CARBON. 9 



But although animal life and plant life are both concerned 

 with the chemical changes of carbon compounds, yet they 

 stand towards carbon in an essentially different aspect, for 

 while the life of an animal eventually leads to the more or less 

 complete oxidation of the carbon in the food consumed and the 

 consequent production of carbon dioxide, the characteristics of 

 a plant's vital processes are the separation of carbon from 

 carbon dioxide and the formation of less oxidised carbon com- 

 pounds. 



The former process is attended by the liberation of energy in 

 the form of heat and mechanical work, the latter by an absorp- 

 tion and storing up of energy received in the form of light. 



Carbon is remarkable for its power of uniting in a vast 

 number of proportions with hydrogen and with hydrogen and 

 oxygen. This power is pictured by the chemist as being due 

 to the atoms of carbon possessing a tendency to link them- 

 selves together. 



To take a simple case, there are several series of hydro- 

 carbons known, of which the following may be taken as 

 representatives : 



The Paraffin Series. The Olefine Series. 



CH 4 C,H 4 



H 



H C H 

 H C H 



| H C H 



H 



QjHg C 8 H,. 



H H C H 



I I! 



H C H H C 



H C H H C II 



H II 



