178 



larger end of a cutoff condensing tube (c) was suspended over the open 

 end of the small bent tube. The upper end was connected to the cylinder 

 of solution by a glass tube (e) which extended almost to the bottom of 

 f. All connections between the glass tubes were made by tight-fitting 

 rubber tubing. The flow of air was regulated by varying the amount 

 of water that passed through the hydrant. A drain tube carried away 

 the excess of water from the pan. The apparatus stood about four feet 

 high and was held in an upright position by a ring-stand. 



r. 



'SZ 



Effect of iu'ration on roots of Zca Mays 



This apparatus was after W. Ostwald as given in his Chemico-physi- 

 cal Measurements. Aeration of plants is mentioned, however, by Julius 

 Sachs in his Vorlesunger iiber Pflanzen-physiologie, 1887, pages 268-269. 



The glass tube fed a constant supply of air into the cylinder of 

 normal solution. The two plants were started at the same time and 

 received like treatment except the aeration of the solution. 



