468 



Messrs. A. D. Hall and C. G. T. Morison. [Dec. 22, 



growth. The use of phosphoric acid on Plot 2 reduces the percentage of 

 nitrogen in both grain and straw to a little lower than normal level, and 

 this reduction is most marked in the grain. Again, silica without phosphoric 

 acid on Plot 1 S gives rise to an intermediate curve of development, nearer 

 to the normal than to the curve representing the plot without either 

 phosphoric acid or silica. Silica added to phosphoric acid (Plot 2 S compared 

 with 2) makes practically no difference in the curve. 



ao% | 1 1 1 1 , 



-Mean 



July 4 ii 18 25 Aug. I 8 



Fig. 8. — Nitrogen. Percentage of whole content present in the Grain. Plots without 



Potash. 



Fig. 8 shows the movement of the nitrogen into the grain ; although both 

 the grain and straw of Plot 1, without phosphoric acid or silica, contain the 

 highest percentages of nitrogen, yet the proportion of the nitrogen within 

 the plant which passes over to the grain is lower on this plot than on the 

 normal ; the transfer again begins at a somewhat later date. The phos- 

 phoric acid alone on Plot 2 induces both an earlier and a greater propor- 

 tionate transfer of nitrogen to the grain than the normal. Silica on Plot 1 S 

 induces an earlier and more complete transfer of nitrogen, though not to the 

 extent caused by the phosphoric acid. On the corresponding plots with 

 potash (fig. 9) very similar results obtain: without phosphoric acid or 

 silica (Plot 3) the transfer of nitrogen to the grain lags behind the normal, 

 while the use of phosphoric acid (Plot 4) accelerates this process beyond the 

 normal, silica (Plot 3 S) acts in the same direction though not to the same 

 extent. 



