6 The Effects of Radio-active Ores and Residues on Plant Life. 



Statements have been made in America and elsewhere that a noticeable 

 change is to be detected in the flavour of certain vegetables when grown in 

 ground dressed with radio-active Ore. One report is to the effect that Vegetable 

 Marrows so grown possess a distinct flavour of Pine Apple ! In order to 

 obtain an authoritative opinion on this point I approached Dr. Keeble, F.R.S., 

 Director of the Royal Horticultural Gardens, Wisley (to whom I am greatly 

 indebted for much valuable advice from time to time in connection with these 

 experiments), who kindly undertook to cook and taste some Marrows for me. 

 Dr. Keeble informed me that he could find nothing in the flavour of any of the 

 Marrows grown with radio-active Ores markedly different from that of others. 



In the course of these researches I have naturally been brought into touch 

 with many others who are interested in the question of radio-active fertilisers. 

 One correspondent suggested that the danger of using radio-active Ores con- 

 taining chemicals of an injurious character could be eliminated by the 

 employment of double-walled pots, by which means the Ore would be pre- 

 vented from coming into contact with the soil. 



Professor Rusby, of Columbia University, U.S.A., has written me several 

 most interesting letters, in one of which he expressed the opinion that if 

 Radium is of value at all to plant life, it is as a stimulant rather than a 

 fertiliser. With this I entirely agree. 



Monsieur Truffaut, of Paris, in reporting upon his own experiments, 

 suggested that Radium might possess the power of releasing additional nitrogen 

 in the soil for the use of plants, and stated that those plants which had received 

 the largest dressing of radio-active material were found to suffer most from an 

 excess of nitrogen, to the point in some cases of killing them. 



It will be noticed that in several of my experiments plants dressed with 

 a Complete Fertiliser, in addition to Radium, have not done so well as those 

 dressed with the Fertiliser only, and this may perhaps be regarded as some 

 corrobo ration of Monsieur Truffaut 's conclusions. 



As is invariably the case in- experimental work, many contradictor} 7 

 results will be found in the following pages, and a close examination of the 

 trial notes together with the records of weights will furnish many highly 

 interesting problems. 



In certain sections the result given by the duplicate " Control 

 (unmanured)" varies considerably from that of the first " Control (un- 

 manured)." This is, I am aware, a factor which all experimenters have to 

 contend with. It has, however, been suggested to me that in the present 

 case the divergence may be due to Radium emanations, and in view of the 

 relative positions occupied by the " Controls " there may be some ground 

 for the idea. 



