264 



similar apparatus was set up as a barometer November 29 and has 

 supported a mercury column representing a complete atmospheric pres- 

 sure since that time (5 mos., 7 days). The mercury rises and falls 

 with the changes in atmospheric conditions, but no fall attributable 

 to the penetration of air through the membrane has taken place. 



No effort has been made to extend these studies beyond the limits 

 indicated in the title of the paper, but as a matter of interest the ap- 

 paratus was set up as an osmometer with a saturated solution of 

 sodium chloride on the inside of the membrane and distilled water on 

 the outside. The contents of the upper tube, a cross-section of which 

 had the same area as the exposed membrane, rose at the rate of 43^ 

 cm. a day for four days. Before the rise had ceased the liquid out- 

 side the membrane was tested with silver nitrate for the presence of 

 sodium chlorid'e. The test showed the presence of the salt in large 

 quantities. 



From these experiments it may be concluded that under the con- 

 ditions described the membrane is impermeable to kerosene and to 

 atmospheric gases, but that it is permeable to sodium chloride. 



6. MOISTUEE CONTENT OF THE GKAINS 



The data thus far discussed pertain to the corn which was 

 thoroughly air-dried before it was immersed in kerosene. The fol- 

 lowing experiments show the effects of similar treatments on grains 

 containing different amounts of moisture at the time of immersion. 



Series C 



Tables II to 14 inclusizr. The effects of different amounts of 

 ivater in the grains at time of immersion in kerosene. Champion 

 White Pearl Corn germinated in a 2^% saturated soil. 



Table 11. Water in Grains Desiccated to Constant Weight at 100° C. 



Table 12. Old Corn. Water Content Equivalent to 2.19 per cent, of Dry Weight 



