Manometric Flame Apparatus
Koenig’s manometric flame apparatus was a laboratory instrument invented in 1862 by the German physicist Rudolph Koenig, and used to visualize sound waves. It was the nearest equivalent of the modern oscilloscope in the late nineteenth and early twentieth centuries.
Benson John Lossing, ed. The New Popular Educator (London, England: Cassell & Company Limited, 1891)