51 
into tlie strongest light by the quantitative relation existing 
between them, which is expressed by saying that a weight of 
one pound, falling through a height of 772 feet, generates an 
amount of heat sufficient to warm a pound of water one degree 
Fahrenheit, and that in lifting the weight so much heat exactly 
disappears. 
11. My main object being to make it appear that the new 
doctrine of conservation of energy does not conflict with the 
belief that a personal Deity is the Creator and Director of the 
universe, it would be out of place, as well as beyond the limits 
of my knowledge, to call in question that doctrine itself. It 
may be as well, however, to mention that the quantitative 
relation between molar and molecular motion is not yet looked 
upon by all scientific men as indubitably proved. Mr. Porter, 
President of Yale College, to whose paper I have already 
more than once alluded, says in p. 85 of that paper : — “We 
question very much, indeed, whether the experiments have 
been conducted with mathematical exactness, or whether the 
laws have been formulated with scientific precision, or, as 
Tyndall phrases it, whether ‘ the inter-dependence 3 between 
the several factors has f become quantitative — expressible by 
numbers/ 33 We may let this pass, however, as having little 
or no bearing upon religion, if the view I would advocate be 
correct. What I would at present observe is, that the argu- 
ment derived from the principle of conservation of energy, as 
extended to molecular motion, will be found, when duly 
examined, to leave the belief in a Creator and Director of the 
universe altogether untouched. That principle, granting it to be 
established, shows that in the universe, as constituted, energy 
is neither lost nor gained. Kinetic energy may be, and con- 
stantly is, either diminished or increased. But when it is 
diminished, the quantity deducted is stored up as poteyitial, • 
energy, while its increase is accompanied by a corresponding 
deduction of potential energy, so that the sum of the two, i.e. 
the total of the energy existing, remains unaltered. This, 
under the name of conservation of vis viva, has been known, so 
far as molar motion is concerned, since the days of Newton, 
as already observed. But I am not aware that it was ever 
looked upon as strengthening the arguments of unbelievers 
derived from the general uniformity of nature. Why, then, 
should the extension of the same principle to molecular motion 
be so looked upon? It is only another instance of that 
general uniformity of inanimate nature which was already 
fully acknowledged. If it was thought previously that man 
could originate force (“creation of force 33 is, I believe, rather 
a new expression), I am not aware that this was ever looked 
e 2 
