430 Mr. W. Sutherland on the 
Pb. As. Sb. Bi. Pd. Pie Fe. Ni. 
107/y...... 200°: \ 8515 431. -1080;>, 102 90‘: 110 “gigs 
TONG / Bee cedSl 8h 1825) 17D 4 Ne 92 91 72 67 
MOO, c0n2 290) (278)* S116) Raley 91. 118, ie 
NER ene? 8 - 605-773 710" 538° 177 12050 Sanne 
SR, 2 + D 5) 5 8 8 8 8 
28 76 25 4] 37 36 83 77 
* Calculated by empirical formula bTM* —-044. 
The last row in this table contains the values of (10/y) UT?/ 
6(M/p)*v, and ata first glance they do not seem to be near 
enough to a constant to verify (18 a), but the row contains 
some metals having such exceptional characters as demand 
modification of the theory leading to (18a). First, As is a 
metal with properties merging into those of a non-metal. 
Its molecule in the vaporous state is As, On this account 
As ought to be excluded from a table of normal metals. 
Although Sb and Bi, two other members of the As family of 
metals, would seem to fall into line as normal metals, I am 
dubious about 5 being the right value of v to use. Fe and 
Ni ought to be excluded from the above table on account of 
their magnetic properties, which indicate a special action and 
reaction between the revolving doublets and the atom. The 
magnetic metals require a special theory. The other metals 
giving distinctly exceptional values are Au, Al, In, and Sn. 
In their case the discrepancy I believe to be due to the fact 
that in these atoms the number of doublets is not identical] 
with the valency of the atom. It is noteworthy that three 
out of the four trivalent metals should contribute values 13, 
14, 14 tothe row. The exceptional results for Au, Al, and In 
can be accounted for by a principle which I have discussed 
in connexion with the tetrad valency of oxygen and the 
constitution of water in “Ionization, &e.” For example, 
the pentad valency of N was traced to its atom having 
associated with it four p electrons and one Z. If the # unites 
with one h to form a doublet the N atom can act as a triad, 
as in ammonia. If, then, the pentad metals Sb and Bi 
behave similarly, we might expect their atoms in the element 
state to form three doublets corresponding to the triad 
valency in addition to the one doublet formed by the union 
of Zand. Perhaps, then, for Bi and Sb in the above table, 
4 should be substituted for 5 in the values of rv. Returning 
then to the triad atoms of Au, Al, and In, we could ascribe 
their valency to two $ and one b electron. For aurie 
chloride AuCl;, the graphic formula would be as shown. Its 
reduction to aurous chloride AuCl ts readily explicable by 
