Part 82

Fig. 319_e_ shows the form of the phonograph as designed by Mr. Edison in 1877. It had a brass cylinder (A) upon which a narrow helical groove was cut, and was mounted upon an axle (B), having a narrow screw-thread corresponding with the groove on the cylinder, and working in the upright (C), so that when the handle was turned the cylinder revolved, and at the same time advanced in the direction of its axis. A heavy fly-wheel (D) was attached, in order that the rate of motion might be nearly uniform. A sheet of tinfoil, or of very thin copper, was wrapped round the brass cylinder, and on this metallic foil rested the steel point attached to the vibrating diaphragm, which was mounted in the ring (F). This point was always adjusted so as to be over the helical groove in the cylinder, and made to touch the tinfoil with a regulated pressure. E shows the manner of firmly supporting the diaphragm in such a manner that it could be readily removed from the cylinder when the latter had to be covered afresh with tinfoil, or the cylinder adjusted for reproducing the sounds. The relation of the diaphragm and point to the tinfoil is shown in Fig. 319_f_, which represents the apparatus in section. The tracing point (_t_) is not attached directly to the vibrating diaphragm, but to an adjustable spring (_s_), and interposed between the spring and the thin metallic diaphragm is a little pad, formed of a ring of small india-rubber tubing. When the mouthpiece (M) is spoken into, the sound vibrations reach the diaphragm (_g g_) through the opening (_o_), and the movements thus communicated to the point (_t_) which indents the tinfoil to various depths, and with varying frequency, as the handle is turned, bringing the whole length of the groove in succession to be operated upon. When the instrument is required to reproduce the speech so easily recorded, all that is necessary is to allow the indentations to re-act on the point that made them. The cylinder is re-adjusted to the tracing point at the end at which it began, the cylinder is set in motion, and the traces made on the tinfoil move the point up and down, the vibrating disc (_g_) following its movements, and thus communicating to the air a system of impulses which are the counterparts in period, force and succession of those that originally entered at _o_. It was usual to attach a conical mouthpiece to the ring (F) in order to concentrate the reproduced sounds, which might then be heard in all parts of a large room. When, in reproducing the sounds, the cylinder was turned with the same velocity as when the words were spoken, the pitch of the voice issuing from the instrument was the same. If it were turned quicker, the pitch was raised; if slower, lowered. The words registered on the tinfoil could be reproduced two or three times, but with decreasing distinctness, as the tracings gradually become obliterated. However, the sheet could be removed from the cylinder, and the speech reproduced at any place at any time afterwards by means of a similar instrument, and a method of stereotyping was proposed for preserving the records. The original phonograph was greatly improved when well regulated clockwork was used for imparting motion instead of the winch. Mr. Edison contrived a modification of the machine, which made it much easier of manipulation, by substituting for the cylinder a flat plate on which a spiral groove was cut. The plate was turned by clockwork, while the vibrating point was made to follow the groove from the centre to the circumference. The phonograph in its original form reproduced speech with peculiarities of its own. The quality was metallic, and reminded one of the intonation of the street Punch. It will easily be understood that the disc itself must necessarily have its own systems of vibration, and these will be further modified by the action of all the other parts. Mr. Edison’s expectations of the capabilities of the instrument not being realized, he turned his attention, after several unsuccessful attempts at its improvement, to the electric light and other subjects, at the same time declaring his conviction that the perfection of the instrument would be but a matter of time; in fact, within a very few years afterwards such improvements were made on Mr. Edison’s instrument as went far to justify this prophecy. These were the work of Dr. Chichester Bell and Mr. Tainter, who, after long continued experiments, found in paraffin wax, with a small admixture of some other substances, a better material for receiving the impressions. A cutting style made to act upon this cuts out a fine groove, the bottom of which is not a series of indentations, but a continuous wavy curve, representing every degree of inflection the vibrating diaphragm. In the new form of the instrument, FIG. 319_g_, which was called the _graphophone_, to distinguish it from Edison’s, the cylinder does not move forward: it is the diaphragm that advances parallel to the revolving axle. The cylinder is driven by a treadle, like a sewing-machine, and there is an ingenious arrangement by which the speed is controlled so that it can be maintained quite uniform. The movement of cylinder and style can be instantly arrested by touching a button, and as readily re-started. Quite recently Mr. Edison has returned to improving the phonograph by using rather thick, solid cylinders of wax, which are previously prepared for use by the instrument itself paring them down to a truly cylindrical and perfectly uniform surface, the result being a great increase of clearness in the speech and tones of music. Mr. Edison’s new instruments are driven by small electro-motors, and the speed is regulated by a centrifugal governor. It is said that these wax cylinders are capable of giving out the same record for a thousand times without perceptible sign of deterioration; and when the cylinders are required to receive a fresh impression, a former one can easily be pared off. The machines can be arranged so as to sound loud enough to be heard by a large assembly; but the quality of the tones of speech or music is most perfect when conveyed from the receiving chamber in front of the diaphragm to one or both of the auditor’s ears by means of a short elastic tube. Half a dozen persons can thus hear the record on the cylinder with such marvellous distinctness as to be able to recognize the tones of a known voice. The very latest form of the instrument, as it has just left Mr. Edison’s hands, is represented in Fig. 319_h_. In this one single very small diaphragm serves both for recording and reproducing the sounds. This is made of extremely thin glass, to which is attached a small projection made of celluloid, which acts on a bar that carries the recording point. The configuration of this point is most ingenious and peculiar, for it is, in fact, double, one part being shaped like a gouge, which cuts into the walls of the minute depression traced on the wax cylinder, while a style-shaped part impresses the wax with punctured indentations. The shaping of its forms is a difficult and delicate operation, for they are very small and are cut in sapphire. The reproduced speech given out by this instrument is said to possess the properties of sharpness and clearness in a remarkable degree. The machine is provided also with a sapphire cutting edge, by which an old record may be pared off by the very motion of the cylinder in receiving a new one. This phonograph is put in movement by ingenious mechanical devices, for giving uniform rotation from such motive power as may be supplied by the foot or by water or by clockwork. This improved instrument lays claim to practical utility, and its manufacture will, it is stated, be shortly commenced on a large scale.

