174 PLANT GROWTH 



solution. The gravel was flooded by a simple automatic 

 device requiring attention about every day. It depends on 

 slow drip from a supply bottle, and an automatic siphon to 

 carry the solution to a bottle below when it reaches the 

 flooded stage. The siphon is shown at the end of the gravel 

 tank. 



REFERENCES 



Bear, Firman E., Soils and Fertilizers, John Wiley & Sons, Inc., 1942. 

 Gericke, W. F., Soilless Gardening, Prentice-Hall, 1940. 

 Laurie, Alex., Soilless Culture Simplified, McGraw-Hill Book Co., 1940. 

 Miller, E. C, Plant Physiology, McGraw-Hill Book Co., 1938. 



Turner, W. J., and V. M. Henry, Growing Plants in Nutrient Solutions, John Wiley and 

 Sons, 1939. 



