—, connexion of, with electricity, iii, 386.f
—, connexion of, with heat and electricity, J. F. Dana, vi, 163.
—, —, with light, G. Gibbs, i, 89.
—, —, with geology, J. Locke, xlvii, 101.
—, conversion of, into electricity, xxii, 386.
—, currents and sparks of electricity from, J. Henry, xxii, 403.
—, destroyed by lightning, xii, 382.
—, Gauss's theory of, tested by observations, E. Loomis, xlvii, 278.
—, Hansteen's discovery in, v, 190.
—, influence of heat on, xxii, 361.