The Last Egyptian by L. Frank Baum

When Fedah seemed asleep, Kāra took the lamp and the bronze dagger from their hiding place and swung back the stone in the rear wall, passing through into the mountain cavern. Then, replacing the stone, he made his way along the crevice, through the circular rock door into the arched passage, and down the latter to the mummy chamber.

Here he removed the lid of Hatatcha's mummy case and carefully dusted the interior. The forty days were ended. The case might have its occupant before morning.