240 E. B. Hunt on the Nature of Forces. 
shuttlecock between attraction and repulsion, just as present con- 
venience dictated. We must have a more grand and simple idea 
of force, ere the labyrinth of molecular mechanics will yield its 
clue. In molecular studies, there is a strong and widespread ten- 
dency to complex hypotheses which but ill accord with the fun- 
damental simplicity of Nature, and which by hiding our igno- 
rance, effectively retard our progress towards knowledge. ‘To 
exorcise this tendency would greatly promote the consistent ex- 
tension of strict mechanical investigation over the rich fields of 
molecular constitution. ; 
ith a view to developing the principles now presented and 
as a preliminary to some discussion of the theoretical views ad- 
vanced by Boscovich and Faraday, I will here proceed to develop 
a few of the properties of central forces varying with an inverse 
function of the distance, and which may be either emanative or 
static by coexistence. 
Assume a centre of force (or other agency) at an origin of rect- 
angular coérdinates, and conceive the force to be radiated uniform- 
ly in all directions, each ray being in its entire length the repre- 
sentative of a constant intensity of action, or of an agency varying 
in intensity with any inverse function of the distance. This me- 
chanism must it is evident, give results identical with those which 
would result from a corresponding spherical wave mechanisiD. 
Suppose now a circular dise to advance or recede relative to the 
origin, by being moved along the axis of X by its centre and be- 
ing maintained perpendicular to it; the reception of rays by this 
disc will be a measure of effect so long as the obliquity of these 
rays can be disregarded. Calling the force or aggregate action 
y, when the disc is at the distance z from the origin, and ¥ diate 
it is at the distance unity ; we have y’: y :: x? : 1, or y=5 If 
now we conceive each ray as having an intensity varying with a 
simple inverse function of z, we shall obtain y= 5, in which ” 
exceeds by two the exponent of variation along each ray. 
“4 
If we differentiate the equation y =4, regarding y as 4 fune- 
/ 
tion of z, we obtain dy Ma be and this is the force deere 
can best be 
wards 
ment corresponding to the Newtonian law. This 
appreciated by deriving it directly. Let the dise advance to 
mining the elementary ring projected around the former position 
of the disc. Calling the disc radius r, and the width of the @ 
ded ring dr, we shall have by proportionality « : —dx::7 + 
