“That was my singular interview with Professor Moriarty. I confess that it left an unpleasant effect upon my mind. His soft, precise fashion of speech leaves a conviction of sincerity which a mere bully could not produce. Of course, you will say: ‘Why not take police precautions against him?’ The reason is that I am well convinced that it is from his agents the blow would fall. I have the best of proofs that it would be so.”

“You have already been assaulted?”

“My dear Watson, Professor Moriarty is not a man who lets the grass grow under his feet. I went out about midday to transact some business in Oxford Street. As I passed the corner which leads from Bentinck Street on to the Welbeck Street crossing a two-horse van furiously driven whizzed round and was on me like a flash. I sprang for the foot-path and saved myself by the fraction of a second. The van dashed round by Marylebone Lane and was gone in an instant. I kept to the pavement after that, Watson, but as I walked down Vere Street a brick came down from the roof of one of the houses and was shattered to fragments at my feet. I called the police and had the place examined. There were slates and bricks piled up on the roof preparatory to some repairs, and they would have me believe that the wind had toppled over one of these. Of course I knew better, but I could prove nothing. I took a cab after that and reached my brother’s rooms in Pall Mall, where I spent the day. Now I have come round to you, and on my way I was attacked by a rough with a bludgeon. I knocked him down, and the police have him in custody; but I can tell you with the most absolute confidence that no possible connection will ever be traced between the gentleman upon whose front teeth I have barked my knuckles and the retiring mathematical coach, who is, I daresay, working out problems upon a black-board ten miles away. You will not wonder, Watson, that my first act on entering your rooms was to close your shutters, and that I have been compelled to ask your permission to leave the house by some less conspicuous exit than the front door.”

I had often admired my friend’s courage, but never more than now, as he sat quietly checking off a series of incidents which must have combined to make up a day of horror.

“You will spend the night here?” I said.

“No, my friend, you might find me a dangerous guest. I have my plans laid, and all will be well. Matters have gone so far now that they can move without my help as far as the arrest goes, though my presence is necessary for a conviction. It is obvious, therefore, that I cannot do better than get away for the few days which remain before the police are at liberty to act. It would be a great pleasure to me, therefore, if you could come on to the Continent with me.”

“The practice is quiet,” said I, “and I have an accommodating neighbour. I should be glad to come.”

“And to start to-morrow morning?”

“If necessary.”