VALUE OF ARTIFICIAL MANURES. 35 



dangerous thing to say, for some people have taken a strong fancy 

 for salt, and if they are told to mix guano with sand, it will sound 

 far too homely. They are much more likely to follow your 

 advice if you tell them to mix it with salt. Therefore it is some- 

 times advisable not to say the exact thing : a little mystery might 

 be, perhaps, under existing circumstances the best ; but, for my 

 own part, I have a great horror for anything like humbugging the 

 practical man. It is not by blind experiments that any great 

 success can well be realised in farming matters. Nor is it by mere 

 theoretical speculations that agriculture will be greatly advanced ; 

 but it is by the joint labours of the practical man in the field, 

 and the researches of the man of science, that great and important 

 results may be confidently expected. 



In the next place I would observe that there are circumstances 

 over which the farmers frequently have no control which greatly 

 influence the efficacy of manures. For instance, you cannot 

 always make certain of good seasons ; and in a bad season the 

 worst manures frequently have as good a chance as the very best. 

 Then, again, you cannot control diseases in plants. You will 

 often find that diseases in a mysterious way attack the wheat 

 crop ; and the fly carries off the turnip plant. All these matters 

 have to be well weighed before you can really come to a just con- 

 clusion respecting the practical value of artificial manures. 



Now, I do not mean to say that in the long run the real value 

 of any description of manure will not be clearly defined. Prac- 

 tical experience has shown that only those manures which contain 

 a large amount of ammonia, or a large amount of phosphate, or 

 both, are really efficient manures. But, supposing you have 

 ascertained that a certain description of manure is efficacious for 

 a particular purpose, say the raising of turnips, how is the farmer 

 to decide what he is to pay for it ? In other words, how can he 

 estimate the money value of the artificial manures which he buys? 

 Now, as hinted already, I would say, the practical value of a 

 manure does not necessarily coincide with its money value. 

 Lirne on soils deficient in that substance produces a very powerful 

 effect ; on some clay soils it is the manure which ought to be 

 used ; but what will you say of a farmer if he gives for lime the 

 same amount of money which he pays for guano ? With great 

 propriety you will say he is a fool. Supposing such a person 

 should say, " I don't care for the value of lime ; I want a good crop, 

 and I am satisfied with the result ; " the man who sold him lime 

 will have a good laugh at him. You may think that I am using 

 exaggerated language, for nobody in his proper senses would 

 reason thus ; but allow me to observe that there is no exaggeration 

 if you replace the word lime by artificial manures. There are 

 manures sold in the market which are not worth one quarter the 



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