In 1875, Alexander Bell used his "harmonic telegraph" to transmit a twanging sound from a reed vibrated by Bell's voice along wires to Watson. Although the instrument transmitted voicelike sounds, the words were not recognizable. Now he knew he was closer to his dream of speech transmission. The striking result on this day came after more tinkering on the instrument, after a simple discovery the previous day. On 2 Jun 1875, the two had been workingon the telegraph. In the transmitter room, Watson was trying to free a reed wound too tightly to the pole of its electromagnet, when it produced a twang. Bell, at work in the receiving room heard the twang and realized the complex overtones and timbre shared characteristics with voice vibrations.[Image: diagram of earlier device under test in Winter 1873]