The Man Who Knew by Edgar Wallace

The room was a small one, and had been chosen for its remoteness from the dwelling rooms. It had formed the billiard room, which the former owner of Weald Lodge had added to his premises, and John Minute, who had neither the time nor the patience for billiards, had readily handed over this damp annex to his scientific secretary.

Along one side ran a plain deal bench which was crowded with glass stills and test tubes. In the middle was as plain a table, with half a dozen books, a microscope under a glass shade, a little wooden case which was opened to display an array of delicate scientific instruments, a Bunsen burner, which was burning bluely under a small glass bowl half filled with a dark and turgid concoction of some kind.