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2d.-Ashtabula signals recorded at both stations.

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S.

at Chicago by mean solar Chronometer

No. 141.

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h. m. S. h. m. S. h. m.

S.

h. m.
h. m. s.
22 09 49 11 59 30
22 12 49.5 12 02 30
22 15 50 12 05 30
22 18 50.5 12 08 30
2d Mean. Electric signals sent from Ashtabula to Chicago,
1st Mean. Electric signals sent from Chicago to Ashtabula,
as above,

12 04 01.02 21 05 53.16 21 33 14.57,
12 07 01.02 21 08 53.65 21 36 15.06
12 10 01.01 21 11 54.13 21 39 15.56
12 13 01.01 21 14 54.62 21 42 16.05

Result:-Centre of the Public Square at Ashtabula, east, in
longitude of Chicago observing Station No. 3, by a mean of
the two sets of signals,

Longitude of Chicago observing station No. 3, west of the meridian of Greenwich,

Longitude of the centre of the Ashtabula Public
Square, west of the meridian of Greenwich,

Equal, in arc, to

Latitude (approximate) as before,

VIII. ERIE, PENNSYLVANIA.

Difference of Longitude by each signal.Ashtabula East of the meridian of Chicago observing station, No. 3.

h. m. S.

0 27 21.41 0 27 21.41

0 27 21.43

0 27 21.43

0 27 21.42

0 27 21.422

0 27 21.42

+5 50 31.20

5 23 09.78

80° 47' 26'.7 W.

41° 52' 04" N.

Station. The point of intersection of the two diagonal lines of the lumber-lot of Mr. William Sandborn, fronting on Sixth street, between Holland and French streets.

1st.

Observations for the Latitude. 1858, August 8th.

By 16 observations on Polaris, north, combined with 16 observations (circum-meridian) on Aquarii, south,

Same night-By 28 circum-meridian altitudes of Altair (a Aquila,) south, combined with 22 circum-meridian altitudes of Cephei, north,

Result-Latitude of station,

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VOL. VII.-G

2d. Observations for the Time. August 8th, 1858. Sidereal chronometer No. 2557, fast:

By 9 observations on a Corona Borealis, west (at 19h. 06m.)

By 8 observations on a Andromeda, east (at 20h. 21m.)

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

m.

S.

33 56.51

33 57.29

+33 56.90

August 9th, 1858. Sidereal chronometer No. 2557, fast:

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By 12 pairs of equal altitudes of a Cygni, observed east and west (at 20h. 86m. 38.44s. or meridian transit)

Result adopted-Chronometer No. 2557, fast of sidereal time for this station (at 20h. 10m.)

3d. The Longitude.

+ 34 02.73

- 34 02 62

In obtaining the difference of longitude between Erie and Chicago, we use the time by sidereal chronometer No. 2557, for the meridian of Erie as derived from the foregoing observations of August 9th. The rate of that chronometer, carried forward from the period of the determination of the said time to that of the signals, is derived from the observations made at Erie on the nights of August 8th and 9th.

The corresponding time for the meridian of Chicago, is derived from the observations made there on the 4th and 12th of August, which give the rate of the mean solar chronometer No. 141, during that interval, and also the means of reducing the Chicago time to the period of the said signals.

The signals and the results derived from them were as follows, viz.—

Determination of the difference of Longitude between Chicago and Erie, Pennsylvania, by electric signals for comparisons of time, August 9th, 1858.

Sidereal Chronometer No. 2557, fast, of Erie, sidereal time, (at 20h. 59m.. sidereal time,) 34m. 02s.81.

Rate

per sidereal day, + 5s.62; or per sidereal hour, + Os.234. Mean solar Chronometer No. 141, slow, of Chicago, mean solar time, (at 11h. 15m. mean time,) 4m. 29s.67.

Rate per mean solar day, + Os.455; or per mean solar hour, + Os.01896.

1st.-Chicago signals recorded at both stations.

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h. m. 8.
11 15 29.67 21 33 16
11 18 19.67 21 36 06.5
11 21 19.67 21 39 07
11 24 19.67 21 42 07.5
11 26 59.67 21 44 48
11 48 08.66 22 06 00.5
11 51 08.66 22 09 01
11 54 11.66 22 12 04.5

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1st Mean. Electric signals sent from Chicago to Erie,

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8.

