The instrument stands about eighteen inches high, and its base is as many inches square. It falls into two parts, the receiver and the transmitter. The receiver is vertical and forms the upright and back portion of the telautograph. At one side of it hangs an ordinary telephone attachment. The transmitter, a sloping desk placed conveniently for the hand, is the front and horizontal portion. The receiver of one station is connected with the transmitter of another station; there being ordinarily no direct communication between the two parts of the same instrument. An attempt will be made to explain, with the help of a simple diagram, the manner in which the telautograph performs its duties. These duties are threefold. In the first place, it must reproduce whatever is written on the transmitter. Secondly, it must reproduce only what is _written_, not all the movements of the hand. Thirdly, it must supply the recording pen with fresh paper to write on, and with fresh ink to write with. In our diagram we must imagine that all the coverings of the telautograph have been cleared away to lay bare the most essential parts of the mechanism. For the sake of simplicity not all the coils, wires, and magnets having functions of their own are represented, and the drawing is not to scale. But what is shown will enable the reader to grasp the general principles which work the machine. Turning first of all to the transmitter, we have P, a little platform hinged at the back end, and moving up and down very slightly in front, according as pressure is put on to or taken off it by the pencil. Across it a roll of paper is shifted by means of the lever S, which has other uses as well. To the right of P is an electric bell-push, E, and on the left K, another small button.