Mr. Martin walked on, and in a few minutes found himself outside Number 407. It was much as he remembered it, but that it was lying empty, and showed signs of being refitted for a new tenant. The windows were almost obscured with patches of whitewash, but peering through them he could see trestles, timber, shavings, all the litter which betrays the presence of the carpenter. So far, then, the letter was correct. Mr. Martin, after a furtive glance round about him, walked up to the door and tried it. It was locked.