Steam, Steel and Electricity

by James W. Steele

The transmitter, as above described, is in the square box, and its round black diaphragm may be seen behind the round hole into which one talks. [[28]] The receiver is the trumpet-shaped tube which hangs on its side, and is taken from its hook to be used. The call-bell has nothing to do with the telephone. It is operated by a small magneto-generator,--a very near relative of the dynamo-the current from which is sent over the telephone circuit (the same wires) when the small crank is turned. Sometimes the question occurs: "Why ring one's own bell when one desires to ring only that at the central office?" The answer is that both bells are in the same circuit. If the circuit is uninterrupted your bell will ring when you ring the other, and a bell at each end of your circuit is necessary in any case, else you could not yourself be called.

[28.] Shouting into a telephone doubtless comes of the idea, unconscious, that one is speaking to a person at a distance. To speak distinctly is better, and in an ordinary tone.

When the receiving instrument is on its hook its weight depresses the lever slightly. This slight movement connects the bell circuit and disconnects the telephone circuit. Take it off the hook and the reverse is effected.

The long-distance telephone differs from the ordinary only in larger conductors, improved instruments, and a metallic circuit--two wires instead of the ordinary single wire and ground connections.

THE TELAUTOGRAPH.--This, the latest of modern miracles in the field of electricity, comes naturally after the telegraph and telephone, since it supplements them as a means of communication between individuals. It also is the invention of Prof. Elisha Gray, who seems to be as well the author of the name of his extraordinary achievement. It is not the first instrument of the kind attempted. The desire to find a means of writing at a distance is old. Bain, of Edinburgh, made a machine partially successful fifty years ago. Like the telegraph as intended by Morse, there was the interposition of typesetting before a message could be sent. It did not write, or follow the hand of the operator in writing, though it did reproduce at the other end of the circuit in facsimile the faces of the types that had been set by the sender. It was a process by electrolysis, well understood by all electricians. Several of this variety of writing telegraphs have been made, some of them almost successful, but all lacking the vital essential. [[29]] In 1856 Casselli, of Florence, made a writing telegraph which had a pendulum arrangement weighing fourteen pounds. Only one was ever made, but it resulted in many new ideas all pertaining to the facsimile systems--the following of the faces of types--and all were finally abandoned.

[29.] The lack of one vital essential has been fatal to hundreds of inventions. Inventors unconsciously follow paths made by predecessors. The entire class of transmitting instruments must dispense with tedious preliminaries, and must use words. Vail accomplished this in telegraphy. Bell and others in the telephone, and Gray has borne the same fact in mind in the present development of the telautograph.

The invention of Gray is a departure. The sender of a message sits down at a small desk and takes up a pencil, writing with it on ordinary paper and in his usual manner. A pen at the other end of the circuit follows every movement of his hand. The result is an autograph letter a hundred miles or more away. A man in Chicago may write and sign a check payable in Indianapolis. Personal directions may be given authoritatively and privately. As in the case of the telephone, no intervening operator is necessary. No expertness is required. Even the use of the alphabet is not necessary. A drawing of any description, anything that can be traced with a pen or pencil, is copied precisely by the pen at the receiving desk. The possibilities of this instrument, the uses it may develop, are almost inconceivable. It might be imagined that the lines drawn would be continuous. On the contrary, when the pen is lifted by the writer at the sending desk it also lifts itself from the paper at that of the receiver.

The action of the telautograph depends upon the variations in magnetic strength between two small electro-magnets. It has been seen that an electro-magnet exerts its attractive force in proportion to the current which passes through its coil. To use a phrase entirely non-technical, it will "pull" hard or easy in proportion to the strength of the passing current. This fact has been observed as the cause of action in the telephone, where one diaphragm, moved by the air-vibrations caused by the voice, causes a varying current to pass over the wire, attracting the other diaphragm less or more as the first is moved toward or away from its magnet. In the telautograph the varying currents are caused not by the diaphragm influenced by the voice, but by a pencil moved by the hand.

To show how these movements may be caused let us imagine a case that may occur in nature. It is an interesting mechanical study. There is an upright rush or reed growing in the middle of a running stream. The stem of this rush has elasticity naturally; it has a tendency to stand upright; but it bends when there is a current against it. It is easy enough to imagine it bending down stream more or less as the current is more or less strong.