IOWA ACADEMY OF SCIENCE 
81 
Mean Surface Temperature. 1900. 
Observations taken at 8 a. m. and 8 p. ni., 75tli meridian time. 
Average D’aily Departure from Normal Temperature of Crop Season of 1900, 
March 1-October 8. Shaded portions show excess ( + ) and unshaded portions defi- 
ciency ( — ) of temperature. Figures show mean daily excess ( + ) or deficiency 
(— ) over areas bounded by light lines. 
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