They left the door only partly open, for too much light might drive the ghost away. Then, sitting down comfortably, the two men passed their time by chatting, taking a sip now and then.
"The ghost seems to have spied us and probably won't come to-day," said the doctor.
"We must have patience. It is supposed to come at one," replied his friend.
So they talked till one o'clock. Everything was quiet, and not a sound came from the street. Suddenly the doctor raised his finger.
"Sh! Sesemann, don't you hear something?"
While they both listened, the bar was unfastened, the key was turned, and the door flew open. Mr. Sesemann seized his revolver.
"You are not afraid, I hope?" said the doctor, getting up.
"Better be cautious!" whispered Mr. Sesemann, seizing the candelabrum in the other hand. The doctor followed with his revolver and the light, and so they went out into the hall.
On the threshhold stood a motionless white form, lighted up by the moon.
"Who is there?" thundered the doctor, approaching the figure. It turned and uttered a low shriek. There stood Heidi, with bare feet and in her white night-gown, looking bewildered at the bright light and the weapons. She was shaking with fear, while the two men were looking at her in amazement.