James's Account of S. H. Long's Expedition, 1819-1820, part 4 - Edwin James; Stephen H. Long; Thomas Say

Allowing the perpendicular fall of the river Platte, from the mountains to its mouth, to be on an average nineteen inches per mile, (which appears reasonable from the rapidity of its current compared with that of the Missouri,) the fall of the Missouri from the place where it receives the Platte to its mouth, to be 16 inches per mile, which agrees with the result from leveling at Engineer Cantonment—and that of the Mississippi from the mouth of the Missouri to the Gulf of Mexico to be 12 inches per mile, it would give for the height of the Platte at the base of the mountains, say at the place of the above observations, 3000 feet above the level of the ocean, and consequently the height of James's Peak would be 11507½ above the same level.

This mountain was clothed in snow for a considerable distance below its summit, when the exploring party visited it, in the middle of July, and at the same time they experienced excessive heat at its base.

*Observations made on the Arkansa, at our camp, situated about twenty-fivemiles below the point where the river issues from the mountains.*
*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 17, 1820.	3^h 27´ 17˝	3^h 08´ 35˝	15´ 03˝ slow. Mean time.
	3 25 58	3 07 15
	3 24 36	3 05 54
July 17, 1820.	Meridian double altitude of Antares		51° 28´
Index error 3´ 22˝. Latitude deduced		38 18 19 N.

	Time per Watch, P.M.	Distance of Sun and Moon.	Index Error.
July 17, 1820.	3^h 26´ 49˝	84° 08´ 30˝	- 3´ 22˝

{xxxix} Assumed longitude 7^h 01´ west. Allowance to be made for error and rate of time-piece, as before.

Longitude of Camp deduced, 7^h 02´ 39˝, or 105° 39´ 45˝ W.

*Camp on the Arkansa, two miles below the river St. Charles, or thirdfork of Pike.*
July 19, 1820.	Meridian double altitude of Antares	51° 36´ 00˝
Index error—3´ 22˝. Latitude deduced	38 14 18 N.

*Camp on the Arkansa, at the place where the Exploring Party wasdivided into two detachments.*
*Equal altitudes of Sun to find error of watch, at midnight.*
	Time before Midnight	Time after Midnight	Error of Watch.
July 21, 1820.	8^h 39´ 58˝	8^h 17´ 50˝	17´ 19˝ slow. Mean time.
8 38 38	8 16 30
8 37 18	8 15 1