Alexander Graham Bell's Hypothesis

I have read somewhere that the resistance offered by a wire ... is affected by the tension of the wire. If this is so, a continuous current of electricity passed through a vibrating wire should meet with a varying resistance, and hence a pulsatory action should be induced in the current ... [corresponding] in amplitude, as well as in rate of movement, to the vibrations of the string ... [Thus] the timbre of a sound [a quality essential to intelligible speech] could be transmitted ... [and] th...