Part 21

I witnessed in 1874 some curious illustrations of the artificial production of vocal sounds, at the Stevens Institute, Hoboken, N.J., where the ingenious Professor Mayer (who will have, I trust, a good deal to say about the scientific significance of telephonic and phonographic experiments before long) has acoustic apparatus, including several talking-pipes. By suitably moving his hand on the top of some of these pipes, he could make them speak certain words with tolerable distinctness, and even utter short sentences. I remember the performance closed with the remarkably distinct utterance, by one profane pipe, of the words euphemistically rendered by Mark Twain (in his story of the Seven Sleepers, I think), “Go thou to Hades!”

Now, the speaking diaphragm in the telephone, as in the phonograph, presently to be described, must reproduce not only all the varieties of sound-wave corresponding to vowel sounds, with their intermixtures of the fundamental tone and its overtones and their inflexions or sliding changes of pitch, but also all the effects produced on the receiving diaphragm by those interruptions, complete or partial, of aerial emission which correspond to the pronunciation of the various consonant sounds. It might certainly have seemed hopeless, from all that had been before known or surmised respecting the effects of aerial vibrations on flexible diaphragms, to attempt to make a diaphragm speak artificially—in other words, to make the movements of all parts of it correspond with those of a diaphragm set in vibration by spoken words—by movements affecting only its central part. It is in the recognition of the possibility of this, or rather in the discovery of the fact that the movements of a minute portion of the middle of a diaphragm regulate the vibratory and other movements of the entire diaphragm, that the great scientific interest of Professor Graham Bell’s researches appears to me to reside.

It may be well, in illustration of the difficulties with which formerly the subject appeared to be surrounded, to describe the results of experiments which preceded, though they can scarcely be said to have led up to, the invention of artificial ways of reproducing speech. I do not now refer to experiments like those of Kratzenstein of St. Petersburg, and Von Kempelen of Vienna, in 1779, and the more successful experiments by Willis in later years, but to attempts which have been made to obtain material records of the aerial motions accompanying the utterance of spoken words. The most successful of these attempts was that made by Mr. W. H. Barlow. His purpose was “to construct an instrument which should record the pneumatic actions” accompanying the utterance of articulated sounds “by diagrams, in a manner analogous to that in which the indicator-diagram of a steam-engine records the action of the engine.” He perceived that the actual aerial pressures involved being very small and very variable, and the succession of impulses and changes of pressure being very rapid, it was necessary that the moving parts should be very light, and that the movement and marking should be accomplished with as little friction as possible. The instrument he constructed consisted of a small speaking-trumpet about four inches long, having an ordinary mouthpiece connected to a tube half an inch in diameter, the thin end of which widened out so as to form an aperture of 2¼ inches diameter. This aperture was covered with a membrane of goldbeater’s skin, or thin gutta-percha. A spring carrying a marker was made to press against the membrane with a slight initial pressure, to prevent as far as possible the effects of jarring and consequent vibratory action. A light arm of aluminium was connected with the spring, and held the marker; and a continuous strip of paper was made to pass under the marker in the manner employed in telegraphy. The marker consisted of a small, fine sable brush, placed in a light tube of glass one-tenth of an inch in diameter, the tube being rounded at the lower end, and pierced with a hole about one-twentieth of an inch in diameter. Through this hole the tip of the brush projected, and was fed by colour put into the glass tube by which it was held. It should be added that, to provide for the escape of air passing through the speaking-trumpet, a small opening was made in the side, so that the pressure exerted upon the membrane was that due to the excess of air forced into the trumpet over that expelled through the orifice. The strength of the spring which carried the marker was so adjusted to the size of the orifice that, while the lightest pressures arising under articulation could be recorded, the greatest pressures should not produce a movement exceeding the width of the paper.

“It will be seen,” says Mr. Barlow, “that in this construction of the instrument the sudden application of pressure is as suddenly recorded, subject only to the modifications occasioned by the inertia, momentum, and friction of the parts moved. But the record of the sudden cessation of pressure is further affected by the time required to discharge the air through the escape-orifice. Inasmuch, however, as these several effects are similar under similar circumstances, the same diagram should always be obtained from the same pneumatic action when the instrument is in proper adjustment; and this result is fairly borne out by the experiments.”

