In the preceding parts, I have mentioned several microphone (transmitters, in telephone lingo) types that were used in early telephone experiments. The first type, the one described by Borseul, was a make-and-break type transmitter, which was used by Reis. This type of transmitter is not very useful, and can hardly transmit understandable speech. The very closely related loose-contact transmitter, is the basis for the carbon microphone. Also related is the variable resistance transmitter used by Elisha Gray in his bid for the telephone. A needle was attached to the transmitter diaphragm, and the other end of the needle touched the surface of a conductive liquid in a conductive cup. When the diaphragm vibrated, the needle made more or less area in contact with the liquid, and the resistance of the circuit varied.