Some years since much interest was created by the invention of Dr. Ward for growing plants in closely glazed cases. It afforded much pleasure to scientific persons and to invalids, and was altogether a valuable and instructive in-door ornament Its chief value, however, was from its adaptation to the transport by sea of new and rare plants. All Fortune's new discoveries were sent from China in this way, and the Tea plant was forwarded thus to be domesticated in India. Consignments are continually arriving from all parts of the world in England and America in Wardian cases, which exclude the sea air and spray, and thus enable the Captain to carry the package on deck, so that plenty of light can be admitted.

The Aquarium is an adaptation of Ward's principle of compensation to the keeping inland of sea animals, fishes, shells, &., in a healthy condition. The contrivance may be made highly ornamental for the study, or even the drawing room. Philip Henry Gosse, a naturalist, has issued in London a beautiful duodecimo volume with highly ornamental plates, from which our wood cut is selected of.

This glass case enables the possessor to study the habits of marine animals, to carefully note their various actions, and their behavior under different circumstances. A result often most curious and unexpected has rewarded the student. The most interesting parts, by far, of natural history, are those minute but most graphic particulars, which have been gathered by an attentive watching of individual animals; witness Wilson's picture of the mocking-bird; Godman's of the insects in a small pool; Vigors' of the Toucan; Broderip's of the Beaver "Binney;" Wol-laston's of the water-shrew ; Bennet's of the bird of Paradise; and multitudes of others.

The inhabitants of the deep sea have hitherto been almost inaccessible to such observation, which must, after all, be the foundation of all correct generalization. The Marine Aquarium bids fair to supply the required opportunities of study, and to make us acquainted with the strange creatures of the sea, without diving to gaze on them.

The idea of maintaining the balance between animal and vegetable life on chemical principles is not so novel as was at first supposed. Priestly first advanced the opinion that plants, in certain circumstances, emitted oxygen gas; and Ingenhousz soon after discovered that the leaves of plants, when immersed in water and exposed to the light of day, produced an air which he announced as oxygen gas. Professor Daubeney in 1833 elucidated the subject. He regarded light as operating upon the green parts of plants as a specific stimulus, calling into action and keeping alive those functions, from which the assimilation of carbon and the evolution of oxygen result; that in fine weather a plant, consisting chiefly of leaves and stems, will, if confined in the same portion of air, night and day, and duly supplied with carbonic acid during the sunshine, go on adding to the proportion of oxygen present, so long as it continues healthy, at least up to a certain point. Considering the quantity of oxygen generated by a very small portion of a tree or shrub introduced, he saw no reason to doubt that the influence of the vegetable might serve as a complete compensation for that of the animal kingdom.

THE FOUNTAIN AQUARIUM.

THE FOUNTAIN AQUARIUM.

Dr. Ward in 1837 was "quite certain that a great number of animals would live and thrive" under the treatment we now see perfected by the Aquarium, in which the animal and vegetable respirations counterbalance each other; the volume of air, with the quantity of vegetable matter required, as compared with the size and rank of the animal, is the problem now solved. The result is, the public exhibition in the London Zoological Gardens of lobsters, fish, shells, corallines, sea-anemones, sponges, and lithophytes, etc., in their natural state, with their brilliant colors and peculiar habits all revealed through the glass which surrounds them. Great care has been found necessary in procuring pure sea water, and that the barrel in which it is brought, even to the bung itself, should be free from any vitiating substance. The decay of leaves in a fresh water Aquarium was obviated by introducing a few common pond snails (Limnea), which greedily fed upon the decaying vegetable matter and slimy mucous growth, so as quickly to restore the whole to a healthy state.

Experiments have demonstrated the kind of sea weeds necessary to keep up a regular compensation for many months without change of water, and this scientific toy, if toy it can be called, when its beauty and value, with the possible discovery of new coloring matters, modes of propagation of fish, etc., are considered, is now quite a fashion. Beautifully has the American poet sung:

"Look on this beautiful world, and read the truth In her fair page: see every season brings New change to her of everlasting youth; Still the green soil with joyous living things Swarms; the wide air is full of joyous wings; And myriads still are happy in the sleep • Of ocean's azure gulfs, and where he flings The restless surge. Eternal love doth keep In his complacent arms the earth, the air, the deep".

Bryant.

The Domestic Aquarium is not usually accompanied by a fountain as shown in the wood cut, but is simply a glass water-tight case, filled, as represented, by various marine animals. It is somewhat amusing, and we have no doubt true, that individuality of dispositions has been discovered in the specimens of the same family, even among the smallest.

Aquariums #1

We have answered a correspondent elsewhere regarding aquariums, with references to former articles on the subject. A few hints for beginners are, nevertheless, in season. No odorous material or poisonous putty should be employed in joining the glass, and all varnish must be entirely dried before use. The shaded back of the aquarium should be placed next the light, as the rays ought to penetrate the water entirely through its upper or horizontal surface. Direct rays of light must be received during some part of the day, being screened by a white blind when the sun may be too powerful; as, should the water become tepid, it would be fatal to many of the inhabitants. Don't overcrowd your tank, but be content with a few specimens, and an occasional change.

The composition of artificial salt water has been found sufficient for zoophytes, but not for fish and other of the higher class of marine animals, except for a certain given time; its ingredients are: