22 Hall, Hozv does the Plant obtain its nutriment ? 



EXPLANATION OF PLATES. 



Plate I. Growth of barley in solutions of varying concentration 

 but similar composition. Fig. i after 8 weeks. 

 Fig. 2 after 4 weeks. 



Plate II. Growth of barley in similar solutions diffused over 

 sand particles. Fig. i after 8 weeks. Fig. 2 after 

 4 weeks. 



Plaie HI. Growth of barley in sand through which solutions of 

 varying concentration were percolating. 



Plate IV. Growth of barley in coarse sand, fine sand, silt, 

 kaolin, and water, the solution being of the same 

 concentration in all. 



Plate V. Lupins grown under similar conditions to the barley 

 \n Plate IV., the roots washed free of the medium. 



Plate VI. Barley grown in nutrient solutions aerated once a 

 day (left) and continuously aerated (right). 



