The Phonograph - 9

The Phonograph - 9

The invention of the phonograph was immediately followed, as usual, by the appearance

of several other incidental and auxiliary devices, some patented, and others remaining

simply the application of the principles of apparatus that had been worked out. One of

these was the telephonograph, a combination of a telephone at a distant station with a

phonograph. The diaphragm of the phonograph mouthpiece is actuated by an

electromagnet in the same way as that of an ordinary telephone receiver, and in this

manner a record of the message spoken from a distance can be obtained and turned into

sound at will. Evidently such a process is reversible, and the phonograph can send a

message to the distant receiver.

This idea was brilliantly demonstrated in practice in February, 1889, by Mr. W. J.

Hammer, one of Edison's earliest and most capable associates, who carried on

telephonographic communication between New York and an audience in Philadelphia.

The record made in New York on the Edison phonograph was repeated into an Edison

carbon transmitter, sent over one hundred and three miles of circuit, including six miles

of underground cable; received by an Edison motograph; repeated by that on to a

phonograph; transferred from the phonograph to an Edison carbon transmitter, and by

that delivered to the Edison motograph receiver in the enthusiastic lecture-hall, where

every one could hear each sound and syllable distinctly. In real practice this spectacular

playing with sound vibrations, as if they were lacrosse balls to toss around between the

goals, could be materially simplified.

The modern megaphone, now used universally in making announcements to large

crowds, particularly at sporting events, is also due to this period as a perfection by Edison

of many antecedent devices going back, perhaps, much further than the legendary funnels

through which Alexander the Great is said to have sent commands to his outlying forces.

The improved Edison megaphone for long-distance work comprised two horns of wood

or metal about six feet long, tapering from a diameter of two feet six inches at the mouth

to a small aperture provided with ear- tubes. These converging horns or funnels, with a

large speaking-trumpet in between them, are mounted on a tripod, and the megaphone is

complete. Conversation can be carried on with this megaphone at a distance of over two

miles, as with a ship or the balloon. The modern megaphone now employs the receiver

form thus introduced as its very effective transmitter, with which the old-fashioned

speaking- trumpet cannot possibly compete; and the word "megaphone" is universally

applied to the single, side-flaring horn.

A further step in this line brought Edison to the "aerophone," around which the Figaro

weaved its fanciful description. In the construction of the aerophone the same kind of

tympanum is used as in the phonograph, but the imitation of the human voice, or the

transmission of sound, is effected by the quick opening and closing of valves placed

within a steam- whistle or an organ-pipe. The vibrations of the diaphragm communicated

to the valves cause them to operate in synchronism, so that the vibrations are thrown

upon the escaping air or steam; and the result is an instrument with a capacity of

magnifying the sounds two hundred times, and of hurling them to great distances

intelligibly, like a huge fog-siren, but with immense clearness and penetration. All this

study of sound transmission over long distances without wires led up to the consideration

and inven- tion of pioneer apparatus for wireless telegraphy-- but that also is another

chapter.

Yet one more ingenious device of this period must be noted--Edison's vocal engine, the

patent application for which was executed in August, 1878, the patent being granted the

following December. Reference to this by Edison himself has already been quoted. The

"voice-engine," or "phonomotor," converts the vibrations of the voice or of music, acting

on the diaphragm, into motion which is utilized to drive some secondary appliance,

whether as a toy or for some useful purpose. Thus a man can actually talk a hole through

a board.

Somewhat weary of all this work and excitement, and not having enjoyed any cessation

from toil, or period of rest, for ten years, Edison jumped eagerly at the opportunity

afforded him in the summer of 1878 of making a westward trip. Just thirty years later, on

a similar trip over the same ground, he jotted down for this volume some of his

reminiscences. The lure of 1878 was the opportunity to try the ability of his delicate

tasimeter during the total eclipse of the sun, July 29. His admiring friend, Prof. George F.

Barker, of the University of Pennsylvania, with whom he had now been on terms of

intimacy for some years, suggested the holiday, and was himself a member of the

excursion party that made its rendezvous at Rawlins, Wyoming Territory. Edison had

tested his tasimeter, and was satisfied that it would measure down to the millionth part of

a degree Fahrenheit. It was just ten years since he had left the West in poverty and

obscurity, a penni- less operator in search of a job; but now he was a great inventor and

famous, a welcome addition to the band of astronomers and physicists assembled to

observe the eclipse and the corona.