—, specific gravity of, at different temperatures, xxxviii, 137.
—, electricity from, xl, 383.
—, rapid production of, in contact with highly heated metals, W. R. Johnson, xix, 292; xx, 308, 418.
—, agent in volcanic action, G. Bischof, xxxvi, 241.
—, destruction of vermin in ships by, xvii, 390.
— pyrometer, W. R. Johnson on, xxii, 96.f
— navigation, ii, 342, 347.
— —, letters on, J. Smith, xxxv, 332; xxxvi, 133.
— —, Atlantic, J. Smith, xxxv, 160.
— —, to the Pacific, by the isthmus of Panama and the western coast of South America, xli, 358.