over not be easily brought into immediate connection with the 
supposition of the presence of a ternary axis in the molecules. The 
trigonal symmetry of the racemic bromide moreover will appear to 
be only an apparent one: these crystals are really only lamellar 
intergrowths of probably monoclinic symmetry. 
Furthermore it may be remarked here, that if the three equal 
substitutes were not highly symmetrical, — as e.g. in the case of 
NH, 
a-propylenediamine: CH (CH,), — the three polar binary axes would 
CH,—NH, 
in fact disappear in the cations, even if the three molecules of the 
base were placed in an analogous way, but that the ternary axis, 
— these being of a polar nature, — would be preserved in salts 
of the type: {Co (Propin),} X,. However it is by no means impossible 
in this case, that one of the three substitutes was present in an 
antilogous (reversed) position with respect to the other two; in that 
case the cation would no longer possess any symmetry-element 
whatever, and the possibility could then be foreseen, that two more 
mirror-image-isomerides might on occasion occur again. Thus, if one 
excludes for the present the possibility of a separation of the «- 
propylenediamine itself into two antipodes, even then for salts of 
the type {Co (Propin),} X, a greater number of isomerides might be 
expected. It is not at all impossible, that the difficulties, which 
always in our experience present themselves, if one tries to get the 
salts of this type in well developed crystals, must be connected with 
the fact that really here a mucture of isomeric salts is always 
operated with, which of course will not erystallise as well as in 
the case of a single, chemically homogeneous compound. We hope 
in the future to have an opportunity, of again drawing attention 
to the properties of these salts. 
§ 5. The crystallographical material, collected during these investiga- 
tions will be published in the next paper (IJ). The data however 
with regard to the rotation of the salts studied in solution, and of 
their remarkable rotation-dispersvon, may find their place here, as 
they can give the right impression about the fact, that one has in 
these cases in reality to deal with ““dissymmetric” compounds, as 
understood in Pasrsur’s principle and to what high degree. 
These experiments were made with a large Lippicu-polarimeter 
from Scumipt and HAENrTsCH; it possessed a telescope-field with three 
