972 
Journal of Agricultural Research 
Vol. XXin, No. I* 
A graduated pipette was used and readings were made to tenths of 
cubic centimeters. 
Temperature records were obtained by means of a Tycos Dial Type 
Mercury Recording Thermometer, manufactured by Taylor Instrument 
t«he‘ ^ at “9 me t er ^ c » s^?dard, spherical, porous, porcelain cup; T, water supply 
water From^p; CT, c^Suk^tube 1 ’ Umg tUbe COVer: M ' merCUfydr ° P to prevent retum of 
Companies, Rochester, N. Y. The daily mean temperature was calcu¬ 
lated by reading the temperatures on the charts for each half hour and 
averaging these 48 readings. The mean temperature for any given pe¬ 
riod of days was obtained by averaging the daily mean temperatures. 
