704 



always the trigonal needles of the active components besides each 

 other, but at 0° C we got only the triclinic crystals of the racemate. 

 Therefore complete proof has been given now, that a fission of 

 the potassium-cohalü-oxalate by spontaneous crystallisation into its 

 optically active components really occurs at temperatures above 13°, 2 C. 



$ 4. Crystallographical research taught us, that both the optically 

 active components occur in commonly not distinguishable crystals 

 of trigonal-tmpezohedrical symmetry, which are com[)letely isomor- 

 phous with those of the optically-active rhodiwn-, and iridium-sahs. 



They have the appearance (fig. 5 and 6) of a prismatic forms of 

 more or less extension; the rkr^/'ogyratory component hitherto always 

 presented the ihombohedron-like shape of fig. 6. 



Tri(jonal-trapezohedrical. 

 a:c = l: 0,8968 (Bkavais); « = 100°27' (Miller). 



Laevogyratory Potassium- Cobalti- Oxalate {-\-\E^0) 



Fig 6. 



Forms observed: B = \lÖiA\ [lOOj, large and very brilliant; 

 c = jOOOll [111], always present, but subordinate; ??i = jlOlOj [2l T], 

 commonly predominant with the lefthanded crystals, and in the case of 

 the dextrogyratory individuals small, but well developed and yielding 

 sharp images; r — |0111| [221], and s — |0221| [111], always present, 

 small, but very lustrous; ^ = j2021j [5 1 T], rather large and yielding 

 good reflections. Hemihedral combination-forms were hardly ever 



