Erratum

INDEX. Vision, single with two eyes arises from structure of the optic nerves, not from habit, 229. ——— singular phenomenon of, observed in viewing very faint stars, iii. 15, 16. Vivian, T. Esq. sends copper to Mr. Faraday for analysis. W Walrus, Sir E. Home on, 233—structure of its hind feet, 234—mode of supplying its duodenum with bile, 235—Feeds on seaweed, 236. Wind, its effect in altering the velocity of sound, 425. Winter birds of passage, 30. Wollaston, W. H. M. D. V. P R. S. on semi-decussation of the optic nerves, 222—on apparent direction of eyes in a portrait, 247—does not depend on the circularity of the iris, 248. Worm (Earth,) brain of, 10, Plate II. Y Young, T., M. D. For. Sec. R. S. on a finite expression for refraction in an atmosphere nearly resembling the earth’s, 159. Z Zevenboompijes, one of the stations chosen by Moll and Van Beek, for experiments on velocity of sound, 428. Zinc, its electro-mechanical effect in alloy with mercury, 182—sensible when only a 1200000th part of the alloy, 183—contact of mercury with, momentary—its effect, 195. ERRATUM. The references to the Figures in Mr. Ivory’s Paper having been accidentally omitted, are to be thus supplied; Fig. 1—page 100. Fig. 2—Prop. 1—page 111. Fig. 3—Prop. 2—page 115. From the Press of W. Nicol, Cleveland-row, St. James’s, London.