206 THE COMPLETE FARMER 



sometimes sand and sometimes clay preponderates, general- 

 ly the former. Tiie sand marl, whether shell or schistus, 

 should be applied to clays ; and clay marls to sands. In 

 both cases they correct the defects of the soil, by rendering 

 it, in the first, less adhesive ; and, in the latter, less open and 

 porous. 



The earths are not the food of plants. They constitute 

 the stomach, analogous to the stomach of animals, in which 

 vegetable and animal matter is received, digested, and with 

 the aid of the leaves [lungs] assimilated to vegetable chyle 

 and blood. The best soil for this digestive process is that 

 in which the three above-named earths are suitably blended. 



A sandy or gravelly soil is called hungry, because it digests 

 rapidly, and dissipates the food committed to its bosom. 

 Hence green crops, or frequent manurings, are necessary to 

 continue it healthy and productive. Such soils are defec- 

 tive in clay and calcareous matter. Their texture may 

 therefore be improved, and their fertility increased, by the 

 application of clay marl ; or, what is the same, by clay and 

 lime separately; though these materials are found most pure 

 and best blended in the substance of marl. The quantity 

 should be proportioned to the natural deficiency of these 

 materials in the soil. From eight to one hundred loads per 

 acre have been applied in one or two dressings; and their 

 beneficial effects have been known to continue thirty years. 

 All the sand soils of Norfolk, England, have been marled, 

 [clayed.] Calcareous matter, combined with sulphuric acid, 

 [oil of vitriol] is usefully applied to soils in the form of gyp- 

 sum, or plaster of Paris ; as is also powdered limestone and 

 chalk, both calcareous. I am induced to believe that neither 

 wheat nor sainfoin grass will thrive in a soil destitute of cal- 

 careous matter, which is the condition \vith most of our sands. 



A stiff, moist clay, is called cold, and is unfriendly to the 

 finer grasses as well as grains. Its texture is too compact 

 to permit the roots to extend freely, and its temperature too 

 cold to carry on the digestive process sufficiently rapid for 

 the plants which grow upon its surface. Sand and lime, or 

 silicious marl, loosen its texture, render it permeable to 

 heat, &c., and powerfully assist to concoct the food of vege- 

 tables. 



Marl may be known by the most ordinary observer. The 

 application of a mineral acid, and even of good vinegar, will 

 cause an effervescence. This is the operation of the acid 

 upon the lime. Its silicious and argillaceous properties may 



