They say, too, that the area of that ark could not contain so many kinds of animals of both sexes, two of the unclean and seven of the clean. But they seem to me to reckon only one area of 300 cubits long and 50 broad, and not to remember that there was another similar in the storey above, and yet another as large in the storey above that again; and that there was consequently an area of 900 cubits by 150. And if we accept what Origen[218] has with some appropriateness suggested, that Moses the man of God, being, as it is written, "learned in all the wisdom of the Egyptians,"[219] who delighted in geometry, may have meant geometrical cubits, of which they say that one is equal to six of our cubits, then who does not see what a capacity these dimensions give to the ark? For as to their objection that an ark of such size could not be built, it is a very silly calumny; for they are aware that huge cities have been built, and they should remember that the ark was an hundred years in building. Or, perhaps, though stone can adhere to stone when cemented with nothing but lime, so that a wall of several miles may be constructed, yet plank cannot be riveted to plank by mortices, bolts, nails, and pitch-glue, so as to construct an ark which was not made with curved ribs but straight timbers, which was not to be launched by its builders but to be lifted by the natural pressure of the water when it reached it, and which was to be preserved from shipwreck as it floated about rather by divine oversight than by human skill.