I50 



EFFECTS OF RADIOACTIVE AIR ON GROWTH 



in two pots, and the pots placed, one under each of the bell-jars, as 

 described in Experiment 41, except that the emanation was delivered 

 over the seeds from a small glass funnel, suspended over the center 

 of the pot at a distance of 50 mm. The ordinary air in the control 

 was similarly delivered over the control seeds (figure 30). 



May 30, 9: 30 A. M. 



The exposed seeds have germinated except directly under the 

 funnel, where germination has not yet begun. 



The control seeds have germinated uniformly, under the funnel 

 as well as elsewhere. 



June I, 9 A. M. 



The exposed seeds have practically all failed to germinate under 

 the funnel, but are quite evenly germinated elsewhere. Numerous 

 decidedly undersized seedlings are scattered throughout the culture. 



Fig. 31. Experiment 42. Inhibition of Germination of Timothy Grass Seed hy 

 direct exposure to Air that has passed over a surface coated with Lieber's Radium 

 Coating, and thus contains Radium Emanation. Cf. figure 30. 



The control seeds are all evenly germinated, and there is no 

 appreciable difference in their height under the funnel and elsewhere. 

 There are also very few undersized seedlings — much fewer than 

 in the exposed culture. 



Complete inhibition of germination has followed exposure under 

 the conditions described. On June i the cultures were photographed 

 (figure 31), and the experiment closed. 



