3d. The Longitude. 1. By the transmission of mean solar chronometer No. 141, from Chicago to Fulton and back to Chicago, between the 22d and 29th of March, 1858. Rate, during the elapsed time, solar day. 0s.744 per mean 1858, March 24th.-Chronometer No. 141, was fast mean solar time at Chicago, appa m. S. 4 56.26 1.49 m. S. + 5 10.72 4 57.75 4 57.75 +10 08.47 (a) Difference-Fulton, west of Chicago, 2. By sidereal chronometer No. 2557: 1858, March 24th.-Chronometer fast of Fulton si dereal time (at Oh. 14m. sidereal time) 1851, March 22d.-Fast of Chicago sidereal time (at Oh. 06m. 44s. sidereal time) Elapsed time, allowing for diff. in long. +1 00 13.75 h. m. S. +0 49 55.67 + 8.51 If we take the time-observations at Fulton, of the 28th March, 1858, as the basis of the comparisons, a similar process to the above, will give us the following additional results, viz.(c) By mean solar chronometer No. 141: Fulton west of Chicago, (d) By sidereal chronometer No. 2557: Fulton west of Chicago, Mean of the 4 results, a, b, c, d, Longitude of Chicago observing station No. 1, 1st Determination. Longitude of Fulton observing station, by the run of the two chronometers, west of the meridian of Greenwich, m. S. +10 08.96 + 10 09.15 +- 10 09 04 + 5 50 30.99 6 00 40.03 On this journey, the chronometers were transported in the rail cars. Each chronometer was carried in a small basket, resting within a nest of elastic curled hair, with a lining of soft green baize between the hair and the chronometer. Every pains was taken to protect them from jolts and all kinds of rough usage. From long experience, I believe that good results for differences of longitude, derived from transporting chronometers, depend much more upon this sort of care and attention to them, than upon any other circumstances attending the operation. A few seconds of time are easily lost by careless handling of the chronometers. In the present month of June, 1859, I determined to test the above result for the longitude, by the method more recently followed, of transmitting time-signals by the electric telegraph. For this purpose, the time-observations of Chicago, given under the dates of June the 22d and 24th, and those now to be given under the date of June 23d, together with the signals, were made. 1859, June 23d. At the Fulton Observing Station, already described. Sidereal chronometer No. 2557, fast: 1st Set. Before the Signals. By 8 observations on a Lyræ, east By 12 observations on a (12) Canum S. h. m. 1 51 04.21 2d Set. After the Signals. By 14 observations on Bootis, west +1 51 04.10 1 51 04.48 +1 51 04.48 Result adopted-Chronometer No. 2557, fast of sidereal time for this station (at 16h. 56m.) +1 51 04.29 The above result, and the results of the time-observations at Chicago of the 22d and 24th of June, applied to the telegraphic signals, give us a second determination of the longitude of our Fulton Station, as follows, viz. Determination of the Difference of Longitude between Chicago and Fulton, Illinois, by electric signals for comparisons of time, June 23d, 1859. Sidereal Chronometer No. 2557, fast, of Fulton, sidereal time, (at 16h. 29m. 23s. sidereal time), 1h. 51m. 04s.16. Rate per sidereal day, +78.025; or per sidereal hour, + 08.2927. Mean solar Chronometer No. 141, slow, of Chicago, mean solar time (at 10h. 32m. 20s. mean time) 4m. 50s.03. 1st.-Chicago signals recorded at both stations. h. m. s. Chicago h. m. s. h. m. s. Electric signals sent from Chicago to Fulton, Difference of Longitude by each signal.Fulton west of the meridian of Chicago observ. ing station No.3. h. m. 8. 0 10 08.77 0 10 08.74 2d.-Fulton signals recorded at both stations. 2d Mean. Electric signals sent from Fulton to Chicago, Result:-Fulton Observing Station is west, in longitude of Chi- 2d Determination, June 23d, 1859. Longitude of Fulton Station, west of the meridian of Greenwich, by the time-observations and the electric signals exchanged June 23d, 1859, 1st Determination, March 1858. Longitude of the same station by the time-observations, and the transportation of the two chronometers between the 22d and 29th of March, 1858, above given, Result adopted-Longitude of Fulton Station, west of the meridian of Greenwich, by a mean of the two determinations, Equal, in arc, to Latitude of this station, as before, Difference of Longitude by each signal.Fulton west of the meridian of Chicago observing station No. 3. h. m. 8. 0 10 08.76 0 10 08.76 0 10 08.76 0 10 08.76 0 10 08.74 +0 10 08.75 +5 50 31.20 6 00 39.95 6 00 40.03 6 00 39.99 90° 09' 59".85 41° 52' 01.33 N. By the triangulation, based on the true meridian, made in March, 1858, taking our departure from the astronomical station whose position is above given, we obtain the positions of other stations, serving as permanent points of reference, in Fulton, as follows, viz. On Nicollet's map, Fulton is placed in latitude 41° 52′ 43′′ N., and longitude 90° 13′ 45′′ West of Greenwich, which, in comparison with our result, if we take the centre of Washington Square as the point of reference, is + 41".2 in latitude, and + 4' 06".6 in longitude. In the last edition (that of 1857) of the map of the territory of the United States, from the Mississippi to the Pacific Ocean, Fulton is laid down in latitude 41° 55′ 27′′ N., and in longitude 90° 12′ 19′′ W., which, in comparison with our result, is 3' 25" in latitude, and +2'41" in longitude. XIV. LYONS, IOWA. Station.--Near the middle of the garden of Mr. Benjamin Lake's house, on Third Street, at the S. W. corner of Third and Exchange Streets. From the station to the point of intersection of the axes or middles of these two streets, is N. 45° 49' 30" E., and the distance is 190 feet. 1st. Observations for the Latitude. Time-stars 6 Tauri west, and a Bootis (Arcturus) east. chronometer fast 1h. 00m. 31.2s. at 9h. 57m. sidereal. chronometer fast 5m. 11.4s. at 9h. 36m. mean time. Latitude of Station. 1858, March 27th. By 22 circum-meridian altitudes of a Hydræ south, and 20 circum-meridian altitudes of a Virginis, also south, combined with 25 circum-meridian altitudes (at lower meridian transit) of Polaris, north, Correction due to the observations for lat. at Fulton, and the survey connecting the two stations, Latitude of station adopted, Sidereal Mean solar 41° 52' 11".78 +1.92 41° 52' 13'.7 N. |