PARTIAL RESULTS OF EXPLORATION. 
459 
Heights by the Barometer —Continued. 
Date. 
Number of 
camp. 
Place. 
Height in 
feet above 
the sea. 
106 
Camp Washington.-.... .... 
2,133 
Summit after camp Washington, 8 . 3 miles... 
2,540 
30 
107 
2, 374 
Bluff after leaving camp, 10.6 miles... 
2, 360 
31 
108 
Fork of Peluse liver____.............................. 
2 , 160 
Nov 1 
109 
Fork ot Peluse liver._____......................... 
1,542 
2 
110 
Fork of Peluse river..,........ ............ 
1,227 
Peluse liiver crossing, 7. 3 miles. 
960 
Bluff on Snake river, 16.6 miles. 
1,239 
111 
Snake liver............ 
354 
Snake River bluff, 1. 5 miles. 
744 
Elevation between s 'nake 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 
5. 
112 
Fork of the Wallah-Wallah river......_______ 
840 
Prairie towards Wallah-Wallah river, 16 miles. 
1,085 
6 . 
113 
Near Fort Wallah-Wallah.•. 
409 
Columbia river bluff, 1.7 miles... 
522 
Memoranda concerning the Meteorological Observations on the Missouri river , by Lieutenant A. J. 
Donclson. 
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: 
4 a. m. +0.20 
5 a. m. +0.15 
6 a. m. .000 
7 a. m. —.010 
8 a. m. —.015 
9 a. m. —.025 
10 a. m. —.040 
11 a. m. —.035 
12 m. —.008 
1 p. m. .000 
2 p. m. +.018 
3 p. m. +.025 
4 p. m. +.030 
5 p. m. +.030 
6 p. m. +.020 
7 p. m. +.010 
8 p. m. +.000 
9 p. m. —.015 
10 p. m. —.025 
11 p. m. —.020 
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. 
