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



EXPERIMENTS WITH TALL NASTURTIUMS. 



In this series the radio-active Ore contained approximately 9 milligrammes 

 of Radium Bromide per ton of Ore and was obtained from a different source 

 to that experimented with in the tests already described. Mine Residue 

 after Radium had been extracted, but still retaining 1-8 milligrammes of 

 Radium Bromide per ton, was also used. These trials embraced a much 

 wider variation in the proportion of Ore or Residue allocated to the various 

 lots, and ranged from i in 14 to i in 2,240, the latter being equivalent to i Ib. 

 of radio-active material to i ton of soil. 



Large pots, partly sunk in the ground, were employed. Each set consisted 

 of four pots, four plants to a pot, making sixteen Nasturtiums in each section. 

 When the plants commenced to run they were staked with small pea sticks. 



Details of the " control " pots and the proportions of Ore, etc., used 

 are given below : 



Control Plain soil only. 



Farmyard Manure (at i 5 tons per acre) added to soil. 



Guano (at i oz. per sq. yard) added to soil. 



i part Ore in 14 parts of soil. Ore mixed in soil. 



<: 



en 



14 

 28 

 28 

 56 

 56 



.. I 12 



112 



., 224 



224 



448 



448 



2,24O 



,, 2,24O 



Residue in 14 



H 

 28 

 28 

 56 

 56 



I 12 



112 



224 



224 



448 



448 



2,240 



2,24O 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



Ore mixed in soil. 



Ore placed at bottom of box. 



From the outset it was noticed that the two sections dressed respectively 

 with farmyard manure and guano showed the most vigorous growth, the 

 latter also bearing the largest leaves. In the matter of earliness to flower, 

 there was really no difference to be seen, but in the amount of blossom produced, 

 the radio-active Ore, i in 14, appeared to yield the most. During the later 

 stages it was difficult to find any distinction between the several lots treated 



