This was a surprise for me. I could not, of course, however much I might suspect him, absolutely rule out of my calculations the possibility that even Cauvin might have hit upon some lucky idea, as so many inventors have done, without knowing much of the technicalities of the subject. I did not forget that the safety-pin was the invention of a lazy workman. And I knew that if I took any active steps against Cauvin and made a mistake--if by some miraculous chance his sudden wealth was honestly acquired--the consequences would be serious. "Well," I said, when we had been assured that no patent of any kind had been taken out by Cauvin, "what am I to do? I can't go to every big motor engineer in England and ask him if he is manufacturing a secret device invented by Jules Cauvin." My friend thought for a few moments. "I think you had better see L--," he said at last. "If there is anything big in hand some kind of whisper of it is sure to have got about, and he would be the first to hear. I will telephone him at once; we shall catch him in his office on the Viaduct." A few minutes later we were in Holborn in L--'s office; he was one of the magnates of the motoring world. I explained the position. "You can make your mind easy on that point," he said emphatically. "There is nothing going in the trade to-day big enough to produce the amount of money your man is evidently receiving. If there were, I must have heard of it; it could not be kept secret. You remember the Marx carburettor? Well, we knew for six months that it was coming, though every effort was made to keep it secret. What we did not know was the exact secret; but you know how it took the market by storm." This, even though it were only negative evidence, seemed to establish conclusively the fact that Cauvin's money, whatever might be its source, was not derived from the motor trade. I made up my mind that this much at least was certain. Next day I travelled down to old-world Chester, where I very speedily discovered that there was in Whitefriars no house numbered 118, and no trace of any person named Wheatley, while the aged vicar of St Mary's knew nothing of the marriage of "Captain James Easterbrook." Everything was fictitious--everything, that is, except the silver-printed wedding card and the clinging perfume of stag-leaved geranium. What did the bogus card indicate? Why had Jules Cauvin's unknown correspondent gone to the trouble of having it printed? And why, in defiance of all social custom, had it been scented with such a perfume as that of the stag-leaved geranium? I felt tolerably sure that here lay the key of the mystery, and that when I laid my hand on the sender of that mysterious card I should be very near indeed to the knowledge of the real source of the strange sequence of events which had raised the good-for-nothing son of an obscure French postman to a dazzling position in the world of society.