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XX. — On the Physical Properties of Soil, and on the Means of 

 Investigating them. By Professor Schubler^ of the University 

 of Tubingen.* 



[The present paper differs from those which have come before, as belonging to 

 the theory, not to the practice of husbandry ; and attempting, therefore, to ascer- 

 tain, not what are the means by the employment of which we may succeed in 

 effecting a particular object, but what are the laws of nature under which all our 

 operations are to be carried on. Both these branches must be followed out toge- 

 ther, but distinctly, in order to render our science complete. Theory must not 

 pretend to teach the occupier of land how he is to manage his farm ; but so 

 neither should the abstract inquirer, while he keeps within his own bounds, be 

 regarded as visionary by the practical farmer. Some of the results brought out 

 in this paper are striking, others will appear inconsiderable ; )^et even these last 

 must not therefore be condemned as useless, because it is essential that, in specu- 

 lating on the causes of such effects as come before us in actual husbandry, we 

 should know not only what hidden powers of nature are operative, but also which 

 of them are incapable of exerting any considerable influence on vegetable or 

 animal life : just as a map points out to the sailor not only those openings of the 

 coast which will afford him a passage, but those also which he must not enter 

 because further progress is barred. — Ph. Pusey.] 



Soils are essentially different in their elementary nature, accord- 

 ing to the particular earths which they contain, and the various 

 proportions in which those earths enter into their composition ; 

 but soils possessing the very same chemical elements may be 

 endued with widely different properties, in an agricultural point 

 of view, according to the mechanical state of fineness or coarse- 

 ness of their particles, and the degree of looseness or firmness of 

 texture resulting from their mode of union. The investigation of 

 these physical properties, as they are called, is of the highest im- 

 portance in bringing us acquainted with the nature of soils and 

 the various means within our power of modifying and improving 

 them according to the given circumstances of the case or the in- 

 tentions which the cultivator of the land has in view. 



The several physical properties which may be supposed to exert 

 a greater or less influence on the fertility of soils, and which on 

 that account we shall more closely investigate, are the following : — 



I. The weight of the soil; its specific gravity, as well as the 

 absolute weight of a given bulk in a dry and moist state. 

 II. Its power of containing water, according to weight and bulk. 



* This dissertation forms the Second Section of * Agronomy/ in a Ger- 

 man work entitled, ' Principles of Agricultural Chemistry, in more direct 

 reference to the Economy of Agriculture and Forestry,' by Professor 

 Schiibler, of the University of Tiibingen: second edition, revised and im- 

 proved by Professor Krutzsch, of the ' Forest and Agricultural Academy of 

 Tharand,' in Saxony, 1838. Translated from the German by the Secretary 

 and Editor of the Society ; who has great pleasure in acknowledging the 

 essential obligations under which his version is laid, in its literary character 

 as well as in its scientific points of interest, by the suggestions, revision, 

 and friendly criticism of Piiilip Pusey, Esq., M.P., one of the members of 

 the Journal Committee. 



VOL. I. 



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