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CHAPTER I 

 HYDROCARBONS 



A SYSTEMATIC study of organic chemistry directly connected 

 with agriculture should embrace the study of those organic 

 compounds which are of primary importance either as con- 

 stituents of plants and animals or as products formed from them 

 either naturally or artificially. In order to understand these 

 compounds in their character and their relation to each other, 

 it will be necessary to consider also a few typical ones which 

 are not directly connected with plants or animals in any gen- 

 eral agricultural sense. 



Organic chemistry was originally so termed because the 

 compounds included in it were produced by living organisms 

 (plants and animals). With the development of this branch 

 of the science of chemistry, many compounds have become 

 known which are truly organic in their character and relation- 

 ships, but have never been associated with either plants or 

 animals; that is, they are still solely laboratory products. 

 This has destroyed the original significance of the term organic. 

 The word is still used, however, but in a broader sense. 



All compounds which we class as organic are compounds of 

 carbon, but a few carbon compounds are still held as truly 

 inorganic, so that to term organic chemistry the chemistry of 

 the compounds of carbon is not strictly true. However, all 

 organic compounds are derivatives of certain fundamental 

 compounds of carbon and hydrogen so that the best definition of 

 organic chemistry is : the chemistry of the hydrogen com- 

 pounds of carbon and their derivatives. 



The hydrogen compounds of carbon will then be the start- 



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