444 SELECTIONS FROM ADDRESSES. 



ly to appropriate them, is a subject of high importance in econ- 

 omical agriculture, and is one which will occupy our special 

 attention. 



By chemical analysis of the crops, grown upon any soil, we 

 are enabled to discover exactly how much of each ingredient, 

 essential to the growth of plants, has been removed from it, 

 and, if we sell the produce of the land, we should estimate the 

 nature and amount of the mineral salts we have removed, in 

 order to enable us to restore, in some form, those ingredients 

 to the soil, which would be ultimately exhausted if this were 

 not done. 



By analysis of the soil, we learn how much of each of these 

 Ingredients exists in it, and by comparison, of the analj^'ses of 

 fertile with those of exhausted soils, the exact difference may 

 be pointed out, and the deficient ingredients may be supplied 

 so as to renovate the soil. 



Chemical science is able to discover the cheapest and best 

 methods of rendering soils fertile, and not unfrequently the 

 sources from whence the wanting ingredients may be obtained, 

 by simple processes, may be indicated. 



In order to renovate a soil, by restoring the substances re- 

 moved from it by crops, we must consider what state the mat- 

 ters should be in, for the production of the best effects, and for 

 long continued action. This requires the joint efforts of the 

 chemist and farmer ; for practical experiments in the field are 

 necessary for the verification of the researches made in the lab- 

 oratory ; and several years, or an entire rotation of crops is 

 needed, to render the value of a new method of manuring 

 certain. 



By hasty generalizations and mere dogmatism, some writers 

 on agricultural chemisty have disappointed and disgusted many 

 sensible practical farmers, and the reproaches which have been 

 cast on book farming are too often well merited ; but they 

 should be referred to the book makers, and not to the science 

 of agriculture, which is not responsible for the errors of all its 

 votaries, whether in the laboratory, the garden, or the field. 

 The farmer requires some knowledge of the science of chem- 

 istry, to be able to judge of the value of books treating of the 



