Winslow —The Mapping of Missouri. 87 
vance over earlier maps. From the results of the Land Office 
surveys many such details were doubtless incorporated. 
Between the years 1836 and 1840, certain surveys were 
conducted and observations were made by I. N. Nicollet, for 
the government along the Mississippi and Missouri rivers. 
The results are contained in Senate Document No. 237, 26th 
Congress, second Session; a map accompanies this embracing 
the territory between 38° and 40° 30’ of Lat. and between 
89° and 101° of Long, He is credited with having made the 
first use of the barometer in connection with such work in the 
west. The longitude of St. Louis cathedral was determined 
to be 90° 15’ 10”, and that of Fort Leavenworth 94° 44’.* 
A fair summary of the existing knowledge of geographic 
locations about the middle of this century, is contained in a 
table in ‘* French’s Historical Collections of Louisiana ”’ (1846- 
53) in which, along with many others beyond the limits of 
Missouri, the following locations are given. They are de- 
rived from determinations of Long, Nicollet and others.f 
o> 5 es 
gee gitey cg RT 
Bea S558" 53 aS: 
Re 4° 4 8 Svs 
New Madrid 4115 sc . 8B" 04 80" SPI 16" 
Cape Girardeau 1957... BF°IR 38" OS 27 0" 
St. Genevieve, church............ 1880... $72: 87° BY 40" OAL 3" 
St. Louis, cathedral garden...... 1390 382 38° 37' 28" 90° 15’ 39” 
Missouri, mouth of, south bank.1408 888 38° 50’ 50" 90° 13! 45” 
Gasconade river, mouth of.......1513  ...... 38° 4140" ....... eee. 
Portland, Callaway county....... 1523 ..... 38° 42'57" 91° 40 15" 
Osage river, mouth of............. 1543... ua" S00" panne 
Boonville 1604 580 38° 57' 18" 92° 41’ 30” 
Grand river, S. W. of mouth...... 3690 sie OP 0 a as 
Old Fort Osage, right bank....... 4786 OS Se Oe eaveuss 
Kansas river, mouth of 1190 - 30° SB 26" 2 onc 
Fort Leavenworth 1820 . 746 39° 22’ 40" 94° 44’ Of 
* According to the measurements of the Land Office surveys the longi- 
tude of Fort Leavenworth is 94° 58’, while the most recent results make 
the longitude of the observatory of Washington University, St. Louis, 90° 
12’ 30”. Similarily the longitude of Fort Osage as determined by J. C. 
Brown in 1826 was 93° 51’, while the Land Office measurements make it 
94°15’; the longitude of Westport was determined by Freemont in 1843 to 
be 94° 22’, and by Land Office measurements it is 94° 37’, 
+ Historical Collections of Louisiana. By B. F. French. Vol. I, p. 298. 
New York: Wiley & Putnam, 1846-53. 
