Organ Pipes with Manometric Flame Capsules
   The manometric flame apparatus was developed by Rudolph Koenig in 1862. It consisted of a small gas flame whose height was modulated by variations in air pressure impinging on a flexible membrane. The resulting capsule could be mounted on an organ pipe with the membrane facing inward. The flame was observed in a rotating mirror that moved the image of the flame constantly to one side, thus providing a time base. 

   This "open organ pipe with three manometric flames ... 45 francs" at the University of Toronto, is item number 237 in the 1889 Koenig catalogue.

   This pipe, with a lead end flap to enable it to be used as either an open or a closed pipe, had a manometric flame capsule mounted in the middle to show that this point is a node when the pipe is open, and has some oscillating air motion when the pipe is closed. 

   The pipe is at the University of Toronto, and is not listed in the 1889 catalogue. It was certainly part of the collection bought by Toronto after the 1876 Centennial Exposition in Philadelphia. 

   This open pipe has two manometric flames. The scale can be obtained from the fingers holding the pipe upright. The apparatus is not in the 1889 Koenig catalogue. 

   REF: Thomas B. Greenslade, Jr., "The Rotating Mirror", Phys. Teach, 19, 253-255 (1981)

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