On the Chemical Properties of Soils. 5 



chemists, does not afford in all cases a sufficient guide to estimate 

 their agricultural capabilities, nor to point out the kind of manure 

 which is particularly well adapted for the special crop which we 

 wish to raise. Even a detailed analysis of a soil gives only the 

 proportions of the different soil-constituents, but generally without 

 reference to the states of combination in which they exist in the 

 soil ; and is altogether silent on the property possessed by all soils, 

 in a higher or lower degree, of effecting striking and important 

 changes in the manuring matters which are placed upon the 

 land. 



That this property belongs to every soil has been recently shown 

 by me and others who have investigated this subject. It has 

 likewise been shown that some soils possess the power of modify- 

 ing the composition of manures much more thoroughly than others. 

 It is, therefore, reasonable to connect the agricultural capabilities 

 of soils in a great measure with their power of retaining certain 

 fertilizing matters with avidity, and of modifying others in a most 

 interesting and unexpected manner. 



It is hardly necessary to dwell upon the importance of an 

 accurate knowledge of the inherent capacity of soils to work up, 

 so to speak, the crude fertilizing matters into new combinations ; 

 to allow the free percolation of other it may be less needful 

 substances, and to provide for a constant supply of food which 

 is neither so soluble as to injure the produce, nor so insoluble 

 as to remain inactive. 



The investigation of the exact circumstances under which these 

 properties manifest themselves demands our serious and imme- 

 diate attention. We stand on the threshold of a wide and fertile 

 field of research, and cannot hope to make any material progress 

 in the practical cultivation of soils and the economy of manures 

 until this subject has been to some extent investigated in a 

 truly scientific manner, independently of all direct application. 

 Useful applications will as assuredly fellow from the sure esta- 

 blishment and clear recognition of scientific principles, as good 

 works from the principle of Christian love deeply engraven in 

 the heart of man. 



It must, therefore, ever be the primary object of every student 

 of nature to increase our knowledge of scientific facts, and thus 

 to furnish the materials from which principles can be deduced, 

 and upon which rational theories can be built. Perhaps no 

 theory in physical science is absolutely true ; nevertheless if it 

 fulfil the chief purpose of every good theory, that is, the arrange- 

 ment of existing scientific facts in a comprehensive form, and 

 their preservation as a common inheritance to mankind, and so 



B 2 



