Geography of Ohio 
197 
make a plot of the actual movements of the winds of a cyclonic 
or of an anti-cyclonic area, the diagram resembles a spiral rather 
than the spokes of a wheel. 
Furthermore, these centers are not stationary; they move 
toward the east. The storm path may have a northern or a 
southern component in its direction of travel, but the prevailing 
direction is eastward. The frequency of these storm paths in 
Ohio increases northward across the state. A large part of the 
state, however, may be affected by a cyclonic or an anti-cyclonic 
area whose center takes a course through Lake Erie or even in 
Canada. 
Thus about either of these centers, ^^high’^ or ^Tow,” we find 
a variety of conditions : a variation in the thermometer readings, in 
the register of the barometer, and in the precipitation. A verti- 
cal plane drawn through a cyclonic or an anti-cyclonic area in 
any direction and studied in detail, will emphasize this variety. 
Because of this fact, Ohio has a variable and interesting climate; 
the changes are sometimes sudden, but the disagreeable weather 
does not endure. 
Other air currents. Associated with the proximity of land and 
water bodies are other atmospheric currents, locally important. 
These are called ^Tand breezes and sea breezes,’’ but in Ohio we 
find a corresponding phenomenon along Lake Erie. During the 
period of sunshine the land heats more quickly than does the 
body of water; the radiated heat warms and consequently lightens 
the air above the land; the heavier air above the water moves 
inland, establishing a cool lake breeze. In the late afternoon, 
the water becoming relatively warmer, a flow of air from the land 
is established, making a land breeze. In the course of a day the 
bottom and the walls of a valley are differentially heated, insti- 
tuting movements of the atmosphere similar in origin to land and 
sea breezes. It is on this principle that we are advised nowadays 
never to build houses on the valley bottom nor on the top of a 
hill, but some distance below the hill top or crest of a ridge; in 
this location the extremes of heat and cold are more moderate. 
CLIMATOLOGY 
Our Government excels all others in the scientific study of the 
climate; nevertheless we have a paucity of students of clima- 
