undated, ca. November 15–19, 1803
7.45% Complete
Aug 30, 1803 Sep 30, 1806

undated, ca. November 15–19, 1803


Took equal alitudes of the sun

  h m s     h m s
A. M. 8 33 32   P.M 2 36 38.5
  8 35 35.5     2 38 27.5
  8 37 30.5     2 40 30.5

Altitude given by sextant [2] ☉'s center 39° 50' 00"

Equal altitudes corrected

  h m s     h m s
A. M. 8 35 35.5 P.M. 2 38 27.5
  m s
Chronometer [3] too slow M. T. 22 56.1
      do. do. Apt. T. 22 55.1

From the Point of the Mississippi & Ohio 25 poles from the highest Land on the Sand point—    From thence to A Signal [5] on the Opposit Side of the Ohio is N. 30 ½ d E [6] 149 poles [7] & 32 po: & 7/10 to the bank— From the Said beginning up the Ohio N 52 ½° W 115 po: to a—    Thence to the aforesaid Signal on the opposit Side of the Ohio is N 68° E—

From the Said Beginning Cross the Mississippi to a Signal is S 33° E— From Said point up the Mississippi is S 74° W 117 po: (to a Bluff of Sand opposit the Lower point of an Island)    From thence to the Said Signal is S 56° E—    (To the upper point of Island is S 53 W, to Lower point is S 15 E)

From the Said point or begn: to the point on the West Side of the Mississippi is S 75° E—    From Said Point to a forked Tree on the East Side of the Mississippi Standing on the banke is S 77° E 700 poles (from thence to the high Land about 500 poles—

From the Signal on the East Side of the Ohio to a forked Tree on the bank below is S 66° E—    To the Point on the W Side of the Miss: below is S 55° E—    To the upper (house) or Signal is S 16° E°    Passing the lower point of the Sand Bar makeing from the Island above

From the highest part of the point along the high land up the Miss: is S 48° W 4 po: 14 Links, S 72 W. 144 po: S 13 W. 8 po: to the river where the bank Caves in. N 85 E 46 poles to the Willows, where the Bank Sease to Cave in in the Course of the 3d Observation

(The Course of the bank on the Spa: [Spanish] Side of the Miss: from the upper house Down is nearly S 85° E. abt. 2 ½ miles, & S 80 E about 450 yards to the lower point—Capt L)

1. This material is separated from the November 16 entry by a blank half page. It may not have been written on the sixteenth but surely was completed during the time the party was at the juncture of the Ohio and Mississippi rivers. It and the next entry are placed here because of this entry's position in the Eastern Journal. (back)
2. The sextant used by the expedition was purchased from Thomas Whitney of Philadelphia, as were many of the other scientific instruments. It was "a brass sextant of 10 Inches radius." Lewis's List and Supplies [June 30, 1803], Jackson (LLC), 1:69, 82, 96; Lewis's description of astronomical instruments, July 22, 1804; Bedini (TT), 337–39, 483; Bedini (SILC), 55, 62–63. (back)
3. Lewis purchased the "Arnold's" chronometer, of "the most improved construction," from Philadelphia watchmaker Thomas Parker, and carried it in a special case. It was of English construction; the maker is not known, but it was commonly referred to as "Arnold's" because John Arnold of London was then one of the best-known makers of chronometers. See November 15, n. 1, above, and Lewis's description of astronomical instruments, July 22, 1804. Andrew Ellicott to Jefferson, March 6, 1803, Lewis to Jefferson, May 14, 1803, Jefferson to Lewis, May 16, 1803, Lewis to Ellicott, May 27, 1803, Lewis's Supplies [June 30, 1803], Jackson (LLC), 1:23, 48–49, 51, 91; Wilford, 128–37; Bedini (TT), 330-31; Bedini (SILC), 60-61. (back)
4. This material comes from the Field Notes (document 2, incorrectly placed as document 3 in Osgood) and is the reverse of a map (see fig. 1) apparently made by Clark while the party was at the junction of the Ohio and Mississippi rivers. (back)
5. Apparently some sort of marker or beacon. (back)
6. Here begins the practice that the captains followed throughout the expedition of giving their courses by the compass, with the estimated distance on each course; this assisted Clark in mapping and might have been intended to assist future travelers. Courses other than due north, south, east, or west were expressed by the number of degrees the course varied from either due north or due south. Thus, "N. 30 ½ d E" would be thirty and one-half degrees east of due north, fifty-nine and one-half degrees short of due east. The bearing may have been taken with a pocket compass, such as one of three purchased by Lewis from Whitney, or with the plain surveying compass. It is not clear whether Lewis and Clark took a bearing at the beginning of a particular course, sighting on the point for which they were headed, or whether they sighted back at the end of a course toward the point at which it began. Distances were apparently estimates. Greenwood, 57–59, 66–67. (back)
7. The pole, or rod, is a unit of measurement commonly given as 16 ½ feet. The link, mentioned below, is the standardized link, 7.92 inches, of the surveyor's chain made of wrought iron or steel. One chain of one hundred links measures 66 feet, or four poles, and eighty chains measures a mile. Lewis purchased a "two pole Chain" (33 feet) in Philadelphia in May 1803. Clark had some basic knowledge of surveying, and Lewis had been instructed by Ellicott and Patterson. Ibid., 53, 272; Lewis's List and Supplies [June 30, 1803], Jackson (LLC), 1:69, 82, 96. (back)