University of Virginia Library

VII. Astronomy

THE following description of the astronomical instruments
employed by Lewis and Clark is found in
Codex O, pp. 1–6, in Lewis's handwriting. Codex
O was used wholly for Astronomical Observations and
Geographical Notes (including Lewis's Summary Statement,
pp. 29–55, ante).—Ed.]

Camp 10 miles above the mouth of the river Platte. July 22ed. 1804.

A summary discription of the apparatus employed in the following
observations; containing also some remarks on the manner in which
they have been employed, and the method observed in recording the
observations made with them.

1st.

• a brass Sextant of 10 Inches radius, graduated to 15′. which
  by the assistance of the nonius was devisible to 15″., and half of this
  sum by means of the micrometer could readily be distinguished, therefore
  7″.5 of an angle was perceptible with this instrument: she was
  also furnished with three eye-pieces, consisting of a hollow tube and
  two telescopes one of which last reversed the images of observed objects.
  finding on experiment that the reversing telescope when employed as
  the eye-piece gave me a more full and perfect image than either of the
  others, I have most generally imployed it in all the observations made
  with this instrument; when thus prepared I found from a series of observations
  that the quantity of her index error was 8′.45—; this sum is
  therefore to be considered as the standing error of the instrument unless
  otherwise expressly mentioned. the altitudes of all objects, observed as
  well with this instrument as with the Octant were by means of a reflecting
  surface; and those stated to have been taken with the sextant
  are the degrees, minutes, &c. shewn by the graduated limb of the
  instrument at the time of observation and are of course the double
  altitudes of the objects observed.

2ed.

• A common Octant of 14 Inches radius, graduated to 20′.,
  which by means of the nonius was devisible to one 1′., half of this sum,
  or 30″. was perceptible by means of a micrometer. this instrument was
  prepared for both the fore and back observation; her error in the fore
  

  ---

  231

  
  
  
  observation is 2°.+, &. and in the back observation 2°. 11′. 40″.3.+

  at the time of our departure from the River Dubois untill the present
  moment, the sun's altitude at noon has been too great to be reached
  with my sextant, for this purpose I have therefore employed the Octant
  by the back observation. the degrees ′. & ″., recorded for the sun's
  altitude by the back observation express only the angle given by the
  graduated limb of the instrument at the time of observation, and are the
  complyment of the double Altitude of the sun's observed limb; if therefore
  the angle recorded be taken from 180°. the remainder will be the
  double altitude of the observed object, or that which would be given by
  the fore observation with a reflecting surface.

3rd.

• An Artificial Horizon on the construction recommended and
  practiced by Mr. Andrw. Ellicott of Lancaster, Pensyla., in which water
  is used as the reflecting surface; believing this artificial Horizon liable
  to less error than any other in my possession, I have uniformly used
  it when the object observed was sufficiently bright to reflect a distinct
  immage; but as much light is lost by reflection from water I found it
  inconvenient in most cases to take the altitude of the moon with this
  horizon, and that of a star impracticable with any degree of accuracy.

4th.

• An Artificial Horizon constructed in the manner recommended
  by Mr. Patterson of Philadelphia; glass is here used as the reflecting
  surface. this horizon consists of a glass plane with a single reflecting
  surface, cemented to the flat side of the larger segment of a wooden
  ball; adjusted by means of a sperit-level and a triangular stand with a
  triangular mortice cut through it's center sufficiently large to admit of
  the wooden ball partially; the stand rests on three screws inserted near
  it's angles, which serve as feet for it to rest on while they assist also in
  the adjustment. this horizon I have employed in taking the altitude of
  the sun when his image has been reather too dull for a perfect reflection
  from water; I have used it generally in taking the altitude of the moon,
  and in some cases of the stars also; it gives the moon's image very perfectly,
  and when carefully adjusted I consider it as liable to but little
  error.

5th.

• An Artificial Horizon formed of the index specula of a Sextant
  cemented to a flat board; adjusted by means of a sperit level and the
  triangular stand before discribed. as this glass reflects from both surfaces
  it gives the images of all objects much more bright than either of
  the other horizons; I have therefore most generally employed it in
  observing the altitudes of stars.

6th.

• A Chronometer; her ballance-wheel and scapement were on
  the most improved construction. she rested on her back, in a small
  

  ---

  232

  
  
  
  case prepared for her, suspended by an universal joint, she was carefully
  wound up every day at twelve oclock. Her rate of going as
  asscertained by a series of observations made by myself for that purpose
  was found to be 15. Seconds and 5 tenths of a second too slow in
  twenty four howers on Mean Solar time. This is nearly the same
  result as that found by Mr. Andrew Ellicott who was so obliging as to
  examine her rate of going for the space of fourteen days, in the summer
  1803. her rate of going as ascertained by that gentleman was 155.6
  too slow M. T. in 24. h. and that she went from 3 to 4. s. slower the
  last 12 h, than she did the first 12. h. after being wound up. at 12.
  OCk. on the 14th. day of May 1804. (being the day on which the detatchment
  left the mouth of the River Dubois) the Chronometer was
  too fast M. T. 6 m. 32. s. & 2/10 This time piece was regulated on
  mean time, and the time entered in the following observations is that
  shewn by her at the place of observation. the day is recconed on Civil
  time, (i e) commencing at midnight.

7th.

• A Circumferentor, circle 6 Inches diameter, on the common
  construction; by means of this instrument adjusted with the sperit
  level, I have taken the magnetic azimuth of the sun and pole Star. It
  has also been employed in taking the traverse of the river:—from the
  courses thus obtained, together with the distances estimated from point
  to point, the chart of the Missouri has been formed which now accompanys
  these observations. the several points of observation are marked
  with a cross of red ink, and numbered in such manner as to correspond
  with the celestial observations made at those points respectively.

RECORDS OF OBSERVATIONS

[The following records of observations from the beginning
of the expedition to the close of the winter of 1804–05 were
entered by Lewis in Codex O, pp. 6–52. Many of them
were copied into the text of the journals proper; where thus
entered, the entry here is omitted, reference being made to the
given date. Occasionally, in the text of the journals, results
are given which are not presented here; they have, in such
cases, been transferred, and are marked [*]. An occasional
difference in copying a series of figures has not been editorially
noted.—Ed.]

The mouth of the River Dubois opposite to the mouth of the
Missouri River is situated in

• Longitude West from Grenwh. 89°. 57′. 45″

• Latitude N. . . . . . . 38°. 55′. 19″. 6

Note—The Longitude of the mouth of the River Dubois was calculated
from four sets of observations of the ☉ & D, in which the ☉ was
twice West, and twice East; two sets with Aldebaran, * East in one,
and W. in the other; and one set with Spica, R., * East, the Longtd.
above stated is the mean result of those observations, and I think may
with safety be depended on to two or three minutes of a degree. The
Chronometer's error on M. T. was found at the mouth of the Ohio by
3 sets of Equal Altitudes, and the Longtd. of the mouth of the River
Dubois as given by this instrument from Equal altitudes of the ☉ on
the 17th of December 1803, was 90°. 00′. 20″. West from Grenwh. making a difference from the Longitude calculated from observation of
2′.35″.

The Latitude is deduced from a number of Meridian altitudes of the
☉ taken with the sextant and artificial horizon, the results of which
observations seldom differed more than from 15 to 20″.; I therefore
believe that the Latitude above stated may be depended on as true to
100 hundred paces.

The mouth of the River Dubois is to be considered as the point of
departure.

St. Charles. May 18th. 1804

(Point of Observation No. 1.) Observed equal Altitudes of the ☉ with
Sextant.[1]

                 

	h	m	s		h	m	s
A.M.	9.	9.	51	P.M.	2.	49.	24.
	".	10.	16.		".	50.	50.
	".	11.	34		".	51.	10.
	Altd. by Sext. at the time of this observtn.				97°.	42.	37
					m	s
Result.	Chronometer too fast M. T				4–	18.	7.
	Longtd. by Chrot. W. from Grenh.				90°	15′.	7″
	Latd. by Hor. ∠ P. M. Obstn. of ☉ Cent.				38°.	54′.	39″

Tuesday May 29th.

Poi[n]t Obsn. No. 2. On a small Island opposite to the mouth of the
Gasconade made the following obsertns.

