CHAPTER III.THE AQUARIUM.

The successful treatment of aquatic plants and animals, in the confined space of a glass Aquarium, depends entirely upon the discovery that there exists in Nature a self-adjusting balance between the supply of oxygen created in water, with the quantity consumed by aquatic animals. And it became equally necessary to know the means by which that supply was continually generated. Without the knowledge of these facts, and the principles by which they are regulated, it would have been impossible to establish such a marine Aquarium as that we may now any day examine in the Regent’s Park; where, in a few glass tanks of very moderate size, we may see examples of some of the most curious forms of animal and vegetable life peculiar to the depths of the ocean—forms so singular, that their first exhibition created a sense of wonder little less intense than that which must have been caused, long years ago, by the first public display of the mountain form of the elephant to thepeople of cold northern countries; and much more so than the recent introduction of the giraffe or hippopotamus, although they have never been seen in Europe since the days of the Romans.

Those principles, the knowledge of which was requisite to enable us thus to view the wonders of the ocean in their living state in an Aquarium, were not mastered at once, or by one man, or in one generation. The nature of certain relations between animal and vegetable life, upon which they are founded, was first advanced by Priestley, towards the close of the last century, who proved that plants give forth the oxygen necessary to animal life. The learned Ingenhauss, a native of Breda, but who principally resided in England, defined this principle still more clearly, in a work the title of which pretty fully explains the entire nature of his discovery. It was published in French, at Leyden, in 1778, and in London, in English, in 1779. The French edition is before me, the title of which I translate, “Experiments upon Plants, which prove their important influence in the purification of the atmospheric air when they are exposed to the rays of the sun, and the contrary results which ensue when they are placed in the shade, or during the night.” The action of the sun’s rays in disengagingthe oxygen generated in plants is thus clearly announced, and the knowledge of this principle is one of those which have mainly conduced, as I have said, to the successful establishment of Aquaria.

In the course of his essay Ingenhauss states, still more directly, that plants “immersed in water,” when exposed to the action of light, emit an air which he announces as oxygen gas; and this idea is the key-stone of the Aquarium.

But, although the discovery of Ingenhauss at once rendered the thing practicable, Aquaria did not then come into fashion. The science of natural history was not at that time sufficiently advanced; for the specimens, even in public museums, were merely heterogeneous collections, assembled without the slightest regard to classification, or any other useful purpose. A stuffed cat with nine legs, stood, perhaps, next to a bottled snake, followed by the skin of a crocodile, to be succeeded in turn by a very moth-eaten specimen of a King Charles spaniel, “supposed, upon good authority, to have belonged to Nell Gwynne.” A few scores of such objects, with the addition of an ostrich egg and a few sea-shells, without any attempt at name or description, formed a very respectable museum in those times; and we may, therefore, easily conceivethat (in so far as experiments illustrative of natural science were concerned) the suggestions of Ingenhauss remained tolerably dormant.

It was not till the year 1833, that Professor Daubeny communicated, to the British Association at Cambridge, a paper concerning some new researches prosecuted in the same direction; and not till 1837, that Mr. Ward became the first to apply the principle to any purpose analogous to that of the Aquarium. In that year he made a report to the British Association, on the hermetically closed glass cases in which he had succeeded in growing many classes of plants, and keeping them in a healthy state without any fresh supply of air. He stated, at the same time, his belief that certain classes of animals would live and thrive under similar circumstances. This was the first direct hint towards the formation of a closed Vivarium, whether atmospheric or aquatic.

In 1842, Dr. Johnston satisfactorily proved the true vegetable nature ofCorallinesby observing their growth in a vessel containing sea-water; and thus was established the first true Aquarium. With the experimental tuft ofCorallinewas a small frond of a greenUlva, and numerousRissoæ, &c., and severalAnnelidsafterwards appeared, having been,no doubt, attached to the branches of theCoralline, or the fronds of theUlva. At the end of four weeks the water was still pure, the Molluscs and other animals alive, and the Confervæ grown; theCorallinehaving thrown out several additional articulations. After eight weeks, the water still remained sweet. But had any animal, of even the lowest order, been so confined, without the accompanying presence of vegetables giving off oxygen, all of that vital gas contained in so small a quantity of water would have been quickly exhausted, and the water would have become corrupt, ammoniacal, and poisonous to the life of any living thing. But the author of this experiment had not in view the testing of the possibility of preserving the forms of ocean life in a healthy state in confinement; his business had been to settle an important point connected with the classification of theCorallines; and having successfully decided that question, the embryo Aquarium was abandoned.

