259 



in this respect ;- but investigations of this kinds have been started 

 now in the author's laboratory. As a method to determine the 

 configuration of such cis- or ^ms-isomerides, when they have 

 the character of alcohols, attention may be drawn to that developed 

 by Boeseken 1 ), which is based upon the measurement of the 

 electrolytic conductivity of the solutions of such hydroxy-compounds, 

 containing boric acid. 



Another instance of a similar kind is found in the case of 

 methane-' 2 ), and of tetra-methylene-derivsitives of special configuration. 

 Let us imagine molecules such as: 



C[{d-C(abc)} 2 {l-C(acb)h] or [CH.{d-C(abc)}] 2 [CH.{l-C(acb) j] 2 , 

 which are represented by the stereochemical models in fig. i6j 

 and i68\ 



Fig. 167. Fig. 168. 



Such molecules possess no less than four or eight asymmetric car- 

 bon-atoms, and also have they neither an inversion-centre, nor a 

 plane of symmetry. Notwithstanding this, these compounds can 

 never be resolved into optically active antipodes, because both 

 molecules have a single quaternary mirror-axis Z~ 4 , perpendicular 

 to the plane of the ring in the second, and placed vertically in the 



1) J. Boeseken, Proceed. Royal Acad. Amsterdam, 16, 216, (1913); 19, 

 1647, (1916); Receuil des Trav. d. Chim. des Pays-Bas, 3439, (1914 '20); etc.. 



2) G. Hartwall, Dissertation, Helsingfors, (1904). 



