NOTICES TO CORRESPONDENTS.

ALL communications relative to advertisements, post-office orders, and orders for the supply of this Journal should be addressed to the PUBLISHER. All contributions, books, and pamphlets for the EDITOR should be sent to 192, Piccadilly, London, W. To avoid disappointment, contri. butions should not be received later than the 15th of each month. No notice whatever can be taken of communications which do not contain the name and address of the writer, not necessarily for publication, if desired to be withheld. We do not undertake to answer any queries not specially connected with Natural History, in accordance with our acceptance of that term; nor can we answer queries which might be solved by the correspondent by an appeal to any elementary book on the subject. We are always prepared to accept queries of a critical nature, and to publish the replies, provided some of our readers, besides the querist, are likely to be interested in them. We cannot undertake to return rejected manuscripts unless sufficient stamps are enclosed to cover the return postage. Neither can we promise to refer to or return any manuscript after one month from the date of its receipt. All microscopical drawings intended for publication should have annexed thereto the powers employed, or the extent of enlargement indicated in diameters (thus-X 320 diameters). Communications intended for publication should be written on one side of the paper only, and all scientific names, and names of places and individuals should be as legible as possible. Wherever scientific names or technicalities are employed, it is hoped that the common names will accompany them. Lists or tables are inadmissible under any circumstances. Those of the popular names of British plants and animals are retained and registered for publication when sufficiently complete for that purpose, in whatever form may then be decided upon. ADDRESS No. 192, PICCADILLY, LONDON, W.

A. B. M.-" Atlas of British Seaweeds," price three guineas, published by Reeve & Co., Henrietta Street, Covent Garden.

J. B. H.-M. P.-Forwarded to the Publisher, for whom they were designed.

CIRCULATING CABINET.-Any microscopist in the neighbourhood of Manchester wishing to join should communicate with Mr. T. Armstrong, Deansgate, Manchester.

W. B. (Hadleigh).-See our notice respecting assumed names, &c. "The Cream of Scientific Knowledge" is pub lished by Tegg, price three shillings. The "Year Book of Facts" is published annually.

BATS. Several correspondents have called our attention to the fact of bats being seen on the wing during January and February this year.

J. E. T.-The cheapest book is Stark's "British Mosses," published by Routledge; but it does not include all the British species.

E. C. J.-Tate's "British Slugs and Snails," is published by Robert Hardwicke, 192, Piccadilly, London.

A. D. M.-You had better communicate with the Secretary of the Society of Amateur Botanists, 192, Piccadilly.

C. A. J.-Any number of instances of small tortoise-shell butterflies during the present winter.

I. M.-We really cannot furnish you with any reference to directions for constructing a shell cabinet.

J. S. M.-Your conferva appears to be Cladophora glomerata.

G. J. P.-The larva of a beetle, probably. If you catch one and rear it, then send us the beetle, perhaps we could tell you the name.

G. 8. B.-We have advisedly discontinued giving notices of Field Clubs. When we inserted them, very few local secretaries availed themselves of the opportunity; and now we think that we can supply matter of more general interest to our readers. At least, we hope so.

J. C. and S. J. M.-With thanks. We think that one answer will satisfy our querist; and space is precious.

J. W. R.-Yes. It is red when in fruit.

G. E. B.-Your specimen is Nostoc commune.-Vauch.

F. R. S.-Your plants were not numbered; but, according to the order in which they were placed,-No. 2, Anucharis alsinastrum; No. 3, Callitriche autumnalis; No. 4, Ranunculus aquatilis-No. 1 not in a condition to be correctly determined.-W.C.

G. E. A.-Most probably you can obtain Theine of Mr. Squire, operative chemist, Oxford Street, London.

A CONSTANT READER.-We regret to have occasion again to call attention to the announcement, so often made, that we can take no notice whatever of anonymous communications.

