interperiodic group with its neighbours. He says: "These bodies are
interperiodic because their atomic weights exclude them from the small
periods into which the other elements fall, and because their chemical
relations with some members of the neighbouring groups show that they are
probably interperiodic in the sense of being in transition stages."

Group V in every case shows fourteen bars radiating from a centre as shown
in iron, Plate IV, 1. While the form remains unchanged throughout, the
increase of weight is gained by adding to the number of atoms contained in
a bar. The group is made up, not of single chemical elements, as in all
other cases, but of sub-groups, each containing three elements, and the
relations within each sub-group are very close; moreover the weights only
differ by two atoms per bar, making a weight difference of twenty-eight in
the whole. Thus we have per bar:--

Iron 72 Palladium 136
Nickel 74 Osmium 245
Cobalt 76 Iridium 247
Ruthenium 132 Platinum A 249
Rhodium 134 Platinum B 257
It will be noticed (Plate XVII, 3, 4, 5,) that each bar has two sections,
and that the three lower sections in iron, cobalt and nickel are identical;
in the upper sections, iron has a cone of twenty-eight atoms, while cobalt
and nickel have each three ovoids, and of these the middle ones alone
differ, and that only in their upper globes, this globe being four-atomed
in cobalt and six-atomed in nickel.

The long ovoids within each bar revolve round the central axis of the bar,
remaining parallel with it, while each spins on its own axis; the iron cone
spins round as though impaled on the axis.