Equal Alds. of ☉ with Sextant.[2]

Note.—The ☉ was so much obscured during the A.M. observation,
that I cannot be positive as to it's accuracy, nor could I obtain the
A. M. obstn. at an earlyer hour from the same cause.

Latitude of place of observation . . N. 38°. 44′ .35″ .3.

Friday June 1s.

Poi[n]t Obstn. No. 3. On the point of land formed by the confluence
of the Great Osage River and the Missouri made the following
observations.[3]

             

Pole *'s magnetic Azimuth by Circumftr.	N.	7°.	W.
		h	m	s
Time by Chronometer at place of Obstn.	P.M.	10.	29.	20.
Pole *'s magnetic Azimuth by Circumfertr.	N.	6°.	10′.	E.
		h	m	s
Time by Chronometer, June 2nd.	A.M.	0.	1	20.
Latitude of place of observation		38°.	31′.	6″.9.

Saturday, June 2nd.

Observed time and distance of ☉'s and D's nearest Limbs, ☉ East,
with Sextant.[3]

     

		Time			Distance
	h	m	s
A. M.	7.	18.	32.	5	74°.	47′.	23″.	7.

Note—this is the mean of a set of 8.

             

	h	m	s
A. M.	8.	13.	45.	74°.	23′.	30″.
	".	16.	42.	".	21.	00.
	".	22.	27.	".	20.	30.
	".	24.	56.	".	19.	20.
	".	26.	21.	".	17.	15.
	".	27.	10.	".	17.	30.

               

		Time			Distance.
	h	m	s
A.M.	7.	42.	12.	74°.	36′.	00″.
	".	43.	52.	".	35.	00.
	".	45.	39.	".	34.	45.
	".	47.	22.	".	32.	00.
	".	49.	34.	".	32.	45.
	".	51.	12.	".	32.	00.

Note—this set is probably a little inaccurate in consequence of the
moon's being obscured in some measure by the clouds

                 

	h	m	s
A. M.	7.	53.	38.	74°.	32′.	00″.
	".	56.	19.	".	29.	15.
	".	58.	32.	".	29.	00.
".	8.	0.	10.	".	28.	45.
	".	2.	12.	".	26.	30.
	".	4.	26.	".	26.	20.
	".	6.	00.	".	25.	45.
	".	7.	38.	".	24.	00.

             

	h	m	s
A. M.	8.	35.	58.	74°.	14′.	7″.5
	".	38.	28.	".	14.	00.
	".	40.	2.	".	13.	20.
	".	43.	9.	".	13.	00.
	".	44.	47.	".	12.	45.
	".	46.	4.	".	12.	00.

Equal altitudes of the ☉ with Sextant

       

	h	m	s
A.M.	8.	58.	9.	P.M.	3°	3′.	49″.
	".	59.	27.		".	5.	8.
	9.	00.	53.		".	6.	37.

Altitude by Sextant at time of Obstn. 95°. 50′. 45″.

         

Meridian Altd. of ☉'s L. L. by Back observation with Octant—	37°.	28′.	—″
Latitude deduced from this observation	38°.	31′.	6″. 9.
Odot;'s magnetic azimuth by Circumferenter.		Due	West
	h	m	s
Time by Chronometer . . P.M.	4.	59.	14.

Altitude by Sextant of ☉'s L. L. 52. 21. 00

     

Odot;'s magnetic azimuth by Circumfetr.	N.	88°.	W.
	h	m	s
Time by Chronometer P. M.	5.	11.	30

Altitude of ☉'s L.L. by Sextant 47°. 16′.—″.

     

Odot;'s magnetic azimuth by Circumftr.	N.	86°.	W.
	h	m	s
Time by Chronometer P. M. . .	5.	23.	14

Altitude by Sextant of ☉'s L. L. 42°. 52.′—″.

Sunday June 3rd.[4]

Observed time and distance of ☉'s and ☽'s nearest limbs, the ☉
East:

               

		Time			Distance
	h	m	s
A. M.	6.	22.	21.	61°.	40′.	—″.
	".	24.	5.	".	40.	—″.
	".	25.	36.	".	39.	45.
	".	26.	44.	".	39.	30.
	".	28.	18.	".	37.	—.
	".	29.	51.	".	37.	30.

           

A. M.	6.	36.	25.	61.	35.	—
	".	41.	27.	".	34.	45.
	".	49.	6.	".	33.	—.
	".	54.	36.	".	30.	15.
	".	55.	41.	".	30.	7.5
	".	57.	—.	".	30.	—.

               

		Time			Distance.
	h	m	s
A.M.	7.	—.	7.	61°.	27′.	30″.
	".	3.	57.	".	27.	30.
	".	6.	1.	".	27.	15.
	".	7.	53.	".	26.	52.
	".	9.	55.	".	26.	—.
	".	11.	5.	".	25.	15.

             

	h	m	s
A.M.	7.	14.	.6	61°.	23′.	30″
	".	16.	2.	".	24.	—.
	".	17.	53.	".	23.	15.
	".	19.	33.	".	22.	—.
	".	23.	28.	".	20.	45.
	".	25.	7.	".	20.	45.

             

	h	m	s
A.M.	7.	29.	16.	61°.	19′.	—″.
	".	31.	17.	".	16.	15.
	".	32.	56.	".	17.	—.
	".	33.	56.	".	15.	30.
	".	34.	50.	".	15.	—.
	".	35.	59.	".	15.	—.

             

	h	m	s
A.M.	7.	39.	55.	61°.	14′.	—″.
	".	40.	55.	".	13.	45.
	".	42.	39.	".	13.	15.
	".	45.	16.	".	12.	45.
	".	46.	38.	".	11.	30.
	".	47.	41.	".	11.	—.

Equal altitudes of the ☉, with Sextant.

         

	h	m	s
A.M.	8.	26.	1.	P.M. The ☉ was obscured by clouds and the observation consequenlty lost
	".	27.	19.
	".	28.	41.
	Meridian altd. of ☉'s L.L. by back observation with Octant	38°.	2′.	—″.

The ☉'s disk was much obscured by clouds during this observation,
not much confidence is therefore due it's accuracy.

Point of observation No. 4. On the Starbord shore one & 1/2 miles
above the mouth of the split rock creek.[5]

Saturday June 9th.

Point of Observation No. 5 On the N. W. side of a small island, two
miles above the prarie of the Arrows.[6]

Observed meridian altd. of ☉'s L. L. with Octant by the back observatn.
37°.—′.—″.

Point of observation No. 6. On the Larbord shore 3/4 of a mile below
the mouth of the lesser Charetton river.[7] 37°. 12′.—″.

Point of observation No. 7. On the S side of an Island near it's upper
point two miles below the mouth of the Grand river.[8]

Wednesday June 13th.

Point of observation No. 8 At the mouth of the Grand River.[8]

Observed time and distance of ☽ from Spica m. * East.—

               

		Time			Distance
	h	m	s
P.M.	9.	17.	49.5.	39°.	36′.	—″
	".	22.	38.	".	28.	—
	".	32.	40.	".	24.	—
	".	41.	39.	".	20.	45.
	".	47.	8.	".	17.	32.
	".	59.	48.5	".	11.	45

             

	h	m	s
P.M.	10.	14.	19.	39°.	1′.	30″
	".	18.	27.	".	—.	30.
	".	21.	51.	38.	58.	15.
	".	27.	12.	".	56.	30.
	".	39.	34.	".	53.	00.
	".	45.	41.	".	48.	—

             

	h	m	s
P.M.	10.	54.	38.	38°.	41′.	45″
	".	59.	49.	".	39.	—
	11.	3.	8.	".	37.	30.
	".	6.	44.	".	36.	45.
	".	10.	40.	".	34.	00.
	".	16.	—.	".	31.	45.

Friday June 15th

Point of Observation No. 9.—On the Starboard shore two miles below
the Island of the Old village of the little Osages.[9]

Observed Meridian Altd. of ☉'s L. L. with Octant by the back
observation 36°. 42′.—″.

Wednesday June 20th.

Point of Observation No. 10.—On a small Island about one mile & 3/4
below Euebaux's Creek.—[9]

Observed time and distance of D. from Spica m . * . West.—

     

		Time			Distance.
	h	m	s
P.M.	10.	59.	40.3	46°.	17′.	25″.