E. S.-It is imposible to identify a fern from a rough sketch, without any details of fructification.

J. H., E. A.-Unavoidably postponed for want of space. Will appear in No. 16.

A. F. (Roundhay).-Not uncommon for Vorticella to attach themselves to Cyclops, which the latter strive to rid themselves of in vain. We have often observed it.-T. K. M. P.-Chlorococcum and Diatomacea are Algæ, though belonging to different sections.

H. G. G.-Your flower belongs to Aronicum scorpioides. A. R. We have not yet been able to obtain a satisfactory explanation of the dendritic spots on paper.

L. N. R.-See Tate's "British Slugs and Snails," pp. 90-91. We do not remember such a list as you desire. Y. Y.-Beyond our province.

E. B. We have met with no one able to identify the Rotifer from your sketch.

R. B.-Such monstrosities in roses are common.

EXCHANGES.

FORAMINIFEROUS SAND.-Address A. T., 52, Bury New Road, Manchester.

FOREIGN MARINE SHELLS offered in exchange for land or freshwater species.-E. C. J., Eldon Villa, Redland, Bristol. FOSSIL FERNs for other fossils.-R. J. J., Howard House, Harrow-on-the-Hill.

DIATOMACEOUS EARTH from Algiers and Barbadoes.J. W. Leakey, 3, Prince of Wales's Avenue, Malden-road, Haverstock-hill.

BUFFALO HORN (sections) for objects of interest.-W. H. R., Post Office, Aberdeen.

CHLOROPS tarsata and its parasite.-Discipulus, School House, Mulbarton, Norwich.

ECHINUS SPINES wanted in exchange.-T. H. M., 78, Weekstreet, Maidstone.

COMMUNICATIONS RECEIVED.-M. H. P.-S. S.-H. G.R. G.-J. C.-B. B. B.-T. P. B.-W. J. K.-T. K. M.W. H. G.-G. F. S.-J. E. T.-J. A.-S. J. M. I.-S. W.H. E. W.-K. D.-A. M.-J. C. (Ulceby).—I. M.-C. A. J.— B. S.-A. F. W. B.-J. M. H.-W. L. S.-E. C. J.-D.-G. S. B. -E. T. S.-W. S. G.-M. P.-J. B. H.-W. G.-G. T. P.— J. W. L.-J. S.-C. N.-J. W. R.-H. A. A.-G. W. G.E. P. (Luton).-W. N.-J. S. (West Cramlington).-J. R.R. G. M.-H. H.-J. B.-T. F. W.-E. J. S. C.-J. E. T.P. P.-G. S.-J. F. Y.-J. A.-W. A. L.-W. H.-A. J. N. M.W. F. P.-R. B.-Y. Y.-P. S. B.-G. E. Q.-W. R.T.-H. J.B. -F. W.-L. N. R.-C. D.-A. B. M.-E. M.-A. T.-B.— J. S. M.-M. P.-L. N.-J. H.-E. L.-P.V.-E. A. (Norwich). -R. S.-T. W. W.-R. E. D.-J. B. (Langhorne).-G. H. LOCAL NAMES.-A. M.-R. E. D.

BOOKS RECEIVED.

"The Popular Magazine of Anthropology." January, 1866. London, Trübner & Co.

"A Plain and Easy Account of the British Slugs and Suails." By Ralph Tate, F.G.S., &c. London, Robert

Hardwicke.

YE! and before winter has quite passed away, we repeat the line, so oft repeated, that it would long since have been worn threadbare, had it not recorded a truth which never grows old, and thus proves its own veracity. It has been said, that if one should repeat ever such an absurdity to a man every morning before breakfast, he is would come to believe in it

at last. Yet there is no absurdity in the creed, that the beautiful is a never-failing source of pleasure, which Keats has told in a line as terse and beautiful as the sentiment it conveys, whilst many act as though they believed it not. Inquire of your own heart what is its greatest joy, what gives it the most unmistakable thrill of pleasure, what vibrates most deeply to its core, and it will be confessed that the power dwells in some small deed or thought which verifies the maxim, that "a thing of beauty is a joy for ever."

