CHRISTIAN THOUGHT. THE CONSERVATION OF SPIRITUAL FORCE. [A Lecture delivered before the American Institute of Christian Philosophy, August 26, 1886.] BY REV. J. W. LEE, D.D., THE Atlanta, Ga. HE doctrine of the correlation, equivalence, persistence, transmutability, and indestructibility of force, or the conservation of energy, has had vast influence upon the thought and the life of our time. It has furnished a new opening through which to behold the nature of things. It has given to men a new working hypothesis and richer views and conceptions of the universe and its Author. The civilization of the present, with all that it contains and all that it promises, is due more to this than to any other scientific doctrine or principle. According to Prof. Balfour Stewart, there are eight forms of energy, or force-the energy of visible motion, visible energy of position, heat motion, molecular separation, atomic or chemical separation, electrical separation, electricity in motion, and radiant energy. Now, taking this earth as a complete whole, containing within itself all these forms of energy, and so isolated from the rest of the universe as to receive nothing from it and to add nothing to it, then the principle of the correlation of forces asserts that the sum of all these forces is constant. "This does not assert that each is constant in itself, or any other of the forms of force enumerated, for in truth they are always changing about into each other— now some visible energy being changed into heat or electricity, and anon some heat or electricity being changed back again into visible energy; but it only means that the sum of all the energies taken together is constant. There are eight variable quantities, and it is only asserted that their sum is constant, not by any means that they are constant themselves." For the purpose of elucidating our principle in the realm of nature, we will consider it as it applies to some of the useful forces whose effects we can measure, and whose origin we can trace and determine. 1. There is the force of conserved fuel. Away back in the carboniferous period of the world's history, there grew immense forests which, in succeeding ages, were turned under the earth, and in the process of the years were changed into coal and oil and gas. These have been treasured for untold ages in the mountains and in the bowels of the earth. Now they are brought forth by the applied intelligence of man, to turn his wheel, draw his car, cook his food, propel his plow, and to light his home and his street. The force in one ton of coal is capable of accomplishing more work in a few hours than one man could in a lifetime. Then there are the great forests which are growing to-day. These also contain force for the propelling of machinery and for the illumination of home and street. These forces originated in the sun. Coal is solidified sunshine, oil is liquid sunshine, gas is diffused sunshine. 2. There is the conserved force of food. This is found primarily in the grass, the wheat, the corn, the rice, the fruit, which grow in our fields. The lower animals feed on these, and through the processes of digestion and assimilation they are transmuted into blood and bone and muscle-thus furnishing man, who stands at the top and the end of the creative process, with a more refined, higher form of food. But whether in the shape of grass, wheat, rice, fruit, or in the more refined form of animal flesh, these various elements of food are only so much transmuted sunshine. Before they ever adorned the surface of our fields, and purified and filled with sweet aroma the air we breathe, or moved in the lowing herd over the meadow, or flew in the beautiful bird through the sky, they were held in solution in the sunbeam. Sunshine constitutes the fuel, the food, and the life of our earth. 3. There is the conserved force of flowing water. This turns |