As the fruit of rare experimental ability Mr. Valdemar Poulsen, an electrical engineer of Copenhagen, has invented the telegraphone. This instrument proceeds upon the fact that the electrical pulses of the telephone, minute and delicate though they are, can register themselves magnetically upon a moving steel wire but one-hundredth of an inch in diameter. The message is repeated as often as the wire is borne between the poles of an electro-magnet in circuit with a telephonic receiver. The accompanying figure shows the transmitter, the traveling wire, and the receiver as it repeats a message. The instrument in its latest form is illustrated opposite page 314. In supplementing the telephone most usefully, this apparatus brings a fresh competition to bear upon the telegraph. In many cases a man of business has preferred to telegraph rather than to telephone a message, because a telegram as a written record affords proof in case of error or dispute. Now suppose that through a telegraphone a broker offers six per cent. interest for a loan; his voice impressed on the wire, duly preserved for reference, identifies him as securely as would his signature on a written offer. Take a different case: a patient rings up a physician only to find him not at home; a message committed to a few yards of wire is listened to by the physician the moment he returns to his office. Take an example of yet another service: a letter may be dictated at Newark and recorded on a wire in Brooklyn, and there, at leisure, be put upon paper by an amanuensis. Or, better still, the message may be spoken upon a small, revolving disc of steel, and mailed to a correspondent who listens to its words as they roll out of his own graphophone. Young children and others unable to write may impress discs that tell their story to correspondents unable to read. So compact withal are the records of this instrument that they may soon give us not only music from the concert-room, and news from the telegraph office, but also the latest popular book. [Illustration: Telegraphone. Diagram of working parts.] [Illustration: TELEGRAPHONE OF VALDEMAR POULSEN] A wire or a disc can repeat its record, vocal or musical, hundreds of times without loss of distinctness. To obliterate this record it only is necessary to pass the steel between the poles of a strong magnet. The Gray Telautograph. A telephone transmits a familiar voice so that its tones are at once recognized. By electrical means a telautograph reproduces writing at a distance so precisely that it may be as readily identified. To understand how this feat is accomplished let us begin with the transmission of vertical marks varying in length. [Illustration: A, sending a vertical line S M by electricity. B, sending a horizontal line S M by electricity.]