If in some deed done or accepted, in some kind word heard or spoken, the power is felt, or the echo recognized, through the long vista of years, how much more is the mind affected through the medium of the eye with the influences of beauty. It matters not that taste varies, and that the standard is not one of weight and measure; to him who recognizes beauty it becomes the joy which is unknown to those who fail to see or appreciate it. We will but advert to the scenes of boyhood, or even of maturity, that have left their impress photographed upon the memory, though not revisited since-scenes which are always recalled with delight, and associated with friendships and affections, not unmingled, perhaps, No. 16.

with a sigh; yet deeper than that lurks the truism, that "a thing of beauty is a joy for ever."

The song of the nightingale, the lark, and the linnet, has doubtless been the same for thousands of years.

The swan that on St. Mary's lake
Floats double,-swan and shadow,

glides as gracefully as on the rivers that ran through the garden of Eden. The wagtail bobbing about the puddle by the road-side still jerks his caudal appendage as vigorously as of yore. The swallow skims the surface of the brook, or sails mid-air with the same fairy-like motion as when Solomon ruled and Homer sang. Yet these have all the same charm for the lover of Nature now as they had thousands of years ago. Whether in the poetry of motion or melody, the influence is unimpaired, and prince or peasant still pauses at the sight or sound, and acknowledges by silence that " a thing of beauty is a joy for ever."

If we descend in the scale of existence, and recall to mind the notable things of insect life, those only which are known to every schoolboy need be cited on our behalf. The peacock butterfly, with his gorgeous wings expanded in the sun; the more modestly-tinted fritillaries, or the little "chalk blue," are beauties which the untutored mind recognizes, and the uncouth boor admires; dragonflies with their gauzy wings, and beetles with their drowsy hum; those favourites of childhood, the ladybird and the grasshopper; the spider, imitating in tints the flower in which it conceals itself; the lace-wing, iridescent in the sun-light; the myriads of ephemera that flit like phantoms into the dusk ; these are all eloquent preachers from the same text:-"A thing of beauty is a joy for ever."

When Mungo Park gathered his little tuft of moss in Africa, far away from home and friends; when a "roving Englishman" in America clapped his hands with delight to see a daisy cherished in a conservatory; when Dr. Hooker in India welcomed the shepherd's purse;-it was the association of

E

these plants with British soil and home affections that caused the thrill of delight. But, if not so much in these, yet in many others, there are beauties which linger about the tender petals, and which communicate sensations of pleasure to those who gaze upon them. Whence comes the love for flowers if not from the pleasure of looking at them and inhaling their odours? The poor city weaver, with his primrose in a broken teapot, cherishes it as he would a sickly child, and loves it because it babbles to him of green fields, and because of its own green leaves, and modest flowers, and sweet odours. There may be some who find a joy in gazing on birds, or butterflies, or beetles, but far more universal than all is the love for flowers. The little blue forget-me-not, the scarlet pimpernel, the yellow buttercup, the fairy-like harebell, the silver stitchwort, the golden tormentil, the fragrant woodruff, the purple loosestrife, the virgin lily,-"They toil not, neither do they spin, yet Solomon in all his glory was not arrayed like one of these." Whether the wanderer passes through woodland or over moor, scrambles along the mountain side, or saunters by the brook in the valley, at every step he will encounter some floral apostle, that even when brushed aside or trodden upon, will whisper to his listless ear," A thing of beauty is a joy for ever."

There is another world of beauty as yet but half revealed. It is a paradise to which man has but lately possessed the key, and into which thousands have never yet glanced an eye. If the visible world has such beauties which enchant the unaided eye and entrance the senses, how much more is there which had never entered into the mind of man to conceive, in that invisible region to which the eye alone could never penetrate, but which the microscope has revealed. The thousand forms of delicate tracery on the frustules of Diatoms, the elegant variety of garniture in Desmids, the mysteries and marvels of insect structure,-feet, antennæ, scales: everywhere, everything-even a drop of stagnant water, re-echo the truism which trembles in every leaf, and nestles in every flower, that "a thing of beauty is a joy for ever."

