^OG ON THE COMPOSITION OF SOILS, &C. 



from its vicinity to the sea, it derives its prolific 

 powers from the salt water ; but by adverting to 

 the principles I have laid down, a much more 

 probable arrangement and combination may be 

 suggested. In the first place, we may suppose 

 that the mechanical texture of the soil and sub- 

 soil is such, and so situated, as not only to 

 obtain a supply of fresh water, but to admit of, 

 and facilitate, a constantly ascending and de- 

 scending motion of such water; and that its 

 chemical constitution is such, as to facilitate the 

 decomposition and reduction of the roots, leaves, 

 and stalks of the vegetables, regularly deprived 

 of life, to a soluble state, without the process of 

 putrefaction, and its consequent loss in car- 

 buretted hydrogene gas, &c. 



All calcareous earths may alike possess anti- 

 septic powers, but all do not possess the capa- 

 city of operating so effectually as that here de- 

 scribed, to supply the requisite motion, change, 

 and quantity of water, by percolation and capil- 

 lary attraction, and consequently no other can be 

 equal in its fertility. 



Sir H. Davy has given a minute analysis and 

 description of almost every kind of soil, and 

 explained the means of chemical investigation. 

 But as, I think, what has been said will be suffi- 

 cient to enable every person to form a pretty 



