CLIMATE. 



CLIMATE. 



Me., on the ocean in latitude 44 44', where i 

 the winter mean temperature is 17'45 Fah- 

 renheit above that of Fort Snelling in Iowa, j 

 the latitude being the same. The climate of 

 Fort Snelling, Dr. Forry informs us, is the 

 most excessive among all the military posts in 

 the United States, resembling that of Moscow in 

 Russia, as regards the extremes of the seasons, 

 notwithstanding the latter is 11 further north. 

 But at Moscow the mean temperature both 

 of winter and summer is lower, that of winter 

 being as 10-78 to 15-95, and that of summer 

 as 97-10 to 72-75. That the influence of 

 the lakes in modifying the climate in their 

 vicinities is not less than that of the ocean, is 

 demonstrated by a comparison of the summer 

 and winter means of posts situated near them 

 in about the same latitude. The difference 

 between the mean temperature of summer and 

 winter at Fort Preble, on the Atlantic, is 41 0> 03, 

 and of Fort Niagara on Lake Ontario, 41-73. 

 At the excessive post, Fort Crawford, Wis- 

 consin, a few minutes further south than the 

 two places first mentioned, the difference 

 amounts to 50-89. Again, a comparison of 

 the difference between the winter and summer 

 means of some other posts situated in the 

 same latitude shows the following results, by 

 which the increase in extremes on going west 

 is strikingly demonstrated. The difference 

 between the mean temperature of summer and 

 winter at Fort Wolcott, Newport, Rhode Island, 

 is 36-55; at West Point, New York, 40-75; 

 Fort Armstrong, Illinois, '49'05; and at Coun- 

 cil Bluffs, near the junction of the rivers Platte 

 and Missouri, 51-35. The highest, lowest, 

 and annual range of the thermometer at three 

 of the posts just mentioned is as follows : 



Annual 



Highest. Lowest. ranre. 



Fort Wolcott, Newport, R. I. 65 2 83 



Fort Armstrong, Illinois - 96 10 

 Council Bluffs 



- 101 



120 



Although the mean temperature of winter on 

 the sea-coast is 6 higher, and of summer 8'71 

 lower than in places situated on the same pa- 

 rallel in the interior, beyond the influence of 

 the lakes, the means of spring are 4'13, and 

 of autumn 0-40 higher in the interior situa- 

 tions. This is the result of a comparison made 

 in the latitude of about 43. 



How strongly are all these views of the east- 

 ern climate of the United States contrasted with 

 the equable temperature found in the Pacific 

 region. At Fort Vancouver, for example, situ- 

 ated on the Columbia river, about seventy-five 

 miles above its mouth, the difference between 

 the winter and summer means is only 23-67, 

 although a degree farther north than Fort Snel- 

 ling, five degrees more northerly than New 

 York, and nearly on the same parallel with 

 Montreal. During a year passed at Fort Van- 

 couver, the lowest fall of the thermometer was 

 to 17. On nine days only was the tempera- 

 ture below the freezing point in the month of 

 January, so that ploughing is carried on whilst 

 the vegetables of the preceding season are still 

 itanding in the gardens untouched by frost. 

 And why does not New York, situated directly 

 on the Atlantic Ocean, derive as much warmth 

 from this magazine of heat as Fort Vancouver 

 does from the more distant Pacific 1 Simply 

 ,332 



because the predominant westerly winds sweep 

 upon one place the chilling blasts of extensive 

 districts of land, cooled to congelation, or co- 

 vered with snow, whilst oveY the other they 

 waft the genial warmth of the sea. For simi- 

 lar reasons the ameliorations of climate expe- 

 rienced in the vicinity of the interior lakes 

 must always be felt most to the eastward. 



The classification of climates distinguished 

 by Dr. Forry in the United States and territo- 

 ries, is founded upon a general division into 

 Northern, Middle, and Southern regions ; the 

 first being characterized by the predominance 

 of a low mean temperature, the Southern" by a 

 high temperature, and the Middle vibrating to 

 both extremes. Each of these general divisions 

 is subdivided into classes or systems sufficiently 

 marked. 



The Northern System has three classes, the 

 first embracing the coast of New England, 

 extending as far south as the harbour of New 

 York; the second including the districts in the 

 proximity of the northern lakes; the third, 

 portions of country alike remote from the ocean 

 and inland seas. 



The Middle division has two classes, the 

 first embracing the Atlantic coast from Dela- 

 ware Bay to Savannah; the second, interior 

 stations. 



The Southern division has also two classes, 

 the first including those parts in which the 

 military posts on the Lower Mississippi are 

 situated, and the second the peninsula of East 

 Florida. 



It is the Northern region which presents at 

 the same time the greatest diversity of physical 

 character and the most strongly marked varia- 

 tions in climate. East of the great lakes, the 

 several mountain ranges seldom exceed the 

 height of 2500 feet above the level of the sea 

 the table-lands, upon which the ridges rest, ris- 

 ing, perhaps, on an average, to half the height 

 named. We have already adverted to the fact, 

 that on the coast of New England the influence 

 of the ocean is manifested in moderating ex- 

 tremes of temperature. Advancing into the 

 interior, the extreme range of the thermometer 

 increases, and the seasons are violently con- 

 trasted, until getting within the influence of the 

 lakes, when a climate like that of the sea-board 

 is found. That the lakes have this capacity to 

 modify the climate in their vicinity will be evi- 

 dent to any one who considers that they occupy 

 not less than 94,000 square miles, having a 

 depth varying from 20 to 500 feet. Beyond the 

 modifying agency of these inland seas, tempe- 

 ratures still more excessive are exhibited, a 

 comparative view of which, including exact 

 estimates for the sea-coast and regions of and 

 beyond the great lakes, has been already given. 



When the climates on the sea-coast and in- 

 terior country remote from the lakes are com- 

 pared in relation to the proportion of fair and 

 cloudy weather, rain and snow, the following 

 results appear. During the year, the propor- 

 tion of fair days on the sea-coast, compared 

 with those of the interior, are as 202 to 240: 

 cloudy days, 108 to 77; rainy days, 45 to 31; 

 snowy, 9 to 16. 



Comparing the climate of the lakes with that 

 of the same region beyond their influence, the 



