The case which, it seemed, I had brought to Paris, looked as if it might have been made to hold a peculiar kind of cigar, much longer than the ordinary sort.  Within, on either side, was a partition, and there was a silver clasp on which the hallmark was English.

“English silver!” I said to myself, thoughtfully.  The three men who had travelled in the carriage with me from London to Dover were all English.  Of the trio, only the nervous little fellow who had reserved the compartment for himself had found the smallest possible opportunity to steal the treaty from me, and exchange for it this red leather case containing a diamond necklace worth twenty thousand pounds.  If he possessed the skill and quick deftness of a conjurer or a marvellously clever professional pickpocket, as well as the incentive of a paid spy, he might conceivably have done the trick at the moment of alarm on the boat’s gangway, not afterwards; for when he had pressed near me in the Gare du Nord he had been on the wrong side.  But for my life I could not guess the motive for such an exchange.

Supposing him a spy, employed to track and rob me of what I carried, why should he have made me a present of these rare and precious diamonds?  Would the bribe for which he used his skill reach anything like the sum he could obtain by selling the stones?  I was almost sure it would not; and therefore, having the diamonds, it would have been far more to his advantage to keep them than to stuff them into my pocket, simply to fill up the space where the case with the treaty had lain.  There would not have been time yet for the real diamonds to have been copied in Amsterdam, therefore it would be useless to build up a theory that the stones given me might be false.

Besides, I reminded myself, if the man were a spy whose business was to watch and be near me, why hadn’t he waited to see what I would do, where I would go, instead of taking a compartment, carefully reserving it, and trusting to such an unlikely chance as that I might force myself into it with him?  Even if the three men had been in some obscure way playing into each others’ hands, I could not see how their game had been arranged to catch me.

Maxine and I had talked for a long time, but not two hours had passed yet since I saw the last of the little rat of a man in the railway-station.  Though I could not understand any reason for his tricking me, still I told myself that nobody else could have done it, and I decided to go back at once to the Gare du Nord.  There I might still be able to find some trace of the little man and of my two other fellow-travellers.  If through a porter or cabman I could learn where they had gone, I might have a chance even now of getting back the stolen treaty.  I had brought with me from London a loaded revolver, warned by the Foreign Secretary that to do so would be a wise precaution; and I was ready to make use of it if necessary.