This is the mean of a set of six observations.

Magnetic azimuth of Pole star by Circumferenter well adjusted with
spert. levl. N. 7°. 55′. W

   

	h	m	s
Time by Chronometer P. M.	12.	49.	46.6

T[h]is is the mean of a set of six observations suffering several minutes
to elaps betwen each.

Saturday June 23rd. 1804

Point of Observation No. 11. On the upper point of a large island about
four miles above the Fire prarie.[10] Observed Meridian altd. of ☉'s
L. L. with the octant by the back obstn. 36°.—′.—″.

[Clark:][11]

Kansas River June 23rd. 1804

Equal altitudes with Sexton / Er. 8′. 45″—

       

	H	M	S
A. M.	8	9	42
"	"	10	59
"	"	12	26

Sunday June 24th.

Point of observation No. 12. On the Starboard shore, about 1/2 a mile
above the mouth of hay-cabbin creek.[12] Observed meridian altd. of ☉'s
L. L. with octant by the back obsert. 36°. 13′.—″

Lattitude 38° 37′ 5″ N.

Tuesday June 26th.

Point of observation No. 13. On the Larboard shore about four mls. above
the mouth of the blue water river.[12] Observed meridian altd. of ☉'s
L. L. with octant by the back observt 36°. 10′.—″

Lattitude 38° 32′ 15″ North.

Wednesday June 27th.

Point of observation No. 14. On the point formed by the confluence
of the Kancez River and the Missouri[12] made the following
observations.

Equal altitude of the Sun, with Sextant

       

	h	m	s		h	m	s
A.M.	8.	22.	23.	P.M.	3.	49.	19.
	".	23.	53.		".	50.	39.
	".	25.	17.		".	52.	3.

Altd. by Sextant at the time of this observt. 81°. 15′. 15″.

Lattitude 38° 31′ 13″

           

Odot;'s magnetic azimuth by Circumfetr.	S.	81°.	E.
	h	m	s
Time by Chronometer . . A. M.	8.	22.	33.
Altd. of ☉'s U.L. by Sextant	81°.	15′.	15″
Latitude of place of observation	39°.	5′.	25″.7
Variation of the nedle	[blank space in MS.]

Observed Meridian Altd. of ☉'s L. L. with Octant by the back observation.
36°. 25′.—″

                 

Latitude deduced from this obsertn	39°.	5′.	38″.5.
Odot;'s magnetic azimuth by Circumferentr.	S.	88°.	W
	h	m	s
Time by Chronometer at p[13] . Obst. P. M.	4.	52.	33.
Altd. of ☉'s L. L. by Sextant.	56°.	51′.	—″.
Odot;'s magnetic azimuth by Circumftr.	S.	89°.	W.
	h	m	s
Time by Chronometer. P. M.	5.	2.	6
Altd. of ☉'s L.L. by Sextant.	53.	10.	15.

Observed magnetic azimuth of pole;*. with my Circumferenter, taking
time by Chronotr.

Time by Chronomtr.—*'s magt. Azimuth

       

	h	m	s
P.M.	9.	54.	—	N.	8°.	W.
	9.	58.	4	N.	8°.	W.
	10.	—.	40	N. 7.	45.	W.

Thursday June 28th.

Observed Equal Altitudes of ☉, with Sextant,[13]

             

	h	m	s		h	m	s
A.M.	8.	9.	42.	P.M.	4.	1.	50.
	".	10.	59.		".	3.	9.5
	".	12.	26.		".	4.	35.5
	Altd. by Sextant at the time of Observtn.				76°.	16′.	52″.
	Meridian altd. of ☉'s L. L. with Octant by the back observation				36°.	31′.	—″.
	Latitude deduced from this obst.				39°.	5′.	25″.7.

Friday June 29th

Observed Equal altitudes of ☉, with Sextant.[13]

         

	h	m	s		h	m	s
A.M.	9.	6.	46.	P.M.	3.	4.	29.
	".	8.	3.		".	5.	51.
	".	9.	29.		".	7.	15.
Altd by Sextant at the time of Obsert					98°.	18′.	45″.

Observed time and distance of ☉'s and ☽'s nearest Limbs, with Chronometer
and Sextant, the ☉ East.—

                   

		Time			Distance.
	h	m	s
A.M.	7.	6.	2.	104°.	13′.	30″.
	".	9.	7.	".	12.	15.
	".	11.	23.	".	11.	30.
	".	15.	38.	".	10.	—
	".	17.	5.	".	9.	45.
	".	18.	33.	".	8.	15.
	".	20.	2.	".	8.	00.
	".	22.	—.	".	7.	30.

                 

	h	m	s
A.M.	7.	33.	57.	104°.	3′	15′'
	".	35.	11.	".	3.	—.
	".	36.	33.	".	3.	—.
	".	37.	37.	".	2.	—.
	".	39.	18.	".	1.	15.
	".	40.	26.	".	1.	—.
	"	41.	23.	".	1.	—.
	".	43.	1.	103°.	59.	53.

                 

	h	m	s
A.M.	7.	51.	21.	103°.	56′.	15″.
	".	56.	49.	".	55.	15.
	".	58.	47.	".	54.	52.
	8.	—	45.	".	54.	—.
	".	3.	49.	".	51.	45.
	".	6.	57.	".	51.	—.
	".	8.	53.	".	50.	15.
	".	10.	44.	".	49.	30.

                 

	h	m	s
A.M.	8.	16.	3.	103°.	48′.	—″.
	".	17.	51.	".	46.	30.
	".	20.	6.	".	45.	—.
	".	21.	42.	".	45.	—.
	".	23.	5.	".	44.	—.
	".	25.	40.	".	43.	15.
	".	28.	3.	".	42.	45.
	".	30.	36.	".	41.	52.

               

A.M.	8.	37.	25.	103.	37.	15.
	".	39.	15.	".	37.	—.
	".	40.	10.	".	36.	—.
	".	43.	3.	".	35.	—.
	".	44.	36.	".	34.	45.
	"	46.	7.	".	33.	30.
	".	47.	34.	".	33.	00.
	".	48.	35.	".	32.	15.

                 

	h	m	s
A.M.	8.	49.	55.	103°.	32′.	—″.
	".	51.	54.	".	31.	45.
	".	52.	57.	".	31.	15.
	".	53.	31.	".	31.	—.
	".	54.	16.	".	30.	45.
	".	55.	11.	".	29.	—.
	"	56.	45.	".	28.	45.
	".	57.	41.	".	28.	15.

Meridian Altd. of ☉'s L. L. with Octant by the back observation
36°. 36′.—″.

Latitude deduced from this obst.    39°. 5′. 21″ .2

Saturday June 30th.

Pot. Obstn. No. 15. On the Larboard Shore 3/4 of a mile below the
Little river Platte.[14] Observed time and distance of ☉'s and ☽'s
nearest limbs; the ☉ East. with Sext. & Chrontr.

                       

		Time			Distance.
	h	m	s
A.M.	7.	55.	36.	90°.	58′.	—.″.
	".	57.	16.	".	57.	45.
	".	58.	49.	".	57.	45.
	8.	1.	20.	".	56.	15.
	".	2.	52.	".	55.	—.
	".	4.	16.	".	55.	—.
	".	5.	26.	".	54.	45.
		6.	11.	".	54.	45.
	".	7.	10.	".	54.	30.
	".	8.	9.	".	54.	30.

           

	h	m	s
A.M.	8.	11.	11.	90°.	50′.	30″.
	".	12.	39.	".	50.	15.
	".	13.	57.	".	50.	—.
	".	14.	57.	".	49.	45.
	".	15.	54.	".	49.	15.

             

		Time.			Distance.
	h	m	s
A. M.	8.	16.	53.	90°.	49′.	—″.
	".	17.	30.	".	48.	45.
	".	18.	53.	".	48.	—.
	".	19.	45.	".	48.	—.
	".	20.	24.	".	47.	45.

Sunday July 1st.

Point Obstr. No. 16. On the Larboard shore one 1/2 miles above the
upper point of the dimond Island.[15]

Observed Meridian Altd. of ☉'s L.L.with Octant by the back obstn.
36°. 59′. 30″.

