ELECTROANALYSIS. 09 



where it is decomposed by means of an auxiliary nickel cathode placed 

 above the mercury in the solution. When the electrolysis is com- 

 plete the SO., in the inner cell is titrated by means of standard 

 alkali and the K in the outer cell by means of standard acid. 



There are disadvantages in the apparatus of Hildebrand, the outer 

 cell of which is a glass crystallising basin, the inner consisting of a 

 beaker with the bottom cut off. The inner cell is kept in a central 

 position by having corks wedged at the sides. F. M. Perkin has now 

 had a vessel made of fused quartz. The centre cell is kept concentric 

 by having quartz rods fused to it and to the inside wall of the outer 

 basin. Being of quartz, the vessel can for cleaning purposes be 

 heated to redness, is absolutely unattacked by alkali, and there are no 

 corks which, if they get accidentally splashed, absorb some of the 

 alkali and vitiate the results. 



Experiments on the analysis of the anions and cations are being 

 carried out with this apparatus, and the results so far have been 



The Study of Hydro-aromatic Substances. — Report of the Committee, 

 consisting of Dr. E. Divers {Chairman), Professor A. W. Crossley 

 (Secretary), Professor W. H. Perkin, Dr. M. 0. Forster, and Dr. 

 H. E. Le Sueur. 



Synthesis of cyclogeraniolene (1:1: 3-trimethylcyclohexerie). 1 — Some 

 years ago Tiemann and Semmler - prepared from the aldehyde citral 

 (geraniol) an open-chain hydrocarbon, C 9 H 16 , named by them geranio- 

 lene. The constitution of this substance (I) follows from that of citral, 

 which was established by Barbier and Bouveault in 1896. 3 When 

 geraniolene is shaken with a 60 per cent, solution of sulphuric acid, 

 an isomeric change takes place, the open-chain hydrocarbon being 

 converted into a mixture of two cyclic hydrocarbons a and f3 cyclo- 

 geraniolene (II and III), in which mixture the a variety is present in 

 larger quantity. 



CMe 2 : CH . CH 2 .CH 2 . CMe : CH 2 — >- CMe 2 <gg 2 ' c^^CH and 



(I) ' (H) " 



CMe 2 <gg=^>CH 2 



(III) 



Constitutional formulas were assigned to these hydrocarbons by Tie- 

 mann, 4 arrived at from a study of their oxidation with potassium per- 

 manganate, and these formulas are proved to be correct by the following 

 synthesis. 



1 : 1-Dimethylcyclohexanone (IV) was treated with an ethereal 



1 Crossley and Gilling, J.C.S., 1910, 97, 2218. 



2 Ber., 1893, 26, 2708. » Compt. rend., 12?, 393. 

 ■ Ber., 1898, 31, 816, 881; 1900, 33, 3711. 



h 2 



