ON ISOMERIC NAPHTHALENE DEKIVATIVES. 299 



solution of hydrogen iodide, the bromine atom in position 1 being dis- 

 placed. Two new dibromonaphthols are thus obtained : that from the 

 tribromonaphthol melting at 155° melts at 137° to 138°, and that from 

 the isomeric naphthol melts at 127°. On digesting these dibromonaphthols 

 with alcohol and sulphuric acid under similar conditions that containing 

 one of the bromine atoms in the hydroxylated ring yields only about 55, 

 whilst that containing both bromine atoms in the non-hydroxylated ring 

 yields about 61 per cent, of ether. 



A comparison of the behaviour of the various chloro- and bromo- 

 betanaphthols towards hydrogen iodide with their behaviour on etheriti- 

 cation is of interest as showing that both changes are subject to similar 

 influences ; they therefore may be discussed from the same point of view. 

 As the reducing eflPect is confined to the bromine atom contiguous to the 

 OH group, this alone being displaced by hydrogen, the OH group must 

 be supposed to be concei'ned in the change. Probably it exercises an at- 

 tractive influence, and this influence must be regarded as subject to modi- 

 fication by every change in the hydrocarbon radicle, so that reduction 

 takes place less readily just as etherification takes place less readily in the 

 case of the more fully substituted compounds. The etherification of the 

 derivatives of betanaphthol has been discussed by Mr. Davis from this 

 point of view in a paper published in the ' Transactions of the Chemical 

 Society ' early in the present year (77, 33). 



On the Constitution of Gamphor. By A. Lapworth, B.Sg. 

 [Ordered by the General Committee to be printed in extenso.'] 



The question of the constitution of camphor has occupied the attention 

 of a large number of chemists for many years, and it still presents oppor- 

 tunities for much speculation. Recently, however, it has come to be fully 

 recognised that the earlier writers on the subject were misled by the ease 

 with which benzenoid compounds could be obtained from many camphor 

 derivatives, and it is now quite clear that the greatest care must be exer- 

 cised in attributing special significance to evidence based on observations 

 of this kind. 



The formation of large quantities of ^j-cymene and carvacrol fi'om cam- 

 phor by the action of phosphorus pentoxide was the basis of some of these 

 earlier speculations, and to carry the arguments to their logical conclusion 

 it would be necessary to make the formulae account for the production of 

 ?u-cymene, which is obtained in considerable amount when zinc chloride 

 or phosphorus pentasulphide is the agent, ^ and also of 1.2.4. dimethyl 

 ethyl benzene and 1.2.3.5 tetramethylbenzene.^ The formation of 

 1.3.4 acetyldimethylbenzeneby the action of sulphuric acid on camphor ^ 

 would also require elucidation. 



It appears natural to suppose that, if we are still unable to discover 

 with certainty the principles underlying the changes referred to, we 

 should also be cautious in interpreting the meaning of other transforma- 

 tions which involve any alteration in the structure of closed rings, and it is 

 now pretty generally recognised that the divergence of opinion which still 

 exists with regard to the constitution of the camphor nucleus must be due 



' Armstrong and Millar, Her. 16, 222.5. - Ibid., loc. cit. 



^ Armstrong and Kipping, Tram. Cliem. Soc, 63. 75. 



