exact member of atoms in titanium.

* * * * *

III.

Occultum was observed by us in 1895, and, finding that it was so light, and
so simple in its composition, we thought that it might be helium, of which
we were unable, at the time, to obtain a sample. When, however, helium
itself came under observation in 1907, it proved to be quite different from
the object before observed, so we dubbed the unrecognised object Occultum,
until orthodox science shall find it and label it in proper fashion.

OCCULTUM (Plate VI, 1).

We here meet the tetrahedron for the first time, with each angle occupied
by a six-atomed group, the atoms arranged as on the end triangles of a
prism. This form recurs very often, and was noted, last month, as seen in
copper (Plate VI, 3); it revolves with extreme rapidity around its
longitudinal axis, and looks like a pencil sharpened at both ends, or a
cigar tapering at both ends; we habitually spoke of it as "the cigar." It
appears to be strongly coherent, for, as will be seen below, its six atoms
remain attached to each other as meta-compounds and even when divided into
two triplets as hyper-compounds, they revolve round each other.

Above the tetrahedron is a balloon-shaped figure, apparently drawn into
shape by the attraction of the tetrahedron. The body below the tetrahedron
looks like a coil of rope, and contains fifteen atoms; they are arranged on
a slanting disk in a flat ring, and the force goes in at the top of one
atom, and out of the bottom of it into the top of the next, and so on,