and as the cylinder moves onward in its former track, the metal point retraces the indentations on the foil from beginning to end, in doing which it communicates the vibrations it thus receives to the metal diaphragm in precisely the same manner, and with the same results as were shown with D. For the diaphragm, more particularly when employed as a resonator or reproducer of the words which have been spoken into the mouth-piece, other substances than metal have been tried, with, it is said, more satisfactory results. One of these is paper, the sounds given off by which are stated to be more distinct than those from iron.
Dr Clarence Holt, of Boston, in a communication to Mr W. H. Preece, writes that he has “constructed a diaphragm upon the principle of the membrane of the human drum of the ear, to be used as a reproducing disc.” Dr Holt continues “that his object was to employ a membrane which from its structure and shape would reproduce the lighter over-tones representing the quality of the voice, and at the same time cut off the sharper exaggerated over-tones embossed as such by the metal disc upon the tinfoil. He says the results of his experiments with such a membrane were very gratifying, and that the material of which it may be made should be either stout felted paper (to be varnished on the outer surface when used for speaking) or drum head moistened and pressed into a concave form before using.”[97]
[97] Published in ‘Nature,’ February 4th, 1878.
The crank (shown in the figure) by which the cylinder is turned is very frequently supplanted by an apparatus consisting of weights and wheels, or else by clockwork, whereby the cylinder is put in motion. The advantage of the working of these arrangements over that of the crank are, that instead of an inequality a regularity of movement of the cylinder is ensured, and it is thus made to advance at the same rate whilst the words are being reproduced as when they are being spoken.
One of the effects of this uniformity of the rotation of the cylinder under its two modes of action is to reproduce the exact pitch or tone of the voice of the speaker, although a departure from it would in no way affect the delivery of the exact words.
Accordingly, therefore, to the difference in the rate of movement of the cylinder during the reception and reproduction of speech, will be the divergence in tone between the original and the reproduced voice. If the cylinder were moved more quickly in redelivering the words the result would be that they would be in a higher, and, in the opposite case, in a lower key. Probably, as one writer has suggested, the curious effect might be produced of a child’s voice being converted into a man’s deep base, or vice versâ.
In view of the results of previous scientific
discoveries, we should not be justified in refusing to admit the possibility, at any rate, of the realisation of some of the applications to which its inventor believes the phonograph will, in the course of time, be put.
It must be admitted that these predictions as to its ultimate capabilities are sufficiently wondrous. They are that—the phonograph will be able to record and reproduce at a future time any air sung to it, so that the vocal triumphs of some of our most accomplished singers may be preserved and resung after their death; that by its means may also be conserved and respoken, likewise after death, a speech delivered by a great statesman or orator; that a dying testator by breathing into it his last wishes may have these securely registered, to be expressed after his demise, if need be, in a court of justice; and that the contents of a book or novel may be read to us in the very accents of its author, long after he has passed away.
Although we have no testimony that anything like an approach to the above results has been obtained by this instrument, such statements as we possess of its action are not a little surprising.