LAW OF DIMIXISIIINC IMVmJNS \7 



The (liagrani Fig. 5 shows a cH)ini)aris()n l)et\vi'('n iIk- 

 returns from these plots, (1) witli corn at 24s. a (luarlcr and 

 straw at *20s. a ton, and (2) when corn is :V2s. and straw 

 at 30s. 



The straight line indicates the cost of production taking an 

 arbitrary base of 80s. per acre for the cultivation, and adding 



Returns &. Cost 

 Shillintfs. 



Mineral Manures +200 lb. 



400 lb. 



600 lb. 



800 lb. Amm. Salts. 



Fk;. 5. — Relation between Cost of rrodiietion anil Ilelurns with varying 

 quantities of Mainirc. 



30s. for each 200 11). of ammonium-salts, ft will l.r s<'cn tliat 

 with the lower prices the crop ceases to be proiital>lc before the 

 third addition of manure is made; tiie second addition is the 

 most profitable, the extra 30s. for manine has produccMJ an 

 increased return of 30s. in the cro}). At the higiier .scale 

 of prices the crop remains profitable throughout, though the 



