433 
The quintessence of this new view is this, that the atoms of a 
solid substance occupy in a definite way the places of points of a 
lattice, in which arrangement the molecules no longer occur as 
separate particles, so that the idea of a molecule would undergo a 
fundamental modification for the solid substance, for it is immediately 
seen that according to this view every solid phase both in physical 
and in chemical sense bad to be looked upon as one large molecule. 
2. It strikes the chemist immediately that as the forces which 
occur e.g. between, Na and Cl atoms in the solid phase have 
certainly to do with the valency, it would follow from the model 
designed by Braee for solid NaCl that Na just as Cl has a va- 
lency of six. This fact is so very remarkable for this reason that 
importance is attached to the fact that the quadri-valency of the 
carbon atom would follow from the model for diamond. 
Also the model given by Brace for calcium-carbonate leads to 
remarkable conclusions. Lt appears namely from this model that 
every Ca-atom is surrounded by six oxygen-atoms, and that the dis- 
tance between the centres of Ca and O is smaller than that between 
Ca and C. Along the sides of the calespar rhomboheder there prevails 
no chemical force, for there is every reason from chemical side to 
assume in CaCO, no binding between Ca and C, but to do so 
between Ca and O. Led by the distances in the model of Brace 
we might distinguish CO,-groups; then, however, it is remarkable 
that every Ca-atom would always be connected with one O-atom 
of six CO,-groups, whereas we should have expected that every 
Ca-atom would be bound to two oxygen atoms of the same CO,- 
group. These remarks suffice, therefore, to show that this model 
cannot be reconciled with our idea of valency. 
This objection can be thus further elucidated. In the representation 
given by the Braces model of the solid substance the considerations are 
perfectly ignored which have led to the firm conviction that the 
atoms in the molecule are bound by forees which are characterized 
by their localized nature and by their definite number. 
Thus BorLTMANN writes '): “Wir erklären die Existenz der aus zwei 
Atomen zusammengesetzten Molekiile durch eine, zwischen den 
Atomen thätige anziehende Kraft, welche wir die chemische Anzie- 
hung nennen. Die Thatsachen der chemischen Valenz oder Wertigkeit 
machen es wahrscbeinlich, dass die chemische Anziehung keineswegs 
einfach eine Funktion der Entfernung der Mittelpunkte der Atome 
ist, dass sie viel mehr bloss an verhältnissmässig kleine Bezirke auf 
— 
!) Vorlesungen über Gastheorie, |’, 177. 
28 
Proceedings Royal Acad. Amsterdam. Vol. XIX. 
