198 Chapter 13
though his progress was slowed by the press of many other duties and experimental pro-
grams. In 1825, he tried the fundamental experiment suggested by Amp è re ’ s theory: the
magnetic forces produced from current-carrying wires should in turn generate electric
effects in a nearby wire loop, but Faraday registered no effect, which increased his skepti-
cism about Amp è re ’ s theory.^9 Returning to Faraday ’ s quest for an alternative “ state ” of a
current-carrying wire, beyond Amp è re ’ s material currents, L. Pearce Williams noted that
“ it clearly had to be something more complicated than a mere arrangement of particles,
for it was difficult to see how a static arrangement could cause a dynamic rotation. ”^10
Averse to the imponderable “ fluids ” favored by Amp è re and others, Faraday turned to the
wave theory of light advanced by Young and taken up by Fresnel, who in 1827 – 1829
published a nonmathematical account in English, which Faraday studied carefully. The
example of light waves offered him another possible way of thinking about the “ state ”
surrounding the wires as able to transmit force via waves without involving the transfer
of matter.^11
Yet sound was the most obvious pattern for such wave transmission, for Young as for
those who came after him; in the 1820s, the wave theory of sound was far better established
than the still controversial wave theory of light. Accordingly, Faraday ’ s turn in 1828 – 30
to investigations of sound form a plausible staging-ground for his reconsideration of the
“ state ” that might unlock the electromagnetic problem he could not solve in 1825. In the
years immediately preceding his breakthrough with electromagnetic induction, Faraday
concentrated on examples of sound transmission that offered suggestive and helpful
avenues he then pursued in electromagnetism.
This new phase began in 1828 with Faraday ’ s involvement in public lectures on sound
at the Royal Institution that were curious exercises in ventriloquism, in which Faraday did
not speak on his own behalf but as the voice of Wheatstone, whose shyness inhibited him
from speaking publicly. A decade younger than Faraday, Wheatstone came from a family
of musical instrument makers and dealers and had no formal scientific education. At age
fifteen, apprenticed to his uncle the year before, Wheatstone composed two songs that
were published. He spent most of his earnings on books, such as a work on Volta through
which he learned of the recent electrical discoveries. Though involved in the music busi-
ness after 1823, Wheatstone did not care much for its commercial side and spent most of
his effort on musical inventions; in 1824, he published a “ Harmonic Diagram ” to help the
public understand key signatures ( figure 13.2 ).
He later noted that “ as an admirer of music ... I remarked that the theory of sound was
more neglected than most of the branches of natural philosophy, which gave rise in me to
the desire of supplying this defect. ”^12 In 1823, he published his first scientific paper, “ New
Experiments on Sound, ” which begins by distinguishing longitudinal from transverse
modes of vibrations, using Chladni ’ s technique on a glass plate covered by a layer
of various fluids (water, oil, mercury) to induce “ crispations, ” slight undulations that
Wheatstone interprets as the “ vibrating corpuscles ” or “ phonic molecular vibrations ” of