34 DEPARTMENT OF AGRICULTURE GEORGIA. [320] 



It is also used in various alloys, as pewter, Britannia 

 metal, plumber's solder, bronze, etc. 



Zinc is an abundant and useful metal, which is found only 

 combined with sulphur and other elements. 



It is used as a coating for iron, which is then said to be 

 galvanized. It is also used with alloys. 



CHAPTER II. 



PLANTS. 



The Structure and Offices of Their Different Parts Roots 

 Stems Leaves, etc. 



As the business of the agriculturalist involves, mainly 

 the cultivation of plants for the purpose of facilitating the 

 development of particular parts of the vegetable organism, 

 intended for his own use, or that of his domestic animals, 

 it becomes a matter of prime importance that he should 

 understand their nature, structure, necessities, methods of 

 development, and their relations to the soil and atmosphere, 

 upon which they are dependent for existence and growth. 



Successful agriculture secures the greatest development 

 of the most useful parts of cultivated plants, at the least 

 practicable cost. 



An intimate knowledge of the normal conditions of 

 plant development and plant nutrition is necessary to suc- 

 cessful agriculture in its full sense. 



Plants are complex organic structures, composed of 

 roots, stems and leaves, each of which contributes to the 

 fulfillment of their destiny, viz : the production of seed or 

 fruit. 



Roots, generally, serve the double purpose of fixing the 

 plant firmly in the soil and supplying all of the food not 

 derived from the atmosphere. In some they serve, also, 

 as a store-house of food for future plants. Roots increase 

 in size in the same manner as stems, but elongate by an 

 entirely different process. 



