might grant and tax a franchise. Land outside the boundaries of the state is of course not subject to taxation.^^ It has therefore been held that in taxing an aggre- gate mass of property, such as the capital of a corporation, foreign real estate must be omitted.^^ An apparent difference of opinion has developed on the taxation of a debt secured by a mortgage of land. It is usually held that the debt, being the principal thing, fixes the nature of the thing to be taxed; that it has no situs where the security is, and is taxable only through power over the owner. It is therefore not subject to taxation in the state where the mort- gaged land lies, if the owner is a nonresident of the state; ^' and " Mt. Sterling O. & G. Co. v. Ratliff, 127 Ky. i, 104 S. W. 993 (1907). ^ Faxton v. McCosh, 12 la. 527 (1861); Paddell v. New York, 211 U. S. 446 (1908). ^ Witherspoon v. Duncan, 4 Wall. (U. S.) 210 (1866). ^ Henderson Bridge Co. v. Kentucky, 166 U. S. 150 (1897). 36 Conway v. Taylor, i Black (U. S.) 603 (1861). 86 Louisville & J. F. Co. v. Kentucky, 188 U. S. 385 (1903). 37 Winnipiseogee, L. C. & W. M. Co. v. Gilford, 64 N. H. 337, 10 Atl. 849 (1887). 38 People V. Barker, 23 N. Y. Misc. 188, 51 N. Y. Supp. 102 (1897); Commonwealth V. American Dredging Co., 122 Pa. 386, 15 Atl. 443 (1888). 39 Territory v. Gila County Delinquent Tax List, 3 Ariz. 179, 24 Pac. 182 (1890); People V. Eastman, 25 Cal. 601 (1864); Arapahoe Coimty v. Cutter, 3 Colo. 349 (1877); Foresman v. Byms, 68 Ind. 247 (1879); Senour v. Ruth (Ind.), 39 N. E. 946 (1895); Theobald v. Clapp, 43 Ind. App. 191, 87 N. E. 100 (1909); Faxton v. McCosh, 12 la. 527 (1861); Davenport v. Mississippi & Mo. R. R., 12 la. 539 (1861); State V. Smith, 68 Miss. 79, 8 So. 294 (1890); Adams v. Colonial & U. S. Mortgage Co., 82 Miss. 263, 34 So. 482 (1903); Holland v. Commissioners of Silver Bow Coimty,
