207 
IE ,, tetrahedron, 
C „ hexahedron (cube), 
O » octahedron, 
Ce „  fourdimensional five-cell, 
Cs u ai sixteen-cell, 
Cc “i ‘ twinty four-cell, 
Sn >» ___n-dimensional simplex, 
Cr, de cross polytope. 
The cases in which we have to deal with a half characteristic 
are also indicated in this table. So e.g. the first polytope of the table 
is limited by equilateral triangles of two different kinds, presenting 
themselves in the numbers 10 and 20. 
Meppel, June, 1912. 
Chemistry. — “Contribution to the knowledge of the direct nitration 
of aliphatic imino compounds”. By Prof. A. P. N. FRANCHIMONT 
and Dr. J. V. Dussky. 
In the January meeting 1907 I had the honour to give a survey 
of the action of absolute nitric acid on saturated heterocyclic com- 
pounds whose ring consists of C and N atoms. This originated in 
the fact observed and described by Dr. Donk, that the so-called 
H 
glycocollanhydride H,C—N—CO, in which the group NH is placed 
| 
OC—N—CH, 
H 
between COvand CH,, nitrated with difficulty, with much more difficulty 
than I had expected because a number of other heterocyclic com- 
pounds with rings of five or six atoms in which the group NH is 
placed in the same manner may be readily nitrated with absolute 
nitric acid at the ordinary temperature. This was not the case here; 
only a treatment of the nitrate with acetic anhydride or, as 1 showed 
with Dr. Friepmann, of the glycocoll anhydride with acetic anhydride 
and nitric acid gave a mono- and a dinitroderivative. 
CH, 
fori 
With the so-called alanine anhydride HC—N—CO and with the 
| | 
OC—N—CH 
H | 
ig CH, 
