On the Chemical Properties of Soils. 



It is not my intention to expound in this place Baron Liebig's 

 views on the assimilation of the food derived by plants from the 

 soil. The changes which fertilizing matters undergo in contact with 

 soil are, as we know, so numerous and so little understood, and the 

 precise combinations in which mineral food is taken up by plants 

 so little know$, that it would be extremely hazardous to propound 

 in detail a new theory respecting the assimilation of mineral 

 food by plants. Baron Liebig, therefore, wisely refrained from 

 expressing his views on this subject in that clear and precise 

 manner which generally distinguishes his writings, and very pro- 

 perly contented himself with indicating that our present views 

 respecting the absorption of mineral matters by plants are not 

 quite correct. 



Professor Way's and my own researches certainly have shown 

 that manuring matters in contact with soil undergo remarkable 

 changes, and fully justify the statement that plants do not take 

 up mineral food in the simple state of solution in which we add 

 it to the soil in the shape of manure, but in totally different 

 states of combination. 



Again, if sandy soils had not the power of retaining soluble 

 fertilizing matters, it would be difficult to comprehend how, not- 

 withstanding the occurrence of heavy thunderstorms or long- 

 continuing rains, the effects of superphosphate or guano, or even 

 sulphate of ammonia, are clearly seen in the increased produce 

 raised on such soils by the aid of these manures. 



The quantity of water running through the soil at such times, 

 is amply sufficient completely to dissolve the soluble manuring 

 matters. If it were, therefore, quite correct that sandy soils had 

 not in any degree the power of absorbing soluble manuring 

 matters, they would be removed by the rain into the subsoil, 

 neighbouring ditch, or drain, and could scarcely produce any 

 effect upon vegetation. 



Experience teaches us that the same kinds of manure produce 

 very different practical results upon different soils. It must be ad- 

 mitted that the composition of different soils varies considerably, 

 and that this circumstance, no doubt, accounts to some extent for 

 the variations in the practical results. 



There are, however, many apparently similar soils, that is to 

 say, soils in which the analysis shows like quantities of the same 

 constituents, such as potash, soda, lime, magnesia, phosphoric, 

 sulphuric and silicic acid, and all the elements present in the 

 ashes of plants, in which, notwithstanding, the same kind of 

 manure produces a different practical result. This appears to 

 me to indicate that the analysis of soils, as usually performed by 



