effects of radium rays in the soil i4i 



Experiment 38 

 Object : To ascertain the effect on the germination and growth of 

 wheat of the rays from RaBr, and radio-tellurium contained in sealed 

 glass tubes placed in the soil. 



June 4, II A. M. 



Twelve grains of wheat {Tri/ /cum vulgar e, Henderson's "Well- 

 man Fife ") were planted without soaking in each of four pots, A, B, 

 C, and D. Each grain was placed in the soil vertically with the 

 embryo-end down, and the embryo-side facing the center of the pot. 

 In the center of pots A, B, and C, were placed vertically the tubes of 

 RaBr^ and radio-tellurium, as follows : 



A. RaBr, 10 mg. 1,800,000 x. End about 10 mm. below the surface. 



B. " " 1,500,000 X . " " " " 



C. Radio-tellurium. " " " " 



D. Control. No tube. 



June 6. 



The tubes have been removed for 18 hours since planting. The 

 average heights of the seedlings that have come up are as follows : 



A B C D 



1,800,000 X 1.500,000 X Radio-tellurium Control 



7 up. Av. ht. 4 up. Av. ht. 3 up. Av. ht. 7 up. Av. ht. 

 3.28 mm. 4*^7 rnm. 6.33 mm. 2.58 mm. 



The tubes were replaced. 



June 7, 10 : 30 A. M. • 



A BCD 



1,800,000 X 1)500,000 X Radio-tellurium Control 



12 up. Av. ht. 12 up. Av. ht. 10 up. Av. ht. 10 up. Av. ht. 

 23.60 mm. 23.90 mm. 24.35 mm. 15. So mm. 



The tubes were again removed at 11 A. M. for another experi- 

 ment. 



