The Bulletin. 



9 



is necospnry in mnkinc; a fertilizer formnla in the nsnnl way. When 

 it is desired, for instance, to apply the equivalent of 5U0 ponnds per 

 acre of a fertilizer niixtnre containin"^ 10 per cent avaihihlc phos- 

 phoric acid, H per cent potash and 5 per cent nitrogen, or i'yO ponnds 

 phosjihoric acid, 7^^ pounds potash, and 25 ponnds of nitrogen, it is 

 only necessary to divide the number of ponnds of ])lant food desired 

 per acre (50, 7:^ and 25) hy the percentage composition of the 

 materials to be used as follows: 



