BY SAND AND CLAY. 253 



gredients which influence the texture, but also the decom- 

 posable minerals, which are equally necessary for the growth 

 of vegetables. Loam, or fine gravel, spread directly upon 

 peat meadows, after they are drained, will render them fertile 

 at once ; provided that a small quantity of lime, ashes, or 

 other alkaline substance is added, to correct the acidity, and 

 dissolve the vegetable matter. 



If the soil is clayey, coarse gravel will ultimately prove the 

 most valuable, for the same reason as above, and loam or fine 

 sand will produce a more immediate effect ; hence, the de- 

 cision of this question, and the practice, w^ill be one way or 

 the other, according to the object we have in view in making 

 the improvement. If a sufficient quantity/ of loam could be 

 added, it would undoubtedly be better than either sand or 

 gravel. 



3. Clay. Sandy, light, peaty and calcareous soils are 

 often benefitted by the addition of clay. The mode of ap- 

 plying it (as derived from experience and confirmed by theo- 

 ry), is to spread it upon the soil in the fall or commencement 

 of winter, that the frost may break it down, and render it fit 

 to be intimately mingled with the soil, by the process of 

 ploughing and harrowing in the spring. Chaptal recommends 

 the practice of baking and then pulverizing, by which pro- 

 cess it approaches nearer to sand in its physical properties. 



The utility of clay in agriculture has long been acknow- 

 ledged, but the manner in which it operates is yet a little 

 doubtful. Some things, however, are well settled. It adds 

 its adhesive and retentive properties to sandy and peaty soils, 

 and furnishes one indispensable earthy ingredient ; but its 

 effects are not wholly accounted for by the texture which it 

 imparts. We must resort to its composition. Now it has 

 been found that some of our clays, especially the clay marls, 

 contain small quantities of carbonate of lime. By adding 

 one earth, therefore, we actually add two, both of which are 

 especially important to soils of the above description ; for, 



