PARTIAL RESULTS OF EXPLORATION. 459 
Heights by the Barometer—Continued. 
Date. Number of Place. Height in 
camp. feet above 
the sea. 
Qeteieze toe: «2. - 25. 106 Camp Washington: s---tcencsaseecoeece ere a ae sacs jacccetcceccs 2,133 
Summit after camp Washington, 8.3 miles..---......-..---..-------- 2,540 
DU saateanter aaisane 107 LOWE! RULE INN Pee seaoesecen comeco occas =o pccecn.copces asoccoeseS 2, 374 
Bluitratser leaving camp) LO Oimilessam eee a eles selec alee osyo= a= 2, 360 
Be moses ses es5e 108 Ikea SO) LAGI EG) miki eaee cos cooSnco CoQ0Se boascd Schoodiocebos sseseoesooss 2, 160 
Nove eiliss25 22-2252 109 Rorks ofe PeMmeeirivete ccs ocic aso cance socio o senate sane aise aaesenistaacmeaat 1, 542 
a= LSC CSREES 110 Fork of Peluse river..---....-.. PROC ODOO SHES REO CeSHeo Gasca ccoose 1, 227 
Peluse River crossing, 7/3 Mi 68s << =<<.ce c)ee eae eee eons 960 
Blitkrontsnake)rivery LG. OmiUes: jam ae sees ool ee eee eee 1, 239 
STN a secoseeo 111 PANG NIG) Paco COCR IOUS SE HE CEHEH COE E EE Se EEeROBbEEnoS Cocace ones 354 
Suakeitiver bluit; liopmilesee 5 sse- 4 ssscefeeeescres sas cle ea ores cree 744 
Elevation between Snake and Wallah-Wallah rivers, 8.7 miles.....--- 1,614 
Elevation between Snake and Wallah-Wallah rivers, 14. 1 miles......-- 1, 013 
Elevation between Snake and Wallah-Wallah rivers, 20.7 miles... ..-. 1, 139 
Elevation between Snake and Wallah-Wallah rivers, 23.2 miles.....--- 1,740 
Btansccemancteess 112 Workiof the) Wallah=Wallahiriver:=ss2)--2-seteseaciesee saeco seeieen eee 840 
Prairie towards Wallah-Wallah river, 16 miles....-....--...----..--- 1, 085 
(Fc edetccepaoe 113 NeartE ont: Wallah-Wallalitas 22h ts .Setoncc ose tine one aoe cee oaetem sehen 409 
Columbia river bluff, 1,7 miles...... feb eOe oat ewsereneacece 522 
Memoranda concerning the Meteorological Observations on the Missouri river, by Lieutenant A. J. 
Donelson. 
The barometer used from St. Louis to Fort Pierre was ‘‘ Green’s closed cistern,” No. 718. 
Its error was assumed to be —.050 inch. At Fort Pierre, after a series of readings, it indicated 
a height of column .050 inch greater than barometer No. 722, which was “ Green’s open cistern,” 
of glass. The latter barometer was used from Fort Pierre to Fort Union. It was compared in 
St. Louis with Dr. Engelmann’s standard, and its error was —.01 inch. 
In the accompanying tables the barometer has been first reduced to the freezing-point; employ- 
ing for this purpose the tables for barometers with brass scales, then corrected for error, and then 
for horary variation. For the latter the following scale, kindly furnished by Professor Blodget, 
and adopted for Fort Union, has been used: i : 
4a.m.+0.20 — 8 a.m. —.015 1lp.m. .000 6 p. m. +.020 
ae 7 p.m. +.010 
5 a.m. +0.15 9 a.m. —.025 2 p.m. +.018 8 p. m. +.000 
6a.m. .000 10 a. m. —.040 3 p.m. +.025 9 p.m. —.015 
s i 10 p. m. —.025 
7 a.m. —.010 11 a.m. —.035 4 p.m. +.030 11 p. m. —.020 
12 m. —.008 5 p.m. +.030 12 p. m. —.000 
Below Fort Union, the variation at 5 p. m. was taken as +.035. The calculation has been 
made by using the Smithsonian meteorological tables. 
The numbers in brackets, in the column of heights, denote the estimated height of the instru- 
ment above low water. 
The point of reference was the level of the sea where the height of the barometric column 
would be 30.000 inches, the temperature being 64°. 
A constant number, 34.9, has been added to each calculated height. 