If we would derive from such sources all the wealth of pleasure which they are capable of yielding, we must be content to relinquish our own individuality, to forget all that relates to "self," and become absorbed into Nature as part of her, to pursue the investigation of her riches without a feeling of cupidity, to catch her spirit, to inquire of her concerning the hidden mysteries of life, not out of mere curiosity, but as a means of understanding her better, and then we shall find ourselves meekly and submissively receiving the lessons which she has to impart, gathering her riches, and bending in homage beneath the hand of Him

That sets a sun amidst the firmament,

Or moulds a dewdrop, and lights up its gem.

THE

AQUARIUM HISTORY.

THE early editions of Mr. N. B. Ward's book on the growth of (terrestrial) plants in closelyglazed cases, contain a supplement treating on aquarium matters; and it is there stated that in a work on the Microscope and Microscopic Objects, written and published in German by Martin Frobenius Ledermüller, a hundred years ago, there is a representation of an aquarium with plants and animals in it, and with the vegetation shown in the act of developing visible bubbles of oxygen under the stimulus of light, the animals being thereby maintained in a state of health. I am obliged to quote from memory, as I cannot procure an early edition of Mr. Ward's book, and later editions do not contain the supplement in question; but I believe I am substantially correct in thus reproducing the statement. However, there is nothing of the kind named or hinted at in Ledermüller's work, a copy of which, in three volumes, quarto, dated 1760-61-62, is now before me.

The representation alluded to is no doubt the one contained in plate 87, vol. ii., and described at length in pages 170 to 174 of the same volume. The vase-shaped glass vessel is shown about three inches high, being about one-third of its real size; it is half full of clear water, with some plants of Equisetum (Water Horse-tail); some Lemna (Duck-weed); and some fresh-water Polyzoa-most likely Alcyonella stagnorum,-with their tentacles expanded. The whole thing looks marvellously like a small aquarium of our day, and it is made to seem still more so from the plate being coloured; but the text does not give one word, nor yet anything which may be construed into the most remote implication that Ledermüller knew anything about making the plants do the service of maintaining the water in a respirable state for the animals. Indeed, it is distinctly stated that the plants were introduced for the sake of the animals found upon them. And on looking at the plate with care, it may be observed that certain small, round, and other shaped bodies are not air-bubbles, but minute plants and animals, which a hand above the vase is dipping out by means of a glass tube immersed in the water. The same volume contains plate 67 (described at pages 129 to 132), and this plate contains a coloured picture of a cylindrical glass jar, nearly full of water containing some Duck-weed (Lemna) and some living Hydras (Hydra viridis most probably); but neither in the plate nor in the text can anything be discovered leading to the supposition that the plants were put into the jar for any other purpose than because the Hydras were attached to them. If it had been known that the water could have been preserved clear and unchanged by the chemical action of the vegetation,

such a fact would most certainly have been told as one of great interest. Neither is any mention made of the reciprocating influence of plants and animals upon each other. (much less of the principle being turned to practical account in vessels containing creatures and plants) in Trembley's elaborate work in French on the Hydra, published at the Hague in quarto, in 1744, and which book Ledermüller quotes.

I may be excused for remarking, incidentally, that to me, here, in Hamburg, surrounded with every known aquarium improvement and luxury, there is produced by contrast a very curious feeling on looking at some of Trembley's beautifully executed copper-plates, representing the collecting of Hydras in the straight-lined canals, bordered by prim avenues of trees, in trim ancient Dutch gardens, and the conservation of the living animals in cylindrical glass jars in the simple fashion of those days. All is quaint, old-world-looking, and geometrical, even to the square cut of the coat-tails of the imperturbable collectors themselves.

