And Joseph was thirty years old when he stood before Pharaoh king of Egypt. And Joseph went out from the presence of Pharaoh, and went throughout all the land of Egypt.
Thirty years - seventeen when brought into Egypt, probably three in prison, and thirteen in the service of Potiphar.
Went out ... throughout all the land of Egypt - made an immediate survey, to determine the site and size of the storehouses required for the different quarters of the country, as well as to provide channels for the irrigation of the whole land, and by a proper distribution of the water supply, to use all the appliances of human effort and machinery for taking advantage of the Providence-sent inundation.