Micrometer Measures.

h ′ ″ inches. tenths. 500ths.
9 15 0 2 2 6 distances of the cusps.
31 0 3 1 ½
10 17 5 1 1 14 enlightened parts remaining.
22 0 1 1 23
11 37 0 1 7 6
38 46 1 5 21 distances of the cusps.
42 26 1 2 18

Continuation of the Observations for adjusting the Clock.

Jan. 11th. ☉’s W. limb on Merid. [[A48]]
E. limb on do.
Centre on do.

Whence clock faster than mean time 0 1′ 46″ per merid. mark.

Equal Altitudes.
h ′ ″
20th. 9 37 20 59 49
39 1 58 6 Mean noon per clock 12 18 34
40 41 2 56 26
21st. W. limb on Merid. 12 20 3
E. limb on do. 22 22
Centre on do. 12 21 12.5
Eq. Alt.
22d. 9 14 10 3 31 10 Mean noon per clock 12 23 50

Eclipse of the Sun, June 24, 1778: Observed by D. Rittenhouse, John Lukens, Owen Biddle, and William Smith, at the College of Philadelphia.

The morning being very cloudy, the beginning of the eclipse was not seen.

At 10h 7′ 40″ per clock, the following micrometer-measure of the enlightened parts was taken, while the Sun appeared for a few minutes between clouds, viz. 1in. 9-10ths. 13-500ths. = 16′ 23″.

11h 6′ 57″ per clock end of eclipse distinctly seen, the Sun having shone clearly for several minutes, the clouds now wholly dispersing, and the remainder of the day continuing clear.