June 20, 1820.|Meridian altitude of sun's lower } | 72° 23´ | limb } | |Extent of horizon, (a level sheet of }| 700 yards. | water) }| |Height of observer's eye above } | 3½ feet. | horizon } | +--------------------------------------+----------- |Index error--4´ 15˝. Latitude } | 40° 59´ 15˝ N. | deduced } | +--------------------------------------+----------- _Equal altitudes of Sun to find error of Watch._ |Time from Noon,|Time from Noon,| Error of Watch. | A.M. | P.M. | |---------------+---------------+---------------- June 20, 1820.| 2ʰ 32´ 26˝ | 2ʰ 32´ 34˝ } | 1´ 15˝ fast. | 2 29 36 | 2 29 46 } | Mean time. --------------+---------------+---------------+---------------- _Camp on the Platte, thirty-two miles below the point where it issues from the Rocky Mountains._ -------------+--------------------------------------+----------------- July 4, 1820.| Meridian double altitude of star } | 48° 10´ 00˝ | Antares, (ᵅ. Scorpii) } | | Index error--3´ 45˝. Latitude } | 39° 57´ 40˝ N. | deduced } | -------------+--------------------------------------+----------------- {xxxvii} _Observations made on the River Platte, seven minutes of latitude south of the Camp of July 4th._ _Equal altitudes of Sun to find error of watch, at noon._ | Time from | Time from | Error | Noon, A.M. | Noon, P.M. | of Watch. -------------+------------------+------------------+------------- July 5, 1820.| 2ʰ 30´ 19˝ | 2ʰ 21´ 17˝ }| 8´ 41˝ slow. | 2 28 57 | 2 19 55 }| Mean time. | 2 27 30 | 2 18 22 }| +------------------+------------------+------------- _A mean of eight lunar distances from sun and times correspondent, to find the longitude. Latitude by account 39° 50´ 40˝ N. Assumed longitude 7ʰ 01´ W._ | Time per Watch, | Distance of | | A.M. | nearest limbs. | Index error. -------------+------------------+------------------+-------------- July 5, 1820.| 7ʰ 33´ 07˝ | 56° 09´ 26˝ | --4´ +------------------+------------------+-------------- Daily variation of watch 1´ 41˝ losing. Longitude deduced, 7ʰ 01´ 23˝, or 105° 20´ 45˝ W. of Greenwich. --------------+------------------------------------+----------------- _Camp at the base of the Rocky Mountains._