Six periods, or "days," are given for the formation of the earth. The use of the words "evening and morning" naturally leads to the conclusion that the _days_ were each twenty-four hours in length. But doubt is thrown over this conclusion by the use of the word _day_ in the second chapter and fourth verse, where the whole creative week is called a _day_. The word translated "day" also means _time_, but it is to be generally taken in the sense of the civil day--from sun up to sun down. Hugh Miller held to the opinion that the creation was represented to Moses in a vision. The periods passed before his mind in succession and had the appearance of days. The evening was the closing of one and the morning was the beginning of another period of time.[122] If a description of the different orders of life had been given, it would have been beyond the comprehension of that primitive people. It was not the design to teach geology. The people were not prepared for such scientific knowledge. But the simple statement that God is the author of all things, could be and was understood by the Israelites. On the sixth day man appears; but there are two records, and in them he is presented in different ways and for different purposes. In the first account man is made in the image of God, and to him is given dominion over the living things, and he is commanded to subdue the earth. The second account states that there was no man to till the ground, and the Lord formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul. The second account cannot be, as has been assumed, a repetition of the first. The two accounts are radically different. One account makes man to have dominion over the beasts, birds, and fishes; the other, to till or cultivate the soil. This agrees with archæo-geology. Men were hunters many ages before they were agriculturists. The one account has man made in the image of God, the other, a _living soul_. The "image of God" and "living soul" may be the same, but why the change? There may be a cause for it. If the theory of the vision be the true one, then Moses saw man in two capacities, differing one from the other. Man may be in the "image of God," and yet in a low, savage condition--subsisting on the chase. Man may be awakened from that condition, the "image of God" may assert its majesty, and make man a religious, worshipful being.[123] That there were two classes the record implies. Cain goes out into the Land of Nod, where his wife conceives, and he builds a city. Where did Cain get his wife, and why did he build a city? No account is given of the birth of his wife, but the natural inference is he obtained her in the Land of Nod.[124] It has been contended that Cain married his sister. If this be true it would certainly have been mentioned. It is too important a matter to have escaped notice. If he married his sister he was guilty of a heinous crime.