The defect of the instrument consisted in the fact that it recorded changes of pressure only; and in point of fact it seems to result, from the experiments made with it, that it could only indicate the order in which explosive, continuant, and liquid consonants succeeded each other in spoken words, the vowels being all expressed in the same way, and only one letter—the rough R, or R with a burr—being always unmistakably indicated. The explosives were represented by a sudden sharp rise and fall in the recorded curve; the height of the rise depending on the strength with which the explosive is uttered, not on the nature of the consonant itself. Thus the word “tick” is represented by a higher elevation for the “t” than for the “k,” but the word “kite” by a higher elevation for the “k” than for the “t.” It is noteworthy that there is always a second smaller rise and fall after the first chief one, in the case of each of the explosives. This shows that the membrane, having first been forcibly distended by the small aerial explosion accompanying the utterance of such a consonant, sways back beyond the position where the pressure and the elasticity of the membrane would (for the moment) exactly balance, and then oscillates back again over that position before returning to its undistended condition. Sometimes a third small elevation can be recognized, and when an explosive is followed by a rolling “r” several small elevations are seen. The continuous consonants produce elevations less steep and less high; aspirates and sibilants give rounded hills. But the results vary greatly according to the position of a consonant; and, so far as I can make out from a careful study of the very interesting diagrams accompanying Mr. Barlow’s paper, it would be quite impossible to define precisely the characteristic records even of each order of consonantal sounds, far less of each separate sound.

We could readily understand that the movement of the central part of the diaphragm in the telephone should give much more characteristic differences for the various sounds than Barlow’s logograph. For if we imagine a small pointer attached to the centre of the face of the receiving diaphragm while words are uttered in its neighbourhood, the end of that pointer would not only move to and fro in a direction square to the face of the diaphragm, as was the case with Barlow’s marker, but it would also sway round its mean position in various small circles or ovals, varying in size, shape, and position, according to the various sounds uttered. We might expect, then, that if in any way a record of the actual motions of the extremity of that small pointer could be obtained, in such sort that its displacement in directions square to the face of the diaphragm, as well as its swayings around its mean position, would be indicated in some pictorial manner, the study of such records would indicate the exact words spoken near the diaphragm, and even, perhaps, the precise tones in which they were uttered. For Barlow’s logograph, dealing with one only of the orders of motion (really triple in character), gives diagrams in which the general character of the sounds uttered is clearly indicated, and the supposed records would show much more.

But although this might, from à priori considerations, have been reasonably looked for, it by no means follows that the actual results of Bell’s telephonic experiments could have been anticipated. That the movement of the central part of the diaphragm should suffice to show that such and such words had been uttered, is one thing; but that these movements should of themselves suffice, if artificially reproduced, to cause the diaphragm to reproduce these words, is another and a very different one. I venture to express my conviction that at the beginning of his researches Professor Bell can have had very little hope that any such result would be obtained, notwithstanding some remarkable experiments respecting the transmission of sound which we can now very clearly perceive to point in that direction.

When, however, he had invented the telephone, this point was in effect demonstrated; for in that instrument, as we have seen, the movements of the minute piece of metal attached (at least in the earlier forms of the instrument) to the centre of the receiving membrane, suffice, when precisely copied by the similar central piece of metal in the transmitting membrane, to cause the words which produced the motions of the receiving or hearing membrane to be uttered (or seem to be uttered) by the transmitting or speaking membrane.

It was reserved, however, for Edison (of New Jersey, U.S.A., Electrical Adviser to the Western Union Telegraph Company) to show how advantage might be taken of this discovery to make a diaphragm speak, not directly through the action of the movements of a diaphragm affected by spoken words or other sounds, and therefore either simultaneously with these or in such quick succession after them as corresponds with the transmission of their effects along some line of electrical or other communication, but by the mechanical reproduction of similar movements at any subsequent time (within certain limits at present, but probably hereafter with practically unlimited extension as to time).

The following is slightly modified from Edison’s own description of the phonograph:—