Latitude deduced from this obstn. 39°. 9′. 38″.6

Wednesday July 4th.

Point Obstn. No. 17. On the Larboard Shore three miles below a high
Prarie hill on same shore, near the 2ed. old vilage of the Kancez.[15]

Observed Meridian Altd. of ☉'s L.L. with Octant by the back obsertn.
38°—′.—″.

Latitude deduced from this obsertn. 39°. 25′. 42″.5.

Sunday July the 8th. 1804.

Point of Observation No. 18. On the Starboard shore immediately below
an high bluff situated 1/4 of a mile below the lower point of
Nadawa Island.[15]

Observed Meridian altd. of ☉'s L. L. with Octant by the back observtn.
39°. 18′.—″.

Latitude by this observation . . . 39°. 39′. 22″.7

Wednesday July 11th.

Point of observation No. 19. On New-found Island opposite to the
mouth of the great Ne-mi-Haw. made the following observations.
with Sextant and Chronometer.

                   

		Alt. d Sextant of.					Time of observation
						h	m	s
Odot;'s	L.L.	88°.	26′.	15″.	P. M.	3.	26.	38.
Odot;'s	Center	"	"	"		".	27.	59.
Odot;'s	U. L.	"	"	"		".	29.	27.
						h	m	s
Odot;'s	L. L.	39°.	3′.	—″.	P. M.	5.	36.	35.
Odot;'s	U. L.	"			".	".	39.	31.
Odot;'s	magnetic azimuth by Circumfetr.				N.	89°.	W.
Altd. of ☉'s L. L. by Sextant						39°.	3′.	—″

     

	h	m	s
Time by Chronometer	5.	36.	35
Latitude of place of observation	39°.	55′.	56″.

Observed time and distance of D from Spica m. *, | East, with Cronomtr.
& Sextant.

                             

		Time			Distance.
P. M.	8.	41.	42.	31.	35.	—
	".	46.	26.	".	30.	45.
	".	50.	18.	".	30.	45.
	".	54.	44.	".	27.	30.
	".	58.	48.	".	26.	—.
	9.	2.	—.	".	24.	—.
	".	7.	15.	".	21.	—.
	".	10.	17.	".	20.	30
	".	12.	15.	".	19.	—.
	".	14.	3.	".	17.	30.
	".	16.	15.	".	16.	30.
	".	18.	22.	".	15.	45.
	".	22.	50.	".	13.	—
	".	30.	33.	".	6.	15.

Thursday July 12th.

Observed Equal Altitudes of the ☉ with Sextant.[16]

     

A M.	7.	58.	59.	P. M.	4.	12.	29.
	8.	—.	19.		".	13.	48.
	".	1.	45.		".	15.	14.

Altitude by Sextant at the time of this Obst. 70°. 42′. 45″.

Observed meridian altd. of ☉'s L. L. with Octant by the back observatn |
40°. 53′.—″.

Latitude deduced from this observatn. 36°. 55′. 56″.

Observed time and distance of ☉'s and D's nearest limbs the ☉. West,
with Sextant.

                       

		Time			Distance.
	h	m	s
P. M.	4.	51.	11.	70°.	31′.	30″.
	5.	5.	48.	".	35.	30.
	".	11.	52.	".	37.	30.
	".	12.	47.	".	38.	—″
	".	16.	30.	".	39.	—″
	".	18.	8.	".	39.	15.
	".	19.	51.	".	39.	30.
	".	21.	9.	".	39.	30.
	".	24.	50.	".	41.	30.
	".	26.	14.	".	42.	30.

                             

	h.	m	s
P.M.	5.	32.	40.	70°.	42′.	—″
	".	33.	53.	".	44.	45.
	".	38.	55.	".	45.	45.
	".	42.	11.	".	46.	30.
	".	43.	42.	".	47.	30.
	".	45.	25.	".	47.	30.
	☉'s Magnetic azimuth by Circumftr.			N.	86°.	W.
				h	m	s
	Time by Chronometer . . P.M.			5.	59.	20.
	Altd. of ☉'s L. L. by Sextant			31°.	26′.	30″.
	☉'s Magnetic azimuth by Circumft.			N.	85°.	W.
				h	m	s
	Time by Chronometer. . P.M.			6.	5.	10.
	Altd. of ☉'s L. L. by Sextant			29°.	19′.	30″.

Observed time and distance of D, and Spica R. *, East, with Sextant.

     

	Time			Distance.
	h	m	s
P.M.	8.	26.	58.	19°.	18′.	15″

Note—this is a mean of four observations which were not so perfect
as I could have wished them, in consequence of the moon being obscured
in some measure by the clouds, which soon became so general as to put
an end to my observations during this evening.

Sunday July 15th.

Point of observation No. 20. On the upper point of an Island mentioned
in the 2ed & 3rd. course of this day.[17]

Observed meridian Altd. of ☉ L. L.
with Octant by back observan. 42°. 11′.—″.

Latitude deduced from this observatn. 40°. 8′. 31″. 8—

This evening I discovered that my Chronometer had stoped, nor can
I assign any cause for this accedent; she had been wound up the preceding
noon as usual. This is the third instance in which this instrument
has stopt in a similar manner since she has been in my possession,
tho' the fi [r] st only since our departure from the River Dubois. in the
two preceding cases when she was again set in motion, and her rate of
going determined by a series of equal altitudes of the ☉ taken for that
purpose, it was found to be the same precisely as that mentioned in the
preliminary remarks to these observations, or 15. s. & 5 tenths too slow
in 24.h.—as her rate of going after stoping, and being again set in motion

has in two instances proved to be the same, I have concluded, that
whatever this impediment may proceed from, it is not caused by any
material injury which her works have sustained, and that when she is in
motion, her error on mean time above stated, may be depended on as
accurate. In consequence of the chronometer's having thus accedentally
stoped, I determined to come too at the first convenient place and
make such observations as were necessary to ascertain her error,
establish the Latitude & Longitude, and determine the variation of the
nedle, in order to fix a second point of departure. accordingly on

Monday 16th. we set out at an early hour; the morning was cloudy;
could find no convenient situation for observation; proceeded untill
a little before noon when we came too

Point of observation No. 21. On the Lard Shore opposite to the center
of good Island[18] where I observed the meridian altitude of ☉'s L. L.
with Octant by the back observation, which gave me for Latitude
40°. 20′. 12″. N. I now set the Chronometer as near noon as this
observation would enable me, and proceeded untill evening, when we
came too on the Stard. shore opposite the lower point of the Island of
the Bald prarie where we encamped.

Tuesday July 17th

Point of Observation No. 22, & of departure No. 2. Camp at the lower
point of the Island of the bald Prarie[19]

Observed Meridian altd. of ☉'s L. L. with Octant by back observation
43°. 27′.—″.

                 

Latitude deduced from this observtn.	40°.	27′.	6″.4
From Equal Altitudes of ☉'s center found that ☉'s Center was truly on the Meridian
	h	m	s
M. T. Pt. Chronometer at	11.	58.	51.
	m	s
Chronometer too slow M. T.	6.	51.6.
Observed Altitude of pole Star with Sextant	81°.	9′.	15″
	h	m	s
Time by Chronometer P. M.	10.	23.	18.

Thursday July 19th

Point of observation No. 23. Under a bold bluff on Lard. Shore, opposite
to the Stard. point terminateing the 4th. course of this day.[20]

Observed Meridian Altd. of ☉'s L. L. with Octant by back observation
44°. 15′.—

Latitude deduced from this obsevt. 40°. 29′. 50″

Sunday July 22nd.

Point of Observation No. 24. on the Starboard shore above the River
Platte, the mouth of which bore S. 15°. E. distant 10 miles.—

Observed Equal Altitudes of the ☉ with Sext2.

       

	h	m	s		h	m	s
A. M.	8.	53.	53.	P. M.	2.	58.	37.
	".	55.	20.		3.	—.	—
	".	56.	48.		".	1.	28.

Altd. by Sextant at the time of observation. 92°. 37′.—″

Observed Meridian altd. of ☉'s L. L. with Octant by the back Obsetn.
46°. 31′.—″

Latitude deduced from this obsevtn. 41°. 3′. 19″.4.

