XV11 



sophy,' entitled " New experiments on Sound," containing the results of 

 his earlier experiments on the vibrations of chords, rods, and surfaces, 

 which excited so much attention among physicists, that it was repro- 

 duced the same year in the ' Annales de Chimie,' and in the following 

 year in ' Schweigger's Jahrbuch.' His next papers, also on Acoustics, 

 were published in the ' Quarterly Journal of Science/ on " New experi- 

 ments on Audition," in 1827, and on " the Kaleidophone," in the follow- 

 ing year. This elegant philosophical toy consists of a steel wire fixed 

 vertically in a heavy base, or in a vice, and surmounted by a silvered 

 glass bead. If this, by an appropriate displacement, be thrown into a 

 compound vibration, consisting of the simple vibration of its entire length 

 accompanied by that of the first harmonic subdivision, a series of beauti- 

 ful circular or elliptic epicycloidal curves are revealed by the persistence 

 on the retina of the reflection of a fixed light from the glass bead ; and 

 if a rectangular wire be employed, the dimensions of which are such that 

 its periods of vibration in two planes at right angles to each other are in 

 the simple harmonic ratios of 1 : 2, 2 : 3, or 3 : 4, the curves formed respec- 

 tively by the superposition of these two modes of vibration will be beauti- 

 fully exhibited. Subsequently, by an aptly contrived mechanism, Wheat- 

 stone succeeded in obtaining a visual combination of rectangular vibra- 

 tions in any given ratio to each other. The principle of the kaleidophone 

 was subsequently applied in the construction of a photometer. In this 

 instrument a silvered bead is made to describe rapidly a narrow ellipse, 

 or to oscillate in a straight line by means of an epicyclic train of the 

 simplest construction ; the relative brightness of two lines, formed by 

 the reflections of two lights to be compared, may be very readily estimated. 



At this period of his life Acoustics (doubtless in relation to his busi- 

 ness) engrossed the chief part of Wheatstone's attention. Tie was 

 especially interested in the application of the free reed to musical instru- 

 ments ; and the elegant little Symphonion, which, from the many objections 

 to the needless employment of the breath, soon gave place to the bellow 7 s 

 o£ the Accordion, offered ample evidence of the success of his labours in 

 this direction. In the construction of these instruments, the admirable 

 mode of fingering, in which the successive notes are placed in double rows 

 alternately on opposite sides of the instrument, so that consecutive notes 

 on either side, which may be touched by the same finger, always belong to 

 the same chord, must not remain unnoticed. 



In 1828 Wheatstone wrote on the resonance of columns of air, and in 

 1831 on the transmission of musical sounds through rigid linear con- 

 ductors, a subject which was subsequently well illustrated at the Poly- 

 technic Institution by the transference to an upper room of music played 

 in the basement. In the same year he contributed to the British Asso- 

 ciation an experimental proof of Bernouilli's theory of the vibrations of 

 air in wind instruments. His principal contribution to Acoustics is a 

 memoir on the so-called Chladni's figures, produced by strewing sand on 



VOL. XXTV. C 



