We next come to vegetation; and it is placed in exactly its right position. For it requires four things: _soil_, _air_, _water_, and _light_ including heat; and these were the four things which then existed. The narrative, it will be noticed, speaks of three groups, _grass_, _herbs_, and _fruit-trees_; and it seems to imply that they appeared at the same time. But since its general plan is that of a series of events, the other view, that they appeared successively, is at least tenable. There is, however, this difficulty. None of these groups were complete before the following periods. Some plants, for instance (including both herbs and fruit-trees), appeared long after the commencement of fishes and birds, and similarly some fishes and birds after the commencement of land-animals. But the difficulty is due to the fact that the classes _overlap_ to a large extent. And the order given in Genesis is nearer the truth than any other would be. Had the writer, for example, placed them plants, animals, birds, fishes; he would have been quite wrong. As it is, by placing them plants, fishes, birds, animals, he is as near the truth as he can be, if classes which really overlap have to be arranged in a consecutive narrative. (6.) _The sun and moon._ We next come to the formation (that is the _making_, or evolving) of the sun and moon. The stars are also mentioned, but it is not said that they were made on the fourth day, and they are not alluded to in the opening command. Now, this alleged formation of the sun _after_ that of light is certainly the most striking point in the narrative, and was long thought to be a difficulty. But science has now shown that it is correct. However strange we may think it, light did undoubtedly exist long before the sun. In other words, the original nebula of our solar system was luminous, and lighted the earth, long before it contracted into a body with a definite outline, and producing such an intense and concentrated light, as could be called a sun. And since the earth would cool much quicker than the large nebula from which it was thrown off, vegetation might commence here before the nebula had become a sun, though this latter point is doubtful.