Chicago

reduced

sidereal

time of

Erie signals.

h. m.

S.

Erie correct sidereal time of

Erie signals.

h. m. s.

h. m. s.
h. m. s.
21 50 58 11 28 39
21 53 58.5 11 31 39
21 56 59 11 34 39
21 59 59.5 11 37 39
22 03 00 11 40 39
2d Mean.-Electric signals sent from Erie to Chicago,
1st Mean. Electric signals sent from Chicago to Erie as above,

h. m.
11 33 08.66 20 46 35.39 21 16 55.12
11 36 08.66 20 49 45.89 21 19 55.61
11 39 08.66 20 52 46.38 21 22 56.10
11 42 08.66 20 55 46.87 21 25 56.59
11 45 08.66 20 58 47.36 21 28 57.08

Result:-Erie Observing Station is east, in longitude, of Chicago Observing Station No. 3, by a mean of the two sets of signals,

Difference of Longitude by each signal.Erie east of the meridian of Chicago observing station No.3.

h. m. S. 0 30 09.69 0 30 09.71 0 30 09.71 0 30 09.71 0 30 09.75 0 30 09.70 0 30 09.70 0 30 09.69

0 30 09.708

Difference of Longitude by each signal.

Erie east of the meridian of Chicago observing station No.3.

h. m. s.
0 30 09.73

0 30 09.72

0 30 09.72

0 30 09.72

0 30 09.72

30 09.722

30 09.708

30 09.715

Brought forward,

Longitude of Chicago observing station No. 3, west

of the meridian of Greenwich,

Longitude of Erie observing station west of the

meridian of Greenwich,

Equal, in arc, to

Latitude, as before,

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+5 20 21.5 80° 05′ 22′′.5 W.

42° 07' 54'.8 N.

My duties required me to return to Chicago immediately after completing the above observations. I arrived there on the morning of the 11th August. The night of that date was unfavourable for observations, which had to be deferred until the night of the 12th. This makes the elapsed time between the Chicago observations, which enter into the above determination of the longitudes of Ashtabula and Erie, from the 4th to the 12th of August; or 8 solar days, during which period we depend on the run of mean solar chronometer No. 141, in deducing those longitudes.

IX. TOLEDO, OHIO.

Station. By a true azimuth derived from observations on Polaris (a Ursa Minoris) with the theodolite, and a horizontal measurement with the chain, from this observing station to the point of intersection of the middle of Jefferson street, with the middle of Superior street, is S. 60° 14' 57" W., and the distance 141 feet.

1st.

Observations for the Latitude. 1858, August 13th.

By 5 circum-meridian altitudes of Pegasi, and 7 circum-meridian altitudes of a Pegasi, both south, combined with 14 observed altitudes of Polaris (a Urs. Minoris) north,

1859, January 24th. By 18 circum-meridian altitudes of ß Orionis, south, combined with 20 observed altitudes of Polaris, north,

By giving the 2d set twice the weight of the first, we

get

Result-Latitude of station,

41 39 02.85

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41 39 01.97

41 39 02.26 N.

When the observations were made for the latitude on the night of August 13th, 1858, the sky to the south was so much clouded that no more observations could be made in that direction, for that object, than are above reported. The result then obtained agrees, however, well with that derived from the satisfactory set of observations made on the night of January 24th, 1859, on the occasion of a second visit. to the same station. It is believed that the result reported is a pretty close determination.

2d.

Observations for the Time. 1858, August 13th.

Sidereal chronometer No. 2557,

fast:

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By 12 pairs of equal altitudes of a Cygni, observed east and west (at 20h. 36m. 38.43s.)

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Result adopted-Chronometer No. 2557, fast of sidereal time for this station, Aug. 13th, 1858, (at 20h. 10m.)

+48 14.85

+48 15.15

3d. The Longitude.

The above determination of the Toledo time, and the Chicago time derived from the observations made there on the nights of August 4th and 12th, combined with the following telegraphic signals, give us the longitude of Toledo, Ohio, as follows, viz:

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