The first step in the development of the earth was, we are told, the introduction of _light_. That this is what Genesis means seems plain, for the _light_ must refer to the _darkness_ of the previous verse, and that referred to the _earth_. As to whether light previously existed in other parts of the universe, Genesis says nothing, it is only concerned with this earth. And in the development of this earth, _light_ (which in nature always includes _heat_) must obviously have come first. For on it depend the changes in temperature, which lead to the formation of winds, clouds, and rain; while it also supplies the physical power that is necessary for the life of plants and animals; so in placing _light_ as the first step, Genesis is certainly correct. Of course, the _source_ of light at this early period was the remainder of the nebula from which our planet was thrown off. It was thus spread over an immense space, instead of being concentrated like that of our present sun; and probably only reached the earth through a partial clearing of the clouds just alluded to. (3.) _The firmament._ The next step was separating the waters _above_ (_i.e._, these dense clouds) from the waters _below_ which are stated to be the seas (v. 9-10) and forming between them a firmament or _expanse_ (see margin), that is to say, the _air_. The idea that the writer thought this expanse meant a solid plane holding up the waters above (because it is perhaps derived from a word meaning firm or solid) is scarcely tenable. For the firmament was called _heaven_, and the upper waters, above this _heaven_, must mean the sources from which the _rain_ usually comes, since it is called _rain from heaven_.[13] And these sources are easily seen to be _clouds_; and no one could have thought that a _solid_ firmament was between the clouds, and the seas. [Footnote 13: Deut. 11. 11.] Moreover this same word _heaven_ (though used in various senses) is translated _air_ later on in this very narrative when it speaks of fowls of the _air_ (verses 26-28, 30). And it also occurs in other passages, in some of which it cannot possibly mean anything but the air, _e.g._, 'any winged fowl that flieth in the _heaven_,' and 'the way of an eagle in the _air_,'[14] which is an additional reason for thinking that it means the air here. [Footnote 14: Deut. 4. 17; Prov. 30. 19.] And the omission, before noticed, to say that God saw that the firmament was _good_, is quite natural, if this means only the air, _i.e._, the space between the clouds and the seas; just as an artist, though he might examine his pictures to see that they were _good_, would not examine the spaces between them. But it is difficult to account for, if it means a _solid_ firmament, which would seem to require God's approval like everything else.