68 LIME ESSENTIAL TO FERTILE SOIL. 



be considered an unnecessary digression, in a treatise on the soils 

 of the tide-water district. But the analysis of liine-stone soils 

 furnishes the strongest evidence of the remarkable and novel fact 

 of the general absence of calcareous earth and the information 

 thence derived will be used to sustain the following steps of my 

 argument. 



All the examinations of soils in this chapter concur in opposing 

 the general application of the proposition that the deficiency of 

 calcareous earth is the cause of the sterility of our soils. And 

 having stated the objection in all its force, I shall now proceed to 

 inquire into its causes, and endeavour to dispel its apparent opposi- 

 tion to my doctrine. 



CHAPTER VII. 



PROOFS OF THE EXISTENCE OF ACID AND NEUTRAL SOILS. 



PROPOSITION 2 continued. 



Sufficient evidence has been adduced to prove that many of our 

 most fertile and valuable soils are destitute of calcareous earth. 

 But it does not necessarily follow that such has always been their 

 composition ; or that they may not now contain enough lime com- 

 bined with some other acid than the carbonic. That this is really 

 the case, I shall now offer proofs to establish; and not only main- 

 tain this position with regard to those valuable soils, but shall con- 

 tend, that lime, in some proportion, combined with vegetable acid, 

 is present in every soil capable of supporting vegetation. 



But, while I shall endeavour to maintain these positions, without 

 asking or even admitting any exception, let me not be understood 

 as asserting that the degree of natural fertility of a calcareous soil 

 is in proportion to the amount of calcareous earth contained; or, 

 that the knowledge of the proportion of calcareous earth, or of lime 

 in any form, contained, would serve to measure the capacity of the 

 soil for production or for fertilization. On the contrary, chalky 

 and calcareous soils, not differing materially in agricultural qualities 

 or fertility, sometimes exhibit remarkable differences in their pro- 

 portions of calcareous earth ; so that one soil, having less than one 

 per cent., may seem as well constituted and as valuable as another 

 having ten per cent., or more. [The reason is, that a very small 

 proportion is enough for the full chemical action ; and that any 

 surplus, even if not hurtful by its amount, will have no other than 

 the comparatively feeble mechanical action which may even be 

 injurious, and in opposition to, and counteracted by the chemical 

 action.] 