The instrument is composed of three parts mainly; namely, a receiving, a recording, and a transmitting apparatus. The receiving apparatus consists of a curved tube, one end of which is fitted with a mouthpiece. The other end is about two inches in diameter, and is closed with a disc or diaphragm of exceedingly thin metal, capable of being thrust slightly outwards or vibrated upon gentle pressure being applied to it from within the tube. To the centre of this diaphragm (which is vertical) is fixed a small blunt steel pin, which shares the vibratory motion of the diaphragm. This arrangement is set on a table, and can be adjusted suitably with respect to the second part of the instrument—the recorder. This is a brass cylinder, about four inches in length and four in diameter, cut with a continuous V-groove from one end to the other, so that in effect it represents a large screw. There are forty of these grooves in the entire length of the cylinder. The cylinder turns steadily, when the instrument is in operation, upon a vertical axis, its face being presented to the steel point of the receiving apparatus. The shaft on which it turns is provided with a screw-thread and works in a screwed bearing, so that as the shaft is turned (by a handle) it not only turns the cylinder, but steadily carries it upwards. The rate of this vertical motion is such that the cylinder behaves precisely as if its groove worked in a screw-bearing. Thus, if the pointer be set opposite the middle of the uppermost part of the continuous groove at the beginning of this turning motion, it will traverse the groove continuously to its lowest part, which it will reach after forty turnings of the handle. (More correctly, perhaps, we might say that the groove continuously traverses past the pointer.) Now, suppose that a piece of some such substance as tinfoil is wrapped round the cylinder. Then the pointer, when at rest, just touches the tinfoil. But when the diaphragm is vibrating under the action of aerial waves resulting from various sounds, the pointer vibrates in such a way as to indent the tinfoil—not only to a greater or less depth according to the play of the pointer to and fro in a direction square to the face of the diaphragm, but also over a range all round its mean position, corresponding to the play of the end of the pointer around its mean position. The groove allows the pressure of the pointer against the tinfoil free action. If the cylinder had no groove the dead resistance of the tinfoil, thus backed up by an unyielding surface, would stop the play of the pointer. Under the actual conditions, the tinfoil is only kept taut enough to receive the impressions, while yielding sufficiently to let the play of the pointer continue unrestrained. If now a person speaks into the receiving tube, and the handle of the cylinder be turned, the vibrations of the pointer are impressed upon the portion of the tinfoil lying over the hollow groove, and are retained by it. They will be more or less deeply marked according to the quality of the sounds emitted, and according also, of course, to the strength with which the speaker utters the sounds, and to the nature of the modulations and inflexions of his voice. The result is a message verbally imprinted upon a strip of metal. It differs from the result in the case of Barlow’s logograph, in being virtually a record in three dimensions instead of one only. The varying depth of the impressions corresponds to the varying height of the curve in Barlow’s diagrams; but there the resemblance ceases; for that was the single feature which Barlow’s logographs could present. Edison’s imprinted words show, besides varying depth of impression, a varying range on either side of the mean track of the pointer, and also—though the eye is not able to detect this effect—there is a varying rate of progression according as the end of the pointer has been swayed towards or from the direction in which, owing to the motion of the cylinder, the pointer is virtually travelling.

We may say of the record thus obtained that it is sound presented in a visible form. A journalist who has written on the phonograph has spoken of this record as corresponding to the crystallization of sound. And another who, like the former, has been (erroneously, but that is a detail) identified with myself, has said, in like fanciful vein, that the story of Baron Münchausen hearing words which had been frozen during severe cold melting into speech again, so that all the babble of a past day came floating about his ears, has been realized by Edison’s invention. Although such expressions may not be, and in point of fact are not, strictly scientific, I am not disposed, for my own part, to cavil with them. If they could by any possibility be taken au pied de la lettre (and, by the way, we find quite a new meaning for this expression in the light of what is now known about vowels and consonants), there would be valid objection to their use. But, as no one supposes that Edison’s phonograph really crystallizes words or freezes sounds, it seems hypercritical to denounce such expressions as the critic of the Telegraphic Journal has denounced them.

To return to Edison’s instrument.

Having obtained a material record of sounds, vocal or otherwise, it remains that a contrivance should be adopted for making this record reproduce the sounds by which it was itself formed. This is effected by a third portion of the apparatus, the transmitter. This is a conical drum, or rather a drum shaped like a frustum of a cone, having its larger end open, the smaller—which is about two inches in diameter—being covered with paper stretched tight like the parchment of a drumhead. In front of this diaphragm is a light flat steel spring, held vertically, and ending in a blunt steel point, which projects from it and corresponds precisely with that on the diaphragm of the receiver. The spring is connected with the paper diaphragm by a silken thread, just sufficiently in tension to cause the outer face of the diaphragm to be slightly convex. Having removed the receiving apparatus from the cylinder and set the cylinder back to its original position, the transmitting apparatus is brought up to the cylinder until the steel point just rests, without pressure, in the first indentation made in the tinfoil by the point of the receiver. If now the handle is turned at the same speed as when the message was being recorded, the steel point will follow the line of impression, and will vibrate in periods corresponding to the impressions which were produced by the point of the receiving apparatus. The paper diaphragm being thus set into vibrations of the requisite kind in number, depth, and side-range, there are produced precisely the same sounds that set the diaphragm of the receiver into vibration originally. Thus the words of the speaker are heard issuing from the conical drum in his own voice, tinged with a slightly metallic or mechanical tone. If the cylinder be more slowly turned when transmitting than it had been when receiving the message, the voice assumes a base tone; if more quickly, the message is given with a more treble voice. “In the present machine,” says the account, “when a long message is to be recorded, so soon as one strip of tinfoil is filled, it is removed and replaced by others, until the communication has been completed. In using the machine for the purpose of correspondence, the metal strips are removed from the cylinder and sent to the person with whom the speaker desires to correspond, who must possess a machine similar to that used by the sender. The person receiving the strips places them in turn on the cylinder of his apparatus, applies the transmitter, and puts the cylinder in motion, when he hears his friend’s voice speaking to him from the indented metal. And he can repeat the contents of the missive as often as he pleases, until he has worn the metal through. The sender can make an infinite number of copies of his communication by taking a plaster-of-Paris cast of the original, and rubbing off impressions from it on a clean sheet of foil.”

