PLATE 3 

 Treatment of Pots reading from left to right 

 Pot 11. 62.08 grams of CaS0,.2H,0. 



Pots 12 and 13. 6.00 grams eacli of CuSOi as anhydrous salt. 

 Pots 14 and 15. 30.00 grams each of FeSOi as anhydrous salt. 



[288] 



