“Heaven preserve us!” he cried; “It is enough to terrify a body. There seems a sort of judgment on the place. Don’t it strike you so, guv’nor?” “It does and it doesn’t,” said Jacob; “you whip up your horse, my man. Ah, here we are, at Pitstow, at last.” “Shall I drive you straight to the police station?” asked the man. “No; you put up here at the sign of the Boar; I shall want you to drive me back before long.” Jacob jumped off the cart and entered the inn. “A private room, quick,” he said; “a room with a fire in it.” Jacob was conducted into a small parlour at the back of the inn. “You can have this room to yourself, sir,” said the landlady. “It so happens that there’s no one using it just now, and the fire is lit all handy.” “That’s right,” answered Jacob; “now bring me pen, ink, and paper. I am in a desperate hurry—I want to write an important letter to catch the next post to London.” “You’ll have to be quick, then,” said the landlady, glancing at the clock over the mantelpiece as she spoke, “for the post will be cleared in ten minutes.” She hurried out of the room to procure writing materials, returning with them almost immediately. “Thank you, ma’am,” answered Jacob; “and now I’ll be all the quicker if I am left alone.” The landlady took the hint and closed the parlour door behind her. The moment she did so, Jacob took Rowton’s letter again out of his pocket. He breathed on the flap, which was securely fastened down, holding it to his mouth with one hand, while he wrote a communication of his own, as if for life or death, with the other. At last he took the moist letter from his mouth. With very little difficulty and with consummate skill he unfastened the flap of the envelope and took the letter from beneath. He opened it, to survey nothing whatever except a perfectly blank sheet of paper. “Ha! invisible ink,” he muttered. “Now, will it make its appearance under the influence of fire or of water? I hope to goodness heat will do it, for I never thought of ordering water, and the mail will be off in a few minutes.” He rushed to the fire as he spoke, and held the blank sheet of paper at a little distance from the bars. After doing so for a few seconds, a satisfied exclamation fell from his lips. Some writing of a bright blue colour was now perfectly visible on the hitherto blank sheet of paper. Jacob read the words, which, to an unobservant eye, meant very little: “Illness has increased; will call to-morrow for ultimatum.” At the foot of this apparently unintelligible sentence was a certain hieroglyphic of a peculiar shape and size.