MODERN HIGH FARMING. 25 



tolerably pure muriate or chloride, and in this form recommend its 

 addition to manures, or direct introduction into the soil. 



If the utility and action of potash are sometimes contested, the 

 same cannot be said of lime, than which few elements in agriculture 

 play a more important part, or one that is better understood. 



The limiug of soils has been a common practice in all countries 

 from the very earliest times ; but it was presumably not until the 

 seventeenth century that the use of burnt lime now universally 

 recommended was introduced. It is employed in quantities vary- 

 ing with the composition and the requirements of a soil, from twenty 

 tons per acre into those which are heavy, compact, and laden with 

 moisture, to five tons per acre into those which are light and of a 

 dryer nature. 



That its scope of usefulness cannot be by any means guaged by 

 the relatively small proportion found by analysis to exist in the 

 plants, we must all agree, and we have often asked ourselves whether 

 in point of fact, the presence of this element in plant organisms is 

 directly connected with their nourishment and growth, or whether it 

 is to be explained by the mere evaporation of the water by which it 

 was conducted into the tissues and there deposited ? 



However this may be, the quantity absorbed from is out of all 

 proportion to the quantity introduced into the soil, as will be seen 

 from the following figures. 



Quantity of Lime absorbed per acre by the undermentioned 

 Cultivated Plants : 



Potatoes, 



71bs. 



Wheat, 

 20 Ibs. 



Beetroots, 

 18 Ibs. 



Clover, 

 70 Ibs. 



And it is therefore not in this direction that we have to seek for its 

 principal chemical action. 



In certain regions pyrites, or sulphurous ores, are disseminated 

 throughout the soils and underlying strata, sometimes in large but 

 generally in minute quantities. The action of heat upon these sul- 

 phur-bearing substances generates sulphurous vapors, and these on 

 meeting the elements undergoing the process of nitrification already 



