CHAPTER X 



EFFECTS ON PLANT GROWTH OF EXPOSED WATER AND 

 FRESHLY FALLEN RAIN 



I. Effects of Tap-Water Exposed to Radium Rays 



Because of the fact, now so well known, that penetrating, or 

 gamma-like radiations are present in probably all soil, the following 

 experiments were made for the purpose of ascertaining the effect on 

 germination and growth of water exposed to the penetrating rays of 

 radium, for it is evident that the water in the soil is naturally thus 

 exposed. 



Experiment 48 



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

 seeds of imbibition of water in which sealed glass tubes of radium 

 bromide have been immersed. 



April 9, 2 P. M. 



Three beakers, a, b, and c, were arranged two thirds full of 

 water, and containing {a) the tube of radium of 1,500,000 activity; 

 {b) the tube of 10,000 activity ; (c) no tube, and serving as the control. 



April 10, 5 : 30 P. M. 



After the water had been exposed to the radium rays [for 26.5 

 hrs., seeds were put to soak in each of the beakers as follows : 



12 seeds of lupine {Liifinus albus). 



15 grains of oats {^Avena: Henderson's " Lincoln"). 



8 grains of corn {Zea Mays: " Hickory King"). 



April II, 5 P. M. 



After soaking for 23.5 hrs. the seeds were all planted in soil in pots. 



The records of observations of the different seeds are given sep- 

 arately, as follows : 



Corn {Zea Mays) 

 On April 14 none of the corn grains had germinated, but on April 

 16 four seedlings were up in the 1,500,000 culture, and five in each 



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