Time Distribution of Rain 125 



rainfall for Madison, Wisconsin, from 1887 to 1807, which was 

 less than .2 of an inch in any day of 24 hours during the periods 

 covered by the table. 



Now, these amounts of effective rain, could they be used with 

 the same economy as we were able to use them in our plant cylin- 

 ders, ought to produce the following yields per acre: 



Bu. per acre 



Barley 40.29 



Oats 64.97 



Maize 71.51 



In making these calculations, the ratio of grain to straw for 

 barley has been taken as 2 to 3, and for oats as 1 to 1.448: and 

 we have used the percentages of water in grain and straw given in 

 tables of feeding- stuffs. In the case of maize, data derived from 

 direct determinations by the writer have been used. 



It will be seen that these computed yields, although much 

 larger than average yields, are, nevertheless, very close to what is 

 expected during our best seasons, when there has been plenty of 

 rain, well distributed, and when the crop has not been affected by- 

 disease or insects. It appears, therefore, that the rainfall for the 

 thirteen states enumerated is sufficient in quantity to produce very 

 heavy crops, not only of the three grains named, but of many 

 others also. 



THE DISTRIBUTION OF EAIN IN TIME USUALLY UNFA- 

 VORABLE TO MAXIMUM YIELDS 



There is little question that in the thirteeen states named, the 

 mean yields of barley, oats and maize would easily be held to 

 41, 64 and 75 bushels per acre respectively, if it were only possible 

 to control the distribution of rain in time and in quantity, as it is 

 controlled by irrigation. As it is, however, such large mean 

 yields can never be reached by tillage alone in a territory as 

 extended as that under consideration. This will be evident from 

 the table which follows, in which the mean yields of barley, oats 



