The Book of the Aquarium/Part 2/Chapter 2
CHAPTER II.
FITTING UP—MATERIALS FOR THE BOTTOM.
Coarse sea sand and pebbles, all well washed, make the best bottom; but if sea sand is not to be conveniently obtained, common silver or gritty river sand will answer every purpose, if washed until they cease to stain the water. Most writers on aquaria—Mr. Gosse especially—condemn silver sand, but I find it a most suitable material: its appearance is cleanly, and it only requires frequent washing in fresh water to fit it for the purpose. In the water-pipe which runs along the wall to supply the kitchen, I have had a hole pierced to form a jet, and this I find of great service in many aquarian operations, and especially in washing sand and pebbles. Where this can be done conveniently, or where the pan containing the materials to be washed can be placed under a tap turned on so as to drip rapidly, the washing can be accomplished with very little trouble, and the materials can remain for a week or two, being stirred up occasionally to hasten the dissolution of solvent matters. The sand should have a depth of two or three inches on the floor of the vessel, and above it should be placed a layer of pebbles, also well washed. The little white pebbles found among gravel look bright and pretty, and if the aquarian is also a lover of the garden, he will turn up plenty of them in digging, so as to keep a supply at hand for use when wanted. The pebbles are not essential, but the sand is, because many of the creatures delight in burrowing, and must have opportunity afforded them of living their own life in a state of confinement.
Rock work is generally considered an essential of a marine tank, but experience has convinced me that the less we have of it the better. I have, in describing the fresh water tank, given instructions for its formation, and here desire only to caution the beginner to repress, as much as possible, any desire for mimic arches, caves, and grottos. In the first place, it must be remembered, that every cubic foot of rock work displaces a cubic foot of water, and reduces the capabilities of the tank for supporting a number of creatures. The more rock the less water, and the less water the fewer animals. Beside this, it is questionable if the use of cement of any kind is advisable; free lime may be expected to dissolve out of it, however much seasoning it may have previous to the introduction of the stock; and as marine creatures are more delicately constituted than fresh water ones, the subsequent loss of many may fairly be attributed to the presence of cement.
In the place of built-up arches, a few rough pieces of stone tastefully disposed at the bottom may be made to produce a good effect: a rough block of granite, or a stem of branching coral in the centre will be far preferable, except for vessels of large size, in which pyramids and arches may be less objectionable. It must be borne in mind, however, that rock work in some form or other is useful, as affording shelter and shade to such animals as love seclusion, and that, in a well managed tank, the rough blocks often get coated with a vegetable growth that increases the strength of the collection, and adds very much to its beauty. In this matter, the mischief arises out of the desire of beginners to display more ornament than is consistent with the nature of the case.
The water, of course, may be obtained direct from the sea, and should, if possible, be dipped in mid-channel. Shore water is not altogether objectionable, for where we find the greater part of our specimens it is evident the water must be suitable for them. In fact, I have found water that I have brought from the sea-side in jars serve just as well as that supplied by the steamer from the open sea; but near the mouth of a river it would be found unsuitable, as it would, also, from any parts of the coast where land springs abound. Earthenware vessels are the best for the conveyance of sea-water and specimens, but if a large quantity be required, a new cask should be used, and the greatest care taken to have it stopped with a new bung, and conveyed quickly to its destination. Mr. Gosse recommends a cask of fir-wood if it can be procured, “the wood of the oak, of which wine casks are usually made, gives out tannin or gallic acid to the contained water, which by its astringency, converts the animal integuments into leather.” In fact, our poor anemones get their hides tanned if any vegetable bitter comes into contact with the water in which they are to be kept. I make it a rule to filter sea water through charcoal before using it; this is not essential if the water appears bright, but is, at least, a precautionary process that may have its advantages.
