J. J. Griffith 391 



Tlic liio.st iinpoitaiit features of the results of this experiiueut arc 

 (rt) The reduction in the weight of straw but not of grain in the 



blende pots. 



(b) The remarkable increase in crop production due to the ap])lica- 



tion of iron pyrites. This was largely due to improved tillering. 



6. Effects of Blende and of Pyrites upon Trifolium incarnatum. 



Trifolium was taken as a catch crop after the oat crop of Experi- 

 ment 5. Germination was satisfactory throughout; but gradually the 

 plants pei'ished so that in six weeks time there were none left except in 

 the control pots. 



7. A crop of n^ustard was taken after the trifolium of Experi- 

 ment 6. The results are given in Table XVI. 



Table XVI. 

 Effects of Blende and Pyrites upon Mustard. 



No. of pots Weight of crop (gm.) 

 35, 36 and 37 16- 1 



38 and 39 (05% 7m) 6-8 



23 and 24 (-2 % FeSj) 5-2 



With -J, -2 and •4 per cent. Zn and with -8 per cent, pyrites the 

 plants flourished for a time but subsequently perished. 



II. Remedial Measures to combat the Influences of Mine 



Refuse. 



1. Two soils A and B were obtained from fields known to be badly 

 affected. 



Soil A contained -48 per cent. Pb, -30 per cent. Zn. 



Soil B contained 1-43 per cent. Pb, -02 per cent. Zn, -W per cent. Cu. 