Neither was Baker (who wrote an English book on the Hydra at about the same time), aware of the compensating principle referred to, for he, as well as his contemporaries, in giving directions for keeping the Hydra in confinement, instruct that the water shall be changed, either by emptying what is in the vessels, or else by pouring in fresh quantities and displacing the old water. Clearly, therefore, these early manipulators knew nothing of aquaria as we now understand them. And yet one finds occasionally, in the course of one's reading, statements to the effect that such-and-such a person kept aquatic animals in confinement at a named date, and that, therefore, the invention of aquaria should date from that time. The first thing to be done in such cases is to correctly define what an aquarium is; and according to my judgment it is any arrangement by means of which certain animals are maintained in health in water which is never changed, but which is permanently kept in a pure and respirable condition for the animals by vegetation growing in it and decomposing the carbonic acid gas given out by the breathing of the animals, the result of such decomposition being the production of the oxygen gas which the animals require, and the carbon which the plants need. Thus a balance is kept up, and this may or may not be made more certain and easy by giving the water a large surface so as to enable it, in addition, to absorb still more oxygen from the atmosphere; or it may or may not be made still more safe by circulating the same water from one vessel to another. The essential points are, the same animals kept a reasonably long time in the same water preserved pure for an indefinitely long time by the action of growing plants. The animals must not be lung-breathers, that is to say, they must not take in air direct from the

atmosphere, but indirectly from it, through the medium of the water in which they live; and the animals which do this are aquatic creatures, both fresh-water and marine, from sponges to fishes, both inclusive, and including also a few reptiles, of which an example may be found in the Proteus (Proteus anguinus), which can breathe by both lungs and otherwise, i.e., by gills, and which is occasionally kept in aquaria. If this rigid definition be applied, it will prevent the creeping in of many errors. For example, according to the rule laid down, a globe of gold fishes with the water changed at intervals cannot be termed an aquarium; neither can any vessel in which any animals are temporarily kept; nor can a duck or seal pond be called an aquarium, even if the water were to be preserved unchanged, because the animals are lungbreathers, and do not breathe through the water. Nor can a fish-pond, whether it be out or in-doors, be termed an aquarium if any but the same water is allowed to flow in and out of it, even though the fish are not lung-breathers.

Madame Jeannette Power has deservedly obtained much celebrity by her persevering and ingeniously made studies of living marine Mollusks-chiefly the Paper Nautilus (Argonauto argo) on the coast of Sicily about 35 years ago, and these researches are given to the world in a pamphlet (p. 76), published in Paris, in 1860, and at page 2 and elsewhere Madame Power says that in the year 1832 she invented aquaria, wherein she studied the animals referred to. But these aquaria, so called, were large cages or open-work boxes, made so as to contain the animals in the sea, and to prevent their escaping. I have seen the drawings of these cages in Paris, with their chains and anchors affixed to prevent them from being washed away. Clearly, therefore, these cages thus anchored off the shore at Messina were not aquaria. But Madame Power had at that period other vessels with animals, not in the sea, but indoors; yet, as the water was changed periodically, and plant life was not avowedly and of aforethought depended upon to keep it pure, these vessels could not be called aquaria.

Then, as to Sir J. G. Dalyell. He kept living aquatic animals in vessels in his house at Edinburgh from before the close of the last century till nearly the middle of the present one, but he continually changed the water and cleaned out his receptacles; and yet, though he in this way amassed much valuable knowledge, his not using the same water and his knowing nothing of the influence of plants to keep it pure, destroyed all claim to his having kept aquaria in the strict sense of the word.

In the year 1842, the late Dr. George Johnston, in his "History of British Sponges and Lithophytes," p. 215, tells how he at some period previous to this date (1842), constructed a small marine aquarium in a six-ounce glass jar, in which was placed some plants

E 2

of Corallina, Ulva, and Conferva, together with some small animals, such as Mollusks, Annelides, and a Starfish. The whole continued to thrive during the eight weeks through which the experiment was made (and how much longer we are not told) with the sea-water unchanged, and Dr. Johnston points out these facts clearly. But the proportionate measurements of the vessel are not given, nor the amount of light permitted to fall on it, nor the temperature of the water; and it may safely be assumed that if the glass was not deep in proportion to its width, the large surface exposure to the atmosphere thereby obtained would have enabled the animals to live for a time without any vegetation visibly introduced in a grown state, as the Doctor describes; so that such plants were not necessary, and in a short period-a few days or a week or so-other plants would have made their appearance, under the influence of light, from spores invisibly contained in the water. Yet these considerations must not be allowed to interfere with the merit of Dr. Johnston; but still, for all that, the object he had in view was to prove the vegetability of Corallina officinalis, and the animals associated with that plant were only incidental.

