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clearly to reveal itself only in the case of those cobalti-salts whose 
anions contain several ovygen-atoms. *) 
It must be proved by future investigations, in how far this influence 
of the oxygen-containing radicals may be considered as a general 
and essential one; and if general, of what nature it actually is. 
In any case it has now become clear that in the phenomenon 
discovered by Pasteur, the optical activity of the molecules at the 
one side, and the enantiomorphism of the crystalforms, as well as 
the phenomena connected therewith regarding the pyro- and piezo- 
electric properties, — do not play an equivalent role. More detailed 
and more extensive investigations in this same direction will perhaps 
be able to teach us more exactly than now, what share the special 
configuration of the molecules really possesses for the occurrence 
of each of these categories of physical phenomena. 
Groningen, March 1915. Laboratory for Inorganic Chemistry 
of the University. 
Chemistry. — “The Allotropy of Bismuth.” 11. By Prof. Ernst COHEN. 
(Communicated in the meeting of March 27, 1915). 
1. In my first paper?) on this matter (published in collaboration 
with Mr. A. L. Ta. Morsverp) we pointed out that bismuth can 
be transformed into a second allotropic modification at 75° C., and 
that this metal as it has been known up to the present is a 
metastable system at ordinary temperatures, in consequence of the 
marked retardation which accompanies that transformation. 
2. However, the results obtained with cadmium, copper, antimony 
ete. gave rise to the supposition that in this case also the previous 
thermal history of the metal might have an influence on the transition 
temperature, which would prove that there exist more than two 
forms of bismuth. 
3. Our dilatometrie measurements carried out in order to clear 
up this point more fully were made in the same way as in the 
experiments with cadmium *). 
1) In this connection it may be remarked that such enantiomorphism as the 
nitrates and perchlorates possess, could also be stated in the case of the rhombic 
dithionates ((S,0,)’-ions). However the crystals of this salt contain much water 
of crystallisation, and effloresce so rapidly, that no exact measurements could be 
made. It is for that reason, that the salts are not described in paper IL. 
2) Zeitschr. f. physik. Ghemie 85, 419 (1913). 
8) Proc. 16, 485 (1913), 
