The Ordeal-Smoke Gauge

Holmes tested the devil's-foot on himself and nearly died. Reckon the experiment he should not have run.

Holmes burnt a measure of the powder over the lamp with Watson beside him — and both were dragged out barely sane. Model the sitting-room experiment: dose against air against time. (The botany is Conan Doyle's invention; the recklessness was Holmes's own.)

Drawn from The Adventure of the Devil's Foot (His Last Bow, 1910) — read the summary & analysis, or try The Terror at Tredannick Wartha, this story's game. More at the Game Room and the tool bench.