Quite recently there has been established in America a big manufactory of phonographs in the form of a toy, which is sure to become very popular everywhere. Here they turn out daily several hundred _real speaking dolls_, which contain clockwork actuating a phonographic cylinder impressed with the words of some childish story or simple rhyme, such as “Jack and Jill,” “Mary Had a Little Lamb,” etc. Each doll of course repeats its little tale as often as the clockwork is set going. These toys are adapted to all nationalities; for, besides many English, there are a number of French, German, Italian, etc., girls employed doing nothing all day long but addressing appropriate words to each little automaton’s waxen cylinder.

The capabilities of the phonograph suggest some curious applications that may be made of it. For example, the songs of a fine singer may thus, in all their modulations, reach people in distant lands, or be made audible to future generations. Thousands of people in England have heard with their ears, through Mr. Edison’s instruments lately brought over by Col. Gournaud, songs and speeches, and pieces of concerted music, sung, said, or played in America months before. Music can be bottled up, so to speak, without the consent of the originators; and, indeed, it is said that an eminent _prima donna_ has applied for an injunction to restrain certain _phonographers_ from reproducing her vocal triumphs with their instruments. A speech of Mr. Gladstone’s, delivered in England, has been phonographically heard in New York with great applause. There is no reason but what, with a loud speaking phonograph uttering an orator’s very words and tones, while instantaneous photographs of his successive gestures and attitudes are projected on a screen, a true and lively impression of his eloquence might be conveyed centuries after his decease. One is almost led to speculate as to the consequences if these nineteenth century inventions had been antedated by a few thousand years: what stores of knowledge we might now possess! and how pleasant it would be thus

To hear each voice we feared to hear no more! Behold each mighty shade revealed to sight, The Bactrian, Samian sage, and all who taught the right!

AQUARIA.

Under the date of May 28th, 1665, the curious gossiping diary of Samuel Pepys contains this entry: “Thence to see my Lady Pen, where my wife and I were shown a fine rarity; of fishes kept in a glass of water, that will live so for ever—and finely marked they are, being foreign.” This doubtless refers to the now well-known gold fishes, which about the time alluded to were introduced into Europe from China, where they had probably been for ages reared and kept in captivity, chiefly for the sake of ornament. Perhaps the reader may be disposed to think that, therefore, the aquarium cannot be distinctively a nineteenth century invention, nor at all a modern invention, in principle at least; but merely the “glass of water,” or the globe of gold fish on a larger scale. Such a notion would be quite incorrect, for the principles which are embodied in the modern aquarium were not recognized and applied until quite recently. Aquatic animals kept for a period in vessels in which the water is changed from time to time cannot be considered as properly forming an aquarium. The beauty and value of a well-regulated aquarium depend not merely on the opportunities it affords of studying the habits of the animals; the spectacle it presents has a far wider interest, as illustrating and confirming the conclusions of science regarding certain great principles which govern the whole animal and vegetable life of this terraqueous globe. Perhaps in the whole range of nature nothing is more wonderful than the direct interdependence of animal and vegetable life, and the exact balance between them, which preserves the composition of the atmosphere unchanged. The constituents of the atmosphere have an immediate relation to both forms of life. No animal can live without a supply of oxygen gas, which it absorbs and replaces by carbonic acid gas. The latter, on the other hand, is absorbed by plants, for these, under the influence of light, decompose the carbonic acid, returning the oxygen to the atmosphere, thus purifying the air by again fitting it for the respiration of animals.

