104 H. G. SMITH. 



Cineol, and therefore eucalyptol, was supposed by Briihl 1 to 

 contain no double linkings, and owing to its optical inactivity, 

 and for other reasons, he suggested for it the following formula : 



C 3 H 7 



i 



H„cr | CH 2 

 I o I 



H 2 C I ,CH 2 



I 

 CH 3 



The oxygen atom entering the molecule during the formation 

 of eudesmol, that substance must have a formula corresponding 

 to eucalyptol. Eudesmol has no rotation, so that it probably does 

 not contain an asymmetric carbon atom, or that the molecule has 

 a racemic modification. It is difficult to depict for eudesmol a 

 corresponding structure to cineol, having one double linking on 

 the terpene type, without the presence of an asymmetric carbon 

 atom which would indicate activity. 



After arriving at the composition of eudesmol and having 

 determined its close connection with eucalyptol, it appeared to 

 me, on considering its reactions, that the difficulty might probably 

 be met by suggesting the quadrivalence of the oxygen atom, as 

 this appears to be in a different state of combination in both 

 eudesmol and eucalyptol than is found to be the case in any allied 

 substance. The question of the valency of an oxygen atom under 

 certain conditions has also been considered by others. 



Briihl 2 advocated the quadrivalence of oxygen in hydrogen 

 peroxide. J. F. Heyes 3 advocated the quadrivalence of oxygen 

 in reference to some peroxides. 



In a paper read before the Chemical Society on June 1st, 1899, 

 on "The salts of dimethylpyrone and the quadrivalence of oxygen," 

 by Dr. J. N. Collie, p.r.s. and Thomas Tickle, the authors are 



i Briihl, Ber. xxi., 461. 2 Briihl, Ber. 1897, xxx., 160 

 3 Phil. Mag., 1888, xxv., 221. 



