PLATE IV. 



Peas grown in soil extract containing 15.8 p. p. m. of Al., and 

 90.0 p. p. m. of Mn. 

 Fig. 1.— 



(1) Tap water. 



(2) Distilled water. 



(3) Soil extract untreated. 



(4) Soil extract plus O.G cc N/1 NaOH. 



(5) Soil extract plus 1.2 cc N/1 NaOH. 



(6) Soil extract plus 1.8 cc N/1 NaOH. 



(7) Soil extract plus 2.4 cc N/1 NaOH. 



(8) Soil extract plus 3.0 cc N/1 NaOH. 



(9) Soil extract, second leaching. 



Fig. 2.— 



(1) As in fig. 1. 



(2) As in fig. 1. 



(3) As in fig. 1. 



(10) Soil extract 75 per cent, distilled water 25 per cent. 



(11) Soil extract 50 per cent, distilled water 50 per cent. 

 <12) Soil extract 25 per cent, distilled water 75 per cent. 

 (13) Soil extract, second leaching, as (9) in fig. I. 