The next step onwards-that of introducing plants for the avowed purpose, stated beforehand, of preserving the purity of the sea-water and of sustaining the animals in health-is due to Mrs. Thynne, who experimented in London in the autumn of 1846, on living madrepores. This lady caused her animals to be the principal things considered, the plants being secondary or incidental; whereas with Dr. Johnston the contrary was the case, and I think that much importance should be attached to this fact, and to a specific intention, previously laid down, and designedly carried out, for the first time, by Mrs. Thynne.

Mr. Ward, in 1841, made an aquarium of fresh water in a twenty-gallon earthenware vessel containing plants and gold and silver fish, but whether he did this with the intention of carrying out the compensating principle, or whether he introduced it only as a green-house ornament, I cannot say; but Mr. Robert Warington's first fresh-water aquarium, set up in the summer of 1849, and his earliest marine aquarinm, made in the beginning of 1852, and Mr. P. H. Gosse's first sea-water arrangements, also begun in January, 1852, were all set going with the balancing principle distinctly in view, as was also a small fresh-water aquarium of Dr. Bowerbank's at about the same period. But the greatest first effort at aquarium-keeping was the public one in the Zoological Gardens, Regent's Park, London, commenced in May, 1853 (the introductory experiments and trials in connection with it having been carried on since the previous autumn), and to that is certainly due nearly all the popular interest in the subject which has since been manifested.

It was in the commencement of 1854 that the Society's then Secretary, the late Mr. D. W. Mitchell, first pointed out to me a tank which he said disproved the necessity of vegetation in aquaria, as the vessel in question had been standing for a long time with healthy animals in unchanged sea-water, and, by accident, no plants had ever been put in. In this, Mr. Mitchell was both right and wrong, for there had been no occasion to introduce plants, and a great quantity of microscopic vegetation had everywhere made its appearance in the tank ; but because it was microscopic, it was by him erroneously not regarded as the useful form of plant-life it proved itself to be; and this observation of Mitchell's led me gradually to avoid the introduction of ready-grown vegetation (save in a few instances), but to depend on the action of light to develop plants on the rock-work of aquaria in course of time. This also led to many changes of form and proportions of tanks, and to the dependence for picturesque effect on the form of the rock-work itself (thus covered with vegetation in situ) rather than on the groupings of introduced plants according to the rule which obtained when aquaria first became general. I believe that such introduced plants do harm rather than good in nine cases out of ten, because at present we do not know how to keep them alive, and their decaying remains do mischief. It is far better to employ self-grown plants which may be exactly regulated by admitting or excluding light, instead of endeavouring to control their too luxuriant growth by the use of scavengering snails which do their office very incompletely. I am much amused when I remember that just before this period of reform, 1857, when customers of mine purchased some additional animals for aquaria, a lot of plants were also bought at the same time to balance the newly-introduced creatures!

It is singular to reflect that the early observersTrembley, Baker, Ledermüller, Ellis, Dalyell, Power, and all others who kept aquatic animals for considerable periods in glass vessels, must at some time or other have exposed such vessels to light for periods sufficiently long to cause plants to appear in the water and keep it pure; yet it never came across their minds to turn such accidents to good account, but they went on, as before, changing the water and cleaning out the vessels. To do otherwise never occurred to Mons. Lucaze-Duthiers, even, when he kept Corals (Corallium rubrum) in confinement on the coast of the Mediterranean during the last four or five years. Connected with this is a curious statement made by M. LucazeDuthiers, to the effect that he had a branch of coral which flourished in captivity very well, till, being removed to Algiers, it remained contracted, because, as the experimenter thought, the water supplied to it was taken from the outside of the harbour, but when dipped from the inside, where it was less