The Blue Clockwork Watch

The fog off the River Thames smelled of sulphur and wet coal. Inspector Lestrade puffed nervously on his briar pipe as he stood over the marble foyer of the Kensington townhouse.

"The door was bolted from the inside, Mr. Thorne," the Inspector said, looking at the silent man kneeling by the corpse. "No footprints on the terrace. No shattered glass. Just Lord Harrington sitting in his chair with a blue pocket watch clutched in his stiff fingers."

Alexander Thorne did not answer. He adjusted his brass-rimmed spectacles and touched the victim's lapel with a silver tweezer.

He scribbled two words on his notepad and held it up to the lantern light: *Potassium Cyanide*.