268 



rajs be taken into account; for the red and orange rajs however, 

 these solutions appear to be laevogjrate. 



Sucl) solutions are opi'icaWy -inactive for a wave-length of 5970 

 A. TT. At this wave-length, invariable moreover for solutions of 

 widelj different concentrations, there is no longer anj detectable 

 difference between solutions of the two antipodes. 



66/0 6860 jtaiT -/f^tdm 



ix/tt/s/rüm* 



Kig. 1. 



Specific Rotation-dispersion of right-handed Potassium-Rhodium-Oxalate. 



(All molecular rotations are 50 times as great). 



It is worth attention, that the solutions do not exhibit for this 

 wave-length anj trace of an absorption-line. Our former supposition 

 connecting the abnormal rotation-dispersion with the eventual occur- 

 rence of selective absorption, thus appears no longer justified. As 

 Werner points out, the phenomenon is met with in the studj of 

 all complex metal-oxalates hitherto investigated: those of rhodium, 

 chromium, and cobaltum, exhibit this propertj in a verj pronounced waj^)- 



1) To an investigator studying the heterogeneous equilibria between the racemic 

 salt and both its antipodes in solution, there could no longer be any difference 

 between the solutions of the d- and ^component or their mixtures, if he worked 

 under conditions which enabled him only to use light of a wave-length of A = 5970 A.U. 

 Indeed, all such solutions would then be found optically mactive. In such circum- 



