VI 



List of Illustrations. 



TEXT-FIGURES — continued . 



Page 



38. Average daily evaporation at Lincoln (solid line), Phillipsburg (long broken 



lines), and Burlington (short broken lines), 1921 84 



39. Mean precipitation in inches (black) and precipitation for 1921 at Lincoln 



(left), Phillipsburg, and Burlington 87 



40. Diagram of containers and development of barley, 1920. Positions of wax 



seals, 6 inches apart, indicated by the cross-lines 94 



41 Average daily temperature (long broken lines), humidity (upper solid line), 



and average daily evaporation at Lincoln, 1921 106 



42. Diagram of containers and root development of crops, 1921. Horizontal 



lines (6 inches apart, except in last two) indicate position of wax 



seals and double vertical lines position of nutrients 107 



