Other Agents Besides Evolution.—There are agents performing an essential part in the formation and continuation of our world which are not mentioned, except incidentally, by geologists. There are some things which cannot be brought into the physicist's laboratory, and which therefore he may not be required specially to discuss; but he should not in his narrowness disparage or ridicule those who insist on looking at them and finding out the part which they play. I will do no more than refer to the creation of matter, to show that it has not been overlooked. But it is of importance to bring into view and meditate on certain agents which have played a most important part in the formation of our world, but which cannot, so far as we see, be evolved from the material which we have been considering.

Light.—We do not know all the mystery of its action. It consists of vibrations in an ether. When and whence came that ether with its properties? There is no evidence that it has developed in the ordinary action of matter. It is certain that it performs a very important part in the economy of nature. It is necessary to the growth of plants and animals. Perhaps no one can tell whether it has come from an antecedent mundane matter, or whether, like matter itself and its forces, mechanical, chemical, gravitating, it may not be the immediate product of the creative power of God, who said, “Let there be light, and there was light.”