Field Experiments on Clover- Seeds. 473 



object in view, tlie farmer selects for liis trials two, three, or 

 more fertilizers, which are either recommended to him by 

 manure merchants, or by their general reputation. Practical 

 experiments of that kind, continued for a numl)er of years and 

 tried upon a A\iriety of crops, no doubt teach many a useful 

 lesson. I do not, therefore, like to say a single word which 

 might appear to disparage such attempts made by the farmer to 

 gain experience in his own way ; nay, 1 have a strong convic- 

 tion that it is better for a man to anange and observe field- 

 trials, though they may not be conceived in the most philoso- 

 phical manner, or carried out with the greatest precision, than to 

 abstain altogether from manifesting- an interest in this matter. 

 At the same time, however, it is a fact that purely practical 

 experiments, professedly made with no other object in view but 

 to test the money-value of certain manures, frequently do not 

 elicit the information which is sought for, but rather lead to mis- 

 conceptions. At the best such experiments are rarely of any 

 value to others differently situated as regards climate or soil, 

 and they certainly do not furnish serviceable facts in building 

 up agriculture as a practical science, Avhich should ever be the 

 aim of the scientific agriculturist. 



If it be borne in mind that the main purpose for which the 

 experiments described in the following pages were instituted, 

 was not to find out the most beneficial artificial manure for a 

 crop of seeds, surprise will not be felt at my excluding from my 

 scheme guano and other complex manures, more likely to give 

 a good economical result than several of the simple saline mat- 

 ters which were actually tried. 



The final aim of all field-trials with manures is to obtain a 

 maximum produce at the least expense, without injuring the 

 land. This most desirable practical advantage, however, is 

 rarely if ever secured at once by direct manuring experiments ; 

 generally speaking, the way leading to its final realization has 

 to be prepared by many preliminary trials, which do not appear 

 to have any direct relation to the final object, but nevertheless 

 miust be regarded as important and indispensable steps towards 

 its attainment. 



As long as we do not know what are the separate effects which 

 salts of potash, or of soda, or of ammonia are capable of pro- 

 ducing when applied to our different crops under the great 

 variety of conditions in which they may be grown, it is not 

 likely that the most profitable use will be made of those complex 

 artificial manures which are now so largely manufactured in 

 England or imported from abroad, and are recommended by 

 dealers in manures more or less confidently for special purposes. 



