Narrative of an Expedition to the Sources of the Mississippi

2 Topography and Astronomy

Topographical materials were collected by Capt. Douglass, U.S.A., for a map of the northwestern portions of the United States, embracing the complete circumnavigation of the great lake basins, and accurate delineations of the sources of the Mississippi, as low down as the influx of the River Wisconsin. Being provided with instruments from the Military Academy of West Point, astronomical observations were made at every practical point over the vast panorama traversed by the Expedition. A line of some four thousand miles of previously unexplored country was visited; his notes and memoranda for a topographical memoir were full and exact; and they were left, I am informed, in a state of nearly perfect elaboration, accompanied by illustrations, and many drawings of scenery. Having written to his family recently, for the astronomical observations, they were transmitted by his son in a letter, of which the following is an extract:—

Geneva, June 23, 1854.

Dear Sir: I inclose you herewith, on another page, the results of my father’s observations of latitude and longitude, so far as I have been able to collect them. His calculations indicate great pains and labor to obtain accurate results. They are too voluminous to copy. I trust, however, that I have been as particular as was necessary in the inclosed memoranda. If anything else is wanting, I should like you to inform me.

I am, sir, with great respect,
Your obedient servant,
MALCOLM DOUGLASS.

V

Results of Observations for Latitude and Longitude during the Expedition 820.By David B. Douglass, Capt. Engineers, U.SA.

		By 3 sets of observations at Cunningham’s Island, 1819, and reduced by exact measurement on the Boundary Bay
		By 1 set of observations at Gibraltar Island (Put-in Bay), taken, like the preceeding, in 1819, and reduced as before
Mean latitude of Detroit		By 1 set of observations taken on Sugar Island, and reduced as before		42° 19 ´ 20 ´´
		By mean results of 2 sets of observations 17 and 21, 1820
		By mean observation, Sept. 29, 1820
Mean longitude of Detroit, by 6 sets of observations, May 17 and 19, 1820				82 39 00
Latitude of Presque Isle, Lake Huron, June 5, 1820				45 19 45
Latitude of Mackinaw, by 4 sets of observations, June 7 and 11, 1820, by meridian observations, Sept. 12, 1820				45 50 54
Height of Fort Holmes. From the water to the brow of the hill near Robinson’s Folly, nearly on a level with Fort Mackinaw			115.8
Thence to the top of the block H of Fort Holmes			260.9
		Total height,	376.7 feet
Longitude of Mackinaw, by several sets of observations, Sept. 12, 1820				84° 28´ 40´´
Mean latitude of Sault de St. Marie, June 16, 1820				46 26 45
Latitude of Turtle Camp, on Lake Superior, June 22—primitive bluff (Granite Point.—S.)				46 41 15
Latitude of Keweena Camp				47 02 30
Mean latitude of Sandy River, July 4, 1820				46 55 24
Mean longitude (by 25 observations for degrees, and 25 observations for time). In time, 6 h. 3 m. 48 sec. In degrees				90 57 00
Latitude of the gallais203 on the Grand Portage of St. Louis, July 6, 1820				46 39 34
Latitude of camp at head of Grand Portage, July 8, 1820				46 41 07
Latitude of camp at west end of Savanna Portage				46 51 47204
Mean latitude of Sandy Lake post, from observations, July 16 and 25				46 45 35
Mean longitude of Sandy Lake post, from 4 sets of observations, July 15 and 16				93 21 30
Latitude of Wolverine Camp, July 23, 1 day from Sandy Lake				47 4 15
Latitude of halting-place above forks of Leech River on the Mississippi, July 20				47 24 00205
Latitude of camp at Lake Winnipec, July 20				47 30 56
Latitude of halting-place near first return camp, July 21				47 27 10
Latitude of return camp; near the above, same day				47 26 40
Latitude of camp at Buffalo hunting-ground, above Pe-can-de-quaw Lake, July 28 and 29				46 00 00
Breadth of river at camp on the Buffalo Plain, 148 yards
Latitude of halting-place between the Great Falls and St. Francis River				45 25 43
Breadth of river at camp above Falls of St. Anthony, 200 yards
Mean latitude of Fort St. Anthony, new site, July 31, by 5 sets of observations				44 53 20
Mean longitude of Fort St. Anthony, new site, July 31, by 3 sets of observations				92 55 45
Latitude of Fort Prairie du Chien, Aug. 6 and 7.				43 03 19206
Latitude of Fox and Ouisconsin Portage, Aug. 14 and 15, 43° 42´ 36´´; say				43 42 00
Latitude of camp near mouth of River De Loup, Aug. 17				44 6 44
Latitude of Fort Howard, Green Bay, Aug. 21				44 31 38
Longitude of Fort Howard (some error), probably between 87° 45´ 30´´ and				87 46 00
Latitude of camp at Sturgeon Portage, Lake Michigan, Aug. 23				44 47 43
Latitude of camp 3 miles north of the Manetowag, Aug. 24				44 12 47
Latitude of camp south of the Sheboyegan, Aug. 25				43 41 26
Latitude of camp at Milwaukie, Aug. 26				43 01 35
Mean latitude of Fort Dearborn, Chicago, by 6 sets of equal altitudes, Aug. 31, and meridian altitude				41 54 06
Mean longitude of Fort Dearborn, 3 sets of observations. In time, 5 h. 50 m. 8 sec. In degrees				87 32 30
Longitude of Detroit, calculated from above				82 54 53
Latitude of camp near head of Lake Michigan, Aug. 31 and Sept. 1				41 38 48
Mean latitude of the extreme south point of Lake Michigan, 4 sets of observations and meridian observation				41 37 28
Latitude of camp next north of the St. Joseph’s, near Kekalamazo, Sept. 3				42 32 16
Latitude of camp at Maskegon River, Sept. 4				43 13 41
Latitude of camp near Point aux Salles, Lake Michigan, Sept. 5				44 5 17
Latitude of camp at Grand Traverse Bay, Lake Michigan, Sept. 7				45 34 24