1235 
§ 8. If we thus review the facts here mentioned and later-on to 
be demonstrated in detail, we can consider it as proved that in all 
the Zuteo-triethylenediamine-cobalti-salts, — just as is foreseen by 
Pastrur’s principle, — the spacial configuration in the molecules, 
different from its mirror-image, is always without exception combined 
with an enormous optical activity of their solutions ; that the enantio- 
morphism of their erystalforms however may sometimes be revealed, 
but evidently does not necessarily appear. From this fact, one may 
furthermore conclude, that the optical activity of the molecules prin- 
cipally seems to be determined by the “unsymmetrical” arrangement 
of the substitutes, as understood by Pasreur, and that it may reach 
enormous values even in those cases where such “unsymmetrically” 
arranged substitutes are all chemically identical. But it appears, that 
for the occurrence of the crystal-enantiomorphism, the chemical mequa- 
lity of these substitutes is a very predominant factor: and from this 
fact the significance of Le Ber's and van ’r Horr’s “unsymmetrical 
atoms’ for the whole problem has now become somewhat more 
comprehensible. | 
For in the question considered evidently ‘wo influences must 
properly be distinguished: «) that of the spacial configuration, which 
differs from its mirror-image, independently of whether the sub- 
stitutes are equal or unequal, and whether the molecule possesses 
any other symmetry-elements (only axes of the first class); and 
4) the greater or smaller chemical differences of the substitutes, 
which are arranged in the manner, indicated sub a). The influence 
sub a) appears principally to cause the phenomenon of optical 
activity; that sub 6) the more or less evident enantiomorphism of 
the crystalline structure, and the resulting polarity of homologous 
directions in it. Evidently the case of the “unsymmetric atoms’ has 
thus to be considered only as an extremely favourable opportunity 
for the occurrence of the complete phenomenon, which is formulated 
in Pasrgevr’s principle: here these influences are superposed, the one 
upon the other, because in most cases where the circumstances 
mentioned sub 6) are present, those indicated sub a) will also be 
present. If the influence mentioned sub 6) is not present, but only 
that sub a), — and this occurs precisely in the simple case of the 
complex cobalti-salts here studied, — then the enantiomorphous 
structure can be revealed eventually in the solid state, but it can 
evidently also be totally absent under the simultaneous influence of 
other factors. In our case the special nature of the electronegative 
part (anion) of the molecule seems to belong to these special circum- 
stances: for the enantiomorpbism of the crystalline structure seems 
82 
Proceedings Royal Acad. Amsterdam. Vol. XVII. 
