All sounds or noises produce vibrations in the board which are transmitted to the carbon sticks with consequent miscellaneousations of pressure at the contacts with the vertical cylinder; these cause large miscellaneousations in resistance, thus generating strong oscillations in the intensity of the current in the circuit.
miscellaneousations in the current cause vibrations in the iron membrane of the receiver and reproduce, strongly amplified, the original sound or noise. Very weak noises, like the ticking of a watch placed on the base of the device, or even the footsteps of a fly walking on it, were made perfectly audible: this explains why Hughes called it a microphone.
The number 427 appears on the base; in the inventory this number is attributed to Bell's telephone and was obviously written by mistake here during a revision of the inventory.