wo new forms, and these are merely
four-atomed tetrahedra, occurring in pairs as object and image. All the
other bodies have already been analysed.

II a.--We come now to the second great tetrahedral group, which though very
much complicated, is yet, for the most part, a repetition of familiar
forms.

MAGNESIUM (PLATE IX, 1).

[Illustration]

We are still among tetrahedra, so have to do with four funnels, but each
funnel contains three rings, and each ring three ovoids; on the proto level
a triple dissociation takes place, for the funnels let free the rings as
large spheres, in each of which rotate three twelve-atomed ovoids, and then
the ovoids break loose from the spheres, and themselves become spherical,
so that we have finally thirty-six proto compounds from the tetrahedron. On
the meta level the contained bodies, a triplet, Mg _a_, a septet, Mg _b_,
and a duad, Mg _c_, are set free from each globe, thus yielding one hundred
and eight meta compounds. On the hyper level the triplet becomes a duad and
a unit; the duad becomes two units; and the septet a triplet and a quartet.

ZINC (PLATE IX, 2).

We can leave aside the funnel, for the only difference between it and the
magnesium funnel is the substitution of a second septet for the triplet,
and the septet is already shown in the magnesium diagram. We have,
therefore, only to consider the spikes, pointing to the angles of the
enclosing tetrahedron, and the central globe. These are set free on the
proto level and the spikes immediately release their contents, yielding
thus thirty-two separate bodies.

The triangular arrangement at the top of the spike is the same as occurs in
copper (_b_ on p. 48), and can be there followed. One of the three similar
pillars is shown in the accompanying diagram under Zn a. The compressed
long oval becomes a globe, with six bodies revolving within it in a rather
peculiar way: the quartets turn round each other in the middle; the
triplets revolve round them in a slanting ellipse; the duads do the same on
an ellipse slanting at an angle with the first, somewhat as in gold (_a_
and _b_, p. 40). The spheres within the globes at the base of the spikes,
Zn _b_, behave as a cross--the cross is a favourite device in the II _a_
groups. Finally, the central globe, Zn _c_, follows the same cruciform line
of disintegration.

CADMIUM (Plate IX, 3).

[Illustration]

Cadmium follows very closely on the lines of zinc; the pillars of the zinc