THE CULTURE OF FARM CROPS. 



CHAPTER III. 



CARBON. ITS PROPERTIES AND RELATIONS TO VEG- 

 ETABLE LIFE. 



Carbon, a word derived from the latin carho, coal, is the 

 name given to a mineral substance which occurs in an in- 

 organic condition in the diamond, in graphite or plumbago 

 (commonly called black lead) in bitumen, petroleum, am- 

 ber and a number of mineral resins, and in an organic condi- 

 tion as charcoal, mineral coal, lampblack, soot, etc. Its three 

 best marked forms are the diamond which is pure carbon ; 

 graphite; which is found sometimes nearly pure, but mostly 

 mixed with more or less iron ; and charcoal which contains 

 a small proportion of mineral matters which form the ash 

 of the wood of which the charcoal is made. An interesting 

 form of vegetable carbon is the fiber of the cotton plant 

 which is almost pure. 



Carbon forms a large proportion of the substance of 

 vegetable matter when it is freed from water ; amounting 

 to from forty to fifty per cent, by weight of all the parts of 

 plants grown as farm crops. It therefore performs an im- 

 portant part in the growth of plants and becomes an in- 

 teresting subject of study for v the farmer. 



The diamond is the hardest substance known, and re- 

 sists a high degree of heat, but is combustible at a very 

 high temperature. When made red hot, and placed in a 

 vessel of pure oxygen, it burns with a brilliant steady 

 glow, combining with the oxygen and forming carbonic 

 acid. It has been artificially, but accidently produced, in 

 iron furnaces in which charcoal has been used as fuel ; but 

 in every other way it has resisted all the efforts of the chem- 

 ists to produce it. Sir Isaac Newton predicted that the 

 diamond would prove to be of organic origin and this has 

 some show of probability from the fact that on burning 



