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The following were the Observations made for ascertaining the Going of
the Clock, by WILLIAM SMITH.
Equal Altitudes.
d h ′ ″ h ′ ″
Nov. 3 9 14 9 2 37 12 } ☉ on Merid. per clock } h ′ ″
15 44 2 35 35 } or mean noon } 11 55 40
Equat. Correspond. + 14.4
Alt.
—-—-——
Correct Noon per Clock 11 55 54.4
4 9 32 48 20 56 } Mean Noon, or ☉ on } 11 56 53
34 33 19 13 } Merid. per. Clock }
36 14 17 31 } Equat. of equal }
37 20 16 23 } Altitudes } + 13.8
14 39 } —-—-——
40 54 2 12 53 } Correct Noon per Clock 11 57 6.8
7 8 51 9 9 29 } Mean Noon } 12 0 19
52 37 8 0 } per Clock } Equat Eq. Alt. + 12
54 1 3 6 37 } 12 0 19 } —-—-—
Cor. Noon 12 0 31
per Clock
_Per Meridian Mark._
d h ′ ″
8 ☉ West Limb on Merid. 12 0 36
East Limb on do. 12 2 52
—-——
Centre 12 1 44
Correct Noon per Clock.
_Applied to Going of Clock._
Nov. 3d, at Noon ′ ″ }
Clock slower than ☉ 4 5.6 } Daily gaining of the Clock
☉ faster than mean time 16 11 } over _mean_ or _equal_ time.
—-—— }
Clock faster than m. time 12 5.4 }
4th, }
Clock slower than ☉ 2 53.2 } ′ ″
☉ faster than mean time 16 9 } From 3d to 4th 1 10.4
—-—— }
Clock faster than m. time 13 15.8 }
7th, }
Clock faster than ☉ 0 31 } From 4th mean to 7th } 1 5.1
☉ faster than mean time 16 00 } at a mean per day }
—-—— }
Clock faster than m. time 16 31 }
8th, }
Clock faster than ☉ 1 44 }
☉ faster than mean time 15 56 } From 7th to 8th 1 9
—-—— }
Clock faster than m. time 17 40 }
Thus the Clock gains at a mean,
per day, 1′ 8″.
Whence, Nov. 2d, at noon, the Clock was 10′ 57″ faster than mean time,
gaining 68″ per day; and 4^h 17′ gains 12″, wherefore at the internal
contact, the Clock was 11′ 9″ faster than mean time.
Whence the contact was at 4^h 5′ 51″ mean time; or 4^h 21′ 2″ apparent
time.
_Eclipse of the Sun, January 9th, 1777._
The Gregorian Reflector, with the magnifying power of 95, was made use
of for this Observation; which, as well as the Observation of the
Transit of Mercury, was made in the College-Library, to which the
Telescope belongs.
While Mr. Rittenhouse was endeavouring to adjust the two-f. reflector
belonging to the Library of the city of Philadelphia, made by Short, and
which had been borrowed on this occasion, I observed with the greatest
certainty the first contact of ☾’s limb with the ☉, which was shining
very bright, and the telescope in the best order, viz. at 8^h 57′ 27″
per clock.
The same was visible, in about 3″ more, to Mr. Lukens, with the equal
altitude instrument, magnifying about 25 times.
Mr. Rittenhouse had not got the other reflector ready to observe the
beginning of the eclipse: but the end was observed by both of us to the
same instant, viz. at 11^h 48′ 50″ per clock.