Accession No


Brief Description

manometric flame capsule on stand, by unknown maker, and rotating four-sided mirror on stand, by Phillip Harris and Company Ltd.; English or Irish; late 19th Century


England; Birmingham; and Ireland; Dublin


Philip Harris and Company Ltd.



Earliest Date

Jan. 1, 1875

Latest Date

Dec. 31, 1900

Inscription Date


metal (iron, brass); wood (mahogany, other); glass


Rotating mirror: height 423mm; width 210mm; depth 210mm Manometric flame: height 400mm; length 90mm; depth 90mm

Special Collection


Purchased from Trevor Philip and Sons, 75a Jermyn St, London on 21/05/2009.


‘Philip Harris & Co. Ltd
and Dublin’ [on plaque on top of rotating mirror]

Description Notes

Manometric flame capsule on stand (unknown maker) and rotating four-sided mirror on stand by Phillip Harris & Co. Ltd.; Birmingham and Dublin; late 19th century

6271.1 Manometric flame capsule for visualising sound waves: Iron stand with wooden manometric flame capsule attached. Rubber diaphragm in capsule absent.

Condition fair; some corrosion to base and scratching to stand.

6271.2 Rotating four-sided mirror which acts as a stroboscope, allowing a rapidly modulating flame to be seen as a separated set of images. Mirror is attached to

Condition fair; some corrosion to base and brass stand. Crizzling/surface salts present on mirror glass.


Torben Rees; 'Koenig's apparatus for the analysis of sound: the first spectrum analyzer'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge; 2009:


A manometric flame apparatus visualises sound waves, in a similar way to a modern oscilloscope. When a sound from a horn is fed into the manometric chamber, a rubber diaphragm (now perished) vibrates in sympathy with the sound; the modulated output is fed to a flame device to show the frequency of the sound.

The rotating mirror apparatus is used in conjunction with the manometric flame. It acts as a stroboscope, allowing the rapidly modulating flame to be seen as a separated set of images. Originally designed by Rudolph Koenig, instruments such as this one by Philip Harris & Co. were copied by many other manufacturers, enabling the designs to reach a wider audience.
Created by: Derek Scurll on 16/06/2009


Images (Click to view full size):