232 Journal of the Asiatic Society of Bengal. [May, 1907. 



alkjl clilorides. If sticli compounds could be isolated, a compa- 

 rison of tlie properties of tliese substances with, these iodochlorides 

 would at once settle the true character of the latter. The easy 

 decomposability of these substances might be explained if we 

 assume the same spatial formula for trivalent iodine as for triva- 

 lent nitrogen. Methyl iodo-chloride being in that case represented 



PIT 

 as r;|>I"-Cl ft would easily pass into CHgCl and ICl. In the- 



case of phenyl iodo chloride, the chlorine atom instead of displac- 

 ing the phenyl group as a whole, perhaps on account of the firm 

 bond between it and the iodine atom, combines w4th one of the 

 more mobile hydrogen atoms, thereby producing chloro-iodo- 



benzene. 



By this work, Thiele and Peter have bridged, to some extent, 

 the gulf separating two important classes of organic compounds 

 (the aliphatic and the aromatic series). Any general view about 

 a reaction, however small in its scope, is a welcome addition to our 

 stock of knowledge, because these small links wnll ultimately lead 

 to the higher generalisation w^hich is yet to come for chemistry. 

 This work is also suggestive in another respect, for from the 

 isolation of these compounds at low temperatures, one is naturally 

 led to consider the possible existence of a number of inteiesting 

 unstable compounds, amongst which may be mentioned the diazo 

 derivatives of the aliphatic amines. The isolation of these diazo 

 compounds, if they exist at all, will, of course, be a matter of great 

 diflSculty, but it might be easy to get from the cool diazotised 

 solution, the corresponding stable azo derivatives, as In the case of 

 the aromatic amines. Attempts were made to prepare the azo 

 compounds corresponding to methyl and ethyl amines by cooling 

 a hydrochloric acid solution of the bases in calcium chloride and 

 ice and adding to it drop by drop a strong solution of sodium 

 nitrite and then adding a hydrochloric acid solution of dimethyl 

 aniline or a caustic soda solution of /3-naphthol. No trace of the 

 formation of an azo dye could be observed- It is, however, just 

 possible that with the higher aliphatic amines or wdth a better 

 source of cold, the azo compounds oC the fatty amines such as 



CHg N = XC^H^N CCHs)g { from CH3N = NOl } could be iso- 

 lated. 



It is said that a newer and simpler chemistry prevails in the 

 case of reactions at high temperatures. This remark holds good 

 in the case of low temperatures also, the only difference being that 

 in the former case, the reactions are mainly dissociative on account 

 of the violent molecular movements at high temperatures, while 

 the low temperature reactions are, in general, additive, the quies- 

 cent character of the molecules favouring this sort of reaction. 



A systematic examination of reactions at low^ temperatures 

 would furnish us with a better idea about molecular mechanics. 

 For a resident in the tropics, however, this is not an easy task as 

 he is seriously handicapped by reason of the higher temperature. 



