h

)—the iodine ovoids—and the external segments contain five-atomed triangles (7

i

). Thus 1,568 atoms have been packed into the beryllium type, and our wonder is again aroused by the ingenuity with which a type is preserved while it is adapted to new conditions.

STRONTIUM: 4 funnels of 368 atoms 1472
Central globe 96
----
Total 1568
----
Atomic weight 86.95
Number weight 1568/18 87.11

The corresponding group, headed by oxygen—oxygen, chromium, molybdenum, wolfram and uranium—offers us another problem in its first member.

Oxygen

(

[Plate VIII]