can recommend either of these houses with the greatest confidence.

Construction of Tanks.—As this work may reach many remote districts, where an aquarian would find it difficult to get a tank properly made, a few hints on the proper mode of construction may be acceptable.

It must be borne in mind, then, that when a tank is filled, its weight is enormous, and hence it is difficult, sometimes impossible, to move it without first removing the whole or greater portion of its contents. Strength in the joints to resist pressure from within, and strength in the table or other support on which the tank is placed, is of the first importance. The bottom of such a tank as we have figured (p. 11), is best formed of a slab of slate, and the two ends may be of slate also; the front and back of plate or very stout crown glass. The most elegant form for such a body is that of the double cube, the length of the tank being just double its width and depth, so that if it were cut into two equal parts two cubes would be formed. The glass must be set in grooves in the slate, and bound outside with zinc or turned pillars of birch wood. The best cement is white-lead putty, or what is known as Scott's cement; the composition of which it is not in my power to inform the reader. If a coating of shell-lac, dissolved in naptha, and made into a paste with whiting, were laid over the white-lead cement, as suggested by Mr. W. Dodgson, of Wigton, the water would be kept from contact with the lead, and the tank would require less seasoning.

The use of slate at the ends is to enable us to affix rockwork or carry across a rude arch; the cement used in constructing rockwork does not adhere to glass. But if rockwork is not thought desirable the slate ends may be dispensed with, and the vessel may be composed wholly of glass, except the bottom, which may be of slate or wood.

In some districts slate is not to be easily obtained, and wood or stone are then the best substitutes, wood being preferable of the two. I have seen some handsome tanks composed wholly of wood and glass; it is only necessary to choose well-seasoned material, and unite the joints very perfectly.

The yellow clay used by potters would be found suitable in some districts; and if the two ends and bottom were formed of such a material, and buttressed together by means of a rude arch, the fire would unite the whole, and render it as hard as stone. Mr. Dodgson, of Wigton, states, through Mr. Gosse's pages, that he has formed two tanks of this kind of clay: they measure three feet long by thirty inches broad and high, holding thirty gallons each. The weight being very enormous, the cost of carriage is so serious a matter that such tanks can only be had in the neighbourhood of a pottery. In London, the substitute for the clay would be terra cotta.

Mr. Warington's Tank is of a peculiar construction, and is intended to admit the light from above only, and also to enable the water to absorb atmospheric air freely. Mr. Warington says:—"After five years' and upwards experience, I have now adopted an aquarium, the form of which consists in a four-sided vessel, having the back gradually sloping upwards from the bottom at an angle of fifty degrees. The chief peculiarity of this tank is, that it admits light at the top only; the back and sides are usually composed of slate."

Bell Glasses, or vases, are now largely used for aquaria. Mr. Hall, of the City Road, was the first who thought of turning a propagating glass upside down to extemporise an aquarium; but he surely never thought that in a few months the aquarium would gain thousands of new followers through that simple trick of his in creating a cheap and elegant tank. Bell glasses for aquaria are to be obtained of any of the dealers in aquarian stock, and at most horticultural glass warehouses. The sizes range from ten inches to twenty inches in diameter, and the prices from one to fifteen shillings. For general purposes of use and ornament, I should recommend vessels of from twelve to eighteen inches. Those below twelve inches are too small to be of much service, and those above eighteen are liable to fracture on the occasion of any sudden change of temperature, especially in winter. Messrs. Phillips have lately, at my suggestion, produced a bell-glass expressly for aquarian purposes; those in use hitherto were made for gardening purposes, and were carelessly blown. The shape I have suggested is one nearly approaching to that of the blossom of the great bearbind, the sides of the vessel describing straight lines, and the edges lipping over in an elegant vase-like form. These are made of whiter and stouter glass than the common propagators, and are, of course, charged at a slightly advanced rate.

Stands for Vases are to be had of various forms and materials. Those formed of turned wood have the preference for elegance and safety; and, as the knob of the vase fits loosely in the depressed top of the stand, the vase can be turned round for inspection.

Messrs. Claudet and Houghton, of 89, High Holborn, have recently brought out improved forms of stands for vases. They are made of terra cotta, elegantly fluted, or ornamented with architectural scrolls, and are either bronzed or coloured to imitate stone. They have also improved the Vase Aquarium, by binding the upper edge with perforated zinc, in which there is a ring to receive the glass cover. Thus, while the lid shuts out dust, the perforated zinc rim admits air, and allows the escape of sulphuretted hydrogen. These vases are strongly recommended to those who cannot afford a well-built tank.

Where extreme cheapness is an object, a deal box with a hole cut in the centre to receive the base of the vase, will make a suitable stand, or a common seed-pan filled in with sand and the vase pressed down into it may answer, at a cost of only fivepence. A stone vase, or any ornamental object, with a suitable depression in the top, can also be turned to account for the purpose.

Glass jars, confectioner's show-glasses, a foot-bath of earthenware, or a few glass milk-pans, may be used for the preservation of aquatic objects, when a properly constructed vessel is not at hand; and even as adjuncts to high-class tanks, such vessels are frequently necessary and have special uses of their own. Still the tank, whether rectangular or vase-shaped, is a distinct thing in itself. The beauty is to be found in its completeness and the extent afforded for a variety of objects; and when we speak of an aquarium, we mean a vessel holding at least eight to thirty or more gallons of water, formed partially or wholly of glass, and stocked with plants and fishes in a living and healthy state. A glass lid is essential to prevent the entrance of dust and escape of any of the inhabitants. Fishes will sometimes leap out, and reptiles crawl out; and without a lid, some pretty objects may be lost.

CHAPTER III.

FITTING UP.

Rockwork claims the first consideration when we proceed to fit up and furnish a tank. For a fresh-water aquarium, I do not recommend rockwork of any kind; and in the case of a vase, rockwork is positively dangerous, from its weight, and, unless very skilfully managed, will be ugly rather than ornamental. In the marine tank a few pieces of rock add to the beauty of the scene and the comfort of the creatures.

In fitting rockwork, some amount of taste and judgment must be brought into exercise. Shells and filagree work are largely used by some folks; but they belong