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The apparent Right Ascensions and Declinations of the stars observed on, were taken from the British Nautical Almanac, except a few whose apparent places are not given in that Ephemeris. The exceptions are as follows, in relation to which the apparent places were taken from the Connaissance des Temps, namely:

Andromedæ
€ Herculis

B Cygni
Cygni

For the determination of the longitudes, now reported, two meridians of comparison were used, namely:-I. Chicago. IX. Toledo, Ohio, after its longitude was derived from chronometric comparisons, by means of the electric telegraph, with the meridian of Chicago.

The time-observations at Chicago, and the observations both for the time and the latitude at those stations whose longitudes are based upon direct connections with the meridian of Chicago, will first be given. Then the same will be done in regard to the time-observations at Toledo, and the observations at those stations whose longitudes are derived from direct connections with the meridian of Toledo. Finally, the observations will be given that were made for verifying the positions of Michigan City, Indiana, and Madison, the Capital of Wisconsin.

The position of the observing station at Chicago, will be shown by reference to the table at page 351 of Vol. VI. of the Society's Proceedings.

Observations for the Time at Chicago.

1st. 1859, July 26th. At Chicago Observing Station No. 3, in latitude 41° 53' 46'.3 N.: longitude 5h. 50m. 31s.2 W. of Greenwich.

Siderial chronometer No. 2557, fast:

By 17 observations on a Coronæ Borealis, west (at 19h. 22m. sidereal)

By 23 observations on & Andromedæ, east (at 20h. 08m. sidereal)

Result-Chronometer No. 2557, fast of sidereal time for this station (at 19h. 45m. sidereal)

h. m. S.

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1 02 50.25

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By comparison-Chronometer No. 141, was slow of mean solar time for this station (at 11h. 26m. mean time)

1 02 50.63

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2d. 1858, August 4th. At the same Station.

Sidereal chronometer No. 2557, fast:

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Result--Chronometer No. 2557, fast of sidereal time for this station (at 19h. 43m. 30s.) by 16 observations on - Coronæ Borealis, west; and 18 observations on a Andromedæ, east

By comparison-Chronometer No. 141, was slow of mean solar time for this station (at 10h. 50m. mean time)

+1 03 46.77

4 31.95

3d. 1858, August 12th. At the same Station. tion-By East and West Stars.

1st Determina

Sidereal chronometer No. 2557, fast:

By 15 observations on a Coronæ Borealis, W. (at 19h. 33m.)

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By 15 observations on Andromedæ, E. (at 19h. 55m.)

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1st Result.

By E. and W. Stars-Chronometer

No. 2557, fast of sidereal time at this station (at

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2d Determination. By equal altitudes of a Cygni, observed

East and West.

August 12th.

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h. m.

8.

h. m.

8.

h. m.

8.

h. m.

the Sextant.

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2

8.

111 41 00 18 31 11.8 24 51 07.9 21 41 09.85 20 36 38.43

time at meridian transit of Cygni, by each pair of equal altitudes.

h. m. 8.
1 04 31.42

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2d Result. By 14 pairs of equal altitudes of a Cygni:-Chronometer No. 2557, fast of sidereal time for this station (at 20h. 36m. 38.438. sidereal time)

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1st Result, as above, by E. and W. Stars (at 19h. 44m.)

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Mean, or Result adopted.-Chronometer No. 2557, fast of sidereal time for this station, August 12th, 1858 (at 20h. 10m. sidereal)

By comparison-Chronometer No. 141, was slow of mean solar time the same night (at 10h. 45m. mean time)

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4th. 1858, August 15th. At the same Station. tion-By East and West Stars.

Sidereal chronometer No. 2557, fast: By 12 observations on a Coronæ Borealis, west (at 19h. 04m.)

By 21 observations on a Andromeda, east (at 20h. 36m.)

h. m.

S.

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1 04 48.20

1st Determina

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1 04 48.51

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1st Result-By E. and W. Stars (at 19h. 50m.)

2d Determination-By equal altitudes.

By 9 pairs of equal altitudes of a Cygni, observed
East and West (at 20h. 36m. 38.42s.)

Mean, or Result adopted-Chronometer No. 2557, fast of sidereal time for this station (at 20h. 13m. sidereal) this night,

+1 04 48.35

+1 04 48.36

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+1 04 48.35

By comparison-Chronometer No. 141, was slow of mean solar time this night (at 10h. 13m. m. t.)

5th. 1859, February 20th. Sidereal chronometer No. 2557, fast:

By 13 observations on 3 Geminorum,

east (at 4h. 33m.)

At the same Station:

S.

4 28.78.

1st Set.

h. m.
1 26 04.08

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1st Result—Chronometer No. 2557, fast (at 4h. 43m.) + 1 26 03.96

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2d Result-Chronometer No. 2557, fast (at 6h. 17m.) + 1 26 04.35

Result adopted-Chronometer No. 2557, fast of sidereal time for this station (at 5h. 30m.)

By comparison-Chronometer No. 141, was slow of mean solar time for this station (at 7h. 28m. mean time)

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6th. 1859, February 23d. At the same Station. Sidereal chronometer No. 2557, fast:

By 9 observations on Arcturus, (« Bootis,) east (at 10h. 09m.)

By 5 observations on ẞ Geminorum, west (at 10h. 59m.)

4 41.29

h. m.

S.

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1 26 20.55

Result-Chronometer No. 2557, fast of sidereal time for this station (at 10h. 34m.)

By comparison-Chronometer No. 141 was slow of mean solar time for this station (at 12h. 20m. mean time)

1 26 20.66

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It was cloudy,

This night was not very favorable for observation. with a few spots of clear sky, within which the only time-stars that were visible were Arcturus and ẞ Geminorum. They do not match very well in Declination,—that of the former being 19° 55', and that of the latter 28° 22', both North. As the latitude of the station is well determined, however, there is probably very little error in the deduced time from that cause. But there was a very strong wind, which made it difficult to hold the sextant as steady as was desirable for close work. As the time deduced affects the accuracy of the longitude of Dunleith, Illinois, herein reported, we will endeavour to verify the result by another series of observations, whenever an opportunity shall occur. We do not apprehend that the error will be found to

exceed a fraction of a second of time.

7th. 1859, February 27th. At the same Station.

Sidereal chronometer No. 2557, fast:

By 10 observations on a Arietis, west (at 5h. 50m.)
By 13 observations on ' Leonis, east (at 6h. 24m.)

h. m.

S.

1 26 45.42

1 26 45.74

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