160 T. G. YUNCKER 



It will be noted in Tables 3 and 4 that the dry series for the 

 most part weighed the most per unit area while the wet series 

 weighed the least, the medium series were intermediate. This 

 was due in part, probably, to the fact that the plants in the 

 moistest conditions were making a more rapid growth. Their 

 tissues would, therefore, be more succulent and less compact than 

 those of the drier series. The plants in the moister conditions 

 due to the accelerated growth were respiring more rapidly and 

 using the organic substances much faster than those of the drier 

 conditions. 



In comparing the results obtained in the transpiration experi- 

 ments with those of the photosynthetic it will be seen that the 

 greater amount of dry matter per unit area is produced in those 

 plants that show the lesser amount of transpiration. Thus it 

 appears that the amount of organic substance formed is not at 

 all proportional to transpiration, as has been held by some 

 authors. 



After each series were completed the soil was removed from the 

 potometers and all the soil taken from any one saturation series 

 was thoroughly mixed and a sample taken to determine the final 

 soil saturation. It was found that the moisture content did 

 not vary more than from 1-5% from the initial percentage of 

 saturation. 



SUMMARY AND CONCLUSIONS 



1. Hogue's Yellow Dent .variety of corn was used in these 

 experiments. 



2. Three degrees of soil moisture were maintained, viz. : 25%, 

 45%, and 65% of possible saturation. 



3. Glazed earthenware pots were used and filled to a depth of 

 5 cm. with gravel and an inverted flower pot to facilitate the 

 spread of water. 



4. A paraffin wax seal which does not come in contact with 

 the plants was used in the experiments. 



5. Leaf areas were figured by the use of a planimeter from trac- 

 ings made of the leaves before drying. 



