Total 2287
----
Atomic weight 126.01
Number weight 2287/18 127.055
The plan underlying the building up of groups is here clearly shown; a
figure is built up on a certain plan, in this case a dumb-bell; in the
succeeding members of the group additional atoms are symmetrically
introduced, modifying the appearance, but following the general idea; in
this case the connecting rod remains unaltered, while the two ends become
larger and larger, more and more overshadowing it, and causing it to become
shorter and thicker. Thus a group is gradually formed by additional
symmetrical additions. In the undiscovered remaining member of the group we
may suppose that the rod will have become still more egg-like, as in the
case of gold.

I b.--The corresponding positive group to that which we have been
considering consists of Na, Cu, Ag, and Au (sodium, copper, silver and
gold), with an empty disk between silver and gold, showing where an element
ought to be. These four elements are monads, diamagnetic, and positive, and
they show the dumb-bell arrangement, although it is much modified in gold;
we may presume that the undiscovered element between silver and gold would
form a link between them.

[Illustration: PLATE VI.]

SODIUM (Plate VI, 2) has been already described (p. 349, January), as a
type of the group, so we need only refer to its internal arrangement in
order to note that it is the simplest of the dumb-bell group. Its twelve
funnels show only four enclosed bodies, the same as we see in chlorine,
bromine, iodine, copper and silver, and which is very little modified in