Fig. 7. Photograph showing the action of anhydrous zinc sulphate on pea plants in 

 the presence of nutrient salts. (Sept. 30th Dec. 20th, 1912.) 



1. 

 2. 



3. 



4. 

 5. 



6. 



7. 

 8. 

 9. 



Control. 



1/5,000 



1/10.000 



1/50,000 



1/100,000 



1/250,000 



1/500,000 



1/1,000,000 



1/2,500,000 



zinc sulphate. 



