LITHIUM (Plate IV, 2, and XIX, 1).

[Illustration]

Here we have some new combinations, which recur persistently in its allies.
The bodies _a_, in Plate XIX, 1, are at the top and bottom of the ellipse;
they come to right and left of it in the proto state, and each makes a
twelve-atomed body on the meta level.

The five bodies within the ellipse, three monads and two sextets, show two
which we have had before: _d_, which behaves like the quintet and quartet
in silicon, after their junction, and _b_, which we have had in iron. The
two bodies _c_ are a variant of the square-based pyramid, one atom at the
apex, and two at each of the other angles. The globe, _e_, is a new form,
the four tetrahedra of the proto level making a single twelve-atomed one on
the meta. The body _a_ splits up into triplets on the hyper; _b_ and _d_
follow their iron and silicon models; _c_ yields four duads and a unit; _e_
breaks into four quartets.

POTASSIUM (Plate XIX, 2).

Potassium repeats the lithium spike; the central globe shows the "nitrogen
balloon," which we already know, and which is surrounded on the proto level
with six tetrahedra, which are set free on the meta and behave as in
cobalt. Hence we have nothing new.

RUBIDIUM (Plate XIX, 3).

Again the lithium spike, modified slightly by the introduction of an ovoid,