FUNDAMENTAL CONCEPTIONS 213 



any case the methylene derivative as such; there was either a spon- 

 taneous conversion to a di- or trimolecular polymer, an olefine or a 

 trimethylene derivative, or a conversion to resinous polymers ana- 

 logous to azulmic acid and the alkylisocyanide resins. Most import- 

 ant was the discovery that these nascent or active methylene residues, 



Z 



^C, are always spontaneously combustible, burning often with 



Y' 



Z 



marvelous evolution of heat to the corresponding oxides, ^C=0 ; 



Y 



this was not surprising in view of the properties of the methylene 

 derivatives described above. Furthermore, the affinity of unsaturated 

 carbon for oxygen is strikingly shown by the fact that these residues 

 have the power of decomposing water, 

 Z Z 



Y Y 



with evolution of hydrogen. 



A subsequent investigation of the primary and secondary alcohols 

 and alkylhalides containing more than one carbon atom proved, 

 first of all, that all these substances have comparatively low points 

 of dissociation. In no case was the decomposition-point found to be 

 higher than 700; it was often as low as 160 to 300. The products 

 of dissociation are water or halogen hydride and C n H 2n respectively; 

 and the latter, as emphasized above, is invariably methylene or a 

 homologue and never an olefine. This naturally means that all these 

 compounds are partially dissociated in this way at ordinary tempera- 

 R H R' 



tures, /C\ ^ ^C + HX, relatively more the lower the 



R' X R' 



actual decomposition-point. It is, therefore, possible that in all the 

 interactions of the primary and secondary alkylhalides with other 

 substances, such as salts, ammonia, metals, benzene, etc., they do 

 not act as such, but by virtue of being partially dissociated. An 

 enormous amount of evidence has accumulated in favor of this con- 

 clusion. Let us consider chiefly the results obtained in the ethyl series 

 including ethyl alcohol and its derivatives. The dissociation or 

 decomposition-point of the following compounds containing ethyl 

 has been determined with a fair degree of accuracy. 