On the 4th of June, 1850, Mr. R. Warrington communicated to the Chemical Society a series of observations on the adjustment of certain relations between the animal and vegetable kingdoms, very important to our present purpose. Two small gold-fish were placed in a glass receiver, a small plant ofValisneria spiralisbeing planted at the same time in some earth, beneath a layer of sand in the same vessel. All went on well by this arrangement, without any necessity for changing the water; the oxygen given off by the plant proving itself sufficient for the supply of its animal co-tenants, and the water therefore remaining clean and pure, until some decaying leaves of theValisneriacaused turbidity, and confervoid growth began to accumulate on the sides of the vessel. To remedy this evil, Mr. Warrington brought to bear the results of previous observations on water in natural ponds under analogous circumstances; and, guided by these observations and their results, he placed a few common pond-snails in the vessel containing his gold-fish and plant ofValisneria.

The new inmates, immediately upon their introduction, began to feed greedily upon the decaying vegetable matter, and all was quickly restored to a healthy state. They proved, indeed, of still further advantage, for the masses of eggs which they deposited evidently presented a kind of food natural to the fishes, which was eagerly devoured by them, so that the snails became not only the scavengers, but also the feeders of the little colony. And so this first of true Aquaria prospered; the animals andplants proving of mutual value and support to each other. The snails disposed of the decaying leaves, which would have tainted the water and rendered it unfit for the healthy existence of the plant, and the plant in turn gave forth, under the rays of sunlight, the supply of oxygen necessary to both fish and snails.

In January, 1852, Mr. Warrington, commenced a series of similar experiments with sea-water; which were, at first, not so satisfactory, but in the end proved as entirely successful. In the course of his experiments, he found the red and brownAlgæ, or sea-weed, less proper for the formation of oxygen than the green. Of the latter class he procured specimens ofEnteromorphaandUlva latissima, which he chiselled from the rocks about Broadstairs, along with the pieces of chalk or flint to which they were attached; and, when he placed them in his own marine Aquarium, he put in along with them, to represent the pond-snails in the fresh-water tank, some of the common sea-snail, better known as the Periwinkle (Littorina littorea). But these proved, it appears, insufficient for the destruction of the mucous and gelatinous matter that arose from the decay of the red sea-weeds, which, however, I have no doubt may yet be cultivated withequal success with the green, as I shall state when describing them. Under the existing difficulty, Mr. Warrington found it necessary to aerate the water by other means, many processes being equally available; such as injecting fresh-water from a syringe, or establishing a drip, of some height, from a vessel containing a supply of entirely fresh-water. Mr. Warrington also discovered, in the course of these experiments, the necessity that the light should pass directly through the surface of the water to the plants, as in natural ponds and seas—a very important step in the successful management of Aquaria; and he therefore had a slab of slate adjusted to the side of his tank which stood next to the light.

These successful experiments, both in fresh-water and marine Aquaria, assign to Mr. Warrington, beyond dispute, the credit of being the originator, or inventor, if the term may be so used, of these charming additions to our conservatories, corridors, and even living-rooms, to which they are certainly a much more attractive and instructive addition than the old globe of blank water, with its pair of gold-fish swimming round and round in ceaseless gyrations, tiresome to behold, in the vain hope of escaping from their glaring and inconvenient prison;in which they would inevitably have perished very shortly but for the daily change of water, which, previous to our knowledge of air-emitting plants and their use, was absolutely necessary.

But another experimentalist was now in the field. Mr. Gosse, whose charming works upon Aquaria and other subjects connected with natural science, have, perhaps, made his name more widely known than that of his predecessor, Mr. Warrington, commenced a series of experiments on the subject of the marine Aquarium, about the same time as the last-named gentleman, in the beginning of January, 1852. His experiments were crowned with such complete success that he was induced to put himself in communication with Mr. David Mitchell, the enterprising Secretary of the Zoological Society, the result of which was the removal of the collection ofAnnelidsandZoöphyteswhich Mr. Gosse had formed, to the gardens of the Society in the Regent’s Park; where it formed the nucleus from which has grown the magnificent series of Aquaria in the building constructed specially for their reception. These marine Aquaria at once became a subject of public as well as private interest, and the Aquarium house was so crowded daily with its curious visitors, that it was difficult to get a glimpse of thewonders of the “ocean floor,” and its zoöphytic denizens, which were so successfully exhibited there; principally through the skilful aid and untiring industry of Mr. Gosse, through whose hands above five thousand specimens passed at the time, collected at the request of the Zoological Society.

