MOLECULES OF CARBON. 177 



The addition of only one molecule of carbon to 

 a hundred molecules of iron, carries with it a 

 peculiar hardness and cutting property by con- 

 verting the iron into steel, and doubles the value 

 of the iron, to which it imparts permanent mag- 

 netic powers. The addition of about fifty per cent 

 of molecules of carbon to the elements compos- 

 ing water (hydrogen and oxygen), characterizes 

 the substance of saps, fruits, and grains serving as 

 food, to be reorganized into the bodies of living 

 animals. The very same molecules of carbon, 

 excited by sunshine on the leaves of plants, carry 

 with them their tenacious properties in the for- 

 mation of fibres of hemp, cotton, flax, jute, &c. 

 Other kinds of merchandise, especially valued for 

 peculiar characteristics, are composed of carbon in 

 variously proportioned combination with the three 

 other kinds of molecules, oxygen, hydrogen, and 

 nitrogen. These compounds develop the several 

 peculiar properties of wood, fruits, grains, grasses, 

 tobacco, opium, drugs and medicines, food and 

 fuel. 



Carbon united with oxygen, as carbonic-acid 

 gas, combines with molecules of the metal calcium 

 in the formation of lime-rocks and marbles, of the 

 bony skeletons of animals, and even of the trans- 

 lucent and iridescent pearls. One half the weight 

 of dried flesh and blood consists of molecules of 

 pure carbon or .charcoal ; a*s also one quarter of 

 the weight of all dried wood. This is shown in 



