CONSTITUTION OF CHEMICAL COMPOUNDS. XXIX 



C 6 H + CO.' = C 6 H 5 .CO.OH + IPO. 



or, . + : 



When acids and bases, in general terms, act upon each 

 other, salts are formed, water being eliminated. Just so 

 when alcohols and organic acids act upon each other, 

 bodies, similar to salts, are formed, water being elimi- 

 nated : . 



H.CO.OH + C'H 8 .OH = H.CO.O.C 2 H 5 -f H 2 0. 

 Salts were defined as acids, in which the hydrogen of the 

 hydroxyl-group is replaced by a base-residue. In this 

 case we have the hydrogen of the hydroxyl-group of the 

 carboxyl replaced by an alcohol residue, and the resulting 

 compound has received the name ether. The name ether 

 is applied to all similar compounds, it being, as is clear, 

 but a special form of the salt. 



In regard to anhydrides the remarks made above are 

 here equally applicable. 



The carbon-compounds, which are formed like metallic 

 oxides, and which correspond to them, have also been 

 called ethers, though the same differences between them 

 and the ethers mentioned may be found, that are met with 

 between metallic oxides and salts. 



f K.O.H -f K.O.H = K.O.K + H 2 0, ") 

 1C 2 H 5 .O.H + C 2 H 5 .O.H = C 2 H 5 .O.C 2 H 5 -f H 2 0. j 



Among carbon-compounds there are other series, which 

 do not occur among inorganic compounds, the character 

 of which is dependent upon the peculiar properties or 

 carbon. If in marsh gas, OH*, we replace two hydrogen- 



TT 



atoms by one 0. we obtain the body 0:0 'TT which occupies 



H OH 



a position intermediate between that of TT.'C^TT and 



These bodies consist of two hydrogen-atoms 



united by the bivalent group 0:0, which has been called 

 carbonyl. Now either one or both of these hydrogen- 

 atoms may be replaced by alcohol-residues, as OH 3 , C 2 H 5 , 

 etc. If only one be replaced, we obtain the compounds 



pTT3 p2TJ5 



known as aldehydes, as 0:0.^ ' 0:0;^ ' etc. If, how- 



1, n, 



ever, both be replaced, we obtain compounds of a some- 



