James's Account of S. H. Long's Expedition, 1819-1820, part 4

by Edwin James; Stephen H. Long; Thomas Say

	Time per Watch P.M.	Distance of Moon and Star.	Index error.
July 21, 1820.	9h 40´ 54˝	51° 45´ 47˝	- 3´ 30˝

Variation of watch 47˝ per 12 hours losing. Error of watch to be estimated. Longitude by account 6^h 58´ W. Lat. determined by subsequent observations.

Longitude of Camp, 6^h 55´ 05˝ or 103° 46´ 15˝ W. of Greenwich.

Equal altitudes of Sun to find error of watch, at noon.

	Time from Noon, A.M.	Time from Noon, P.M.	Error of Watch.
July 22, 1820.	2h 58´ 21˝	2h 34´ 09˝	18´ 06˝ slow. Mean time.
	2 56 59	2 32 47
	2 55 36	2 31 23
July 22, 1820.	Meridian double altitude of Antares		51° 40´
Index error—3´ 30˝. Latitude deduced		38 12 22 N.

{xl} Camp on the Canadian River of August 6th.

Aug. 6, 1820.	Meridian of altitude sun's lower limb	71° 52´
Extent of natural horizon, or sheet of water	82 yards.
Height of observer's eye above horizon	38 inches.
Index error of sextant	- 3´
Latitude deduced	35° 16´ 19˝ N.

Camp on the Canadian River of August 22d.

Aug. 22, 1820.	Meridian double altitude of moon's lower limb	72° 18´ 15˝
Index error—4´ 00˝. Latitude deduced	35 26 29 N.

Camp on the Canadian River of August 31st.
Equal altitudes of Sun to find error of watch, at noon.

	Time from Noon, A.M.	Time from Noon, P.M.	Error of Watch.
Aug. 31, 1820	3h 27´ 43˝	2h 23´ 40˝	31´ 52½˝ slow. Mean time.
3 26 21	2 22 18
3 24 55	2 20 57

Altitudes of Sun and times correspondent, to find the Latitude.

	Times per Watch, A.M.	Double altitudes of sun's upper limb.	Index error.
Aug. 31, 1820.	10h 29´ 20˝	121° 18´ 00˝	- 4´ Error and variation of watch to be allowed. Lat. by account 34° 57´ N.
	10 30 24	121 32 00
	10 32 05	121 52 30
	10 33 12	122 06 30
	10 34 13	122 17 30
Mean 10h 31´ 51˝		121° 49´ 18˝
Latitude of Camp deduced from the above			34° 57´ 35˝

	Time per Watch, A.M.	Distance of Sun and Moon.	Index error.
Aug. 31, 1820.	7h 32´ 06˝	77° 50´ 15˝	- 4´