1887. An illustration of the gramophone recorder is given in Fig. 193.

Instead of a wax cylinder this machine employs a flat disc on which the record is formed as a volute spiral groove, gradually drawing toward the center. It is produced as follows: A zinc disc is covered by a thin film of acid resisting material, such as wax or grease, and is placed in a horizontal pan, mounted to revolve as a turn table about a vertical axis. A stylus and diaphragm, with speaking tube attached, are arranged above the disc, and when spoken into the vibrations of the diaphragm cause, through the stylus, a record to be traced through the wax, down to the zinc. As the waxed disc and pan are revolved, the stylus and diaphragm are gradually moved by gears toward the center of the disc. While the record is being traced the waxed disc is kept flooded with alcohol from a glass jar, seen in the cut, to soften the film and prevent the clogging of the stylus. The disc, when completed, is then rinsed off and etched with acid, chromic acid being used, to prevent liberation of hydrogen bubbles. The etched disc is then electrotyped to form a matrix, and from this electrotype hard rubber duplicates of the original record are molded, which are capable of giving 1,000 reproductions. These rubber discs are placed on the reproducing instrument, which is arranged to cause the stylus to freely trail along in the spiral groove, and when the disc is rotated under the said stylus its record is converted into articulate speech. Such flat disc records give quite loud reproductions, are not easily destroyed, and may be compactly stored and transported. In the gramophone the diaphragm stands at right angles to the record disc and the stylus does not vibrate endwise to make a path of varying depth, as in the phonograph and graphophone, but the stylus vibrates laterally and traces a little zigzag line. The cost of a talking machine is from $5 to $150. The wax cylinders cost from 25 cents to $3.00, and the cylinders will hold a record of from 800 to 1,200 words, equivalent to about three or four pages of print in an octavo volume. An important part of such machines is the motor, which must maintain a uniform rate of speed, and much ingenuity has been displayed on this part of the machine. Probably the largest use of the phonograph or graphophone is for home amusement and exhibition purpose. The coin operated, or “nickel-in-the-slot” machine, finds a popular demand, while its utilitarian use as an amanuensis, or stenographer, is as yet a subordinate one. Although twenty-one years of age, and of full growth, the phonograph is ever a wonderfully new and impressive device. When listening to it for the first time the conflict of emotions which it excites is difficult to analyze. A voice full of human quality, of clear and familiar enunciation, and speaking in the most matter of fact way about the most matter of fact things, proceeds from an insignificant and insensible bit of metal, presenting the apparently anomalous condition of speech without a speaker. When convinced that there is no trick, astonishment struggles with admiration and a desire for a personal introduction. We speak into it, and have the unique experience of listening to our own voice emanating from a different part of the room, instead of our own mouths. It is really difficult to believe one’s own senses, and no wonder that it inspires the superstitious with a feeling of awe. If Mr. Edison had lived a few centuries earlier, and had produced such an instrument, his life might have paid the penalty of his ingenuity, for without doubt he would have been classed as a wizard, and of close kin to the evil one. The phonograph is the truth-telling and incontrovertible witness whose memory is never at fault, and whose nerves are never discomposed by any cross-examination. As evidence in court its word cannot be doubted, and the witness confronted by his own utterances from the phonograph must yield to its infallible dictum. The dying father, unable to write, may dictate to it his last will and testament, and leave a message for his loved ones, and long after the sod is green on his grave, that message would still be audible, and fresh and true to all the tender inflections of the heart’s emotions. By its aid the Holy Father, at Rome, may give his personal and audible blessing to his children throughout the world, though separated by thousands of miles. Who can tell what stories of interesting and instructive knowledge would be in our possession if the phonograph had appeared in the ages of the past, and its records had been preserved? The voices of our dead ancestors, whose portraits hang on the wall, and the eloquent words of Demosthenes and Cicero would be preserved to us. In fact, we should be brought into vocal contact with the world’s heroes, martyrs, saints, and sages, and all the great actors and teachers whose personalities have made history, and whose teachings have given us our best ideals. But perhaps the most practical and best characterization of the phonograph is given in Mr. Edison’s own terse words. He says: “In one sense it knows more than we know ourselves, for it retains the memory of many things which we forget, even though we have said them. It teaches us to be careful of what we say, and I am sure makes men more brief, more businesslike, and more straightforward.”