— influence of the sun's rays, xiii, 188; xviii, 181.
— — of the violet ray, xviii, 171.
— instrument, new, called a Solar Index, M. Conant, xlix, 301.f
— iron, see [Iron.]
— intensity, at great elevations, J. D. Forbes, xxxi, 369.
— —, at different places in Europe, xl, 30.
— —, in Ireland, H. Lloyd, xxxv, 296.
— —, daily variation and changes in, H. Lloyd, xlvi, 391.
— —, in different places in the United States, xl, 378.
— investigations, by W. Scoresby, xlviii, 33.