Artificial Water is now used so extensively as to justify some special remarks here upon it. It must be understood that where real sea water can be easily obtained, as at spots near the coast, it is undoubtedly the best, though, in some respects, the artificial preparation is preferable, because less liable to certain eccentric changes of constitution, which will fall under our attention further on. Sea-water contains the spores of plants, and the germs of many forms of animal life which may have development in the tank, and when these births occur, it is a special gratification to the possessor. But such germs may also decay, and cause putrescence; and if a tank is neglected, the water is liable to get cloudy, the stones black, the sides of the vessel semi-opaque, and the animals diseased. Death soon sets his black seal on the undertaking when such a state of things occurs, and the collection, however costly or well formed at first, may be lost. Now such misfortunes as these are preventible, as it will be my duty to show presently, but I here call attention to the fact, that artificial sea-water is much less liable to get out of condition from the very absence of organic matter, which on first reflections, we should regard as a disadvantage. Thus, the prepared material has certain advantages over the natural; we lose the chance of rearing new additions to the stock through the introduction of minute organic germs; but incur no danger of those same germs perishing and polluting the bright lymph.
But artificial water is quite unsuited for animal life of any kind, until it has been brought into condition by means of growing weeds for eight or ten days, and for crustacea, star fishes, and fishes proper, it is not suitable till it has been in use for many months, and even then some species lose their health in it, and at last perish. But for anemones of all kinds, many mollusks and crustaceans, and some other forms to be presently described, artificial water does well, and improves daily if properly managed. Unless, therefore, the aquarian is bent upon domesticating the rarer and more delicate sea specimens, he may avail himself of the aid of the chemist, and manufacture sea-water from the river or the pump.
Composition of Marine Salts.—The limited space of this work will not enable me to enter upon the consideration of the chemistry of this question so fully as I have done in “Rustic Adornments;” nor, perhaps, is it necessary here to do more than point out the simplest method of procedure. There are at least seven ingredients besides water, used in the natural laboratory, but the chemist dispenses with some of these, and finds every purpose served by using a selection of the chief of them. The composition of sea water is as follows:—
|
0,964.744 | ||
|
0,027.059 | ||
|
0,003.666 | ||
|
0,000.765 | ||
|
0,000.029 | ||
|
0,002.295 | ||
|
0,001.407 | ||
|
0,000.033 | ||
|
0,000.002 | ||
| 1,000.000 |
Mr. Gosse, in July 1854, communicated to the “Magazine of Natural History” the results of experiments in the imitation of this composition, and a formula for the artificial preparation of sea-water. In the fictitious preparation the component salts were reduced to four, so that no less than three of the original ingredients were dispensed with. If the reader will note in what minute quantities the bromide of magnesium, the sulphate and carbonate of lime occur, and at the same time bear in mind that river and spring waters always contain a considerable proportion of the last-mentioned ingredient, it will be easily understood that the absence of those materials in the preparation does not materially affect its value. The preparation on Mr. Gosse’s plan is composed as follows:—
Common Table Salt |
3½ ounces. |
Epsom Salts |
0¼ ounces.„ |
Chloride of Magnesium |
Chloride of Potassium |
The recipe may be given in another form to avoid the perplexity of avoirdupoise and troy weights, thus:—
Common Salt |
Epsom Salts |
Chloride of Magnesium |
Chloride of Potassium |
Management of Artificial Water.—When the salts are ready, it is best to mix them in an earthern pan or jar, and allow them to settle and refine for a day or two. To dissolve them in the tank is decidedly a bad plan, though it is daily recommended by the dealers. Any one who will dissolve a portion in a clean bell glass, and allow it to stand for a week, using the clearest water, and adding nothing but the salts, will observe, at the end of that time, a minute gritty deposit, similar to iron rust, mixed with minute fragments of sand. This deposit proves that the chemicals we obtain are not pure; and, perhaps, it is not desirable that excessive purity should be obtained, but it certainly is desirable to keep such matters out of the tank. When the salts have been stirred up once or twice, so as to dissolve them thoroughly, test them for the last time with the hydrometer, till it registers 1.027 or thereabouts; it may safely range from 1.026 to 1.028 without interfering with the success of the experiment. Hydrometers, registered for sea-water, are not everywhere obtainable, and the specific gravity-bulb, sold by Mr. Lloyd, for a shilling, answers the purpose just as well. Mr. Cox, of 100, Newgate Street, has lately supplied me with an hydrometer of a register of 1.000 to 1.050, made in Paris—the cost was seven shillings. I prefer it to the bulb because it can be put to other uses.
