(

[Plate XXI]

, 1 and 4, and

[Plate XX]

, 6 and 7) contains the nitrogen "balloon," elongated by its juxtaposition to

b

63. The central tetrahedra appear as usual.

KRYPTON: Six arms of 224 atoms 1344
Central tetrahedra 120
-----
Total 1464
-----
Atomic weight 81.20
Number weight 1464/18 81.33

Meta-Krypton

differs only from krypton by the substitution of