THE MOVEMENT OF WATER ETC. 121 



Iron, which is absolutely necessary for the formation of 

 chlorophyll, is derived from its different compounds. 



Besides the above mentioned elements, Chlorine, which 

 is derived from chlorides, is necessary to the normal develop- 

 ment of some plants, as the Soba {Fagopyrum esculentum); 

 and Silicon, which is taken up by plants in the form of 

 .silicates or silicic acid, is important in some plants, as the 

 Take, in giving firmness and rigidity to their tissues. 



In order to prepare a solution for water-culture, one of the following 

 groups of chemical compounds may be taken. 



1. 2. 3. 



Distilled water, Distilled water, Distilled water, 



Potassium nitrate, Potassium nitrate, Potassium sulphate, 

 Calcium sulphate, Potassium superphosphate, Calcium nitrate, 



Magnesium sulphate, Magnesium sulphate, Magnesium phosphate. 



Calcium phosphate, Calcium nitrate, Ammonium nitrate, 



Ferrous sulphate. Ferrous phosphate, Ferrous chloride. 

 Sodium chloride. 



5. THE MOVEMENT OF WATER AND SUBSTANCES IN 

 SOLUTION ABSORBED BY THE ROOT. 



If a living branch of the Sakura be cut off and put into a 

 vessel containing a solution of amlin-violet, it will be seen 

 that the colouring-matter rises through the xylem with the 

 water. 



If the bark of the jSakura be cut away in the form of a 

 -ring around the circumference, the leaves will not wither. 



If the stem of the Hechima (Luffa Petola) be cut off ten 

 or more inches above the ground, watery fluid will flow out 

 from the cut surface of that portion of the stem which is 

 connected with the root. 



From the first and second experiments it will be known 

 that water and substances in solution absorbed by the root 

 are conveyed upward passing through the xylem, in which 



