Structure of Simpler Organic Compounds. 69 



i to three alkyl groups (^0 OH, as in No. 4), the alcohol is 

 said to be " tertiary." 



From the general conceptions advanced as to the nature 

 of isomerism in the carbon compounds the existence of all 

 these isomerides might be predicted ; they have, in fact, 

 all been isolated, and the correct constitution of each 

 individual member has been determined by means of 

 various synthetical and other reactions to which reference 

 will be made later. Their constitution may also be 

 regarded in another light. They may be considered as 

 derived from methyl alcohol, CH 3 OH, by the replacement 

 of the hydrogens in the methyl radicle by an alkyl radicle. 

 Thus, normal butyl alcohol (formula 1) may be regarded 

 as methyl alcohol in which one hydrogen is replaced by 

 the propyl radicle (C 3 H 7 ), and written C 3 H 7 CH 2 OH. 

 The group ^C OH is in this connection designated 

 "carbinol," and normal butyl alcohol is, therefore, also 

 called propyl carbinol. Similarly isobutyl alcohol (for- 

 mula 2) is called isopropyl carbinol, secondary butyl 

 alcohol (formula 3) is methyl ethyl carbinol, and tertiary 

 butyl alcohol (formula 4) is trimethyl carbinol. The 

 general formulae of the three classes of alcohols may be 

 thus represented 



Primary alcohols R CH 2 OH 



K \ 



Secondary alcohols >CHOH 



R'/ 



R \ 



Tertiary alcohols >C OH 



when R = alkyl radicle and R 1} R', R" may be the same or 

 different radicles. 



Now, if a certain substance has been obtained, arid its 

 empirical formula has been determined, it is always pos- 



