592 Scientific Proceedings, Royal Dublin Society. 
Persistence of properties after change of state. 
When an assemblage is broken up into groups by the breaking 
of the ties which keep the groups fixed in the same relative situ- 
ations with respect to one another, disturbing movements may 
cause the equilibrium to fluctuate and produce a liquid state in 
which the groups move with respect to one another while the parts 
of the same group preserve the same constant arrangement. <And 
when this is the case it is evident that any properties of the assemblage 
which are traceable to the arrangement of the parts in the groups and do 
not depend on anything outside them, will persist in the liquid state. 
This reminds us of some chemical compounds, such as terpene — 
and camphor, which not only in the liquid state, but also in the 
state of gas preserve the power of rotating the plane of polarization, 
and that in its fullest intensity.’ 
Different kinds of assemblages may display common properties. 
In complex assemblages extensive breaking down of links and 
rearrangement may be conceived to take place without destroying 
all the simple groupings, or in other words, when grouplets are. 
once formed, whether they have been formed alone or in conjunc- 
tion with other grouplets, one may conceive them to be capable of 
taking part in a succession of different combinations and entering 
into the composition of larger groups without the ties which link 
their parts together being broken or permanently disarranged. 
And the properties of assemblages of different kinds which contain 
groups of the same kind may be expected to be similar so far as 
they are conferred by these common groups. 
We may compare with this the fact that the behaviour of 
chemical compounds is often such as to convey the impression that 
the changes which they undergo leave untouched some of the 
atom-groupings within them. Thus the different alcohols all 
contain a hydroxyl group,” and all the substitution derivatives of 
benzene contain the 6-carbon-atom benzene nucleus. 
1 Ann. Scient. de l’Ecole Norm., Sup. 1, p. 1, and Bischoft’s ‘‘ Handbuch der 
Stereochemie,’’ p. 142. See Jdid, p. 141 as to persistence of the property in the 
amorphous state. Comp. Zeitschr. f. Kryst., &c., 27, p. 475. 
2 Lothar Meyer’s Grundziige der Theoretischen Chemie, Leipzig, 1893, p. 80. 
