_Lockwood, M. B._, variation of the magnetic needle at Providence, R. I., xliv, 314. Locust, seventeen year, habits of, xiii, 224. ----, ---- ----, notice of, _S. P. Hildreth_, xviii, 47.^f ----, ---- ----, remarks on, _D. Thomas_, xxi, 188. Locusts in China, xxxi, 193. Lodoicea sechellarum, notice of, _J. E. Teschemacher_, xxxvii, 396. Logan, murder of the family of, xxxi, 11. Logarithmic tables, corrections in _Hassler's_, xxii, 181. ---- and exponential theorems, new mode of obtaining, _T. Strong_, xlviii, 36. Logwood, on hæmatoxylin the coloring principle of, xliv, 357. _Long's_ expedition to the Rocky Mountains, vi, 374. _Long, G. W._, description of a frame bridge, xviii, 123.^f ----, on the origin of springs and fountains, xvii, 336. ----, a parasite tree, xxvi, 106.^f Long lake and Mud lake, Vt., on the eruption of, _S. E. Dwight_, xi, 39.^f Longevity of trees, xxii, 379. ---- of the yew tree, xxix, 353. ---- ---- ----, _Bowman_, xxxi, 358. Longitude, notice of _F. Baily's_ method of determining, by the culmination of the moon and stars, ix, 107. ----, determination of, by means of shooting stars, xxxix, 372; xlii, 399. ----, arc of, between Dublin and Armagh, xxxviii, 113. ---- deduced from the eclipse of Sept. 18, 1838, xxxix, 367. ---- of New York, v, 143. ---- of New York City Hall, xxxviii, 113; xl, 43. ---- of Alexandria, D. C., xxxix, 368. ---- of Boston, xl, 43. ---- of Brooklyn, N.Y., xxxix, 369; xl, 43. ---- of Burlington, N.J., xxxix, 368. ---- of Dorchester Observatory, Mass., xxxix, 369; xl, 43. ---- of Dover, Ohio, xxxix, 368; xl, 43. ---- of Germantown, Penn., xxxix, 368. ---- of Haverford School, Penn., xxxix, 368. ---- of New Haven, xxxiv, 309; xxxix, 369; xl, 43. ---- of Hudson Observatory, Ohio, xl, 43. ---- of Philadelphia State House, xxxix, 368; xl, 43. ---- of Philadelphia High School Observatory, xl, 43. ---- of Princeton, N.J., xxxix, 368; xl, 43. ---- of Southwick, Mass., xxxix, 369; xl, 43. ---- and latitude of Turtle Island, Lake Erie and South Bend lake, Michigan, xxxviii, 154. ---- of Washington capitol, xxxix, 368; xl, 43;--marine observatory, xl, 43. ---- of Weasel mountain, N. J., xxxix, 368. ---- of Wesleyan University, Middletown, Ct., xxxix, 369. ---- of Williamstown College, Mass., xxxix, 369. ---- of Western Reserve College, Ohio, xxxix, 368.