459* PHONOGRAPH PHONOGRAPHY der must be rotated with the same uniform motion both when receiving and when repro- ducing sounds, for the tones vary with the ra- pidity of its rotation; if it be turned faster than when it received the sounds, the pitch of the tones will be higher, and if slower the pitch will be lower. As absolute uniformity of mo- tion cannot be secured by turning the cylinder by hand, as is now practised, the quality of tones, or those peculiarities which constitute the difference between one voice and another, cannot be reproduced ; but careful experiments have made it probable that this difficulty can easily be overcome, and that it will soon be possible to reproduce the human voice with all its modulations. To secure this absolute uni- formity of motion in the instrument, the in- ventor has devised a train of wheels, like those of a clock, to be worked by a spiral spring and controlled by a governor, which will act auto- matically, and which may be started, stopped, or reversed at pleasure. This, it is believed, will cause the words of a speaker to be repro- duced in the exact tones of the original. But much depends also upon the iron diaphragm which receives the vibrations and the point which records them. The diaphragm now em- ployed is made of the thin iron ferrotype plate used by photographers. Experience has proved that this is the best thickness for the diaphragm both in the phonograph and the telephone, but thicker and thinner plates have been used with good results, and it seems that no plate is too thick or too thin for the purpose. There must be, however, a certain proportion between the thickness of the diaphragm and its diameter, and it is probable that this relative proportion is governed by some law which will eventually regulate the structure of all diaphragms. It is shown too that if the diaphragm be " damped " by inserting between it and the mouthpiece a small section of rubber tube, the vibrations ob- tained are more perfect. The point by means of which the vibrations are now recorded is made of steel, but its use is open to objections, and the inventor proposes to substitute a dia- mond point, which has given the best results. It is also hoped that the voice of the machine will be improved by the substitution of some better material for receiving the record of the vibrations than the tin foil which is now used. Thus far this has proved the best fitted for the purpose, but it is believed that something else will be discovered which will add both to the intensity and quality of the sounds. If the phonograph is to be made anything more than a philosophical plaything and to have any prac- tical utility, it will be necessary to find some means of preserving its record, which seems im- possible while it is made upon thin and yielding foil. The inventor has already devised a plan by which he confidently expects to multiply the intensity of the impressions, so that the tones may be increased indefinitely in volume ; and it has been suggested that the preservation of the record may be secured by stereotyping or electrotyping it. Difficulty has been ex- perienced in replacing the foil on the cylin- der after it has once been removed ; for unless the readjustment be very accurate, the sounds must necessarily be impaired. To secure this accuracy, the inventor has made a new machine in which the cylinder is superseded by a plate rotated in a horizontal plane by clockwork be- neath it. The plate, which is square and about ten inches in diameter, has cut into its surface a volute spiral starting from the centre. In practice this spiral is to be covered with foil, cut to fit exactly into a place made for its re- ception, so that it may be removed and re- placed at will, or even sent to a distance and fitted into a similar place in another instrument. Each sheet of foil has a capacity for recording about 40,000 words. An arm, at the end of which is a mouthpiece, with its point beneath, like that in the present instrument, will record the vibrations on the spiral as it revolves. It is believed that this has many advantages over the present cylinder machine, and that it will supersede it for practical use. Mr. Edison, who is consulting electrician of the Western Union telegraph company, is the originator of the quadruplex system of telegraphy, and of the telephone which bears his name (see TELE- PHONE). He is also the author of other impor- tant discoveries in electricity and magnetism. PHONOGRAPHY (Gr. <j>ovjj, voice, and -ypa<j>e~iv, to write), a system of shorthand, mainly in- vented by Isaac Pitman, of Bath, England, and published in 1837, since when various changes have been made by the inventor and other shorthand writers. In England the only text books of the art are those that are prepared or sanctioned by the inventor ; but in the United States three distinct versions or modifications of the system are in common use, substantially as presented in the text books of James E. Munson and Andrew J. Graham of New York, and Benn Pitman (a brother of the inventor) of Cincinnati. The 24 English consonant sounds are each represented by a simple straight or curved line, the requisite number of distinct characters to write them all being obtained by giving these lines four different directions, and by making them both light and heavy. In the alphabet of phonography, on p. 459, the first 16 consonants are arranged in pairs of light and heavy signs; this is because of the near relation of such sounds. By comparing the two sounds of any pair, it will be found that one is but a slight modification of the other ; that they are produced at the same point and by the same contact of the organs of speech, in almost precisely the same manner, the only difference being that in one case the action of the organs is accompanied by a light or breath sound simply, and in the other the same action is accompanied by a heavy or partially sup- pressed vowel sound. This under tone or sub- vocal constitutes the only difference between the syllables ^oay, &ay ; ie, die ; cAest, jest ; /rate, ^ate ; /end, end ; ^igh, tlij ; seal, zeal ;
