“To nobody,” repeated the Professor emphatically. “Not even to Hanslet, however urgent the need may seem. I am going away for a time; how long that time may be I cannot tell. I do not wish my whereabouts to be known, as that would possibly place me in considerable danger.” “You’re not surely going alone, sir!” exclaimed Harold. “You’ll let me come with you, especially as you say there is danger attached to your journey?” But the Professor shook his head. “The danger may exist in London equally,” he replied. “It is essential that someone I can trust should remain here. Otherwise, my boy, I should be more than pleased to take you with me. Now, listen very carefully to these instructions. Do not leave the house for long at a time, especially in the evening. Open all my correspondence, and deal with it to the best of your ability. Should there be among it any letter of a startling character, put a message in the personal column of _The Times_, ‘The asp has struck,’ and sign it ‘Cleopatra.’ Do you follow this so far?” “Yes, sir,” replied Harold simply, but gazing at his employer in bewilderment. There was something theatrical about these extraordinary precautions utterly foreign to the Professor’s usual methods of procedure. “Very well,” continued the Professor. “If I find it necessary to communicate with you it will be by letter. The contents of the letter you may neglect. It may be typewritten, or in a disguised hand. You will know the letter is from me by the fact that it will be addressed in the first place to Westbourne Grove. The word _Grove_ will be ruled through, and the correct word _Terrace_ substituted for it. The envelope will in fact, convey the message. If the contents of the letter are to be read, which will only be if any unexpected developments take place, the envelope will be stamped with a three-halfpenny stamp. If, on the other hand, it is stamped with a penny and a halfpenny stamp, you will immediately proceed to the Post Office from which it was sent, which you will discover from the post-mark, where you will wait till I join you. If the envelope is stamped with three separate halfpenny stamps, you will go to Inspector Hanslet, explain what I am now telling you, and persuade him to come with you at once to the place indicated by the post-mark. Is that clear?” “Perfectly clear, sir,” replied Harold. “I’ll just make a note of that code, if you don’t mind, sir.” “No, make no notes!” commanded the Professor. “I have purposely contrived the code so simply that you can carry it in your head. You must realize that our actions will very probably be watched, in fact, I should not be surprised to learn that they have been under observation for some considerable time. Now, the next thing I want you to do is to type out a few copies of this paragraph and distribute them to the news agencies.”