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

*Equal altitudes of Sun to find error of Watch.*
	Time from Noon, A.M.	Time from Noon, P.M.	Error of Watch.
June 20, 1820.	2^h 32´ 26˝	2^h 32´ 34˝	1´ 15˝ fast. Mean time.
2 29 36	2 29 46

*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 Antares, (^ɑ. Scorpii)	48° 10´ 00˝
Index error—3´ 45˝. Latitude deduced	39° 57´ 40˝ N.

{xxxvii} *Observations made on the River Platte, seven minutes of latitudesouth of the Camp of July 4th.*
*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 5, 1820.	2^h 30´ 19˝	2^h 21´ 17˝	8´ 41˝ slow. Mean time.
2 28 57	2 19 55
2 27 30	2 18 22

	Time per Watch, A.M.	Distance of nearest limbs.	Index error.
July 5, 1820.	7^h 33´ 07˝	56° 09´ 26˝	-4´

Daily variation of watch 1´ 41˝ losing.

Longitude deduced, 7^h 01´ 23˝, or 105° 20´ 45˝ W. of Greenwich.

*Camp at the base of the Rocky Mountains.*
July 8, 1820.	Meridian double altitude of Antares	49° 17´ 30˝
July 8, 1820.	Index error —3´ 45˝. Latitude deduced	39 23 52 N.
July 9, 1820.	Meridian double altitude of Antares	49 18 15
Index error -3´ 45˝. Latitude deduced	39 23 29 N.
Mean latitude of the camp	39 23 40 N.

At our camp on Boiling-spring Creek, at the distance of about 25 miles from James's Peak, (the same designated by Pike as the highest peak,) trigonometrical observations were made for determining the height of the peak above the level of the adjacent country. A base of 1048½ feet was accurately measured, and angles taken at its extremities, to ascertain another side of the triangle, to serve as a base to determine the height of the mountain. The angles at the extremities of the primary base, corrected for the index error of sextant, were 104° 32´ 15˝ and 65° 28´ 45˝—and the extent of the secondary base as found by calculation, 133372.5 feet. The angles taken at the extremities of the secondary base, included between that line and the lines of vision, to an object distinctly visible at the summit of the peak, were 96° 21´ 15˝ and 81° 17´ 45˝, corrected as above. The angle of elevation of the top of the peak, observed at the extremity {xxxviii} of the secondary base, most remote from the peak, was 3° 41´ 15˝, corrected also for index error of sextant. The final result of these observations, gives for the height of the peak above the plain in which the observations were made, 8507½ feet.

In order to ascertain with precision, the angle of elevation of the summit of the peak, an artificial horizon of water was employed, and the double angle of elevation observed. The angle of elevation as it stands corrected for refraction, is 3° 39´ 26˝. The estimate as above gives the height of the peak above the true level of the place of observation, no correction having been made for the spherical figure of the earth.