It was an addressed envelope. The writing I instantly recognised; I had seen it on the scraps of paper which Hume had taken out of Lawrence’s waste-paper basket. The envelope had been neither stamped nor posted. The address--it could hardly have been vaguer--was “George Withers, Esq., General Post-office, London.” Without hesitation I tore the envelope open. I had reached a point at which I felt that, at any and every cost, I must get out of the darkness into the light. The contents of the letter I give verbatim. “Dear Tom, “I am going to see that scoundrel to-night. He had better take care, or something will happen to him, of that I am sure. And he will be sure before I have done with him. In any case, I’ll write you at length to-morrow.” “B.” Two points struck me about this odd epistle: it contained neither a date nor an address, and, while “George Withers” was on the envelope, the letter itself began “Dear Tom,” the inference being that “George Withers” was an assumed name, to which it had been arranged that communications should be directed. The “B.” of the signature was, I had little doubt, the “Bessie” of the scraps of paper; in which case the “E,” which Mrs. Peddar had discovered on the linen, stood for “Elizabeth.” There still remained the puzzle of the “M.” The letter had scarcely a reassuring effect. That the “scoundrel” alluded to was Lawrence, and that “to-night” was last night, I thought was probable. If that were so, then it seemed that this young girl had gone to Lawrence with anything but friendly intentions; and it was quite certain that something had happened to him, as she had predicted. One could only hope that it was not the something which she had in her mind’s eye; and that, in any case, she had had no hand in the happening. As a clue to the lady’s identity the letter did not carry one much forwarder. As I was wondering what was the next step which I should take, a thought occurred to me--the photograph which I had taken from Lawrence’s mantelshelf. I had it in the pocket of my coat. I took it out. It was an excellent likeness; the operator had caught her in a characteristic pose, and made of her a really artistic picture. But it was not with the likeness that I was at that moment concerned. I looked at the back of the portrait, to see by whom it had been taken. There was the name of one of the best London photographers in London. Eureka! the thing was done. I had only to go to the man’s establishment to gain particulars of the original. Surely, when he had been told the circumstances of the case, he would not refuse to let me have them. Filled with this idea I began to feverishly roll up the plum-coloured cloak. As I did so there came a rapping at the door. “Who’s there?” “I want to speak to you.” The voice was Hume’s. Fortunately I had locked the door, or he would quite possibly have walked straight into the room. “I will be with you directly.”