Note 20 — THE PHONOGRAPH.
Reading edition
Never make a contact between the stylus and the cylinder until the latter is covered with the tinfoil. Do not begin to turn the cylinder until assured that everything is in its place. Take care, when the stylus returns to the point of departure, to bring the mouthpiece forward. Always leave a margin of from five to ten millimètres on the left and at the beginning of the sheet of tinfoil; for if the stylus describes the curve on the extreme edge of the cylinder, it may tear the sheet or come out of the groove. Be careful not to detach the spring of the caoutchouc pad.
To fix the tinfoil, apply varnish to the end with a paint-brush; take this end between the finger and thumb of the left hand, with the sticky part towards the cylinder; raise it with the right hand and apply it quite smoothly to the cylinder; bring round the sticky end, and join them firmly.
To adjust the stylus and place it in the centre of the groove, bring the cylinder to the right, so as to place the stylus opposite the left extremity of the tinfoil; bring forward the cylinder gently and by degrees, until the stylus touches the tinfoil with force enough to imprint a mark. Observe if this mark is quite in the centre of the groove (in order to do this, make a mark with the nail across the cylinder), and if it is not, adjust the stylus to the right or left by means of the little screw placed above the mouthpiece. The depth of the impression made by the stylus should be ⅓ millimètre, just enough for it to leave a slight tracing, whatever the range of vibrations may be.
To reproduce the words, the winch must be turned with the same velocity as when they were inscribed. The average velocity should be about eighty turns a minute.
In speaking, the lips must touch the mouthpiece, and deep guttural sounds are better heard than those which are shrill. In reproducing, the tightening screw must be loosened and brought in front of the mouthpiece, the cylinder must be brought back to its point of departure, the contact between the stylus and the foil must be renewed, and the cylinder must again be turned in the same direction as when the sentence was spoken.
To increase the volume of reproduced sound, a tube of cardboard, wood, or horn may be applied to the mouthpiece; it must be of a conical form, and its lower end should be rather larger than the opening of the mouthpiece.
The stylus consists of a No. 9 needle, somewhat flattened on its two sides by friction on an oiled stone. The caoutchouc pad which connects the plate with the disk serves to weaken the vibrations of the plate. If this pad should come off, heat the head of a small nail, apply it to the wax which fastens the pad to the plate or to the spring, so as to soften it; then press the caoutchouc lightly, until it adheres to the place from which it was detached. The pads must be renewed from time to time, as they lose their elasticity. Care must be taken in replacing them not to injure the vibrating plate, either by too strong a pressure or by grazing it with the instrument employed to fix the pad.
The first experiments should be with single words or very short sentences, which can be extended as the ear becomes accustomed to the instrument’s peculiar tone.
The tone is varied by accelerating or slackening the rotatory movement of the cylinder. The cries of animals may be imitated. Instrumental music may be reproduced by placing a cardboard tube before the mouthpiece. The airs should be played in rapid time, since, when there is no system of clockwork, they will be more perfectly reproduced than those which are played slowly.