In October, 1905, I paid Mr. Edison a visit at his laboratory, when he showed me the phonograph as now perfected. Chief among his improvements is a composition for records which is much harder than the wax formerly employed, and may therefore revolve more swiftly with no fear of blurring. His reproducer is to-day a built-up diaphragm of mica, highly sensitive. In the reproducer arm is placed the highly polished, button-shaped sapphire which tracks with fidelity the grooves which sound has recorded on the cylinder. These features, combined in a mechanism of the utmost accuracy in make and adjustment, have opened for the phonograph a vast field in the business world. Some of the great firms and companies of New York and other cities now use phonographs instead of stenographers; a letter or a contract is dictated to a revolving cylinder with all the swiftness of ordinary speech. Afterward a secretary listens to the reproducer and writes the letter or contract at any speed desired. On occasion a cylinder bearing a message may be sent to a correspondent who listens to its words as sent forth from his own phonograph, no intermediate writing being required. Such instruments are extensively used in teaching foreign languages, learners being free to have a difficult pronunciation repeated until it is mastered. Mr. Edison has much improved the musical records familiar throughout the world; these are now produced in molds of gold with a delicacy that refines away the scratchiness of tone so unpleasant in earlier cylinders.
Telephone Messages Recorded for Repetition at Will: The Telegraphone.
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.
Telegraphone.
Diagram of working parts.
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.