Philipp Reis, a physics instructor in Friedrichsdorf, Germany, developed a unique telephone receiver in the early 1860’s. The unusual telephone receiver was driven by a little-known phenomenon called magnetostriction, rather than magnetic attraction and repulsion. Magnetostriction denotes the propensity of certain ferrous metals to change length when exposed to fluctuating magnetic fields. Reis’ initial implementation consisted of a wire coil wrapped around an iron knitting needle and inserted into the S-holes of a violin; he improved this design by clamping a wire wrapped iron rod to a wood box resonator. Variable sound currents caused the rod length to change proportionately to the fluctuations in timbre, causing the box to resonate. Although Reis was able to transmit understandable speech, the Reis telephone receiver required more current.