194 
Frank Carney 
PRECIPITATION 
There is always moisture in any natural atmosphere, but in 
order that we may observe this moisture it is necessary that the 
atmosphere be cooled. A warm atmosphere holds its moisture. 
An atmosphere at any temperature holds some moisture, that is, 
it is practically impossible to take all the moisture out of an atmos- 
phere. The form in which precipitation falls depends upon the 
temperature; below freezing, it comes as water in crystal form; 
at other times as rain; at still other times, under proper condi- 
tions, it collects invisibly, forming, if this collection is kept up 
long enough, a dew or frost. 
Quantity, The quantity of precipitation is in itself not the 
most important factor about precipitation. For all practical 
purposes, especially for agriculture, we are concerned more with 
the seasonal distribution of this precipitation. An area during 
the year may have forty inches of rain and yet have that rain so 
distributed seasonally as to make it impossible to grow crops. 
Another feature of the atmosphere’s moisture is of interest 
physiologically. An atmosphere which continues to hold a great 
deal of moisture becomes oppressively humid, and makes work 
disagreeable, particularly in warm weather; in cold weather, it 
intensifies the effect of low temperatures. 
Seasonal distribution. In Ohio we are interested in precipi- 
tation in one other particular. The unequal distribution of rain- 
fall and snowfall gives rise to floods. The earth is not able to 
soak up the moisture as fast as it comes, and the moisture has to 
run off. Along the Ohio river this is a matter of industrial con- 
cern. Shipping conveniences make it necessary for men to have 
wharves and buildings well out on the stream. A sudden change 
of twenty or thirty feet in the depth of that stream necessarily 
causes loss. If the sudden flood depth is unannounced, dis- 
asters follow; the government, therefore, under the direction of 
the Weather Bureau, times the progress and intensity of these 
floods, and has made arrangements for keeping the people down- 
stream informed; thus they have an opportunity to protect their 
property. 
A long period of either rain or drought, between early spring and 
fall, is detrimental to farming interests. Almost every year in 
some sections of the state, the farmers suffer loss either through 
