The sky, according to some, extended overhead like an immense iron ceiling, and according to others, like a huge shallow vault.

As it could not remain suspended in space without some support, they imagined it to be held in place by four immense props or pillars.

The floor of the temple naturally represented the earth.

The columns, and if needful the four corners of the chambers, stood for the pillars.

The roof, vaulted at Abydos, flat elsewhere, corresponded exactly with the Egyptian idea of the sky.