55 



mated optinuini, and the tumblers set away in a dark 

 closet. From lime to time, distilled water was added 

 to restore that lost by evaporation. Solutions were ob- 

 tained for analysis by washing the 100 grams of soil 

 into a jar with 500 cc of distilled water, the Jar thor- 

 oughly shaken at short intervals and then allowed to 

 settle, after which the supernatent extract was filtered 

 throuah a Pasteur-Chamberland filter. The soils were 

 incubated from June 15 to August 1, 1917. The data 

 so obtained are given in Table IX. 



Table IX. — The Influence of Ammonium Sulphate on 



the Development of Soluble Manganese in Acid 



Soils. XOr, cmd Mn. in p. p. m. of Air Dry Soils. 



