CHEMISTRY. 



nG5 



No attempts appear to Iku'c been mnde to synthesize !lie iinalogous 

 i-(!arbon riug- : 



I I 



tliough a(;enaphthene, a body in tlie aromatic series, without donbt 

 contains such a ring. Fluorene is a hydrocarbon containing a 5-carbon 

 ring-, and several known bodies of the fatty series are ch)sely allied to 

 the hypothetical 4 and 5 carbon rings. These are furfuran, pyrrholiue, 

 succinimide, and parabanic acid. The author adopts the following 

 scheme of nomenclature for the 3, 4, 5, and C carbon rings: 



He also proposes to distinguish the possible isomers by numbering 

 the carbon-atoms in the ring as suggested by Baeyer {Ber. d. chem. Ges., 

 XVII, 9(50). The author describes fully the methods of preparation and 

 the proi)erties of a number of trimethylene derivatives, and promises 

 at an early date to do the same for some tetramethyleue derivatives. 



The following table contains a list of the trimethylene bodies witli 

 their chief characters: 



