284 EXPERIMENTS. [CH. XV 



Experiments on inorganic salts. 



(1) Compare the amounts of ash which are obtained 

 from equal dry weights of leaves of normal and etiolated 

 potato plants. 



Weigh the sulphated ash. 



(2) Compare p.c. of PjOb and alkalis (soda and potassa) 

 in the ash of young leaves and of grains of wheat or barley. 



Obtain normal ash and estimate P2O5 and alkalis as 

 directed on p. 282. 



(3) Compare the amounts of calcium oxalate in young 

 and old leaves of Sempervivv/m tectorum. 



