74 W. A. Norton on Molecular Physics. 
States of Aggregation of Matter—These are three essentially 
different states of equilibrium. In the solid form, the particles 
immediately contiguous to each other are in a condition of equl- 
librium under the action of their own molecular forces; if more 
distant particles exercise any effective ae it is attractive, and 
neutralized by a similar action on the other ‘side of the particle. 
more definite, each io tae! of on mass is surrounded 
by others at various orders of distance from it; and each pair 
of molecules at the first iniek of distance from each other are in 
a condition of equilibrium by themselves, which is equivalent 
to saying that their electric atmospheres are separated by the 
distance | Oa, fig. 1. For the second order of sega: action 
should then be attractive, but it may very well when a 
permanent equilibrium of the mass has been edited; the at- 
mospheres of two particles at this order of distance will be so 
expanded by their attractive oe on the line of their centres, 
that, for the diminished value of — — thus resulting, the distance 
between the atmospheres on ahie line will be the increased dis- 
tance Oa for the curve corresponding to this diminished value of 
=. Upon this supposition, each particle would be separately in 
equilibrium with every particle contiguous to it, both at the first 
second order of distance. We shall have occasion to note 
hereafter that this state of things is prsbabl more or less perfectly 
realized under different circumstances of Pen poa tal As to 
the action of more distant molecules, it is first to bserved 
that no effective action, either attractive of rare pr ttas can be 
transmitted to other more distant particles on the same line. 
Under these circumstances, one molecule, in receiving the action 
of another, intercepts the action that would otherwise take effect 
upon other more distant molecules. This being admitted, it 
may be perceived, on examining Table I, that the attractive ac- 
tions of particles which lie beyond the second order of distance 
from a given particle, will be in a great measure intereepted by 
intervening particles, In what has now been stated with respect — 
to the solid condition, we have had in mind a homogeneous mass 
val molecules only. We cannot here enter upon the considera- 
ont the case in which the molecules are aggregated into 
: Por the wid state, the contiguous icles repel each other; 
al nce more distant & st no pak Niet or a feeble — 
n the case of a solid, the sensible 
yarticles | at lie at the first and sec- : 
