Effect of Organic Substances on Copper Sulphate 287 



into percentage of the initial numbers, and these resuUs have Ixtn 

 used in the discussion of the table. 



In each case in which copper sulphate was used the control con- 

 tained an equimolar amount of potassium sulphate. The controls 

 therefore differed from the tests simply in the substitution of potas- 

 sium for the copper. 



EXPERIMENT 4. 

 Started February 13, 1006. 



Temperature, 2o°-24°, 



"Best water" is ammonia-free, distilled water. 



EXPERIMENT 5. 

 Started Febrdary 15, 1906. 



Temperature, 22°-24°. 



EXPERIMENT 6. 

 Started February 20, 1906. 



Temperature, 21-23' 