Observed time and distance of D and Antares. *. West, with Sextant.—

               

	Time			Distance.
	h	m	s
P. M.	10.	23.	20.	58.	42.	—
	".	28.	3.	".	43.	30.
	".	32.	7.	".	44.	—.
	".	35.	4.	".	45.	7.
	".	38.	15.	".	47.	—.
	".	41.	34.	".	48.	15.

Monday July 23rd.

Observed Equal Altitudes of the ☉ with Sext.[21]

       

	h	m	s			h	m
A. M.	8.	—	49.	P. M.	3.	51.	56.
	".	2.	9.		".	52.	14.
	".	3.	38.		".	53.	45.

Altitude by Sextant at the time of Obstn. 72°. 49′—″

Observed Meridian Altd. of ☉'s L. L. with Octant by the back observt. 46°. 55′—″

Latitude deduced from this Obstn. [blank space in MS.]

Tuesday July 24th.

       

☉'s Magnetic Azimuth by Circumftr.[22]		S.	85°.	E.
		h	m	s
Time by Chronometer	A. M.	8.	8.	8.
Altd. of ☉'s U. L. by Sextant.		75°.	5′.	15″.

Wednesday July 25th.

Observed Equal Altds. of the ☉ with Sextant.[23]

       

	h	m	s		h	m	s
A. M.	8.	5.	20.	P.M.	3.	44.	38.
	".	6.	42.		☉.	Obscured by cloud
	".	8.	7.5		3.	47.	27.

Altd. by Sextant at the time of Observtn. . . . . . 74°. 19′. 30″

Thursday July 26th.

Observed Equal Altitudes of ☉ with Sextant.[23]

       

	h	m	s		h	m	s
A. M.	7.	33.	32.	P. M.	4.	15.	24.
	".	34.	55.		".	16.	51.
	".	36.	22.		".	18.	14.

Altitude by Sextant at the time of Obst. . . . . . . 62°. 18′. 15″

Friday July 27th.

Observed time and distance of D and a. Aquilæ,*. West, with
Sextant.[23]

               

	Time.			Distance.
	h	m	s
A. M.	2.	47.	6.	64°.	48′.	15″.
	".	55.	9.	".	50.	30.
	".	59.	39.	".	51.	30.
	3.	2.	12.	".	52.	—.
	".	4.	42.	".	52.	45.
	".	6.	31.	".	53.	—.

I wished to have taken one or two sets more with moon and Aquilæ,
but the clouds obscured the star. I was also anxious to have taken
some sets with Aldeberan, then in reach of observation and East of the
moon, but was prevented by the intervention of the clouds, which soon
became so general as to obscure the whole horizon.—

Observed meridian Altitude of ☉'s L. L. with Octant by the back obs 48°. 44′

Latitude deduced from this obstn. . . . . . . . . 41°. 5′. 35″.2

Tuesday July 31st.

Point of observation No. 25. Camp at Council Bluffs, Larboard shore.[24]

Observed Meridian Altd. of ☉'s L. L. with Octant by the back observtn.
51°. 4′. 30″

Latitude deduced from this obsertn. 41°. 18′. I". 5

Wednesday August Ist.

Observed meridian Altd. of ☉'s L. L. with Octant by the back observtn.
51°. 29′. 30″

Observed Equal Altitudes of the ☉, with Sextant.[25]
☉'s Magnetic azimuth by Circumferenter N. 86°. E.

         

		h	m	s
Time by Chronometer	A. M.	7.	52.	55.
Altitude by Sextant of ☉'s U.L.		68°.	47′.	15″.
Latitude of place deduced from two observtns. of ☉'s
Merdn. altd. being as mean of the same		41°.	17′.	0″.2.

Saturday August 4th. 1804

Point of observation No. 26. On the Starboard shore, opposite to the
mouth of pond inlet.[26]

Observed meridian altd. of ☉'s L. L. with Octant by the back observatn.
53°. 20′. 30′.

Latitude deduced from this obsertn . . . . . 41°. 25′. 3″.8

note—the ☉'s disk was frequently obscured in the course of this
observation, it is therefore probable that it is not accurate by 2 or 3
minutes of Latitude, and I believe it too much by that sum.

Sunday August 5th.

Point of Observation No. 27. On the Larboard shore of main channel,
and on the starboard side of the Sand Island.—[26]

Observed meridian Altd. of ☉'s L. L. with Octant by the back observtn.
54°. 3′.—″

Latitude deduced from this observation . . . . 41° 30′. 6″.7

Wednesday August 8th.

Point of observation No. 28. On the Starboard shore, the mouth of the
river E-ā-nearh war,-da-pon or Stone river bearing Due N. distant
one 1/2 miles, made the following observations with Sextant. 1

         

		Altitude of			Time by Chronometer.
						h	m	s
☉'s	U. L.	80°.	14′.	15″.	A.M.	8.	26.	59.
☉'s	Center	"	"	"		".	28.	29.
☉'s	L. L.	"	"	"		".	30.	3.

Point of observation No. 29. On the Larboard Shore, the mouth of
Stone river bearing due E. one mile distn.[27]

Observed meridian Altitude of ☉'s L. L. with Octant by the back
observatn. 56°. 9′.—"

Latitude deduced from this observt. 41°. 42′. 34″.3.

Saterday August 11th.

Point of observation No. 30. On the Starboard shore one mile above
the mouth of the Creek of Evil Sperits.[28]

Sunday August 12th.

Point of Observation No. 31. On the Larboard shore in the center of
a bend, being North, and by measurement 974 yards from the Lard.
shore opposite to the point of observation of yesterday.[29]

Observed Meridian altitude of ☉'s L. L. with Octant by the back
obstn. 59°. 8′.—″

Latitude deduced from this observatn. 42°. 1′. 47″. 6.

Monday August 13th.

Point of observation No. 32. On the Larboard shore about three miles
East of the Maha vilage.[30]

Observed time and distance of ☉'s & D's nearest limbs, with Sextant.—

                   

		Time.		Distance.
	h	m	s
P. M.	3.	57.	9.	95°.	56′.	15″
	4.	1.	32.	".	58.	—.
	".	4.	45.	".	59.	30.
	".	6.	51.	96.	—.	—
	".	7.	57.	".	—.	30.
	".	9.	17.	".	—.	45.
	".	11.	52.	".	1.	7.5
	".	13.	—.	".	2.	—

             

	h	m	s
P. M.	4.	51.	9.	96°.	12′.	30″
	".	52.	33.	".	13.	—
	".	54.	5.	".	13.	30
	".	55.	26.	".	14.	—
	".	56.	22.	".	14.	15.
	".	57.	36.	".	14.	30.

             

	h	m	s
P. M.	4.	33.	18.	96°.	7′.	45″
	".	34.	44.	".	8.	30.
	".	35.	7.	".	8.	37.5.
	".	37.	22.	".	9.	15.
	".	38.	24.	".	9.	45.
	".	39.	22.	".	9.	45.

                 

	h	m	s
P. M.	5.	7.	59.	96°.	17′.	45″
	".	10.	56.	".	18.	30.
	".	12.	23.	".	19.	45.
	".	15.	5.	".	20.	15.
	".	16.	6.	".	20.	15.
	".	17.	1.	".	20.	45.
	".	18.	5.	".	21.	—
	".	19.	1.	".	21.	22.5.

Tuesday August 14th.[31]

               

Odot;'s magnetic azimuth by Circumferenter	N.	87.	E.
	h	m	s
Time by Chronometer A. M.	7.	3.	4.
Altitude by Sextant of ☉'s U. L.	59°.	19′.	15″
Odot;'s magnetic azimuth by Circumferenter	N.	88.	E.
	h	m	s
Time by Chronometer. . . . A. M.	7.	41.	19.
Altd. of ☉'s U.L. by Sextant.	62°	—′.	—″

Observed Equal Altitudes of the ☉, with Sextant.

         

	h	m	s		h	m	s
A.M.	7.	45.	16.	P.M.	3.	45.	15.
	".	46.	43.		".	46.	47. not certain
	".	48.	12.		".	Lost by clouds
	Altd. given by Sextant at the time of obstn.				63°.	26′.	45″.

observed Meridian altitude of ☉'s L. L. with Octant by the back
observatn. 60°. 45′. 30″.

