269 



Finally it maj be remarked, that the optically-active salts have 

 no appreciable tendency to auto-racemisation. After heating on the 

 water-bath dnring some time, no appreciable diminution of the original 

 rotatory power appears to have occurred. A slight hydrolysation, 

 however, could be stated in these cases. The salts are slowly 

 decomposed by the continued action of violet light or by strong 

 heating, while a black powder {Rho?), and some rhodium-hydroxide 

 are set free. 



§ 3 I. Racemic Potassium-Rhodium-Oxalate (-f 4^ H/.)). 



This compound crystallizes in big, ordinarily flattened, garnet-red, 



CL. 



Fig. 2. 

 Racemic Potassium-Rhodium-Oxalate (+41/2 HoO). 



stances no difference would apparently be any longer present here and in the 

 well-known case uf sodium- chlorate ; in other words: in this singular point the 

 descriptive number of components would be diminished with one. However, it 

 must be insisted, that this is only valid for one definite temperature and one 

 definite pressure, as [u.] is a function of both. For wave-lengths only slightly smaller 

 or greater than 5970 A.Ü., the system is again a ternary one, in which the 

 functions of d- and /-components are reversed. 



