tween passing clouds, and fewer observations were obtained than was desirable for a close determination of the time. A set of observations was obtained on a Virginis, S., for the latitude; but Polaris, North, was hidden from view, and the result from meridian observations, on only one side of the zenith, being considered imperfect for a close approximation, they were not used. The Longitude. A second determination of the longitude of this station, is derived from the above time-observations, made at New Buffalo; combined with those at Chicago on the nights of May 19th and 21st, and the telegraphic signals, as follows, viz.— Determination of the difference of Longitude between Chicago and New Buffalo, Michigan, by electric signals for comparisons of time, May 20th, 1859. Sidereal Chronometer No. 2557, fast, of New Buffalo sidereal time (at 14h. 23m. 29s. sidereal time), 1h. 33m. 13s.17. Rate per sidereal day, + 6s.966; or per sidereal hour, + Os.29. Mean solar Chronometer No. 141, slow, of Chicago mean solar time (at 10h. 26m. 51s. mean time), 4m. 40s.65. Rate per mean solar day, Os.0196. Os.47; or per mean solar hour, 1st.-Chicago signals recorded at both stations. Times of signals given at Chicago by mean solar Chronometer No. 141. h. m. s. 10 22 10 10 25 10 10 37 10 10 40 10 10 43 10 1st Mean. h. m. 8. 14 23 29.83 14 19 58.31 Electric signals sent from Chicago to New Buffalo, Difference of Longitude by each signal.New Buffalo station is east of the meridian of Chicago observing station No.3. h. m. S. 0 03 31.52 0 03 31.51 0 03 31.48 0 03 31.48 0 03 31.48 0 03 31.494 2d.-New Buffalo signals recorded at both stations. Times of signals given at New Buffalo by sidereal Chronometer No. 2557. 8. Times of New Buffalo signals, as noted at Chicago by mean solar Chronometer No. 141. New Buffalo correct sidereal time Chicago Chicago of h. m. s. h. m. 8. h. m. s. 10 50 50.65 14 44 02.25 14 47 33.71 h. m. h. m. 8. 16 20 47 10 46 10 16 23 47.5 10 49 10 16 26 47 10 52 09 16 29 48.5 10 55 10 16 39 49 10 58 10 2d Mean. Electric signals sent from New Buffalo to Chicago, 1st Mean.-Electric signals sent from Chicago to New Buffalo, as above, Result:-New Buffalo Observing Station is east, in longitude, of Chicago observing station No. 3, by a mean of the two sets of signals, Longitude of Chicago Station No. 3, Difference of Longitude by each signal.New Buffalo station is east of the meridian of Chicago observing station No.3. h. m. 8. 03 31.46 0 03 31.45 0 03 31.44 0 03 31.44 0 03 31.45 0 03 31.49 - 0 03 31.47 +5 50 31.20 2d Determination. Longitude of New Buffalo Station, +5 46 59.73 We have here two satisfactory results for the longitude; but the unfavourable state of the sky on both nights prevented a satisfactory determination of the latitude of this station. A third visit, made on the 23d of May, gave an opportunity for a third trial of the difference of longitude between this place and Chicago, and for observing for the latitude. The night, this time, was clear, and good pairs of stars, both for the time and the latitude, were selected. Those for the latitude, and the result, are already given at the beginning of this article, XVIII. Observations for the Time. 1859, May 23d. Sidereal chronometer No. 2557, fast of New Buffalo sidereal time: By 12 observations on a Coronæ Borealis, east (at h. m. S. +1 33 33.47 12h. 19m.) By 13 observations on Leonis, west (at 12h. 41m.) + 1 33 33.64 Result-Chronometer No. 2557, fast of New Buffalo The Longitude. The above result for the New Buffalo time, and the observations of the 22d and 24th of May, for the Chicago tine, combined with the following telegraphic signals, give us a third result for the longitude, as follows, viz.— Determination of the Difference of Longitude between Chicago and New Buffalo, Michigan, by electric signals for comparisons of time, May 23d, 1859. Sidereal Chronometer No. 2557, fast, of New Buffalo sidereal time (at 15h. 11m. 27s. sidereal time), 1h. 33m. 34s.71. Rate per sidereal day, + 7s.351; or per sidereal hour, + 0s.3063. Mean solar Chronometer No. 141, slow, of Chicago, mean solar time (at 11h. 02m. 52s. mean time), 4m. 41s.76. Rate per mean solar day, + Os.02764; or per mean solar hour, +0s.00115. 1st.-Chicago signals recorded at both stations. Times of signals given at Chicago by mean solar Chronometer No. 141. h. m. S. 10 58 10 11 01 10 11 04 10 11 22 10 11 25 00 1st Mean. Correct mean solar time of Chicago h. m. s. Times of Chicago signals, as noted at New Buffalo by sidereal Chronometer No. 2557. h. m. s. New Buffalo S. Chicago reduced sidereal time of Chicago h. m. s. h. m. 11 02 51.62 16 45 01.5 2d.-New Buffalo signals recorded at both stations. h. m. s. h. m. 16 54 06.5 11 07 13.5 16 57 08.5 11 10 15 17 00 09 2d Mean. 11 11 55.12 15 16 59.85 15 20 31.74 11 13 15 Result:-New Buffalo Observing Station is east, in longitude, of Chicago observing Station No. 3, by a mean of the two sets of signals, VOL. VII.—M Difference of Longitude by each signal.New Buffalo station is east of the meridian of Chicago observing station No.3. h. m. s. 0 03 31.87 0 03 31.88 0 03 31.908 -0 03 31.894 SUMMARY.-Longitude of this Station: By determination 1st, of March 16th, 1859, Mean, giving double weight to the last. Longitude of New Buffalo Station, west of the meri dian of Greenwich, Equal, in arc, to 5 46 59.68 5 46 59.47 5 46 59.89 5 46 59.78 86° 44' 56'.7 W. Latitude of this station, as before, 41° 47' 48" N. The above results, connected with observed azimuths of the sun, and distances determined by triangulation in our survey of this harbour, made in September, 1857, (see map G. No. 57), give the positions of other points in New Buffalo, as follows, viz.— In Colton's map of the United States, of 1851, this place is laid down in latitude 41° 51′ 30′′ N., and in longitude 86° 42′ West. XXI. NILES, MICHIGAN. Station. In the yard in the rear of the Methodist Church, near the N. W. corner of Fourth and Main Streets. From this station to the intersection of the middle of Main Street, with the middle of Fourth Street, is S. 22° 31'. E. 221 feet. 1st. Observations for the Latitude. 1859, June 8th. α By 14 altitudes of Polaris, north, combined with 2 altitudes of a Virginis S., observed at 16 and 21 minutes of time after meridian passage, we get: Latitude of station (approximate), Reduction to the point of intersection of Main and Latitude (approximate) of the intersection of Main and Fourth streets, 41° 49′ 56" 2" 41° 49' 54" N. The sky to the south was so cloudy, that a satisfactory set of observations on a star passing the meridian to the south of our station, could not be obtained to combine with those on Polaris, north, for the latitude. The index error of the sextant had, however, been very carefully measured on the day of these observations, and hence we believe that the latitude, here stated, is within four or five seconds of the truth, which is quite near enough for satisfactory results in computing the time from altitudes of East and West Stars, two sets of which were obtained to-night. |