138 Part I. Chapter 2. 
The hydrography proves that there can be no deficiency in rainfall, for 
the innumerable lakes and streams are constantly full. In Assiniboia, the great 
plains project north of the boundary and form an area over 20,000 square 
miles (51,800 qkm). There are dry belts under the lee of the mountain ranges 
of British Columbia and a belt of excessive moisture on the Pacific coast. The 
immense areas of water in the great central lakes alter the climate by imparting 
humidity to the air and moderating those extremes which are characteristic 
of a continental climate. The foregoing tables present the details regarding 
temperature for the four most striking months of the seasons, precipitation or 
depth of snow for each month of the year, as taken from the U. S. Monthly 
Weather Review (1903. XXXT). See pages 136—137. 
2. United States. 
The United States, exclusive of Alaska displays nearly all the variations 
of climate known in the temperate zone”). One of the most interesting facts is 
the low winter temperature of this country as compared with that of the same 
latitudes in western Europe; for example, the temperature of 32° F. at New 
York, latitude 40° 43’, is met at Hamburg, Germany, 950 miles farther north. 
The permanent low-pressure area in the North Pacific contributes many of the 
storms that appear in the extreme northwest. These depressions sometimes 
reach 29 inches, but, strange to say, they are what may be called dry storms, 
as they do not gain moisture enough for precipitation in the east until they 
reach the lake region. Other storms come up from the Gulf of Mexico and 
pass over the lakes; these give the most abundant precipitation to the country 
east of the Mississippi River. The lower lake region and the St. Lawrence 
Valley form the great highway for nearly all the storms of the country (80 to 
85 per cent). In the months of August to October, there are peculiar depres- 
sions called hurricanes, which are formed in the Caribbean Sea toward the 
east, and, moving first in a westerly direction, recurve in Florida or the eastern 
Gulf of Mexico and move up the Atlantic coast, gradually widening and at the 
same time diminishing in energy. 
verage air pressure. In the cold months, November to March, the normal | 
charts show areas of high pressure in the south Atlantic states and in the region 
ER 
a RN ws; 
to the north or west of the middle Rocky Mountains. The latter high area 
moves east occassionally to the middle and upper Mississippi valleys, and when 
this is the case the whole country east of the Mississippi is visited by cold 
weather and temperatures far below the normal. In the remaining months, 
the Rocky Mountain high area moves to the Pacific and its place is taken by 
a low area. The second high area moves to the middle Atlantic and some- 
times it takes a position to the west of its normal place, in which case the 
eastern part ofthe country is brought under the most intense heat. Such was 
ı) HazEen, H. A.: The Climate of the United States. Report International Meteorological 
Congress, United States Department Agriculture, Weather Bureau. Bulletin II, Part III. 1896. 
