AND AGRICULTURE. 



15 



In all vegetable substances, 

 the organic or combustible part 

 is very much the largest ; it 

 makes from ninety to ninety- 

 nine parts out of every hundred 

 of their weight. 



The organic parts of all vege- 

 table substances consist of four 

 elements; these elements are 

 called carbon, hydrogen, oxygen, 

 and nitrogen : they are called 

 elements, or elementary bodies, because they 

 have never yet been divided or decomposed. 



CARBON is a solid substance, generally of a 

 black color ; it has no taste or smell ; usually 

 burns, very rapidly, and gives out* much heat. 

 Common charcoal, coke, the substance left in 

 retorts after the gas has been distilled from the 

 coal, lamp-black, black-lead, and the costly 

 and brilliant diamond, are only different varieties 

 of carbon. 



HYDROGEN is found only in the form of a 



Questions. Of which do vegetables contain the most? 

 State the proportions. Of what is the organic part of 

 plants composed ? Why are they called elementary bodies : 

 What is carbon ? Name some of its varieties. What is 

 hydrogen ? 