Latitude deduced from this observatn. 42°. 12′. 10″.9

Wednesday August 15th.

Observed Equal Altitudes of the ☉, with Sextant.[32]

         

	h	m	s		h	m	s
A. M.	8.	0.	29.	P.M.	3.	28.	42.
	".	1.	52.		".	30.	11.
	".	3.	28.		".	31.	38.
	Altd. by Sextant at the time of this observt.				68°.	45′.	45″.

Observed meridian Altd. of ☉'s L. L. with Octant by the back observt.
61°. 27′.—″

Latitude deduced from this observt. 42° 15′. 13″.4

Saturday, August 18th.

Observed meridian altd.[32] of ☉'s L. L. with Octant by the back observt.
63°. 23′.—″

Latitude deduced from this obset. [blank space in MS.]

Observed Equal Altitudes of the ☉ with Sextant.

         

	h	m	s		h	m	s
A. M.	7.	38.	1.	P.M.	3.	46.	48.
	".	39.	28.		".	48.	13.
	".	40.	58.		".	49.	42.
	Altd. by Sextant at the time of Obstn".				60°.	8′.	—″

Tuesday, August 21st.

Point of Observation No 33. On a large sand bar Stard., 4 miles above
the mouth of the river Souix.[32]

Observed meridn. Altd. of ☉'s L. L. with Octant by the back observation
65°. 47′.—″

Latitude deduced from this observatn. 42°. 28′. 29″.

Friday, August 24th.

This day the Chronometer stoped again just after being wound up;
I know not the cause, but fear it procedes from some defect which it is
not in my power to remedy.[32]

Monday August 27th.

Point of Observation No. 34. On the Stard. shore, opposite to the lower
point, or commencement of the white C[h]alk Bluff.[32]

Observed Magnetic azimth. of ☉ by Circumftr. S. 85° . E.

             

	h	m	s
Time by Chronometer A. M.	7.	41.	52.
Altd. of ☉'s U. L. by Sextant.	60°.	4′.	—″
Odot; magnetic Azimuth by circumferentr.	S.	84°.	E.
	h	m	s
Time by Chronometer A. M.	7.	46.	13.
Altd. of ☉' U. L. by Sextant .	61 .	57′.	—″

Observed time and altitudes of ☉ with Sextant

         

		Time.				Altitude of
	h	m	s		h	m	s
A.M	7.	49.	37.	Odot;'s U. Limb.	63°.	8′.	15″
	".	51.	3.	Odot;'s Center.	"	"	"
	".	52.	40.	Odot;'s L. Limb.	"	"	"

Point of Observation No. 35. On the Stard. shore opposite to the upper
point of the white Chalk Bluffs.[33]

Observed Meridian Altd. U. L. with Sextant by the fore observation
115°.—′. 45″

Latitude deduced from the observtn. 42. 53. 13

Thursday August 30th.

Point of Observation No. 36. On the Lard. Shore at the lower point of
Calumet Bluff.[33]

Observed equal Altd. of the ☉, with Sextant

         

	h	m	s		h	m	s
A.M.	8.	14.	51.	P. M.	2.	49.	24.
	".	l6.	22.		".	50.	59.
	".	18.	3.		".	52.	38.
	Altd. given by Sextant at time of obstn.				70°.	42′.	—″

Friday August 31st.

Observed time and distance of ☉'s and D's nearest limbs, with Sextant.
the D West.[33]

               

		Time.		Distance.
	h	m	s
A.M.	11.	12.	18.	41°.	51′.	—″
	".	14.	23	".	48.	—
	".	15.	49	".	47.	45
	".	16.	42.	".	46.	30
	".	17.	52.	".	46.	30
	".	19.	32.	".	45.	45

Saturday September 8th

Point of observation No. 37. On the Lard. Shore 3 1/2 miles below Mr.
Trudeau's House,[34]

Observed ☉'s Magnetic azimuth with Circumfertr S. 85°. E.

             

	h	m	s
Time by Chronometer A. M.	7 .	27 .	59
Altd of ☉'s U. L. by Sextant.	51°.	4′.	30″.
Odot;'s Magnetic Azimuth by Circumferentr.	S.	84.	E.
	h	m	s
Time by Chronometer A. M.	7 .	33 .	30 .
Alt. by Sextant of ☉'s U.L.	53°.	2′.	—″.

Observed time and Altitude of ☉, with Sextant

         

		Time.				Altitude of
	h	m	s
A.M.	7.	33.	30	Odot;'s U.S.	53°.	2′.	—″
	".	35.	5.	Odot;'s Center	".	" .	—.
	".	36.	41.	☉'s L.L.	".	" .	—.

I could not obtain the meridian altitude of sun this day in consequence
of not being able to come too in time, without infinite danger
of injuring the boat. the evening was cloudy, which prevented my
taking the altitude of any fixed star.

September 9th. Sunday

Point of Observation No. 38. On the Lard. Shore opposite to the upper
point of boat Island.[34]

observed. ☉'s Magnetic azimuth by Circumferentr S. 89°. E.

             

	h	m	s
Time by Chronometer A.M.	7.	6.	3
Altd. of ☉'s U.L. by Sextant	43°.	—′.	—″.
Odot;'s Magnetic azimuth by Circumfetr. S. 88°. E.
	h	m	s
Time by Chronometer A.M.	7.	12.	3.
Altd of ☉'s U.L. by Sextant	44 .	57.	15.

Observed time; and Altd. of ☉, with Sextant.

         

		Time				Altitude of
	h	m	s
A.M.	7.	12.	3.	Odot;'s U.L.	44°.	57′.	15″.
	".	13.	31.	Odot;'s Center	" .	" .	" .
	".	15.	4.	☉'s L.L.	" .	" .	" .

Point of Observation No. 39. On the Stard shore, near a point of woodland,
being the extremity of the third course of this day.[34]

Observed Meridian altd. of ☉'s U. L. with Sextant fore observation—
—104°. 51′. 30″.

Latitude deduced from this Observatn. 43°. 11′. 56″.1.

Monday September 10th.

Point of Observation No. 40. On the Lard. shore, under a high bluff, 2
miles below Ceder Island.—[35]

Observed Meridian Altd. of ☉'s U. L. with Sextant by the fore Observtn.
103 . 53 . 15

Latitude deduced from this observtn. [blank space in MS.]

Point of Observation No. 41. On the Stard Shore 4 miles above the point
of observation at noon—Observed time and distance of ☉'s & ☽'s
nearest limbs, the D East.

                   

			Time.		Distance.
	h	m	s	°	′	″
P. M.	4.	31.	15	76.	55.	15
	".	34.	5	".	56.	—.
	".	35.	7	".	56.	30.
	".	36.	14	".	57.	15.
	".	37.	50.	".	57.	—.
	".	38.	54.	".	57.	30.
	h	m	s	°	′	″
P. M.	5.	25.	26.	77.	9.	15.

Monday September 17th. 1804.

Point of Obstn. No. 42. On the Lard. shore, one mile and a haf above the
mouth of Corvus Creek[35] observed equal altitudes of ☉ with Sextant.

         

	h	m	s		h	m	s
A. M.	7.	46.	49.	A. M.	2.	59.	50.
	".	47.	25.		3.	1.	30.
	".	49.	12.		".	3.	3.
Altd. by sextant at the time of Observatn. 53°. 17′. 45″.

Observed meridian Altitude of ☉'s L. L. with Octant by the back
Observation 87°. 31′. 00″.

Wednesday September 19th. 1804.

Point of Observation No. 43. On the Lard. shore opposite to the mouth
of the lower of the two rivers of the Siouxs pass.[35] Observed Meridian
Altd. of ☉'s U. L. with Sextant by the fore observation
95°. 30′. 15.

Saturday Septr. 22ed. 1804.

Point of observation No. 44.On the Stard. shore, about one mile below
the lower Island of the three sisters.[36]

Sunday September. 23rd. 1804.

Point of Observation No. 45. On the Lard. Shore 3 miles below Elk Island.
observed meridian altd. of ☉'s U. L. with Sextant by the fore observation
91°. 48′. 45″

Tuesday October 2ed. 1804.

