METEOROLOGY. 315 
and three years’ continuous observations at Fort Pierre, with one also at Fort Randall, furnish 
much more reliable data. The mean resnlts for winter are given in the table below.* 
5 S BA ЕТЕ 
bd EEE Remarks, 
3 а 5 б © © 2 
4 3 E Sud m dd 
o4 gr Feet. о о о 
Fort Kearney 40 38 98 57 | 2,360 | 33.1 | 13.7 | 14.8 | 20.5 | Mean 23°, 0; 6} years’ observations, 
Fort Randall 43 01 98 12 (PR ж SRS 
Fort Pierre 44 23 | 100 12 1,660 | 24.6 | 13.1 9.9 | 15.9 
Fort Clark «iuo sad 47 00 | 100 45 1, 876 130, 20, winter, 1833-34. 
Fort Union 48 00 | 104 00 | 2,022 199, 4, January, February, 1833. 
Fort Shelling wicca. 2 Var! 44 53! 93 10 820 | 16.8 | 9.1 | 7.5 | 11.1 | Mean 16°, 1; 354 years’ observations, 
A comparison of these winters is made with those at the nearest points where long series 
have been obtained, from which it appears that the mean of the three winters at Fort Pierre 
is probably near the true mean, since the same winters at Fort Kearney vary only 0.60 from 
that of six years at that post, although each separately varies widely. 
But the observations at Forts Clark and Union in 1882—83 are not so easily reconciled. The 
same years observed at Fort Snelling, the nearest post, show that entirely different climatic 
conditions affect the three places. 
January, 1832. February, 1832. 
о о 
Fort Snelling 17.2 6.5 
Fort Union 21.3 17,5 
Winter, 1833—34. | Mean of 35 winters. 
о о 
Fort Snelling ......------------| 22.7 16.1 
Wort Clark. Lassa 13. 2 
The only conclusion from the comparison is, that Fort Union partakes of the milder winter 
climate of the western coast, as observed still more strikingly at Fort Benton. Forts Kearney 
and Laramie occupy a similar relation to each other and to the Pacific climates, and the long 
series at those posts show that the former has a winter temperature 7°.10 colder than the latter, 
while the periodical curves follow nearly the same course, keeping from four to ten degrees 
below. A similar relation of climate may be expected to prevail between Forts Union and 
Benton. But Fort Clark shows two winter months much colder than for the same period at 
Fort Snelling, which, together, were 39.85 below the average of thirty-five years. This, 
together with the great differences in the three winters observed at Fort Pierre, favor the con 
clusion that this portion of the Missouri lies intermediate between the жо systems of climate 
that the prevalence of winds from either quarter determines 
extremes seem to be represented by the Fort Pierre series, 
the Missouri five degrees higher than he had fixed it in 
give any data for the change, and the 
(for winter) east and west of it, and 
the character of the weather. Both 
о Mr. Blodgett’s book gives the isochimenal line for this part of 
the charts de Screen бе» Meteorological Register of 1855, but he does not 
former appears most correct. 
