Map showing, in five degrees of density, the distribution, within the territory of the United States east of the 100th Meridian, of that portion of the population which is, in whole, or in part, of foreign parentage, embracing i.e. all persons having father or mother or both foreign. Compiled from the returns of population at the ninth census of the United States, 1870. By Francis A. Walker. (Julius Bien, Lith., 1874)