In his interesting record of his early essays, Mr. Gosse gives us many valuable particulars concerning his successive experiments, and the various disappointments to which he was at first subjected; many of them from causes now too well understood to require repetition. His principal difficulty arose from over-crowding, although his tank did not appear, as he states, too much filled. Another disappointment was caused by putting in animals before the smell of the putty, with which the glass sides were fixed, had sufficiently gone off.

Mr. Gosse’s tank was made with a slate bottom, and birch pillars, in which were grooves to receive the glass; and its dimensions were, two feet long by one foot six wide, the depth not being mentioned.

Taking these dimensions into consideration, it will be easy to conceive, when the following list of specimens which Mr. Gosse introduced into his Aquarium is examined, that his population was too dense for the extent of his province, although thespace might not have appeared too much filled for picturesque effect. Of vegetable specimens, he introduced at once the following:—

1. A tuft ofFurcellaria fastigiata.2. Two ofRhodymenia palmata.3. One ofDictyota dichotoma.4. A smallFucus serratus.5. OneLaminaria digitata.6. Two tufts ofPadina pavonia.7. Several masses ofCorallina officinalis.8.Griffithsia setacea.9.Delesseria alata.10.Plocamium coccineum.11.Phylophora rubens.12.Zostera marina.

1. A tuft ofFurcellaria fastigiata.

2. Two ofRhodymenia palmata.

3. One ofDictyota dichotoma.

4. A smallFucus serratus.

5. OneLaminaria digitata.

6. Two tufts ofPadina pavonia.

7. Several masses ofCorallina officinalis.

8.Griffithsia setacea.

9.Delesseria alata.

10.Plocamium coccineum.

11.Phylophora rubens.

12.Zostera marina.

In a few days the water, poured carefully to these specimens, became clear as pale green crystal, the green tinge being too slight to obscure the colour of any object seen through its medium.

From these weeds alone, before any supply of Zoöphytes or Molluscs were intentionally added, a whole host of minute animal life swarmed forth; some, doubtless, issuing from eggs newly hatched; others from the shelter of the matted ramifications of some of the sea-weeds, in which they had been taken, as in a net. Among these swarming creatures were Annelids of the genusSyllis,Rissoæ, and other minute shell-fish, but principallyIsopodousandEntomostracous Crustacea, many of them being so minute as not to be perceived without the use of a powerful lens.

Of the animals next placed in this tank, of only two feet by one foot six inches, the following is the list given:—

There were thus above seventy specimens, animal and vegetable, already in the tank, without counting the swarms of smaller creatures, some the young of large species, daily increasing in size; yet, our bold experimentalist, anxious to conquer his “Russia” at one grand invasion, still poured in fresh specimens. These consisted of:—

These additions brought the collection up to above a hundred specimens, and no doubt the tank made a glorious show; but Mr. Gosse, though the Napoleon of his specialty, was forced to acknowledge that there was an “impossible.” Although his collection was superb, and his interesting tank did not look over-crowded, yet he soon discovered that a forbidden limit had been passed, and that the creatures of the ocean that have yards—fathoms—of their native element to their own separate share, cannot accommodate themselves to the allotment system, in the proportion of a square inch to each individual.

To remedy this state of things, the evil effects of which soon became apparent, artificial aeration was resorted to, by means of another vessel, which kept up a continuous supply of dripping fresh water. But even this assistance did not enable the crowded colony to exist more than ten days. In the first place, there were many predatory species, which destroyed their associates; these kinds must, therefore, be excluded from an Aquarium, or kept in aseparate tank. But, after all, the impossibility of providing a sufficient supply of oxygen was evidently the great and principal cause of failure. The Univalves and smaller Crustacea disappeared first, a disagreeable smell giving intimation that decay was going on, the creatures that had perished having, many of them, died in concealment, under the stones, weeds, &c., at the bottom of the Aquarium. The first signs of unpleasant effluvia rising from the tank must, therefore, be carefully attended to; and, in such cases, the Aquarium ought to be immediately searched for the cause; which, when discovered, should be immediately removed.

Plate XI.A DESIGN FOR A PLAINLY-MOUNTED AQUARIUM.