I forbear from dwelling further on the interest and value of this noble invention, or of considering some of the developments which it will probably receive before long, for already I have occupied more space than I had intended. I have no doubt that in these days it will bring its inventor less credit, and far less material gain, than would be acquired from the invention of some ingenious contrivance for destroying many lives at a blow, bursting a hole as large as a church door in the bottom of an ironclad, or in some other way helping men to carry out those destructive instincts which they inherit from savage and brutal ancestors. But hereafter, when the representatives of the brutality and savagery of our nature are held in proper disesteem, and those who have added new enjoyments to life are justly valued, a high place in the esteem of men will be accorded to him who has answered one-half of the poet’s aspiration,

“Oh for the touch of a vanished hand, And the sound of a voice that is still!”

* * * * *

NOTE.—Since the present paper was written, M. Aurel de Ratti has made some experiments which he regards as tending to show that there is no mechanical vibration. Thus, “when the cavities above and below the iron disc of an ordinary telephone are filled with wadding, the instrument will transmit and speak with undiminished clearness. On placing a finger on the iron disc opposite the magnet, the instrument will transmit and speak distinctly, only ceasing to act when sufficient pressure is applied to bring plate and magnet into contact. Connecting the centre of the disc by means of a short thread with an extremely sensitive membrane, no sound is given out by the latter when a message is transmitted. Bringing the iron cores of the double telephone in contact with the disc, and pressing with the fingers against the plate on the other side, a weak current from a Daniell cell produced a distinct click in the plate, and on drawing a wire from the cell over a file which formed part of the circuit, a rattling noise was produced in the instrument.” If these experiments had been made before the phonograph was invented, they would have suggested the impracticability of constructing any instrument which would do what the phonograph actually does, viz., cause sounds to be repeated by exciting a merely mechanical vibration of the central part of a thin metallic disc. But as the phonograph proves that this can actually be done, we must conclude that M. Aurel de Ratti’s experiments will not bear the interpretation he places upon them. They show, nevertheless, that exceedingly minute vibrations of probably a very small portion of the telephonic disc suffice for the distinct transmission of vocal sounds. This might indeed be inferred from the experiments of M. Demozet, of Nantes, who finds that the vibrations of the transmitting telephone are in amplitude little more than 1-2000th those of the receiving telephone.

THE GORILLA AND OTHER APES.

About twenty-five centuries ago, a voyager called Hanno is said to have sailed from Carthage, between the Pillars of Hercules—that is, through the Straits of Gibraltar—along the shores of Africa. “Passing the Streams of Fire,” says the narrator, “we came to a bay called the Horn of the South. In the recess there was an island, like the first, having a lake, and in this there was another island full of wild men. But much the greater part of them were women, with hairy bodies, whom the interpreters called ‘Gorillas.’ Pursuing them, we were not able to take the men; they all escaped, being able to climb the precipices; and defended themselves with pieces of rock. But three women, who bit and scratched those who led them, were not willing to follow. However, having killed them, we flayed them, and conveyed the skins to Carthage; for we did not sail any further, as provisions began to fail.”

In the opinion of many naturalists, the wild men of this story were the anthropoid or manlike apes which are now called gorillas, rediscovered recently by Du Chaillu. The region inhabited by the gorillas is a well-wooded country, “extending about a thousand miles from the Gulf of Guinea southward,” says Gosse; “and as the gorilla is not found beyond these limits, so we may pretty conclusively infer that the extreme point of Hanno was somewhere in this region.” I must confess these inferences seem to me somewhat open to question, and the account of Hanno’s voyage only interesting in its relation to the gorilla, as having suggested the name now given to this race of apes. It is not probable that Hanno sailed much further than Sierra Leone; according to Rennell, the island where the “wild men” were seen, was the small island lying close to Sherbro, some seventy miles south of Sierra Leone. To have reached the gorilla district after doubling Cape Verd—which is itself a point considerably south of the most southerly city founded by Hanno—he would have had to voyage a distance exceeding that of Cape Verd from Carthage. Nothing in the account suggests that the portion of the voyage, after the colonizing was completed, had so great a range. The behaviour of the “wild men,” again, does not correspond with the known habits of the gorilla. The idea suggested is that of a species of anthropoid ape far inferior to the gorilla in strength, courage, and ferocity.

