"And God said, 'Let light be' and light was." It has already been pointed out that these words differ from those used in describing any other creative act. They are the only ones which seem to imply an instantaneous fulfilment of the command. Another matter which has long since been observed, is their exact harmony with what science teaches us respecting the nature of light. Light is not a material substance, but a "mode of motion." It consists of very small undulations propagated with inconceivable velocity. Hence of it, and of it alone, it could not be correctly said that it was created. To say that God made light would be inexact. The words which are used exactly suit the circumstances of the case. But the discovery of the correlation of forces has given to these words a much more extended significance, while at the same time it furnishes a satisfactory reason for their occurrence at this particular point. So long as they were supposed to refer to light simply, they seemed out of place. Light was not apparently needed till there were organisms to whose existence it was essential. But we now know that to call forth light, was to call force in all its modifications into action. It has been seen that matter and force are the two elements out of which everything that is discernible by our senses is built up. The formation of matter has already been described in the original act of creation. But till force also was evolved, matter must of necessity remain in that chaotic state to which verse 2 refers. To matter is now added that which was required to enable the progressive work of Creation to be carried on. The first result of this would probably be that the force of gravitation would begin to act, while, from what the telescope reveals to us, we may conjecture, that at the same time the whole incoherent mass would be permeated with light and heat, and some, at all events, of those elementary substances with which chemistry makes us acquainted would be developed, and the whole mass, acted upon by the mutual attraction of its several particles, would begin to move towards, and accumulate about its centre of gravity.