86 EFFECTS OF EXPOSING SEEDS 



in the propagating-house. Control culture same as in Experiment i. 



February 9, 9 A. M. 



The cotyledons of all four seeds are emerging, but they are not 

 yet raised above the surface of the soil. 

 February 11, 3 : 30 P. M. 



The cotyledons are all clear of the ground, all spreading and 

 showing the plumule. In height the plants are intermediate between 

 the radiated and the control in Experiment i. Length of hypo- 

 cotyls above the surface of the soil as follows : 



Radium 



7.00 mm. 



13.00 



15.00 



15.00 



50.00 mm. Total. 



85.00 mm. Total. 

 Average height, 12.50 mm. Average height, 14.16 -|- mm. 



February 16, 12 M. 



Length of Hypocotyls Above the Surface of the Soil 



Total. 



April 15, 6: 20 P. M. 



Twenty seeds of " Lincoln" oats, with the glumes removed, were 

 placed in two parallel rows with the radicle ends touching and the 

 embryo side upermost. Over them was laid the tube of RaBrg 

 (1,500,000 X ), resting on the radicle ends of the seeds. 



Control with empty tube, and both sets placed in the dark room. 

 April 22, II : 30 A. M. 



After an exposure of 6 days and 15 hours, both sets of seeds 



