Dr Forry on the Climate of the United States. 81 



seasons strongly contrasted, and a corresponding dryness of 

 the atmosphere (unlike the first two classes, in which the 

 air is moist and the changes of the seasons slow and uncer- 

 tain), a constant and rapid succession is observed among the 

 seasons. Summer, for example, succeeds winter so rapidly 

 that there is scarcely any spring, the influence of which is 

 surprisingly manifested in the vegetable kingdom. As the 

 summers of the third class are remarkable for extremes of 

 temperature, the mercury often rising in June, July, and 

 August, to 100° Fahr. in the shade, so the winters are equal- 

 ly characterised by extreme severity. From November to 

 May, cold Aveather prevails, the ground being often covered 

 with snow to the depth of three or four feet, and the general 

 range of the thei'mometer being from the freezing point to 

 30° below zero. 



The lowest temperature, taking the mean of a month, oc- 

 cun*ed at Forts Howard and Snelling. At the former, the 

 mean of the month of February 1829, at 7 o'clock A. ar., 

 is — 3°.17, and the mean of December 1822, at Fort Snelling, 

 is — 3°.61. This, it is to be observed, is merely the average 

 of the morning observations for the month. Although the 

 extreme severity of the winters at the posts remote from 

 large bodies of water, has been already fully illustrated ; yet 

 the following remarks made by Sui'geon Beaumont, when 

 stationed, in 1829, at Fort Crawford, Wiskonsan, which is in 

 the latitude of Fort Wolcott, R. I., may be added in further 

 elucidation : " The month of January was remarkably mild 

 and pleasant, the ground dry and free from snow, and the 

 Mississippi unusually low and unfrozen. February was ex- 

 tremely cold, the weather clear and dry, and the thermome- 

 ter ranging during the month from the freezing point to 23° 

 below zero. From the 1st to the 16th, the mercui*y stood 

 every moi'ning, with the exception of three (the Gth, 7th, 

 and 8th), between — 4° and — 23°, and did not rise above 20° 

 above zero during these days. On the 2d, 3d, 4th, 5th, 9th, 

 10th, 11th, 13th, 14th, and 15th, the mercury at sunrise stood 

 respectively at 14°, 16^ 4^ 16°, 23", 18°, 20°, 18°, 10°, 6°, and 

 4' below zero ; and on the 9th and 14th, it continued under 

 — 8° during the 24 hours. During the month the prevailing 

 VOL. XXXIX. NO. LXXVII JULY 1845. F 