A Caution to the Uninitiated.—Some beginners have attempted the preservation of marine specimens in solutions of common bay-salt, and have expressed surprise that they perish rapidly in a solution of salt obtained from the sea. Anyone at all acquainted with chemistry would readily predict, that there could be no more certain way of killing the creatures than the adoption of such a plan of preserving them. When bay-salt is prepared, many of the more soluble materials, chloride of magnesium especially, remain behind in the mother liquor, because the chloride of sodium crystallizes first, hence bay-salt alone does not produce sea-water; we must have the aid of the experienced chemist, or turn chemists and prepare it for ourselves.
Those not experienced in chemical manipulations may find some difficulty in obtaining and weighing accurately the several ingredients; and I should advise them to purchase the preparation sold by Mr. Bolton, of 146, Holborn Bars. This merely requires to be dissolved according to the instructions just given. Mr. Bolton has given minute attention to the preparation of the salts, and is now improving them by compounding with them the minute quantities of the more subtle ingredients, which were originally omitted by Mr. Gosse. The salts are sold in packets, at the rate of three gallons for a shilling; a price which must be considered reasonable when we consider the purity of the article, and the care taken in its manufacture.
Filtering.—When the salts are well mingled with the water, pass the liquid, through a filter, into the tank, which is supposed to have been already well-seasoned, and furished with a bottom of sand and pebbles, and any ornaments that may be deemed necessary. A bee glass, with a bit of sponge thrust into the orifice, is a convenient form of filter, but if such a thing is not at hand, take an old flower pot, and wash it quite clean, thrust a piece of sponge through the hole in the bottom, and throw into it a handful of powdered charcoal. This may be suspended above the tank, or stood on two slips of wood, and filled from time to time, till the whole of the water has been passed through it.
Some healthy plants of Ulva latissima and Enteromorpha compressa are now to be introduced, and the whole left undisturbed for at least a week or ten days, when the stocking with animal life may commence; some of the hardy Actinia being the best of all to start with. But if the aquarian is in a fever to see something alive in the new vessel, he may drop in half-a-dozen Actinia mesembryanthemum, one day after the introduction of the plants, and unless he has made some mistake in the preliminaries
ACTINIA MESEMBRYANTHEMUM, DYCTYOTA DYCHOTOMA.
they will do well. I have, for the sake of gaining information, placed this anemone in water the instant it was prepared, and without filtering it, without suffering the loss of one; indeed, I have some by me now which a year ago were so operated on; they attached themselves directly, and lived through all the trials incident to a new tank, in which there was not a single drop of natural sea water. Mr. Hall tells me he has, on emergencies, kept them alive for a week in soap-suds, and even in more offensive liquids; and judging by the life the creature leads on the sea shore, now submerged in the cool waters, and now exposed to the burning sun, it is not at all surprising that it has a hardy constitution. Still, this hasty proceeding is not to be recommended; let time develop the powers of the water, let the solar light reach the plants through the green medium of the stained glass, and soon a lovely beading of oxygen bubbles will appear, to indicate that all is right, and then the animals may follow each other in proper order to their domestic home.
If a little real sea-water, even a pint or two, can be obtained to mix with the artificial, the ripening of the latter will be considerably hastened, but it is an interesting fact in the chemistry of the aquarium that, though in the first preparation of sea-water certain of the ingredients are left out of the prescription, in process of time those very same ingredients are to be discovered in it by means of analysis. How do they get there? They are communicated to it by the vegetation, and hence as the water acquires age, like good wine, it increases in strength, and after some months use, will maintain creatures in health that would perish in a day in water recently prepared.
The preparation costs, when prepared from ingredients bought at wholesale price, about three-pence a gallon; but it is a much better plan to purchase it ready prepared, the price then being only four-pence per gallon, or a three gallon packet for one shilling.