Fis. 7. 



Photograph showing tlie action of anhydrous zinc sulphate on jiea plants in 

 the presence of nutrient salts. (Sept. 30th— Der. -iOth, iyf2.) 



1. 



2. 



3. 

 4. 

 5. 

 6. 



7. 

 8. 

 9. 



Control. 

 1/5,000 



1/io.onn 



1/50,000 



1/100,000 



1/250,000 



1/500,000 



1/1,000,000 



1/2,500,000 



zinc sulphate. 



