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SCIENCE PROGRESS 



The case is altogether different when hydrogen chloride is 

 concerned. The product of the union, the long-known " kunst- 

 camphor," is an unusually stable substance which is volatile 

 without appreciable decomposition, and from which the chlorine 

 is removed with difficulty by alkali or alkaline salts. This 

 substance appears to be identical with bornyl chloride, which, 

 together with isobornyl chloride, is formed by the action of 

 phosphorus pentachloride on borneol. 1 



From that compound a hydrocarbon, bornylene, is obtained 

 which stands in a natural relation to borneol and to camphor. 



CMe 



CMe 



CMe 



CH, 



CH, 



CH 



Bornylene. 



The chloride must therefore be — 



CMe 



CH 



Camphor. 



CH 



and its production from pinene must be the result of con- 

 siderable isomeric change, the exact course of which can only 

 be guessed at. 



The constitution of pinene dibromide is also a matter of 

 doubt. According to Wallach, on the one hand 2 it yields 

 cymene when hydrogen bromide is withdrawn by heating it 

 with aniline ; on the other hand, it is converted by reduction 

 into a dihydro-camphene identical with that which is derived 

 from pinene hydrochloride. 3 Both these changes involve in- 

 ternal rearrangement, whatever formula is assumed from the 

 bromide. 



Another question of some interest is involved in the obser- 



1 Wagner and Brickner, Ber. [1899] 32, 2302 ; [1900] 33, 2 121. 



2 Annalen, 264, 1. 



3 Semmler, Berichte [1900], 33, 3420. 



