62 



THE RUSTS OF GRAINS IN THE UNITED STATES. 



heading of the grain, that is, the main growing period, it is seen that 

 in 1903 the monthly precipitation was above normal in all the States 

 with the exception of North Dakota, averaging 0.68 inch above 

 (D): in 1904 the monthly precipitation was above normal in only 

 three States, Kansas, Missouri, and North Dakota, being below nor- 

 mal in all the others, averaging slightly above normal for the dis- 

 trict (E); and in 1905 

 the monthly precipita- 

 tion was above normal 

 in all the States with 

 the exception of Mis- 

 souri, averaging 1.29 

 inches above normal 

 (F). In considering 

 the month during 

 which the grain in the 

 different States heads 

 out, it is seen that in 



1903 the precipitation 

 was below normal in 

 Texas, Nebraska, Iowa, 

 and Korth Dakota, and 

 above normal in the 

 other States, averag- 

 ing 0.78 inch above for 

 the district (67). In 



1904 precipitation was 

 above normal in some 

 States and below nor- 

 mal in others, averag- 

 ing about normal for 

 the district (H). In 



1905 precipitation was 

 generally excessive 

 over the whole region, 

 1.05 inches above for 



7EX. 



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Fig. 1. — Precipitation chart, showing average monthly departure 

 from normal in several States in 1903, 1904, and 1905. X, Normal 

 line for a 7-month period preceding the maturity of the grain; X', 

 normal line for a 3-month period preceding the maturity of the 

 grain; X", normal line for 1 month including the heading period; 

 A, D, and G, lines for 1903; B, E, and H, for 1904; and C, F, and I, 

 for 1905. The lines show departure of precipitation from normal 

 during the periods indicated, respectively, the distance between 

 two adjacent horizontal lines representing 1 inch of rainfall. 



with the exception of Wisconsin, averaging 

 the States collectively (/). 



In considering the precipitation record for the three years, whether 

 for the seven months preceding harvest, for the 3-month growing 

 period in each State, or for the month in which the heading period 

 occurs in each State, it is found that the year 1905 was wetter than 

 either of the other two. If rust depends wholly on the amount of 

 precipitation, whether in a 7-month period, 3-month growing period, 

 or 1-month heading period, the year 1905 should have had more 



216 



