But 72, 74, 76, are Iron, Cobalt and Nickel.

So there does probably exist a new group with bars (183), 185, 187, 189,
with atomic weights.

X=bar 185; atoms 2590, wt. 143.3
Y= 187, 2618, wt. 145.4
Z= 189, 2646, wt. 147.0.
They come probably among the rare earths. Probably also Neodymium and
Praseodymium are two of them, for their weights are 143.6, 140.5.

* * * * *



CHAPTER III.

THE LATER RESEARCHES.

The first difficulty that faced us was the identification of the forms seen
on focusing the sight on gases.[2] We could only proceed tentatively. Thus,
a very common form in the air had a sort of dumb-bell shape (see Plate I);
we examined this, comparing our rough sketches, and counted its atoms;
these, divided by 18--the number of ultimate atoms in hydrogen--gave us
23.22 as atomic weight, and this offered the presumption that it was
sodium. We then took various substances--common salt, etc.--in which we
knew sodium was present, and found the dumb-bell form in all. In other
cases, we took small fragments of metals, as iron, tin, zinc, silver, gold;
in others, again, pieces of ore, mineral waters, etc., etc., and, for the
rarest substances, Mr. Leadbeater visited a mineralogical museum. In all,