" I hold in my band and deliver to you one of the Copley 

 medals, which has been awarded by us to Professor Liebig. 

 My principal difficulty, in the present exercise of this, the 

 most agreeable part of rny official duty, is to know, whether 

 to consider M. Liebig's inquiries as most important in a 

 chemical or in a physiological light ; however that may be, 

 he has a double claim on the scientific world, enhanced by 

 the practical and useful ends to which he has turned his 

 discoveries." 



"It is the best book," writes Mr. Nuttall, "ever pub- 

 lished on Vegetable Chemistry as applied to Agriculture, 

 and calculated undoubtedly to produce a new era in the 

 science." 



Extract from a letter from Mr. Colman, Commissioner for 

 the Agricultural Survey of Massachusetts, dated February 

 15th, 1841 ; 



"It is the most valuable contribution to Agricultural sci- 

 ence, which has come within my knowledge. It takes new 

 views on many subjects, which have been long discussed 

 without any progress towards determinate conclusions ; and 

 reveals principles, which are of the highest importance. 

 Some of these principles require further elucidation and 

 proof; but, in general, they are so well established by facts 

 within my own observation, that in my opinion the truth, if 

 not already reached, is not far distant." 



From Silliman's Journal, January, 1841 ; 

 " It is not too much to say, that the publication of Profes- 

 sor Liebig's Organic Chemistry of Agriculture, constitutes 

 an era of great importance in the history of Agricultural 

 science. Its acceptance as a standard is unavoidable, for , fol- 

 lowing closely in the straight path of inductive philosophy, the 

 conclusions which are drawn from its data are incontrovertible." 

 "To some, the style of this work may seem somewhat 

 obscure ; but it will be found, on a re-perusal, that great 

 condensation, brevity, and terseness, have been mistaken 

 for obscurity." "We can truly say, that we have never 

 risen from the perusal of a book with a more thorough con- 

 viction of the profound knowledge, extensive reading, and 

 practical research of its author, and of the invincible power 

 and importance of its reasonings and conclusions, than we 

 have gained from the present volume." 



