192 
Frank Carney 
other features. If the precipitation throughout the year is 
fairly high but all falls in a particular month instead of being dis- 
tributed with some uniformity through the twelve months, the 
region may be a desert. If the wind blows always from one quar- 
ter instead of varying as it does in Ohio, disagreeable features may 
be said there to characterize the climate. 
TEMPERATURE 
As influenced by latitude. Temperature depends very largely 
on latitude. The latitude regulates the area covered by a unit 
sunbeam. A sunbeam of a given cross-section area, when the 
sun stands directly over the equator, will cover on the equator an 
equal area, but at that same instant, in our latitude, the same area 
of sunbeam may be spread over twice as much land. In the for- 
mer case, the energy of the beam is concentrated; in the latter, 
it is scattered. The sunbeams, passing through the atmosphere, 
we are told, do not warm the atmosphere, but the temperature of 
a land area appears to be connected very closely with the tempera- 
ture of the atmosphere. The atmosphere, therefore, must get 
its warmth from another source than the sun’s rays which pass 
directly through it. This other source is radiation from the sur- 
face of the earth. Sunlight warms the land and the water sur- 
faces, which radiate their heat and warm the atmosphere. Conse- 
quently, in those parts of the earth where the sunbeams are more 
vertical, the surfaces are warmed more, and through radiation the 
atmosphere adjacent is also kept warmer. In our latitude we 
never have vertical sun rays, but throughout the year the degree 
of obliqueness changes very much. 
Furthermore, our highest temperatures do not come when the 
position of the sun gives the least oblique rays, for the reason that 
the general temperature depends also on the gradual warming of 
the atmosphere by the continued radiation of surface heat. As 
a result, the climax of summer is not in the mathematical middle 
of the summer months, but lags behind; and our lowest winter 
temperatures follow the middle of the winter months. 
During May, we note that the heat received in a particular day 
by a given area in this latitude is not entirely radiated during 
the following night. Next morning a slight increment of the 
previous day’s warming remains, and to this will be added the 
