5° 
The Ohio Naturalist. 
[Vol. VII, No. 3, 
By a comparison of these curves it is comparatively easy 
to see the relation between the weather and crop yield, insofar 
as the average temperature and total rainfall of whole months 
affect the yield. It is apparent, however, that for some of the 
crops the period of usually favorable or unfavorable weather are 
less than one month in length and are not shown in the monthly 
data. 
It is probable that wheat, for example, is affected by alter¬ 
nate freezing and thawing, short periods of severe cold, snow 
covering, etc., more than by monthly temperature of precipita¬ 
tion conditions. The February preceding the lowest wheat yield 
of the period gave the coldest week ever experienced in many 
sections of the State. The low yield of 1875 was preceded by 
the coldest winter on record, that of 1896 was preceded by a very 
cold January and that of 1900 by a cold February and" March. 
The good yields of 1891, 1984 and 1898 were preceded by mild 
winters. 
Fig. 1. Precipitation for July and yield of corn per acre. 
The relation between the yield of corn and the rainfall in 
July is not so well marked in a small district as in a large one, 
yet nearly every year with a large corn yield in this county had 
a^Julvi rainfall above the normal, and nearly every year with 
ajsmall yield of corn had a small July rainfall. One exception, 
however, was the year 1S83 which had a July rainfall above the 
