In 1905, Heinrich Rubens and Otto Krigar-Menzel published a paper describing a unique acoustics teaching apparatus. They developed a flammable gas-filled tube with holes in the top that revealed the acoustic standing wave behavior inside the pipe via the height of flames above the pipe. Interestingly, their article holds the distinction of being printed immediately following Einstein’s Nobel-prize winning paper on the photoelectric effect. From that auspicious beginning, the “Rubens tube” has been used for over a century in the teaching of acoustical resonance behavior. This paper will describe the tube’s operation, examples of its use, and commentary on and investigations involving the flame tube found in the literature.