No. 4.] COMMERCIAL PLANT FOOD. 71 



of five were capable of truth telling, should we exhort the 

 one to lie, or attempt to reform the other four? 



But can a farmer come to know from his own observa- 

 tions what are the elements of plant food of which he is 

 most in need, or must he depend upon others to decide this 

 matter for him ? Years ago I was an assistant to Prof. W. 

 O. At water at the time when he was conducting experiments 

 in several States with various plant food mixtures, and I 

 have not forgotten the striking facts develo})ed by these few 

 tests. On certain farms in the Connecticut valley the only 

 ingredient which seemed to cause any material increase of 

 cro}) was potash, while in Maine phosphoric acid exerted 

 a predominating influence ; and it was clearly evident that 

 it would be unwise for the farmers of the two locations to 

 purchase plant food in the same proportions. But you say 

 that in these cases the farmers had ex})ert help in discov- 

 ering their need«, and without that aid they would not 

 have succeeded so well. I am not so impressed with the 

 impotence of farmers as some are. When they are con- 

 vinced of the importance of any fact or principle in their 

 practice, they have not shown utter inability to master it. 

 As a matter of foct, a goodly number of crop producers 

 have already taken intelligent direction of their plant-food 

 supply, and the dealers are simply complying with their 

 requests. Does a farmer wish to know whether he shall 

 buy generously of potash, or not ? Let him purchase a dis- 

 solved bone or an acid phosphate and an ammoniate, leaving 

 out the potash, and carefully note the results. Is. he a dairy 

 farmer, who is buying large amounts of nitrogenous foods? 

 Let him supplement his farm manures, if he must supple- 

 ment them at all, with an acid phosphate, or an acid phos- 

 phate combined with a potash salt, and, in comparing the 

 eflect of this mixture with that of a superphosphate con- 

 taining nitrogen, learn whether he can afford to further 

 invest in this latter costly element. Is he a farmer who 

 tills a limited garden area in the summer and a still more 

 limited surfiice under glass in winter? Let him consider 

 whether he should not take the special needs of his par- 

 ticular crops as a guide in his ])ractice, and so use larger 

 proportions of potash and nitrogen than the average super- 



