She began to think what she was going to do. Suppose she had just gone on walking till she came to a policeman. She could picture the conversation,

“Now, miss, let’s get this straight. You say you heard this man make a statement to the effect-”

“No, no, I didn’t hear him. I can’t hear anything-I’m deaf-”

It would be quite hopeless. There had been experiences which resembled it closely enough to assure her of that. Besides the next question would be as to the identity of the men she had watched, or at the very least a description of them. Of the nearer one she had seen a turned shoulder, a dark raincoat, a black felt hat, and a profile. Of the other man she had had a better view. She supposed he could have been called quite goodlooking, but by the time you came to make a list of anyone’s features, what was there left of that or of any other impression? The features themselves would sound so exactly like those of a great many other people. She had often wondered how a clever writer managed to convey the living presence of some character in a book. She had no such talent, and when she thought of herself trying to describe the man in the gallery all she could think of was a bare inventory-a drab raincoat as against the first man’s dark one, height medium, age somewhere about thirty, hair neither fair nor dark, eyes neither grey nor blue, no beard or moustache to blur the line of the lips when he spoke. Of course she ought to have waited and tried to see where he went. But equally, of course, it wouldn’t have been any good, because he would have soon found out that she was following him, and he would only have had to hail a taxi or walk into an hotel to get away from her. Detectives followed people, but she hadn’t the least idea how they did it without being seen, and when she thought about the man seeing her and knowing that she was following him the tea-room floor began to shake under her just as the street had done.