300 REPORT— 1900. 



to the occurrence of unsuspected intramolecular changes during reactions 

 which are at present deemed susceptible of only one simple interpretation. 



In the case of a problem of this kind in which a very large amount of 

 experimental material has to be dealt with, some of which appears to 

 point conclusively to one view and some in an equally unequivocal manner 

 to another, it would appear to be the most logical course to sift the 

 material in such a way that the relative value of the evidence on each 

 side may be compared, and, if possible, so as to gain a clue as to the exact 

 points at which the tendency appears to change, so that particular atten- 

 tion may then be directed to those points. 



In the present communication it is proposed first of all to select from 

 the material those facts which bear directly on the points at issue, 

 accepting only those conclusions which no longer reasonably admit of 

 dispute, and then to discuss the significance of the rest of the evidence 

 relating to the still undecided question of the ultimate structure of the 

 camphor molecule. 



A.— GENERAL NATURE OF CAMPHOR. 



Camphor has the formula CjoHmO : it is a ketone, as it yields well- 

 defined hydrazones, an oxime and a seraicarbazone. It is saturated, and 

 therefore must be considered to consist of two closed carbon rings, of which 

 one includes the carbonyl or ketone group ^ CO. 



As it will clearly be of importance to be able to refer to either of these 

 rings, one will afterwards be termed the ketone ring, and the other the 

 hydrocarbon ring. 



B.— PROPERTIES AND TRANSFORMATIONS 

 OF THE KETONE RING. 



1. The Ketone Ring contains the Group — CHo.CO — 



That the carbonyl group > CO of camphor is in direct attachment to 

 a methylene group — CH^ — is proved conclusively by the following 

 considerations : — 



(a) Formation of Camphoric Add by the Oxidation of Camphor. 



When camphor is treated with the usual oxidising agents it is con- 

 verted into camphoric acid, CioH,g04, a saturated, dicarboxylic acid. 

 This transformation is simply explained only by the assumption that the 

 change proceeds in accordance with the scheme 



/CH2 /COOH 



CsH, / I -> C3H, / 



^CO ^COOH 



Camphor. Camphoric Acid. 



(b) Formation and Properties of the siynplest Substitution Derivatices of Camphor. 



(i) Halogen and Nitro-compounds. — Camphor ordinarily yields only 

 mono- and c?i-substitution derivatives (termed a-derivatives) on treat- 

 ment with the characteristic substituting agent such as the halogen or 

 nitric acid, and with aliphatic saturated ketones the position of substitution 

 is at the carbon atom contiguous to the carboxyl group. 



