11 



iiad been longer cultivated, and the vegetable mould, the accumula- 

 tion of centuries, had been more nearly exhausted ? 



Of the advantages in respect to fertility of a considerable propor- 

 tion of calcareous matter in soils, there is no doubt. Yet the opera- 

 tion of lime in any of its forms to the purposes of vegetation is as yet 

 a subject involved in so much obscurity, that we can hardly speak 

 upon it with any confidence ; and the particular office that it 

 performs in the wonderful processes of vegetable life and growth, 

 is among those triumphs which chemical science has yet to achieve. 



The theory of Dr. Dana, of Lowell, given in the report of the 

 learned geological surveyor, of the last year, is original and probable. 

 Future experiments, and much more extended observations are neces- 

 sary, in order to determine its soundness. The fertility of a soil de* 

 pends, to a certain extent, upon the presence of lime ; but it is not 

 in proportion to its quantity. The presence of lime in the form of a 

 carbonate amounts, it seems, in some of the fertile soils of Europe, 

 as given by the French chemists, to 25, 28, 30, and 37^ per cent.; 

 yet in some of the richest of the western soils it does not amount to 

 more than 3.3 per cent.; and lime, in all its forms, does not exceed 

 5.1 per cent. This is certainly a great disparity ; and it suggests the 

 inquiry, whether this difference is actual, or the result of different 

 modes of analysis or examination. The theory of Dr. Dana, and the 

 observations of many intelligent practical men confirm the sugges- 

 tions, implies that the office performed by lime in the soil is not pri- 

 mary, but secondary. The most productive soils are those in which 

 the various earths are compounded but not chemically combined ; 

 but the earths alone, however intermixed, will not give fertility, with- 

 out vegetable soluble matter. The quantity of lime or of silex taken 

 up in the formation of the plant is small and inconsiderable. The 

 vegetable matter in the soil constitutes the food of plants. Lime and 

 marls may be useful in their mechanical influences and changes upon 

 soils of an aluminous and argillaceous character, when applied in large 

 quantities ; a use, which the cost of lime in Massaceusetts forbids us 

 to expect will prevail to any considerable extent, excepting in the 

 limestone regions. But it would seem, that the main effects to be 

 expected from lime is in neutralizing the acids, which render a soil sour 

 and unproductive ; in converting insoluble into soluble matter ; and 

 in thus preparing the vegetable matter in the soil for the food of 



