Jar 1 contained in weight one-eighth grass mixed with pow- 

 dered quartz ; no other fertilizer. 



Jar 2 contained ordinary farm land and fertilizer in the pro- 

 portion : phosphorus 10 per cent., potash 6 per cent., and nitro- 

 gen 4 per cent. 



Jar 3 contained ordinary fertile farm soil. 



Seed was planted the same time in each jar. The growth in 

 Jar 1 illustrates how well green manure supplies plant food. 



