"Look here, Mr Sant!" the bluff old seaman exclaimed as soon as I had closed the door, which he locked. "I've been rummaging the ship. Does this interest you?" And he brought out from the drawer in his table a bottle of medicine. It had apparently been recently bought from a chemist, for it was wrapped up in the usual paper, which was still quite clean and fresh, and sealed in the usual way. "This was found by your French friend concealed in Humber's trunk. Your man would be up here, only he is watching the fellow below, and as he is supposed to be on duty his absence might rouse suspicions." As Captain Jackson ended he handed me the bottle. "It does interest me, indeed," I said. "If Humber were ill enough to need medicine--and he certainly does not look it--he would hardly have brought this all the way from London without opening it." And I thought of the bottle wrapped in white paper which, on an earlier visit to London, Humber had received from Blind Heinrich at Waterloo. "I'll have a look at it, anyhow," I said. My first precaution was to soften the sealing wax with a match, so that I could unwrap the bottle without tearing the paper, and, if necessary, so replace it that no suspicion that it had been tampered with should be aroused. The bottle might prove useless as a clue. In that case we should have to seek further, and to replace the bottle in Humber's trunk in such a condition that he must inevitably see that it had been opened would certainly arouse his suspicions and defeat our object. I soon had the paper opened out. The bottle of medicine seemed genuine enough. It bore the label of a well-known West End firm and the name of Mr Humber. I tasted the contents. "Cough mixture" was my comment, and Captain Jackson at once confirmed me. "Humber never had a cough," he remarked reflectively. "Now for the paper," I said, and began examining it. It was perfectly blank, and I was experiencing a pang of disappointment when, catching on the paper the reflection of the swinging lamp, I detected in one corner a faint, glistening line. Lemon juice, I was confident. Under appropriate "treatment" a number of neat figures arranged in groups of three sprang into vivid prominence on the inside of the paper wrapping. They ran: 123--5--8; 27--32--6; 46--23--11; 294--12--3; 18--1--8; and so on. I swiftly copied out the figures for safety, and handed the original paper to Captain Jackson, who, on board his own ship, was, of course, the supreme and unquestioned authority, and I wanted his full approval and support to any action that might be necessary. The figures were meaningless as they stood, but I had not forgotten old Heinrich's systematic search for that odd volume of _Royal Love Letters_. I had my copy in my bag and fetched it at once.