10 PREFACE. 



tice cannot, however, be regarded as a matter of indiffer- 

 ence. 



The more correct ideas which science has given us of 

 the growth of plants, and the part played in the process by 

 the soil, air, mechanical operations, and manure, is not re- 

 garded in the light of an improvement by the practical 

 man, simply because his ignorance does not enable him to 

 appreciate the information. Unable to find out the con- 

 nection between scientific teaching and the phenomena pre- 

 sented in his daily pursuit, he naturally comes to the con- 

 clusion, from his point of view, that there really exists no 

 connection between them. 



The practical agriculturist is guided by facts observed 

 in his own neighbourhood for a long period ; or, if his views 

 are more comprehensive, he follows certain authorities 

 whose system of husbandry is held to be the best. It never 

 enters into his thoughts to submit this system to proof, for 

 he has no standard of comparison at hand. What Thaer dis- 

 covered to be useful in Moglin was held to be equally so 

 for all Germany, and the facts which Lawes found to be 

 true on a very small piece of land at Rothamsted have be- 

 come axioms for all England. 



Under the dominion of tradition and of slavish submis- 

 sion to authority, the practical man has lost the faculty of 

 forming a right conception of the facts which daily pass 

 before his eyes, and in the end can no longer distinguish 

 facts from opinions. Hence, when science rejects his ex- 

 planations of any particular facts, it is asserted that the 

 facts are themselves denied. If science declares that we 

 have made progress in substituting for deficient farm-yard 

 manure its active ingredients, or that superphosphate of 

 lime is no special manure for turnips nor ammonia for 

 corn, it is imagined that the utility of these substances is 

 contested. 



Long disputes have arisen about misconceptions of this 



