ENGELMANN'S TABLE OF MEANS AT ST. LOUIS. 15 
field (or the mean of several if they can be had) to the monthly means of the stationary barom- 
eter. I add, therefore, my monthly means for the last fourteen months. But the observations 
made west of the Bock" mountains:cannot be referred to my barometer atall. It is hardly 
necessary to add—what everybody who is in the habit of observing the barometer knows—that 
observations made in the forenoon, principally from 8 to 10 o'clock a. m., are generally higher, 
and those made in the afaro, principally between 2 and 4 o'clock, are mostly lower than 
the average of the day. "The noon observations come nearest the mean of the day. The barom- 
eter, at least in the Mississippi valley, is usually highest with westerly and northwesterly winds, 
and lowest with southerly and southeasterly winds. It is mostly higher, but much more irreg- 
ular, in winter, and lower, but more regular, in summer. 
Mean Brot PON of barometer E. at St. Louis, 482 feet above the Gulf. 
Table of means corrected for temperature. 
June, 1853 29.466 
July, 1853 29.483 
August 1853 29.431 
September, 1853 29.474 
October, 1853 29.538 
November, 1853 29.601 
December, 1853 29.508 
January, 1854 29.577 
February, 1854 29.507 
March, 1854 29.459 
April, 1854 29.444 
May, 1854 29.334 
June, 1854 29.418 
July, 1854 29.491 
G. ENGELMANN. 
Sr. Louis, September, 1854. 
The discrepancy found to exist by Dr. Engelmann in the Bunten barometers after our return 
from California did not exist as between themselves up to the termination of the exploration 
in July, and must have arisen from some cause on our homeward Journey, and is disregarded, 
therefore, in the discussion. 
' Horary variations of the barometer in California. 
1. In the elevated portions of the interior. 
Hour. - Inch, Hour. Inch. 
5 a.m —.007 2p. m —.025. 
5a. m —.005 3 p. m —.030 
6 a. m +.012 4p.m —.035 
7 a. m +.025 5 p. m —.033 
8 a. m -+-.030 6 p.m —.025 
9a, m +.035 p.m —.015 
10 a. m +.040 8 p. m. —.005 
lla. m +.045 9p. m +.008 
12 m +.015 10 p. m +.015 " 
lp.m —.005 ll p.m +.013 
