The Wohirn Pot- Culture Experiments, 1914. 313 



of soil each, and each .experiment was in duplicate. The soil 

 used was the same as with the copper salts, and the same 

 procedure generally was followed. 



Germination was only retarded in the cases where nitrate 

 of lead was used, and also with the two heavier (-10 per cent. 

 and "05 per cent.) dressings of lead as chloride, but eventually 

 all the plants came up. Throughout the period of growth 

 they all grew well, the phosphate series perhaps looking best, 

 and then the carbonate. At first the nitrate and chloride 

 plants were behind the others, but none of them showed any 

 signs of a toxic influence being exerted. The comparative 

 harvest results are given in Table II. 



Table II. — Lead Salts on Wheat, 1914. 



It will be seen that in no case was there any sign of injury, 

 although lead had been used up to "10 per cent. Indeed, the 

 general result was to point, on the whole, to a stimulating 

 effect rather than the reverse. This was specially marked 

 with the phosphate series and the nitrate one. With the 

 carbonate and sulphate the results were very similar to the 

 untreated, and with the chloride the straw seemed to be some- 

 what reduced. 



It is quite clear, therefore, that lead can be used with 

 impunity up to '10 per cent, with any of the salts employed 

 here. 



II. The Relation of Lime to Magnesia in Soils. 



1914. The addition of Lime to a Soil rich in Magnesia. 



In this experiment a soil from Herefordshire was originally 



taken in 1909. This contained at the outset magnesia 2*29 



per cent., lime 'So per cent. Lime was subsequently added to 