It might be supposed that animals which live entirely beneath the surface of water are removed from the influence of atmospheric oxygen, and that they form exceptions to this law. But such is not the case, for water absorbs and holds in solution a certain quantity of air, the oxygen of which is taken up by aquatic animals. In the lower forms of animals inhabiting water, the absorption of this vital element takes place at the general surface of the body; but in the more highly organized creatures there are special organs appropriated to this purpose, of which the gills of a fish may be cited as a typical example. The giving out of carbonic acid is an action as universal in the animal world as the absorption of oxygen, and all aquatic animals tend to charge the water in which they live with this gas. Fish, or any other water animals, will soon die if they are placed in water from which all the air has previously been expelled by boiling, or by placing under the receiver of an air-pump. In this case the creature dies from want of oxygen; but it would also die, even if supplied with oxygen, were the poisonous carbonic acid emitted by itself allowed to accumulate in the liquid. In nature, this carbonic acid forms the food of aquatic plants and sea-weeds, and these restore oxygen to the water. If a bunch of watercresses be placed in a bottle filled with water, and exposed to strong sunshine, the leaves may soon be seen covered with small bubbles of gas. This gas may be collected and examined by a suitable arrangement of the bottle, and it will be found to be pure oxygen.

The merit of having first imitated the plan of nature for the preservation of aquatic animals appears to belong to Mr. Ward, the inventor of the “Wardian cases” for ferns and other plants. He, in 1841, formed in London a fresh-water aquarium, in which, for the first time, the animals were kept in a healthy condition by the compensating action of plants. Mr. Gosse, Dr. Price, and others, made experiments with marine animals and plants, about 1850. Mr. Mitchell, who was then secretary to the Zoological Society of London, saw about this time a small aquarium on the balancing principle at Dr. Bowerbank’s, and this suggested the erection of the fish-house in the Zoological Gardens, Regent’s Park. This was opened in 1853, being the first public aquarium ever constructed. The tanks remain at the present time in nearly their original condition, and this aquarium has been remarkable, not only as predecessor of the many public aquaria which have since been erected, but for having given rise to a movement in favour of aquaria as domestic establishments. The setting-up of household aquaria became almost the rage of the day, and so many books and magazine articles devoted to the subject appeared during the ten years following the establishment of the Regent’s Park aquarium, that the literature of the subject is quite considerable. Mr. Gosse showed how water for marine aquaria could be produced by adding to fresh water the solid constituents of sea-water; and, in the marine aquaria of some inland towns far distant from the sea, this artificial sea-water is the only kind used. After the establishment of the Regent’s Park aquarium, public aquaria were opened successively in Dublin, Galway, Edinburgh, Scarborough, Weymouth, the Crystal Palace, Brighton, Manchester, and Southport; and on the continent at Paris, Hamburg, Hanover, Boulogne, Havre, Brussels, Cologne, Vienna, and Naples; also in North America at San Francisco, and in other places. The general interest in public aquaria, and especially marine aquaria on the large scale, seemed to increase as the comparative failure of the domestic tanks lessened the taste for them. The causes of the failure so often attending the attempt to maintain aquaria on the small scale arise partly from the amateur naturalist’s want of exact knowledge, and the great amount of attention and care required, and partly from the inherent difficulties of the subject. An aquarium, even on the largest scale, and with every appliance that science can suggest, only represents, after all, _a few_ of the conditions which actually exist in nature; but in small vessels, with a limited quantity of water, without the continual motion of the liquid, which belongs naturally to seas and streams, and with circumstances of light and temperature widely different from those which are obtained in nature, it is not surprising that the success of domestic aquaria should be but very partial, and that the taste for them should have declined accordingly.

