—, improvements on his galvanometer, xxvi, 378f;
experiments with, 379, 381.
—, on a large thermoscopic galvanometer, xxxiii, 365.
—, geology of the U. States, west of the Allegany Mountains, xli, 160.
—, lead region of the West, xliii, 147.
—, magnetic dip in the United States, xli, 15.
—, — — at Baltimore, xlii, 258.
—, on magneto-electricity, and electro-magnetic machines, xxxiv, 125.f
—, connection between geology and magnetism, xlvii, 101.