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.

        14 bars of 72 atoms 1008
        Atomic weight 55.47
        Number weight 1008/18 56.00
IRON (Plate IV, 1, and XVII, 3): 

        14 bars of 74 atoms 1036
        Atomic weight 57.70
        Number weight 1036/18 57.55
COBALT (Plate XVII, 4): 

        14 bars of 76 atoms 1064
        Atomic weight 58.30
        Number weight 1064/18 59.11
NICKEL (Plate XVII, 4): 

(The weight of cobalt, as given in Erdmann’s Lehrbuch, is 58.55, but Messrs. Parker and Sexton, in Nature, August 1, 1907, give the weight, as the result of their experiments, as 57.7.)

[Illustration:  PLATE XVIII.]

The next sub-group, ruthenium, rhodium, and palladium, has nothing to detain us.  It will be observed that each bar contains eight segments, instead of the six of cobalt and nickel; that ruthenium and palladium have the same number of atoms in their upper ovoids, although in ruthenium a triplet and quartet represent the septet of palladium; and that in ruthenium and rhodium the lower ovoids are identical, though one has the order:  sixteen, fourteen, sixteen, fourteen; and the other:  fourteen, sixteen, fourteen, sixteen.  One constantly asks oneself:  What is the significance of these minute changes?  Further investigators will probably discover the answer.

      14 bars of 132 atoms 1848
      Atomic weight 100.91
      Number weight 1848/18 102.66
RUTHENIUM (Plate XVIII, 1): 

      14 bars of 134 atoms 1876
      Atomic weight 102.23
      Number weight 1876/18 104.22
RHODIUM (Plate XVII, 2): 

      14 bars of 136 atoms 1904
      Atomic weight 105.74
      Number weight 1904/18 105.77
PALLADIUM (XVIII, 3):