W. A. Norton on Molecular Physics. 69 
grounds, their comparative values. But we can assume that 
u=v, for some supposed value of , determine the ratio of n to 
m on this supposition, and calculate the values of / for various 
aoe of z, both greater and less than that for which we have 
laken f/=0 
The preceding table contains the results of numerous calcula- 
: _ 4 i mm 
tions made after this manner: in which & stands for oie 
n 
Fypm these results it appears that for values of 7 greater than 
4938, or thereabouts, there are two alternations of the effective 
. force f, as the distance between the molecular-atmospheres increases 
indefinitely from zero. The first is from a repulsion to an attrac- 
ion; the second is from an attraction to a repulsion. The re- 
pulsion which becomes effective beyond the limit of the attraction, 
at first increases, and then decreases, extending to an indefinite 
distance. If the ratio, = , be less than about 4°938, the effective 
action of the two molecules upon each other will be repulsive at 
all distances. It will be observed also that the range of distance 
within which an attractive force takes effect is greater in propor- 
tion as the value of — is greater, and that this becomes reduced 
mm 
nearly to zero, when this ratio is equal to 4938; also, that in 
all cases in which an effective attraction manifests itself at any 
distance whatever between the molecules, that is in the case of 
every known solid and liquid, the effective repulsion within the 
limit of the attraction, obtains at less distances between the 
electric atmospheres of the molecules than about 3r, that is, 
4n once and a half the diameter of either atmosphere. 
or the more accurate determination of the least value of the 
Tatio ~ we have the following results of computation: 
For /=0, when aaeBr, — =4'93827 ; for /=0, when x=2°9r, 
nr 
m7 498449; for f=0, when a=2'87, —=4-934409; for f=0, 
when 2=2-7 x ” =4-93847. If then the ratio - be greater than 
m™m 
49344, the two alternations of effective molecular force above 
Mentioned will have place; if the ratio be less than 49344, the 
Hective action of the one molecule upon the other will be re- 
Pulsive at all distances. 
_ Itis assumed in the foregoing calculations, that the surface of 
_ €ach molecular atmosphere which receives the impulses, whether 
attractive or repulsive, propagated from the other through the 
_ Antervening electric ether, may be regarded as the same as that 
