18 SOILS. 



deserved estimation being denominated rich sands. They 

 are cultivated at a moderate expense; and at all seasons have a 

 dry soundness, accompanied by moisture, which generally 

 secures excellent crops, even in the driest summers. 



Rich sands are early in maturing the cultivated plants 

 and thence they are familiarly termed kindly soils. They are 

 fit for the production of every variety of herbage and grain. 

 They yield to the richer clays in the power of producing 

 wheat, but they surpass them in the production of rye and 

 barley. They are well su'ued to the growth of the cultivated 

 grasses; but their distinguishing character is their peculiar 

 fitness for the raising of the plants cultivated for their roots 

 and tubers. 



Gravels, like sand, have all the gradations of quality, from 

 fertility to barrenness. The latter are, in general, termed 

 hungry soils, from their tendency to absorb manure without 

 any apparent corresponding benefit to the land; but as their 

 staple becomes firmer by the admixture of other earth, so do 

 their properties improve. The richer kinds produce every 

 species of grain, except beans and wheat, which may be grown 

 on them however, but not to decided advantage. They are 

 not only admirably adapted to the growth of barley and oats, 

 but may be generally regarded as trusty soils, with regard to 

 the quality of the grain which they yield; and being quick in 

 their powers of producing vegetation, they are in some places 

 termed sharp or quick soils. 



Lime, commonly called calcareous earth, though one of 

 the primitive earths, is never found naturally in a pure state, 

 forming an arable surface. It is nevertheless present, perhaps, 

 in all good soils; is widely diffused, and performs an important 

 function in the vegetable economy. In nature, this mineral is 

 usually found in combination with acids. Combined with car- 

 bonic acid, it constitutes the numerous varieties of marble, 

 limestone and chalk. In this and other combinations, it exists 

 in rocks, in soils, in the waters of the ocean, in plants, and in 

 animals. 



It is chiefly from the carbonate that the lime used in agricul- 

 ture is obtained. If a piece of limestone or chalk, pulverized, 

 be placed in strong vinegar, or sulphuric acid (oil of vitriol), 

 diluted with water, there will be an effervescence. This is 

 owing to the carbonic acid being set at liberty, which rising 

 throws up bubbles in rapid succession, and escapes in the form 

 of gas. The carbonic acid is also driven off by exposing the 

 carbonate to a strong heat; and that which remains is the 

 caustic earth to which we give the name of quick-lime. The 

 burning of limestone is for this purpose. 



