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'sIsland, 1819, and reduced byexact measurement on the Boundary Bay
By 1 set of observations at GibraltarIsland (Put-in Bay), taken, like thepreceeding, in 1819, and reduced as before
Mean latitude of Detroit By 1 set of observations taken onSugar Island, and reduced as before42° 19 ´ 20 ´´
By mean results of 2 sets of observations17 and 21, 1820
By mean observation, Sept. 29, 1820
Mean longitude of Detroit, by 6 sets ofobservations, 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'sFolly, nearly on a level withFort Mackinaw115.8
Thence to the top of the block H of FortHolmes260.9
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, June22—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 gallais[ [203] on the Grand Portage ofSt. Louis, July 6, 1820 46 39 34
Latitude of camp at head of Grand Portage, July8, 1820 46 41 07
Latitude of camp at west end of Savanna Portage 46 51 47[ [204]
Mean latitude of Sandy Lake post, from observations,July 16 and 25 46 45 35
Mean longitude of Sandy Lake post, from 4 setsof observations, July 15 and 16 93 21 30
Latitude of Wolverine Camp, July 23, 1 day fromSandy Lake 47 4 15
Latitude of halting-place above forks of LeechRiver on the Mississippi, July 20 47 24 00[ [205]
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, sameday 47 26 40
Latitude of camp at Buffalo hunting-ground, abovePe-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 Fallsand 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, July31, by 5 sets of observations 44 53 20
Mean longitude of Fort St. Anthony, new site, July31, by 3 sets of observations 92 55 45
Latitude of Fort Prairie du Chien, Aug. 6 and 7. 43 03 19[ [206]
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), probablybetween 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 setsof 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 LakeMichigan, 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, LakeMichigan, Sept. 5 44 5 17
Latitude of camp at Grand Traverse Bay, LakeMichigan, Sept. 7 45 34 24