The Effects of Radio-active Ores and Residues on Plant Life. 3 



RESUME OF THE 1914 EXPERIMENTS. 



In my report of the Experiments with radio-active Ores carried out at 

 Reading in 1914 (Bulletin No. 6) I explained at some length the reasons which 

 led to instituting these tests. Briefly, these were : 



The great value of Radium in the successful treatment of certain forms of human 

 disease having been established, it had been freely suggested that its remarkable properties 

 might prove beneficial to plant life. Further, a report reached me that in Cornwall some 

 very fine crops had been obtained from poor garden ground, as the result of dressing 

 the land with soil which had been removed from a neighbouring Radium mine. In order 

 to gain more definite particulars I visited the district in question, but as the incident had 

 occurred a year or so previously I was unable to examine the results. The information 

 I gathered, however, convinced me of the desirability of undertaking, in the interests of 

 scientific research, a series of controlled experiments on a comprehensive scale. 



The first difficulty was that of obtaining radio-active Ores, but this having 

 been surmounted, another presented itself in the question of fixing the degree 

 of strength in which to use them. As at that period no controlled experiments 

 had, so far as I was aware, been conducted in this country, I had no reliable 

 data to work upon, and consequently had to more or less feel my way. I 

 therefore decided on proportions varying from i part Ore to 12 parts soil, 

 to i part Ore ta 2,240 parts soil, and to test them (a) thoroughly incorporated 

 in the soil, and (b) placed in a layer at the bottom of a pot or box. 



The radio-active Ores used in 1914 were : 



Ore A containing approximately 8 milligrammes of Radium Bromide 



per ton of Ore. 

 Ore B containing approximately 9 milligrammes of Radium Bromide 



per ton of Ore. 

 Slime, or Mine Residue containing approximately 1-8 milligrammes of 



Radium Bromide per ton. 



The subjects selected for experiment were Radishes, Lettuces, Peas, 

 and Flowering Annuals, in addition to which germination tests were made 

 with seeds of Rape, Red Clover and Smooth-stalked Meadow Grass. 

 All that was attempted was to ascertain : 



(1) Whether radio-activity has a harmful or beneficial effect upon 



plant life ; 



(2) Whether, if beneficial, strong or weak dressings of radio-active Ore 



should be employed ; and 



(3) Whether radio-active material can be used with advantage to 



accelerate germination. 



The conclusions to which I came are outlined in the following brief 

 summary of the experiments : 



Whilst not pretending that the results of a single season's experiments, embracing 

 only a few subjects, can be regarded as sufficiently definite to prove the value, or otherwise, 

 of the effects of Radium on plant life in general, the tests afford some evidence that Radium 

 possesses the property of developing and increasing growth. 



Many of the Radish, Lettuce and Pea trials which were dressed with radio-active 

 Ore showed considerable superiority over those grown in plain soil, but the cost of the 

 Ore far outweighed the worth of the larger crop. 



The quantity and degree of radio-active material required to ensure the best return 

 cannot be definitely stated, but the experiments certainly indicated that a light dressing 

 is likely to give as good results as a heavy one. 



In the trials with Rape seed, the influence of the radio-active material in accelerating 

 germination was most consistent in all the tests, but it was evident that a very small 

 quantity of low-grade Residue proved as effective as a much greater amount of Ore 

 containing a far larger proportion of Radium. 



In the germinating tests in the laboratory also there was no indication that better 

 results are obtainable with Ore possessing considerable radio-activity than^ with Residue 

 of low value, nor did these trials generally prove superior to the " Controls." 



