Fig. 19. Photograph showing the action of manganese sulphate on pea plants 

 in the presence of nutrient salts. (Oct. 2nd Dec. 20th, 1912.) 



1. Control. 



2. 1/5,000 manganese sulphate. 



3. 1/10,000 

 i. 1/25,000 



5. 1/50,000 



6. 1/100,000 



7. 1/250,000 



8. 1/500,000 



9. 1/1,000,000 



