RECAPITULATION. 213 



uncommon, and not to be counted as a loss or disadvantage in 

 practice, in this country. 



The foregoing reasoning, and the conclusions thereby reached, in 

 regard to the duration of calcareous manures, may be deemed a 

 continuation of the subject of Chap. VIII., " on the mode of ope- 

 ration by which calcareous earth increases the fertility and pro- 

 ductiveness of soils/' It may be useful here to recapitulate, and 

 bring together in a small space, the main positions which I have 

 asserted and maintained. 



1. Besides the chemical power and action of calcareous earth as 

 manure, to neutralize acids, to alter and improve the texture of 

 soils and their relation to moisture, and also other beneficial 

 agencies, before discussed at length, the principal and most import- 

 ant action of the carbonate and other subsequently resulting salts 

 of lime, in soils, is the combining with organic or alimentary ma- 

 nures, and also with other earthy parts of the soil. The several 

 matters, so combined, are rendered, by their combination, fixed in 

 the whole soil, and secure from waste and from other diminu- 

 tion, except for the supply of alimentary matter to growing plants. 

 To this extent, then, and with the exceptions stated, the combined 

 matters would be permanent. For this purpose, and to the extent 

 required by growing plants, their vital forces can decompose the 

 combination of organic, calcareous, and other earthy constituents, 

 and take from it freely the parts which the plants require from the 

 soil for their support. The organic part of the compound is mainly 

 drawn upon, and diminished by growing plants ; the calcareous (or 

 other lime) part thus furnishes an extremely small amount only. 

 Putrescent matter, if again supplied to the soil, will replace in the 

 combination whatever organic matter had been withdrawn by grow- 

 ing plants. It the soil is not allowed to obtain the requisite sup- 

 ply of organic or putrescent matter, the fertility of the soil will 

 continue to be reduced by growing crops gradually exhausting the 

 previous supply; although the lime parts of the soil may not be 

 appreciably lessened. If, on the contrary, putrescent matter shall 

 be furnished to a calxed soil, or be permitted to accumulate in it 

 by natural means, in greater quantity than the lime parts can 

 combine with, more lime will be required. 



2. If without such state of combination existing, owing to the 

 absence or insufficient quantity of either part, the excess of the 

 other part would be subject to, and continually undergoing waste. 

 If the part in excess was the putrescent, or organic, it would 

 rapidly and entirely be removed by decomposition, solution, and 

 other natural modes of its waste. If the excessive matter was in 

 lime, whether caustic, or carbonated, or as any other soluble salts 

 of lime, this also would be gradually dissolved, and lost j and 

 though the progress of such waste would be very slow, yet in the 



