Page:Proceedings of the Royal Society of London Vol 60.djvu/159

144 Dr. J. H. Gladstone. The Relation between the Trivalent Metals.

Metal. Specific refraction. \ / Combining proportion. Product. Aluminium........ 0-352 3-00 1-05 G-allium.............. 0-214 4-79 1-02 Yttrium............. 0-197 5-45 1-07 Indium .............. 0-153 6*15 0-94 Lanthanum........ 0-143 6-79 0-97 Cerium............... 0-143 6-83 0-98? Gold........... 0-127 8-11 1-03 Arsenic............. 0-200 5-00 1-00 Antimony.......... 0-204 6-32 1-29 Chromium.......... 0-296 3-74 1-23 Iron................... 0-355 4-32 1-53

The trivalents proper and arsenic agree still more closely amongst themselves, and give a mean of 101, which is practically identical with that of the bivalents proper.

The other trivalents, which have well-marked higher valencies, exhibit, as before, a somewhat higher product. Quadrivalent Metals.

Metal. Specific refraction. V Combining proportion. Product. Zirconium......... 0-242 4-76 1-15 Tin..................... 0T61 5-45 0-88 Lead................... 0-129 7T9 1-02? Thorium............ 0-123 7-62 0-94 Iridium.............. OT65 6-95 1-15 ? Platinum........... 0-172 6-98 1-20

In this case the mean is T06, nearly the same as with the bivalents and trivalents, but the numbers are not so regular.

We have observations on one pentad, namely, antimony. This gives—

Specific refractive energy........... 0200 ^Combining proportion............. 4’9 Product .................................. ... 0-98

These tables show: First, that the metals which have the same valency, have the same, or nearly the same, constant of refraction for equivalent weights.