200 Chapter 13
the plate. 13 Wheatstone also excited such crispations by blowing a flute close to the moist-
ened glass plate, forming “ a circle round the end of the tube, and afterwards appearing to
radiate in right lines; on the harmonics [overtones] of the tube being sounded, the crispa-
tions were correspondingly diminished in magnitude. ” He thus applied his own instrument
to extend Chladni ’ s static experiments and, in the process, evoked dynamic, transient wave
phenomena that will be of increasing importance in what follows, as will Wheatstone ’ s
insistence that “ the molecular vibrations pervade the entire substance of the phonic [vibrat-
ing body], ” using “ molecular ” in the then-current sense of minute portions of substance.
He also showed his experiments to Ø rsted, who told Wheatstone of his own very similar
earlier experiments, discussed earlier.^14 Here, as at many other points in this story, the
protagonists reencounter and reinforce each other.
Wheatstone also shows his continuing interest in the problems of transmission of sound.
In this first paper, he described his experiments transmitting sound along a long rod, noting
his astonishment that “ all the varieties of tune, quality, and audibility, and all the combina-
tions of harmony, are thus transmitted unimpaired, and again rendered audible by com-
munication with an appropriate receiver. ” Wheatstone exploited this device in his Enchanted
Lyre or Acoucryptophone ( “ hearing a hidden sound ” ), first shown in London in 1821
( figure 13.3 ), in which a rod through the ceiling connects a piano in a room above to a
lyre whose sympathetic resonance mysteriously transmits the hidden instrument. Its eerie
sounds moved Wheatstone to note that “ so perfect was the illusion in this instance from
the intense vibratory state of the reciprocating instrument [the lyre], and from the intercep-
tion of the sounds of the distant exciting one [the piano], that it was universally imagined
to be one of the highest efforts of ingenuity in musical mechanism. ”^15
In 1827, Wheatstone presented his new kaleidophone (literally “ hearing beautiful
forms ” ), which made visible the wave motion of a vibrating rod traced out over time by a
luminous point at its end, a silvered glass bead ( figure 13.4 ).^16 Though Wheatstone depre-
catingly called this a “ philosophical toy, ” the sonic counterpart to a kaleidoscope, he traced
it back to Young ’ s experiments making visible the vibrations of a piano wire and noted that
“ this instrument possesses higher claims to attention; for it exemplifies an interesting series
of natural phenomena, and renders obvious to the common observer what has hitherto been
confined to the calculations of the mathematician, ” namely the wave theory of light.^17
Surely these words, and the striking instrument as well (still to be seen in science
museums), must have resonated with Faraday ’ s concern to penetrate the mathematical fog
and reach the concrete details of the underlying “ state ” of wave motion. Indeed, in
what follows Faraday himself acted as the resonator responding to and retransmitting
Wheatstone ’ s original impulse, as if they together constituted an Enchanted Lyre. In Febru-
ary, 1828 Faraday delivered Wheatstone ’ s new communication “ On the Resonances, or
Reciprocated Vibrations of Columns of Air, ” thus allowing his friend to “ speak ” through
Faraday ’ s own resonantly vibrating column of air, transmuting the agony of Wheatstone ’ s
shyness into felicitous ventriloquism.^18