XU TREFACE. 



The truth or error of the notions which guide our 

 practice cannot, however, be regarded as a matter of 

 indifference. 



The more correct ideas wliicli science has given us of 

 the growth of plants, and the part phiyed in the process 

 by the soil, air, mechanical operations, and manure, is 

 not regarded in the hght of an improvement by the 

 practical man, simply because his ignorance does not 

 enable him to appreciate the information. Unable to 

 find out the connection between scientific teaching and the 

 phenomena presented in his daily pursuit, he naturally 

 comes to the conclusion, 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 folloAvs 

 certain authorities whose system of husbandry is lield 

 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. "Wliat Thaer discovered 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 Eothamsted have 

 become axioms for all England. 



Under the dominion of tradition and of slavish sub- 

 mission 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 explanations of any particular facts, it is 



