Offhand I can deduce very little, Only that the words are written with a broad-tip quill...

Basil: [Regarding Fidget's note] Offhand I can deduce very little, Only that the words are written with a broad-tip quill pen that has spattered, twice; that the paper is of native Mongolia manufacture, no watermark; and has [smacks his lips against the paper] Basil: been gummed, if I'm very much in error... [smells paper] Basil: ...by a bat who has been drinking Rodent's Delight, a cheap brandy served only in the seediests pubs. Dr. Dawson: Hmm. Amazing. Basil: Oh, not really, doctor. We still don't know where it came from. Perhaps a closer inspection will tell us something. [Looks at note under microscope] Basil: Coal dust, clearly of the type used in sewer lamps. [Takes note and sets it on fire] Dr. Dawson: Basil! Basil: Shh. Don't speak. [He grinds the ashes in a crucible and pours them into a beaker] Basil: Excuse me, Doctor. [Takes beaker and a bottle of liquid] Basil: Steady hand... [pours a drop into beaker and sets it at the other end of a pipe; he boils a liquid on the other end, watching as it goes through the pipe] Basil: Come on, come on. Good, bad, bad, good. Come on, come on, come on. [Liquid finally reaches beaker; chemical explodes] Basil: Aha! We've done it, old fellow! This chemical reaction could only be triggered by the paper's extreme saturation with distilation of sodium chloride. Dr. Dawson: Salt water? Great Scott. Basil: It proves beyond a shadow of a doubt, this note came from the riverfront area. [Pins a map of the river on the wall] Dr. Dawson: Now, steady on, Basil... Basil: No, it's elementary, Dawson. We simply look for a seedy pub at the only spot... [Pins dart on map] Basil: ...where the sewer connects with the riverfront.

Offhand, I can deduce very little. Only that the words are written with a broad-pointed quill pen which has spattered, twice. That the paper is of native Mongolian manufacture, no watermark. And has been gummed, if I'm not in error (SNIFFS) by a bat who has been drinking Rodent's Delight, a cheap brandy sold only in the seediest pubs. - Hmm. Amazing. - Oh, not really, doctor. We still don't know where it came from. Perhaps a closer inspection will tell us something. Mmm-hmm. Hmm. Mmm-hmm. Coal dust. Clearly of the type used in sewer lamps. - But Basil... - Shh. Don't speak! Excuse me, Dawson. Steady hand. (BUBBLING) - (BUBBLING RAPIDLY) - Yes. Yes. Good. Come along, come along, come along, come along, come along. (LAUGHS) Yes, yes. Good, good. Mmm. No, bad. Good, good. Go, yeah. Come along. Come along, come on. Don't go back up. Yes. Come along. Come on. Yes... Yes! (CHORTLES) We've done it, old fellow! This reaction could only have been triggered by the paper's extreme saturation with distillation of sodium chloride. Salt water? Great Scott. It proves, beyond a doubt, this list came from the riverfront area. Now, steady on there, Basil. No, no. Elementary, my dear Dawson. We merely look for a seedy pub at the only spot where the sewer connects to the waterfront. - (dock creaks) - (Basil whispering) Stay, Toby. Stay.