— experiments, season favorable for, W. R. Johnson, xxv, 60.

— fish, on the coast of Cape Cod, D. H. Storer, xliv, 213.

— —, Gymnotus, xl, 386.

— fluids, the existence of two, opposed by R. Hare, vii, 103.f

— —, observations on, C. G. Page, xxxvi, 353.

— induction, decomposition of water by, M. Hachette, xxiv, 142.

— —, currents of electricity from, of different orders, J. Henry, xxxviii, 232.f

— —, polarity produced by, xxxviii, 3.

— —, R. Hare, letters on, to M. Faraday, xxxviii, 1, 19; xli, 1.

— —, M. Faraday, in reply to R. Hare, xxxix, 108; xlii, 291.