The next accounts which have been regarded as relating to the gorilla are those given by Portuguese voyagers. These narratives have been received with considerable doubt, because in some parts they seem manifestly fabulous. Thus the pictures representing apes show also huge flying dragons with a crocodile’s head; and we have no reason for believing that batlike creatures like the pterodactyls of the greensand existed in Africa or elsewhere so late as the time of the Portuguese voyages of discovery. Purchas, in his history of Andrew Battell, speaks of “a kinde of great apes, if they might so bee termed, of the height of a man, but twice as bigge in feature of their limmes, with strength proportionable, hairie all over, otherwise altogether like men and women in their whole bodily shape, except that their legges had no calves.” This description accords well with the peculiarities of gorillas, and may be regarded as the first genuine account of these animals. Battell’s contemporaries called the apes so described Pongoes. It is probable that in selecting the name Pongo for the young gorilla lately at the Westminster Aquarium, the proprietors of this interesting creature showed a more accurate judgment of the meaning of Purchas’s narrative than Du Chaillu showed of Hanno’s account, in calling the great anthropoid ape of the Gulf of Guinea a gorilla.

I propose here briefly to sketch the peculiarities of the four apes which approach nearest in form to man—the gorilla, the chimpanzee, the orang-outang, and the gibbon; and then, though not dealing generally with the question of our relationship to these non-speaking (and, in some respects, perhaps, “unspeakable”) animals, to touch on some points connected with this question, and to point out some errors which are very commonly entertained on the subject.

It may be well, in the first place, to point out that the terms “ape,” “baboon,” and “monkey” are no longer used as they were by the older naturalists. Formerly the term “ape” was limited to tailless simians having no cheek-pouches, and the same number of teeth as man; the term “baboon” to short-tailed simians with dog-shaped heads; and the term “monkey,” unless used generically, to the long-tailed species. This was the usage suggested by Ray, and adopted systematically thirty or forty years ago. But it is no longer followed, though no uniform classification has been substituted for the old arrangement. Thus Mivart divides the apes into two classes—calling the first the Simiadæ, or Old World apes; and the second the Cebidæ, or New World apes. He subdivides the Simiadæ into (1) the Siminæ, including the gorilla, chimpanzee, orang, and gibbon; (2) the Semnopithecinæ; and (3) the Cynopithecinæ; neither of which subdivisions will occupy much of our attention here, save as respects the third subdivision of the Cynopithecinæ, viz., the Cynocephali, which includes the baboons. The other great division, the Cebidæ, or New World apes, are for the most part very unlike the Old World apes. None of them approach the gorilla or orang-outang in size; most of them are long-tailed; and the number and arrangement of the teeth is different. The feature, however, which most naturalists have selected as the characteristic distinction between the apes of the Old World and of the New World is the position of the nostrils. The former are called Catarhine, a word signifying that the nostrils are directed downwards; the latter are called Platyrhine, or broad-nosed. The nostrils of all the Old World apes are separated by a narrow cartilaginous plate or septum, whereas the septum of the New World apes is broad. After the apes come, according to Mivart’s classification, the half-apes or lemuroids.

I ought, perhaps, to have mentioned that Mivart, in describing the lemuroids as the second sub-order of a great order of animals, the Primates, speaks of a man as (zoologically speaking) belonging to the first sub-order. So that, in point of fact, the two sub-orders are the Anthropoids, including the Anthropos (man) and the Lemuroids, including the lemur.

The classification here indicated will serve our present purpose very well. But the reader is reminded that, as already mentioned, naturalists do not adopt at present any uniform system of classification. Moreover, the term Simiadæ is usually employed—and will be employed here—to represent the entire simian race, i.e., both the Simiadæ and the Cebidæ of Mivart’s classification.

And now, turning to the Anthropoid apes, we find ourselves at the outset confronted by the question, Which of the four apes, the gorilla, the orang-outang, the chimpanzee, or the gibbon, is to be regarded as nearest to man in intelligence? So far as bodily configuration is concerned, our opinion would vary according to the particular feature which we selected for consideration. But it will probably be admitted that intelligence should be the characteristic by which our opinions should be guided.

The gibbon may be dismissed at once, though, as will presently appear, there are some features in which this ape resembles man more closely than either the gorilla, the orang-outang, or the chimpanzee.