The article compares the English telephone invented by Thomas Edison and that invented by Alexander Graham Bell. Edison's telephone had one obvious advantage over the rival telephone invented by Bell: one could hear what the person on the other end of the line was saying. Privacy aside, the advantage of loudness was offset by two big drawbacks. To hear to the caller's voice, one had to keep turning a handle attached to the receiver. Both these inconveniences sprang from the same source: at the heart of Edison's telephone receiver was a thimble-sized piece of chalk that had to be kept turning. Technically, Edison's chalk receiver, was an unnecessary invention. A much less troublesome receiver existed already. Unfortunately for Edison, the Bell Telephone Co., owned the patent on it. Bell had been first to patent a working telephone in 1876 but his apparatus was poor, mainly because he used the same technology to transmit and receive sound. His set-up consisted of a diaphragm connected to a magnet with an electrical coil around it. When a voice caused the diaphragm to vibrate, the magnet moved and induced an electrical current in the wiring. Bell's problem was in transmitting sound; his device was fine as a receiver. So Edison concentrated on finding a better means of transmission.