Point of Observation No. 46. On a large sand bar Lard. shore, opposite to
the gorge of the bend look-out[37] . Observed the meridian altd. of ☉'s
U. L. with Sextant by the fore observation 84°. 45′ 15″.

Latitude deduced from this observation. N. 44°. 19′. 36″. 3

Monday October 8th. 1804.

Point of observation N°. 47. On the Lard. shore, in the point fromed
[formed] by the junction of the Weterhoo river with the Missouri.[38] Observed meridian altd. of ☉'U. L. with Sextant by the fore observation
77°. 35′.—″.

Latitude deduced from this observation No. 45°. 39′. 5″.

Thursday October 11th. 1804.

Point of observation No. 48. at our camp on the Lard. shore a small distance
above the upper point of an Island on which the lower village
of the Ricaras is situated.[38]

Observed Equal Altitude of the ☉ with Sextant.

         

	h	m	s		h	m	s
A. M.	9.	8.	7.	P. M.	3.	41.	49.
	".	10.	1.		".	42.	36.
	".	11.	57.		".	44.	40.
Altitude by Sextant at the time of observtn.				42°. 16′. 45″.

Wednesday October 17th. 1804.

Point of Observation No. 49. On the Stard. shore, opposite to a high projecting
Bluff; which from the great number of rattlesnakes found
near it, we called the rattlesnake Bluff.[39]

Observed meridian altd. of ☉'s U. L. with Sextant by the fore observation
69°. 17′.—.

Latitude deduced from this observation N. 46. 23′. 57″

Monday October 29th. 1804.

Point of Observation No. 50. On the stard. shore at council camp, about
half a mile above the upper Mandan Village.[40]

Observed meridian Altd. of ☉'s U. L. with Sextant by the fore observation
58°. 55′. 15″.

Latitude deduced from this observation N. 47°. 22′ 56″. 7

☞The Chronometer ran down today. I was so much engaged
with the Indians, that I omited winding her up.

Tuesday October 30th. 1804.

at the same place Wound up the Chronometer, and observed equal Altitudes
of the ☉ with Sextant.[40]

       

A. M.	8.	4.	44.	P. M.	lost in consequence
	".	7.	31.		of the sun's being
	".	10.	31.		obscured by clouds.
Altitude given by Sextant at the time of Obstn.					44°. 53′. 15″.

Wednesday October 31st. 1804.

The river being very low and the season so far advanced that it
frequently shuts up with ice in this climate we determined to spend the
Winter in this neighbourhood, accordingly Capt. Clark with a party of
men reconnoitred the country for some miles above our encampment;
he returned in the evening without having succeed[ed] in finding an
eligible situation for our purpose.

Thursday November 1st. 1804.

The wind blew so violently during the greater part of this day that
we were unable to quit our encampment; in the evening it abated; we
droped down about seven miles and land on N. E. side of the river at a
large point of Woodland.

Friday November 2ed. 1804.

This morning early we fixed on the site for our fortification which we
immediately set about. This place we have named Fort Mandan in
honour of our Neighbours.

Fort Mandan, Sunday November 11th. 1804.

Point of Obstn. No. 51. Observed Meridian altitude of ☉'s U. L. with
Sextant by the fore observation[40] 51°. 4′. 52″.

Latitude deduced from this observation N. 47°. 21′. 32″. 8.

Saturday December 22ed. 1804.

Observed Equal altitudes of ☉. with Sextant.[41]

           

	h	m	s		h	m	s
A. M.	9.	6.	43.	P.M.	1.	25.	39.
	".	9.	52.		".	28.	57.
	".	13.	9.		".	32.	10.
					h	m	s
Chronometer too slow on Mean time					0.	39.	37.6

Monday January 7th. 1805.

Observed time and distance of ☉'s and D's nearest limbs, with Sextant.[41] ☉. West.

               

		Time			Distance.
	h	m	s
A. M.	2.	21.	—.	79°.	25′.	45″.
	".	23.	55.	".	26.	15.
	".	25.	3.	".	26.	30.
	".	26.	3.	".	27.	—.
	".	27.	47.	".	27.	15.
	".	29.	29.	".	28.	—.

             

	h	m	s
P.M.	2.	38.	12.	79°.	30′.	15″.
	".	39.	22.	".	31.	—.
	".	40.	19.	".	31.	45.
	".	41.	36.	".	32.	15.
	".	42.	33.	".	32.	45.
	".	43.	25.	".	33.	—.

Sunday January 13th. 1805.

Observed Meridian altitude of ☉. U. L. with Sextant and glass artificial
Horizon.[41] 43°. 18′. 30″
Latitude deduced from this observation. N. 47°. 20′. 52″.6

Monday January 14th. astronomical 1805.

Observed an Eclips of the Moon. I had no other glass to assist me
in this observation but a small refracting telescope belonging to my
sextant, which however was of considerable service, as it enabled me
to define the edge of the moon's immage with much more precision
than I could have done with the natural eye. The commencement
of the eclips was obscured by clouds, which continued to interrupt me
throughout the whole observation; to this cause is also attributable
the inacuracy of the observation of the commencement of total darkness.

I do not put much confidence in the observation of the middle of the
Eclips, as it is the wo[r]st point of the eclips to distinguish with
accuracy. The two last observations (i.e.) the end of total darkness and
the end of the eclips, were more satisfactory; they are as accurate as
the circumstances under which I laboured would permit me to make
them.—

         

	h	m	s
Commencement of total darkness	12.	28.	5.
Middle of the Eclips	12.	57.	24.
End of total darkness	13.	41.	30.
End of the eclips	14.	39.	10.[42]

Tuesday January 15th 1805.

Observed equal Altitudes of the ☉ with sextant and Glass artificial
horizon adjusted with a sperit level [43]

             

	h	m	s		h	m	s
A.M.	8.	26.	32.	P. M.	—	—	—
	".	29.	14.		—	—	—
	".	32.	1.		1.	49.	46.
Altitude given by the sextant at the time of obtn.					26°.	6′	15″.
					h	m	s
Chronometer too slow on mean time					1.	1.	57.7

Chronometer's daily rate of going, as deduced from this observation, and that of
the 22ed. of December 1804 is too slow on mean time 55s. 8.

☞I do not place much confidence in this observation in consequence
of loosing the observation of the Altitude of the ☉'s L. L. and
center P. M. and that [of] his U. L. was somewhat obscured by a
cloud. the weather was so could [cold] that I could not use-water as
the reflecting surface, and I was obliged to remove my glass horizon
from it's first adjustment lest the savages should pilfer it.

Sunday January 20th. 1805.

Observed Equal altitudes of the ☉, with Sextant & glass horizon.[43]

             

	h	m	s		h	m	s
A.M.	8.	40.	20.	P.M.	1.	21.	55.
	".	47.	15.		".	24.	47.
	".	50.	10.		lost by a cloud
	Altitude given by Sextant at the time of obst.				31°.	40′.	15″.
					h	m	s
	Chronometer too slow on main time				1.	15.	20.3

☞the horizon was removed from it's first adjustment.

Saturday January 26th. 1805.

Observed Meridian Altitude of ☉'s U. L. with sextant and artific.
Horzn. of water[44] 48°. 50′.—″

Latitude deduced from this observatn. N. 47. 21. 47.

Monday January 28th. 1805.

Observed Equal altitudes with Sextant and artificial Horizon on the
construction recommended by Mr. Andrew Ellicott, in which sperits
were substituted for water, it being to could to use the latter.[44]

             

A.M.	8.	7.	29	P.M.	1.	52.	34.
	".	9.	51.		".	54.	58.
	".	12.	20.		".	57.	26.
	Altd. by Sextant at the time of observation				33°.	25′	—″
					h	m	s
	Chronometer too slow on mean time				1.	11.	12.2
					—	—	51s.2

☞the accuracy of this observation may be depended on.

Longitude of Fort Mandan as deduced from the observation
of the end of total darkness when the eclips of the moon
tok place the 14th. of January Astronocl. 1805

   

	h	m	s
W. from Greenwich	6.	37.	31.2 or 99°. 22′. 45″.3

Longitude of Fort Mandan as deduced from the end of the

   

	h	m	s
same eclips	6.	37.	47. or 99°. 26′. 45″.

Wednesday February 6th. 1805.

