In Great Britain almost every town or watering-place of any note is to have its aquarium, the North of England, with its usual energy, eminently taking the lead.

Scotland, so far from being behindhand, has, within the last few days already opened its first, at that charming little place, Rothesay, so much frequented by the people of Glasgow. There, through the influence of its patron, the Marquis of Bute, has been established an aquarium, which, when quite complete and in working order, will not only be an ornament and attraction to the town, but I have every reason to believe will be of great scientific value, for on this rock-bound rock-bound north-west coast of Scotland is a grand marine fauna. This, without some aid and central base for operations, such as this aquarium will afford, could hardly ever be worked out satisfactorily. Rothesay will I hope prove to be a famous place in future aqarium reports, especially in its record of rarities and new species discovered in Britain. It is fortunate in having a curator, Mr. Barker, who has his "heart and soul in the cause," and from whom we hope much. Already he reports to me that the northern stone crab (Lithodes arctica), which, up to the present time, has only been reported as British from one or two isolated captures by the trawlers of Yorkshire and Lincolnshire, has been discovered in some numbers by the collectors sent out on behalf of this aquarium. Large Nephrops Norvegicus also have been found abundantly by them: this species, although known by the name of the "Norway lobster," has hitherto been found in Britain most commonly on the eastern Irish coast, from whence the English, and even some of the continental, aquaria have been supplied. In Dublin I have often seen this species sold in the streets, after being boiled, as "prawns," at a few pence per dozen; they are a very great delicacy, and quite equal to the common. lobster (Homarus vulgaris) as an article of food. As an aquarian animal they are very attractive; their bright colour, their dignity of bearing, their habit of throwing up great earthworks for the protection of their hiding-places-make them great objects of attraction to visitors.

At the Rothesay Aquarium marble has been greatly used, for the first time, in the construction of the tanks. This I believe is a very important application, one which will be largely adopted in place of slate, as at present used for smaller tanks. Slate, from its laminated structure, is liable to split when any lateral pressure is

put upon it, while marble remains intact. Again, though slate is somewhat unsightly unless enamelled, it unfortunately happens that this so-called " enamel" chips or peels off under the action of any sea-water with which it may come in contact; and the tanks then become unsightly and untidy in appearance. My readers will naturally say that the enamel being outside the tanks, it should not come in contact with the sea-water; but all who know the great difficulty of making large show-tanks absolutely water-tight will see the inadvisability of using a material which, in the present immature stage of aquarium construction, adds greatly to the first cost, and then afterwards only adds to the many complications of management.

Unfortunately the aquarium at Rothesay suffers from the same failing as every other aquarium yet constructed-namely, the miserable leakage of water from reservoirs and tanks. It seems such a pity that, for the sake of a comparatively small fee, Aquarium Companies have hitherto persistently refused to engage a really competent engineer to superintend the earlier stages of construction. Had this been done there is little doubt that much anxiety in the management would have been saved, besides the disastrous consequences of the wear from leakage, which, from its very insidiousness, is a dreadful enemy to cope with. Aquarium construction has so far been treated entirely from an architectural staud-point, whereas it is eminently engineering, and large sums of money have been spent upon external decorations, which earn nothing, while tanks, pipes, and especially reservoirs, being out of sight, are neglected, to the infinite damage of future dividends. In fact, it amounts to this, that a well-constructed aquarium is a most valuable property, which, with little outlay after first cost, will earn large results, both biologically and financially; while a badly constructed one is a veritable "white elephant."

The most valuable addition recently received to the animals now exhibited in Britain is several very fine Italian eels (Muræna Helena), which, with other animals, came from Naples to the Crystal Palace Aquarium, all of them being successfully transported on this long voyage by Captain Badcock, of the S.S. Aurora,' who has before, with great care and generosity, in this manner lent a helping hand to Science. This handsome fish has rarely been recorded as British: it is described by Yarrell as the "Murry," while Mr. Couch calls it the "Muræna." The figures

of this species in both works are very poor, Yarrell having copied the original drawing, as he avows, through the kindness of Mr. Couch. This drawing was taken from a dead specimen, as indeed seems to be the case throughout Couch's work: certainly many of the figures represent the colours of dead fish, and give no idea of living examples of the species represented. The Murry is a much handsomer fish than the figure suggests, both in symmetry and colour. At present these are the only live specimens exhibited in Britain. I ought to add that one other-brought in the same manner by the same gentleman eighteen months agois in good condition, having grown much, in a tank in the same aquarium. In this consignment is also a fine Callappa crab and a most lovely specimen of Anthea cereus: if the latter is a type of the Mediterranean sea-anemones, they must indeed be beautiful.

Recently the literature of Aquaria has been greatly added to. In the 'Field' there has been a somewhat lively correspondence upon the rival systems,-that of Brighton, which consists of changing the water at frequent intervals, and the system of the Crystal Palace Aquarium, where the water is never changed, but simply circulated through the tanks from a large cool and dark reservoir containing several times more water than that exhibited. By this system the water is thoroughly aërated and the temperature is kept even. In this correspondence in the 'Field' the arguments in favour of the Brighton Aquarium system have been answered and exploded.