Many public aquaria proved commercial failures; but we select for special description two which have been thoroughly efficient, and are remarkable for size, reputation, and successful management. The arrangements at these two institutions as regards the aëration and renewal of the water are, however, quite different. Some plan by which the same sea-water might be supplied with oxygen, and kept in a clear and pure condition, was necessary for the very existence of the inland marine aquarium at the Crystal Palace, whereas the position of Brighton made the natural sea-water more available. The success of the former method at the Crystal Palace Aquarium, under the judicious system adopted by Mr. W. A. Lloyd, the superintendent, perhaps renders this aquarium one of the most interesting, in a scientific point of view, of any yet in operation. The water here is never changed by the addition of sea-water; but fresh water is added as required, simply to supply the loss by evaporation; and any solid constituents which the animals may abstract from the water as material for their shells is replaced, so that the ordinary composition of sea-water is maintained. This is merely imitating Nature, for the evaporation from the surface of the sea is compensated by the fall of rain and the influx of rivers, the latter constantly bringing in the various salts held in solution. The following particulars regarding the Crystal Palace Aquarium are derived from Mr. Lloyd’s excellent handbook, which contains not only clear descriptions of the inhabitants of the tanks, but interesting historical notices and a well-written disquisition on the principles which should regulate the construction and management of aquaria.

_THE CRYSTAL PALACE AQUARIUM._

The building was commenced in July, 1870, and was opened in August, 1871. It was designed by Mr. Driver, of Victoria Street, and presents an admirable simplicity, which entirely accords with the purpose for which it was erected. The whole available space has been occupied, and nothing has been wasted on unmeaning or fantastic embellishments. Even the decorative shams, in which ordinary painters delight, have been excluded. No part of the walls or of the woodwork is painted to look like marble, or even to imitate oak. The building, which is about 400 ft. long and 70 ft. broad, is situated at the north end of the Palace, partially occupying the site of the portion which was so unfortunately burnt down in 1866. It is but one storey high, and besides a large reservoir beneath the floor, holding 100,000 gallons of sea-water, there is a series of sixty tanks, with thick plate-glass fronts, which collectively contain 20,000 gallons of water. This water, weighing over 1,000,000 lbs., was brought from the coast and conveyed to the Palace by the Brighton Railway Company at a very moderate rate. For many weeks after the water was placed in the reservoir and tanks it was very turbid, from taking up the lime used in their construction and in that of the rockwork. In this condition it was very alkaline; but the lime was slowly precipitated by the carbonic acid of the air, the water became clear, and vegetation appeared in the tanks. The great capacity of the reservoir facilitates the cleansing of the water; for, supposing that the water in one of the tanks, holding, say, 6,000 gallons, became turbid from any cause, the water from this tank could be run off into the reservoir, where its mixture with the much larger quantity would not sensibly affect the purity of the mass, from which within half an hour the tank could again be filled.

All the tanks are constantly receiving water from the clear and cool reservoir below, in which there are no animals, so that the motion of the water in the tanks, like that of the ocean, is incessant. The water issues from the pump at a rate (indicated by a counter) of from 5,000 to 7,000 gallons per hour. The pump is worked by a steam engine of three horse-power, and the machinery requires the unremitting attention of three engineers, who succeed each other by turns, each working for eight hours. Two sets of the machinery—pumps, steam engines, and boilers—are provided, one being always kept in reserve, ready for use in case of any accident. Even in winter, when, from the lower temperature, the water contains the largest amount of oxygen, it is found that the stopping of the circulation of the water for only a few hours occasions manifest discomfort to some of the animals. The water is poured into the two centre tanks in an equally divided stream, and by a simple fall of a few inches from tank to tank it flows by two routes to the lowest tank, from which it passes into the reservoir below. This incessant circulation of the water constantly exposes fresh surfaces to the action of the air, by which oxygen is absorbed. But besides this, other small streams of water are made to forcibly enter the tanks from jets, by which a large quantity of air is carried down in very small bubbles. The removal of carbonic acid is accomplished by the vegetation which spontaneously makes its appearance in sea-water under suitable circumstances. It has been found quite unnecessary to introduce purposely any kind of sea-weeds, for the spores of low forms of vegetation are always present in the water, and they develop rapidly under the stimulus of light. Indeed, one of the difficulties of aquarium management is to avoid this excessive vegetation by limiting the light as much as possible, and yet leave sufficient illumination for the observation of the animals. The amount of light falling upon each tank is very carefully attended to at the Crystal Palace, and where it cannot be diminished sufficiently to check the overgrowth of vegetation, without at the same time interfering with a proper view of the animals, certain molluscs and fishes which live upon _algæ_ are put into the tanks to consume them. This spontaneous vegetation is so vigorous that a comparatively small quantity suffices to remove from the water all the carbonic acid which it may derive from the animals and decomposing matters.