Observed equal altitude of the ☉ with Sextant artificial horizon with
water[44]

         

	h	m	s		h	m	s
A. M.	7.	59.	31.	P. M.	1.	49.	31
	8.	1.	36		".	51.	24
	".	3.	5.		".	53.	41.
	Altitude given by Sextant at the time of Obst.				32°.	11′.	15″

Observed time and distance of ☉' and D's nearest limbs with Sextant
the ☉ West.

             

		Time			Distance.
P. M.	2.	8.	32.	87.	28.	15
	".	12.	16.	".	30.	—
	".	15.	58.	".	30.	45.
	".	18.	48.	".	32.	—
	".	20.	—.	".	33.	—
	".	22.	25.	".	34.	—

               

		Time.			Distance.
	h	m	s
P. M.	2.	26.	15.	87°.	35′.	15″.
	".	29.	40.	".	35.	45.
	".	31.	37.	".	36.	30.
	".	33.	27.	".	36.	45.
	".	35.	3.	".	37.	30.
	".	36.	38.	".	38.	—.

I do not place great confidence in these observations, as the person who
took the time was not much accustomed to the business. Capt. Clark
was absent.

Saturday February 23rd. 1805.

Observed time and distance of ☉'s an D's nearest limbs with Sextant,
☉ East.[45]

               

		Time			Distance.
	h	m	s
A. M.	6.	12.	15.	66°.	24′.	15″.
	".	14.	17.	".	23.	45.
	".	16.	14.	".	22.	45.
	".	17.	51.	".	22.	—.
	".	20.	23.	".	21.	25.
	".	22.	l8.	".	21.	—.

             

	h	m	s
A. M.	6.	25.	56.	66°.	20′.	—″.
	".	28.	5.	".	19.	15.
	".	29.	6.	".	19.	—.
	".	30.	58.	".	18.	—.
	".	32.	38.	".	17.	45.
	".	34.	59.	".	17.	15.

Immediately after the Lunar observations observed Equal altitudes of
the ☉ with Sextant and artificial Horizon with water.

             

	h	m	s		h	m	s
A. M.	6.	41.	5.	P. M.	—.	46.	20.
	".	43.	9.		".	48.	30.
	".	45.	19.		".	50.	35.
Altitude given by Sextant at the time of observation					40°.	15′.	45″
					h	m	s
Chronometer too slow Mean Time					2.	28.	14.9

Monday March 25th. 1805.

Observed ☉'s magnetic Azimuth with Circumferenter[46] S. 60°. W.

                     

		h	m	s
Time by Chronometer	P.M.	5.	7.	49.
Altitude of ☉'s L. L. by Sextant		32°	2.′.	0″.
☉'s Magnetic Azimuth by Circumferenter		S.	61°.	W.
		h	m	s
Time by Chronometer	P. M.	5.	11.	31.
Altitude of ☉'s L. L. by Sextand.		30°.	49′.	15″
☉'s Magnetic Azimuth by Circumferentr.		S.	63°.	W.
		h	m	s
Time by Chronometer P. M.		5.	19.	30″.
Altd. by Sextant of ☉'s L. L.		28°.	13′.	30″.

Thursday March 28th. 1805.

Observed Equal altitudes of the ☉ with Sextant & water artifc. Horizon.

         

	h	m	s		h	m	s
A. M.	8.	45.	28.5	P. M.	4.	17.	4.
	".	47.	9.		".	18.	15.5
	".	48.	57.		".	20.	43.
Altitude by Sextt. at time of Observation					48°.	50′.	—″.

Saturday March 30th. 1805.

Observed Equal Altitudes of the ☉, with Sextant and artificial Horzn. of
Water.[46]

       

A.M	8.	42.	46.	P. M.	4.	17.	33.
	".	44.	27.		".	19.	15.
	".	46.	10.		".	20.	59.
Altd. by Sextant at the time of observt.					49°.	45′.	00″.

[Here ends the series of observations entered in Codex O,
which was sent down to St. Louis with the boat that left the
Mandans, April 7, 1805. From this time on, Lewis entered
his observations in the text of the journal, taking a new point
of departure On April 12, 1805, at the mouth of the Little
Missouri, he begins "Point of Observation No. 1," and continues
to "Point of Observation No 46.," at Traveller's Rest Creek.
Until September 30, 1805, Clark does not enter anything but
the latitude deduced from observations; from that time, however,
until November 24, 1805, on the Pacific coast, he enters
a number of observations—among them are the following,
found in Codex H, pp. 23, 24, transferred hither from the text
of the journal.—Ed.]

Celestial observations taken in the junction of the Columbia & Lewis's
Rivers.

Thursday October 17th. 1805

Altitude taken with Sextant the error of which is 8′—45″ Subtraitive.

       

	h		m		s
A. M.	7	—	40	—	13
"	"	—	42	—	58	Altitude produced	22°	—	25′	—	15″.
"	"	—	43	—	44

Observed time and Distance of Sun and Moon's nearest limbs, Sun East.

               

		Time			Distance				Time			Distance
	h	m	s					h	m	s
A. M.	7.	51.	43	60°	47′.	15″.	A. M.	8.	00.	26	60°.	43′.	45″
	"	53.	33	".	46.	30.		".	1.	22	".	43.	15
	".	54.	35	".	45.	45		".	3.	8	".	43.	0
	".	55.	55	".	45.	0		".	4.	43	".	42.	30
	".	57.	37	".	45.	"		".	6.	5	".	43.	0
	".	58.	29	".	44.	"		".	7.	52	".	41.	30

Magnetic Azmoth of the Sun, time and distance

       

		Axms				Time				Distance
				h		m		s
A. M.	S.	75°	East	8	—	15	—	45	33°.	4′.	30″
"	S.	74°	East	8	—	19	—	43	34.	13.	0

Equal Altitudes with Sextant.

       

	h	m	s		h	m	s
A. M.	8.	23.	0.	P. M.	3.	21.	53.
	".	24.	25.		".	23.	50.
	".	26.	49.		".	25.	42.

Altitude produced from the observation is 35°. 9′. 30″.—

Friday October 18th. 1805

Took one altitude of the Sun's upper limb

   

					h	m	s
Alt	28°.	22′.	15″.	at	8.	1.	24	A. M.

Observed time and distance of Sun and Moon's nearest limbs Sun East.—

                           

		Time			Distance
	h	m	s
AM	9.	37.	46	47°.	15′.	30″.
	".	40.	32	".	14.	15
	".	41.	47	".	14.	"
	".	42.	55	".	13.	30
	".	43.	44	".	12.	45
	".	46.	2	".	12.	30
	".	47.	18	".	12.	0
	".	48.	35	".	11.	45
	".	49.	45	".	11.	15
	".	50.	53	".	11.	"
	".	52.	0	".	9.	30
	".	53.	46	".	9.	30

Took an altitude of the Suns upper Limb

   

				h	m	s
58°.	34′.	45″	at	10.	3.	59	A. M.

Took a Meridian Altitude Suns upper Limb which gave 68°. 57′. 30″.—

The Latitude produced is 46°. 15′. 13.″ 9 North

I measured the wedth of each river by angles as follows i. e.

The Columbia River is 960 yards wide
The Lewis's River is 575 do do

Imedeately below the junction the Columbia River is from one to
three miles wide including the Islands.

[Lewis apparently took fewer observations during the winter
at Fort Clatsop than while at Fort Mandan. For such as are
recorded, see text of the journals proper, January 1 to March 23,
1806. On the return journey he marks "Point of Observation
N°. 55," on April 1, 1806. After a few observations (embodied
in the text of the journals), to correct his instruments, the next
point of observation is dated May 25, 1806, and situated on
the Kooskooskee (see text of journals). At the Quamash
Flats, he made observations, all embodied in text of the
journals, save the following, which is found on the first flyleaf
of Codex L.—Ed].

by octant ☉'s L. L. 51°. 20′ June 9th. 1806.

June 9th. 1806.

Error of the Sextant 6′. 15—or Subtractive

   

Error of Octant by the back observation on the distant fragment of the broken limb	2°. 30′. 4″.5 +
	additive.

[The final observation was that made on Maria River, by
Lewis, July 23, 1806, and entered both by him and Clark in
the text of the journals.—Ed.]