For sale, a late Victorian chemical harmonica or singing flame demonstration apparatus.
This rare piece is comprised of a solid turned brass base with horizontal tube with gas attachment at one end. Running vertically from the base are four gas taps and pencil thin burners of different lengths with an adjustable mount attached to each one. The mounts form a rest for the base of four cylindrical glass tubes of different sizes which are in turn supported at a higher level by a support bar emanating from the central stem.
The principle is based upon the oscillation of a gas flame when it is enclosed within a glass tube, the outcome of which is sound. These sounds can then be tuned to differing pitches by altering the height of the tube mount on the burner shaft.
The discovery was originally made by professor of physics at the Leiden University in The Netherlands, Petrus Leonardus Rijke where he used a glass tube in which he placed a piece of gauze which was heated until red hot, upon removing the flame a loud sound as emitted until the gauze cooled down. His experiments were including in British Scientist. Lord Rayleigh’s definitive text on sound in 1877 as were the experiments of the German physicist Karl Friedrich Julius Sondhauss during the middle part of the nineteenth century.
This apparatus was almost certainly supplied by Max Kohl and examples appear in the company’s catalogue of 1900 where they are illustrated in various sizes (single to four tube options). This is of course the largest of the options and cost 64 German marks at the time.
The glass tubes are replacements and one has a small hairline fracture at the base but is in good solid order.