201 
varying inversely as the square of the distance, whilst it stands 
as a lull dennition of the power, is inconsistent with the prin 
ciple of the conservation of force ” Then as regards our actual 
knowledge or experience of this law of gravity, when we test 
it at the surface of the earth, do we find it even then invariable ? 
On the contrary, we know very well that there is a marked 
variation m the weight of bodies— i. e., in the force of their 
gravity— at the equator and in arctic latitudes : and this is 
equally inconsistent with the law of “the conservation of 
lorce, as is the variation arising from distance in space. Or 
grant that these variations are practically the same, which I 
need not dispute— but I am obliged on the present occasion 
to touch lightly on such illustrations— still I wish to point 
out, that if both theory and our actual experience affirm that 
the force of gravitation varies, then the law is not “invari- 
able ; and, at any rate, according to Professor Faraday— 
and as must almost be self-evident-a force that thus varies 
must be inconsistent with the conservation of force. It is 
also mconsistent with the law of continuity ; for all who have 
studied modern physical astronomy know that the force of 
gravitation theoretically grows weaker and weaker, till it dies 
away, and that bodies are supposed to get out of the sphere 
of their former centres of attraction, and to travel away into 
annlferl M er %h 0 “fi® our . Vice-President’s apt expression 
apphed to another i lustration, “the law of continuity snaps 
“dwffidlin md ,fd Mr -. Grove himself has told us of the 
dwindling away of Ins imagined worlds. 
I need not here enter upon the refinement which might be 
advanced, that a “law” which defines that a certain force in 
nature varies invariably, and varies in a given manner, may be 
tiuly regarded as an invariable law. I will onlv remark this 
woT?" 1 lkS b ° f continuit y will neither admit that 
worlds have been created nor that they can be destroyed nor 
'T “1° be in a state of absolute 
stability ! but tells us that they “dwindle away,” “ever 
of ToSityT n6W/ ^ V6rJ r6VerSe ° f aU ° Ur 0rdinar ^ ideas 
But to resume. The uniformity, real or apparent of na 
ombinS SU of h r a L th 1 h° f ° r th - e 
combination, of light, of heat, of vegetation, or of life so far 
certain pnncffil U “ dersta “ d the “> ^ seem to speak to us of 
selves accordffit /* work > energizing, as it were, of them- 
we call theh “f . S °“^ rul6S ° r laWS which constitute what 
these laws do ^ le ’. ani ^ u P on the whole we may admit that 
t £® ®; a T® do aot uniformly and invariably. There is then 
this settled course of things, which we calf nature, and which 
