be noticed that the four lower sections of the bars are identical in all
the members of this sub-group, each ovoid containing thirty atoms. The
upper ring of ovoids in iridium and platinum A are also identical, but for
the substitution, in platinum A, of a quartet for a triplet in the second
and third ovoids; their cones are identical, containing twenty-one atoms,
like those of silver and tin.

14 bars of 245 atoms 3430
Atomic weight 189.55
Number weight 3430/18 190.55
OSMIUM (Plate XVIII, 4):

14 bars of 247 atoms 3458
Atomic weight 191.11
Number weight 3458/18 192.11
IRIDIUM (Plate XVIII, 5):

14 bars of 249 atoms 3486
Atomic weight 193.66
Number weight 3486/18 193.34
PLATINUM A (Plate XVIII, 6 _a_):

14 bars of 251 atoms 3514
Atomic weight ------
Number weight 3514/18 195.22
PLATINUM B (Plate XVIII, 6 _b_):

V a.--THE SPIKE GROUPS.

I place within this group lithium, potassium, rubidium, fluorine, and