730 
DR. CARPENTER ON THE MUTUAL RELATIONS Of 
netism, Optics, and Thermotics, have undergone during that period, and of the accumu- 
lation of facts which more or less distinctly indicate the existence of such relations 
to those who know how to read them aright. Amongst those who have laboured 
most successfully in this line of inquiry. Prof. Faraday stands pre-eminent ; but the 
author is not aware that any other attempt has been made to formularize the entire 
series of these mutual relations, than that which has been put forth by Prof. Grove 
in his short treatise ‘On the Correlation of Physical Forces;’ in which he seeks to 
establish “that the various imponderable agencies, or the affections of matter which 
constitute the main objects of experimental physics, viz. heat, light, electricity, mag- 
netism, chemical affinity, and motion, are all correlative or have a reciprocal depend- 
ence : — that neither, taken abstractedly, can be said to be the essential or proximate 
cause of the others, but that either may, as a force, produce or be convertible into 
the other; thus heat may mediately or immediately produce electricity, electricity 
may produce heat, and so of the rest” (p. 8). 
That the same view might be probably applied to the mutual relations of some of 
the Vital forces, did not escape Prof. Grove’s sagacity, as will appear from the fol- 
lowing passage near the conclusion of his essay : — “ 1 believe that the same principles 
and mode of reasoning might be applied to the organic, as well as the inorganic 
world, and that muscular force, animal and vegetable heat, &c., might, and at some 
time will, be shown to have similar definite correlations; but I have purposely 
avoided this subject, as pertaining to a department of science to which I have not 
devoted my attention” (p.49). I’he forces here alluded to by Prof. Grove, however, 
— those of muscular motion and heat, — are really physical in their manifestations, 
though generated in living bodies ; the purely vital operations of growth, development, 
and reproduction are not even named by him; and not the slightest hint is given by 
him of the existence of any such relation between the Vital and Physical forces, as 
it is the chief object of this paper to establish. 
Believing, as the author himself does, that all force which does not emanate from 
the will of created sentient beings, directly and immediately proceeds from the Will 
of the Omnipotent and Omnipresent Creator (which is evidently the idea entertained 
by Locke*), — and looking therefore at what we are accustomed to call the physical 
forces, as so many modi operandi of one and the same agency, the creative and sus- 
taining will of the Deity, — he does not feel the validity of the objections which have 
been raised by some to whose opinions on philosophical questions he attaches great 
weight, against the idea of the absolute metamorphosis or conversion of forces. In 
deference to those opinions, however, he would here say in limine that his present 
object is to show, that the same relation (in whatever way defined) exists among 
the several vital forces, whose operation may be traced in living bodies, as exists 
among the physical ; and that the vital and physical forces are themselves con- 
nected by a similar relationship. And as a mode of expressing that relationship 
* Humau Understanding, Book II. Chap. xxi. On Power, § 4. 