Mr. Gosse having taken out the whole of the specimens, dead and alive, and carefully cleansed the tank, a much smaller number was put in, which, being well selected, and having sufficient space, throve abundantly well; and the ingenious experimentalist was at last amply rewarded for all his persevering exertions. This result benefited others as well as himself, for a general taste suddenly arose for this kind of pursuit, among all who read the various works which soon appeared on the subject; and, to gratify the new taste, a host of dealersin Aquaria have sprung up, who are driving a brisk and profitable trade.

The first experiments of Mr. Gosse sufficiently point out the kind of cautions to be observed in the formation of a marine Aquarium. The vessel itself may be either quite plain in its frame-work, as shown inPlate XI., or made more or less ornamental, to assimilate, if necessary, with surrounding objects or furniture. The rustic style of frame, designed inPlate XII., has been found to accord well with the general character of the Aquarium itself, and it produces an agreeable contrast with the usual forms of the furniture of our ordinary sitting-rooms.

Plate XII.A DESIGN FOR AN AQUARIUM MOUNTED IN HANDSOME RUSTIC-WORK.

Those made by the dealers are generally formed with slate floors and backs, and zinc columns and mountings; the smallest and most simple, about fifteen inches long by ten inches broad, costing from a guinea to twenty-five shillings, and those of the proportion of two feet by one foot six costing from two pounds ten to three pounds. A small syphon will be useful, in order to remove a portion of the water, if required, without disturbance; and also a syringe, in order to aerate the water when necessary, if a second reservoir of fresh-water, ina suitable position, should not be convenient. A miniature landing-net is also useful for the removal of decaying matter, or occasionally the living specimens when any change may be required.

A layer of sand and pebbles, about three inches deep, placed upon the slate flooring, is the first step towards arranging the interior of the tank. Upon this beginning, removing the sand and stones in places to procure a firm basis, the rock-work may be built; which should be picturesque and fanciful in character, as partially suggested in the two Plates, leaving miniature archways and caves for the shelter of such creatures as shun the light, either constantly or occasionally. Such a disposition of the rock imparts, at the same time, many pleasing effects to the pictorial composition. These matters are not, however, much attended to by dealers, whose arrangements of the Aquaria they offer for sale are generally tasteless enough. But that is perhaps all the better, as it entails upon the amateur the necessity of providing his own taste, which is at all times both a useful and pleasant effort of mind, and which, moreover, leaves, after each period of exertion, a permanent trace of an increased refinement which influences the whole character.

In the distribution of the rocks, I would always allow at least one point to project above the water, in order to afford the opportunity to those animals whose instincts lead them to seek occasional exposure to the air, the means of gratifying it by that contrivance. I have thought, indeed, of constructing a kind of double Aquarium, and perfecting a contrivance by means of which a large portion of water should flow gradually from one tank to the other at fixed periods, in imitation of the ebb and flow of the tide. Many interesting phenomena would be exhibited in this manner, such as the closing of theActiniæas the water receded, and their expansion as it covered them on its return. This alternation, too, might be found highly advantageous to the health and development of the animals whose natural habitat lies between high and low water-mark, and whose constitution is therefore framed to require entire or partial exposure to the air at certain intervals of time. I also prefer, as preserving a similar set of analogies, a sloping bottom, similar to that of the coast. For instance, if the slate back of the Aquarium be placed next the light, which is its proper position, as the light ought to penetrate the water entirely through its upper or horizontal surface, then Iwould fill the side next the slate back nearly to the top with pieces of rock, gradually reducing their height, till, at the other side, they should hardly rise above the floor of sand and pebbles, leaving, at last, a flat portion of the pebbly or sandy bottom quite level.

When this form of rock-work is decided upon, the Aquarium should be of rather wider proportions than usual, in order to allow of the slope being pretty gradual. Supposing the tank to fill entirely the recess of a spare window, which is a position in which it looks exceedingly well, a solid slate back may be found to darken the vessel or the room too much; in such a case, a glass back must be preferred, which can be shaded from the direct influence of the light by a blue or green shade of calico neatly fitted to the frame; and it must be borne in mind, as essential, that the Aquarium must be so placed as to receive the direct rays of light during some part of the day, being screened by a white blind when the sun may be too powerful; as should the water becometepid, it would be fatal to many of the inhabitants of the miniature sea.

With due observance of these precautions, the amateur may hope to frame and establish anAquarium in a suitable form, and in a suitable position for the reception of its inmates; an account of which, and of the manner of their introduction, will form the subject of the ensuing chapters.

Back to Index Next