70 W. A. Norton on Molecular Physics. 
from which the electric sary proceeds outward, but it will 
be readily seen that the be supposed to differ ‘within cer- 
—. limits, without vitiating ee result that for certain values 01 
pas = two alternations of the effective force will subsist. The forces 
mnsly also experience losses, to a certain extent, in their propaga- 
tion, and this general principle still hold go ood. 
It aes also be observed soy when ets particles are remote 
ing to the law of inverse atte A discussion of the phenom- 
ena of evolution of cometary envelopes, and of the outstreaming 
of jets of nebulous matter from particular parts of the surface 
of the nucleus, eos be had before we can decide how far the 
tion of cometic uation from the nucleus.’ 
The general law of the variations of the force of effective 
jagheenlar action is graphically represented by the curve 7, a, ™, 
ce, n, in fig. 1. The abscissas represent the comparative distances 
between the electric atmospheres of the two molecules, and the 
ordinates the intensities of the effective fares corresponding to 
these distances. When the ordinate lies above the axis of ab- 
scissas, the force is attractive; when it Liste ae. the force is re- 
ulsive. The two axes are asympto tothecurve. The curve 
as been constructed from the i HOE results obtained on the 
4 apie that f=0, when x=5r. 
here are four points, marked a, 6, c, d, to be especially noted. 
a and c, where f=0, represent positions of equilibrium; a being 
a position of stable, and ¢ of unstable equilibrium. When the 
atmospheres are separated by the distance Od the attraction has 
its maximum value, bm; and when they are at the distance 
the repulsion, beyond the outer limit of the attraction, has its 
maximum value, dn. In order that two particles may unite, 
when influenced by their own proper forces only, the distance 
7 In the memoir by the author “On the Theoretical Determination of a Di- 
mensions of Donati’s Comet,” published in No. 87, vol. xxix, and in No. 94, ve 
ourn s reached, a 
‘oie of by the Body nto er intensity, 
‘of ra 
steoun wih 
