14 AMERICAN HUSBANDRY. 



pulverization was thoroughly attended to. Chym- 

 istry had not then shown the nature of the earths, or 

 the part they perform in vegetation, nor had the nu- 

 tiitive principles of matter been ascertained to the 

 degree they have been by the labours of Chaptal 

 and Davy. The error of Tull, therefore, vi'as a par- 

 donable, though a most pernicious one, as, by al- 

 lowing manures to act only mechanically, or as the 

 addition of so much common earth, he conceived 

 they might be entirely dispensed with, provided the 

 system of pulverization was closely followed. TuU's 

 theory attracted much ' attention, as it seemed to 

 establish the position that where manures were lim- 

 ited and labour abundant (precisely the case of Eng- 

 land), the application of this labour to the soil, with- 

 out reference to manures, could supply any supposed 

 increase of population with food. His theory he 

 was accustomed to sum up in these words : " By 

 continually stirring the earth, we may keep it con- 

 tinually fertile." Tull lived, however, to witness 

 the fallacy of his conclusions, and found that he 

 had carried his imagmations too far; as the deterio- 

 ration of the soil of his extensive farm, subjected to 

 his mode of treatment and experiments, so far re- 

 duced his crops as seriously to impair his fortune 

 and his prospects. The introduction of the drill 

 husbandr)' must, however, be considered a great ad- 

 vance in agriculture ; and even his errors were not 

 without their use, by directing the attention of re- 

 flecting and practical men to the causes of his fail- 

 ure, and serving as warnings not to deviate, in c ulti- 

 vating the soil, so widely from the course nature so 

 clearly points out. It served to demonstrate the 

 value and necessity of manures, and the propriety 

 of a^change or rotation of crops ; things which Tull 

 most pointedly opposed. Tull admitted the value 

 of a change of seed, while he derided the idea of a 

 change of crop, and was severe on Woodward and 

 Bradley in the controversy to which his opinions 



