197 



From these figures it will be seen that in every case where 

 lithium salts, even in so small a quantity as 0.00375 P ar ts of lithium 

 in zoo parts of soil are present,' a harmful influence will be exerted 

 on a wheat crop. 



The experiments will be continued with smaller quantities of 

 lithium. 



Experiments on the influence of magnesia in soils. 



Previous experiments having shown that magnesia applied as 

 such to the soil of Stackyard Field produced very marked results 

 on the wheat crop according as the proportion of magnesia to lime 

 increased, experiments were carried out with a view of ascertain- 

 ing if this held good with the insoluble forms only, and what would 

 be the effect of magnesia in the form of carbonate, and as dolomite. 



The soil of Stackyard Field contains 0.40% of lime and 0.20% 

 of magnesia and it had been found that by adding magnesia (Mg O) 

 so as to bring the proportion of this substance in the soil above 

 that of the lime contained, the crop was proportionally diminished, 



