Even the stony-faced Dorrington could not repress a smile and something very like a chuckle as he turned the end of the street and struck out across Golden Square towards his rooms in Conduit Street. The simple Frenchman, only half a rogue--even less than half--was now bamboozled and put aside as effectually as his cousin had been. Certainly there was a diamond, and an immense one; if only the Bouvier tradition were true, probably the famous "Mirror of Portugal"; and nothing stood between Dorrington and absolute possession of that diamond but an ordinary sort of case such as he dealt with every day. And he had made Bouvier pay a fee for the privilege of putting him completely on the track of it! Dorrington smiled again. His dinner was spoilt by waiting, but he troubled little of that. He spread before him, and examined again, the pieces of glass and the cork. The bottle had been a druggist's ordinary flat bottle, graduated with dose-marks, and altogether seven inches high, or thereabout. It had, without a doubt, contained the chloroform wherewith Léon Bouvier had been assaulted, as Dorrington had judged from the smell of the cork. The fact of the bottle being corked showed that the chloroform had not been bought all at once--since in that case it would have been put up in a stoppered bottle. More probably it had been procured in very small quantities (ostensibly for toothache, or something of that kind) at different druggists, and put together in this larger bottle, which had originally been used for something else. The bottle had been distinguished by a label--the usual white label affixed by the druggist, with directions as to taking the medicine--and this label had been scraped off; all except a small piece at the bottom edge by the right hand side, whereon might be just distinguished the greater part of the letters N, E. The piece of glass that had lain a little way apart from the bottle was not a part of it, as a casual observer might have supposed. It was a fragment of a concave lens, with a channel ground in the edge. III At ten precisely next morning, as usual, Mr. Ludwig Hamer mounted the stairs of the house in Hatton Garden, wherein he rented half a room as office. He was a tall, fair man, wearing thick convex _pince-nez_. He spoke English like a native, and, indeed, he called himself an Englishman, though there were those who doubted the Briticism of his name. Scarce had he entered his office when Dorrington followed him.