The Woburn Pot- Culture Experiments , 1913. 417. 
(c) The Influence of Manganese and Cerium Salts on Wheat. 
As long ago as 1904, experiments were conducted at Woburn 
which seemed to indicate that the soaking of wheat seed in a 
2 per cent, solution of the sulphate or the chloride of manganese 
produced some beneficial effect. The phosphate and carbonate 
of this metal had, however, not been tried as applications to 
the soil, and it was resolved to carry out an experiment with 
these salts, giving them in quantity to supply respectively 
•01 per cent., -005 per cent., *0025 per cent., *001 per cent, of 
manganese. 
Cerium was another metal not hitherto tried, and of this 
the oxide and sulphate were taken, the quantities given 
supplying respectively *01 per cent., -005 per cent., -0025 per 
cent., and *001 per cent, of the metal. 
These two sets were carried on side by side with the zinc 
and copper experiments just recorded, but the results were, in 
both cases, entirely negative, none of the applications showing 
any indication of stimulation or of toxic effect. Any further 
account of this work is, therefore, unnecessary. 
II. The Relation of Lime to Magnesia in Soils. 
1913. The addition of Lime to a Soil rich in Magnesia. 
The soil experimented on was the Herefordshire one which 
had been used for the work of the years 1909-12, recorded in 
the R.A.S.E. Journal 1912. 
This soil at the commencement (1909) contained magnesia 
2*29 per cent., lime -83 per cent. In that year lime was added, 
making the amounts up to 1*25 per cent., 1*50 per cent., 1*75 
per cent., 2*0 per cent., 2*25 per cent, respectively in five 
separate pots, a sixth remaining as the untreated one. In 1910 
and 1911 no further additions of lime were made, but in 1912 
more lime was added, bringing the respective percentages up 
to 2*5 per cent., 3*0 per cent., 3*5 per cent., 4*0 per cent., and 
4*5 per cent. Wheat (this being the fifth crop in succession) 
was sown on November 26, superphosphate and sulphate of 
potash were added to the soil, and, later on, a top-dressing of 
nitrate of soda was given. The germination in all cases was 
excellent, and by March 13 the lime sets looked distinctly 
better than the untreated, the latter not having tillered out in 
the same way as where lime had been applied. 
The crop with the heaviest lime dressing (4*5 per cent.) for 
a time held back behind the others, but, later on, it improved 
greatly. This was the same application which in 1912 had 
given a low result as compared with the others. 
The whole experiment was of such an instructive nature 
that it was decided to send it en bloc to the Bristol Show, where 
VOL. 74. p 
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