MOLECULAR ARCHITECTURE 403 



Just as Ampere in 1816 had regarded the salts of ammonia 

 as formed by the union of " ammonium " (ammonia and 

 hydrogen) with chlorine, iodine, sulphur, etc., so Liebig re- 

 garded the compound ethers as formed by the union of ETHYL 

 (aetherin and hydrogen) with chlorine, bromine, iodine, etc. 

 If aetherin be represented by the modern formula, C 2 H 4 , of 

 olefiant gas, then ethyl must be represented as C 2 H 5 , thus : 



ammonium = NH 3 + H = NH 4 = Am 

 ethyl = C 2 H 4 + H = C 2 H 5 = Et 



On this view 



alcohol = ethyl hydroxide = (C 2 H 5 )OH or EtOH 



ether = ethyl oxide = (C 2 H 5 ) 2 O or Et 2 O 



muriatic ether = ethyl chloride = (C 2 H 5 )C1 or EtCl 



just as, according to Ampere's view, 



sal-ammoniac = ammonium chloride = (NH 4 )Cl.or AmCl 

 Actually, Berzelius and Liebig doubled the formulae of these 

 radicals and wrote 



aetherin = C 4 H 8 = Ae 

 ethyl = C 4 H 10 = E 



ether = C 4 H 10 O = Ae + H 2 O, or EO 



alcohol = C 4 H 12 O 2 = Ae + 2H 2 O or EO + H 2 O 



ethyl chloride = C 4 H 10 C1 2 = Ae + H 2 Cl 2 or E + C1 2 . 



It will be seen that in doing this they broke away finally 

 from the idea that the relative sizes of the molecules could 

 be deduced from measurements of vapour density ; thus, 

 alcohol, with a lighter vapour than ether, was now repre- 

 sented as a compound of ether and water, and all their 

 derivatives were regarded as containing at least four atoms 

 of carbon. 



Dumas and Peligot (1834) discover a new alcohol in 

 spirit of wood. Methylene and methyl as radicals. 

 In 1834 Dumas and Peligot read to the Academy a paper 

 " On a New Alcohol and on the different Ethereal Com- 

 pounds derived from it" (Mem. Inst^ 1838, 15, 557-632). 



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