Central tetrahedra 120
----
Total 3054
----
Atomic weight ----
Number weight 3054/18 169.66
META-KALON again substitutes two _z_'s for _x_ and _y_.

META-KALON: Six arms of 496 atoms 2976
Central tetrahedra 120
----
Total 3096
----
Atomic weight ----
Number weight 3096/18 172
Only a few atoms of kalon and meta-kalon have been found in the air of a
fair-sized room.

It does not seem worth while to break up these elements, for their
component parts are so familiar. The complicated groups--_a_ 110, _b_ 63
and _c_ 120--have all been fully dealt with in preceding pages.

* * * * *

There remains now only radium, of the elements which we have, so far,
examined, and that will be now described and will bring to an end this
series of observations. A piece of close and detailed work of this kind,
although necessarily imperfect, will have its value in the future, when
science along its own lines shall have confirmed these researches.