But by far the most valuable contribution is that of Mr. W. Alford Lloyd, which appeared in the July number of the 'Popular Science Review,' entitled "Aquaria; their Present, Past and Future." In this exhaustive article Mr. Lloyd, in his usual happy style, commencing with a story of how, eighty-six years ago, the late Sir John Graham Dalyell used to supply his aquarium (then without a name) with water,-goes carefully through the somewhat complicated history of the rise and progress of aquaria. Then, so differently to some others, who seem only to look upon aquaria as a means of raising money, he shows why his system is such a great success, by a careful and masterly explanation of the bearing of physics, chemistry and engineering upon the question. I make no apology to my readers for quoting the following extracts from his paper:

'If it be urged that small reservoirs may be made to do as makeshifts, because money and space for them cannot be afforded, there is some kind of reason in that. But if it be averred to the contrary as a principle, then that indicates a singular amount of no knowledge which, if possible, is something more than wonderful. My arguments are founded on the clear and simple obviousness of the fact that a given quantity of dead organic matter diffused through a large quantity of water sullies it less than if it were small, and on the necessity of maintaining an evenly moderate temperature for the reasons already given, avoiding the high and low ranges of the atmosphere; and I show that the easiest manner of attaining this is by having a large reservoir sunk in the earth at a distance giving a known temperature. Thus, referring to the sunk thermometers at the Greenwich Observatory, with a thermometer having its bulb on a level with the scales of the sunk instruments, the lowest (January) mean monthly reading in a named year was 36-4° F., with a mean daily range of 6·9° F.; and under the same circumstances the highest (July) mean monthly reading was 66.9° F., with a mean daily range of 19.9° F. But from the showing of other thermometers whose bulbs are sunk in the ground to the respective depths of one inch, three feet, twelve feet, and twenty-five feet, the temperatures become strikingly even for the whole year through-so much so, that at twenty-five feet deep the mean monthly reading of January was 52° F., with a mean daily range of only 0·025° F.; and the mean monthly reading of July was 49.0° F., with a mean daily range of but 0-06° F., the highest mean daily range at that depth in any month of the year being 0-07° F. in August."

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"Indeed if a reservoir were one hundred times as large as the show tanks, and was kept at 50° F., then the tanks might be in an atmosphere at 212° F. (the heat of boiling water), and yet the water would be only 52.12° F., and the most delicate English animals would live in it.

In a note to a preceding passage Mr. Lloyd supplies the following further particulars as to the temperature of the water in the Crystal Palace Aquarium :

"The water in the Crystal Palace Aquarium has a very small range of from 52° F. in very cold, to 61° F. in very hot, weather. In April last (1876) we had, at Sydenham, blue skies, a bright sun, and an oppressive warmth, with 74° F. in the shade, on the 8th of the month. On the 12th, four days after, we had a leaden firmament, and clouds of blinding snow and sleet driven by a bitter north-east wind, with the thermometer at 29° F., giving so great a range as 45° F. within a week. Yet the water in the aquarium had a range of only 1° F. 54° F. to 53° F."

He then proceeds to give some interesting details:

"Yet in this comparatively small quantity (120,000 gallons) of unchanged fluid we have, from September, 1871, to March 31, 1876 (four and a half years), given to the animals in it the following enormous quantity of food without the water being otherwise than always sparklingly clear :

1. Sandhoppers (Talitrus), in pounds weight

2. Shrimps (Crangon) in quarts

3. Crabs (Carcinus)

(Cancer), large

{

in gallons

12

4735

137

1450

32

2195

18

3544

7

100

3159

14

400

9. Fish, chiefly whiting (Gadus), in pounds weight

10. Smelts' roe (Osmerus)

11. Green seaweed (Ulva), purchased

12. 99 And, in addition, we obtain occasional and unrecorded supplies from neighbouring fishmongers when the regular supply ruus short. Of this animal food, all but the denominations 9 and 10 are kept alive in a series of reserve tanks till the moment of being eaten. Scarcely any uneaten food, and never any excrement, is manually removed; but all which is not consumed by the animals is chemically dissipated, without filtering, by the enormous volumes of air constantly being injected into every tank by machinery, the speed of which is accelerated (i. e., the oxygenation is quickened) when the water is slightly turbid from an excess of organic matter. All this I have explained more at length in the Official Handbook to the Crystal Palace Aquarium,' and in Observations on Public Aquaria,' both published at the Crystal Palace. It is this power of oxygenating, or consuming, or burning, at a low temperature, termed by Baron Liebigeremacausis, which expresses the real work done in an aquarium, and the force necessary to do that work."

(Conferva), grown in tanks, quantity unknown.

"Of the general influence of aquaria on Zoology we have curious. evidence in Mr. Gosse's most excellent Manual of Marine Zoology for the British Isles,' published in. two volumes, in 1855-1856, in which the author cnumerates 1785 species, from sponges to fishes, and of which he

* From the Greek "to remove by burning, or by fire." The words "caustic" and "cautery" have the same derivation.

SECOND SERIES-VOL. XI.

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