"Oh, Duke, open it, open it!" he screamed.
But this was more than Duke could do. The door was fast shut, and no pushing or knocking from this side was of the least avail. There was no handle. Examining it by the light of his candle, Duke discovered a small keyhole, but what was the good of a keyhole without a key?
Noel burst into tears.
"Oh, Duke, we shall never get out, never! Mother does not know where we are, and she'll never guess that that picture is a door."
The prospect was appalling. The candle shining full on Duke's face showed it quite white. The adventure was turning out very differently from his expectations. He could hardly keep back his tears.
Curiously, the sight of his distress roused Noel's courage.
"Don't cry, Duke," he said softly. "Mother is sure to come and look for us, and if we shout very loud she'll hear us."
"I'm not crying," said Duke stoutly. "I dare say mother knows all about the picture, and if not, there must be another way out. Come along. Let's see where these steps lead to."
Duke led the way, holding the candle high that Noel might see each step. Thus they went down a long, narrow, crooked flight of steps, which seemed to lead down into the heart of the earth. It ended in a low, arched passage, just wide enough for the boys to walk side by side. They could walk upright, but most men would have had to stoop. The passage was not damp, but it had a strange earthy smell. It inclined slightly downwards, and as they went on the air grew fresher till presently a breeze blew in their faces which brought a smell of the sea.
"Does the sea come up here?" asked Noel, inspired with a fresh fear.