INTRODUCTION 7 



of science to subjects which so well merit to engage 

 their talents and energies. Perfect agriculture is the 

 true foundation of trade a)id industry ; it is the foun- 

 dation of the riches of states. But a rational system 

 of agriculture cannot be formed without the applica- 

 tion of scientific principles ; for such a system must be 

 based on an exact acquaintance with the means of 

 nutrition of vegetables, and with the influence of soils, 

 and actions of manures upon them. This knowledge 

 we must seek from chemistry, which teaches the mode 

 of investigating the composition and of the study of 

 the character of the different substances from which 

 plants derive their nourishment." 3 



Soon after Liebig's first work appeared the investi- 

 gations at Rothamsted by Sir J. B. Lawes were under- 

 taken. The most extensive systematic work in both 

 field experiments and laboratory investigations which 

 have ever been conducted have been carried on by 

 Lawes and Gilbert at Rothamsted, Eng. Dr. Gilbert 

 had previously been a pupil of Liebig, and his associa- 

 tion with Sir J. B. Lawes marked the establishment 

 of the second experiment station. Many of the Roth- 

 amsted experiments have been continued since 1844, 

 and results of the greatest value to agriculture have 

 been obtained. The investigations on the non-assimi- 

 lation of the atmospheric nitrogen by crops, published 

 in 1 86 1, were accepted as conclusive evidence upon 

 this much-vexed question. The work on manures, 



