Page:Popular Science Monthly Volume 20.djvu/297

Rh apart varying according to the size which it is intended to give the bed. Rooted plants are gathered from the lake and interwoven with the stakes. They continue to grow and form the floor of the bed, upon which more plants brought up from the lake are piled, until a kind of hill is formed half a yard in diameter and about two feet high. These hills are placed at distances apart which vary according to the nature of the vegetables that are to be raised upon them; the weeds of which they are formed soon dry up and decay, and the plants which are to be cultivated, consisting mostly of melons and allied species, are taken from the seedbeds in which they have been started, and planted upon them. At first, the plants are watered regularly, but their roots soon reach the water beneath the floor, and they then take care of themselves. The products of the gardens are gathered during the summer as they mature, by means of little boats which circulate among the floats, and are taken to the city and sold to a population which willingly pays a good price for them. The floating gardens will last for a great many years, or until the stakes which support them are rotted away, and may be perpetuated for an indefinite period by simply renewing the stakes at the proper time. They can be moved, but are generally fixed at the spot which the cultivator selects as most convenient for himself. Floating on the surface of the water, they rise and fall with the rise and fall of the lake, without any interruption to the development of the crops growing upon them. A very large amount of produce is raised upon the lake. Besides those plants which are cultivated directly, it furnishes several other useful productions spontaneously, such as the lotus, whose roots look like giant asparagus, without having its taste or flavor, but the seeds of which remind one of fresh nuts; water chestnuts (Trappa nutans), which are abundant; and quantities of water-lilies, the seeds and roots of which are often eaten. The fish also are excellent, varied, and abundant. The government derives a considerable revenue from the rent of fishing and gardening privileges.

Characteristics and Diversities of Deep-Sea Fauna.—M. A. Milne-Edwards has derived some novel and interesting if not startling conclusions from the study of the deep-sea fauna which were discovered by the dredging expeditions in the Caribbean Sea. He has been especially struck by the differences that exist between the animals of the bottom of the ocean and those of the surface and littoral. When, he says, we compare the specimens, we seem to have under our eyes two distinct fauna, which belong neither to the same period nor the same climate. The importance of this fact ought not to escape any one, and geologists should take it into account in determining the age of any formation. In reality, there are being formed to-day in the same seas deposits of which the contemporaneousness can not be put in doubt, but which contain the remains of beings entirely dissimilar. The animals in the deposits near the shores are related to the highest types of organization; those of the deep-sea-beds are of a more ancient character. Some among them exhibit incontestable affinities with fossils of the secondary epoch; others resemble the larval state of certain existing species. The infinite variety of zoölogical forms excites astonishment, and makes the application of existing classifications almost impossible. Transition types abound, with numerous intermediaries between groups, which we have hitherto been in the habit of considering as distinct. "Researches," continues M. Milne-Edwards, "on the animals of great depths have only been begun; and when we compare the limited extent over which dredgings have been made with the immense spaces that have never been penetrated, when we reflect on the many causes which still make the retreats of certain animals inaccessible to any means of investigation that we have, we become convinced that the results which have been obtained are only a small part of what the future has in reserve for us. We can not, then, insist too much on directing the attention of men of science of all countries to the usefulness of making their efforts coordinate, and of undertaking methodical explorations in the seas to which they have the most easy access. Our zoölogical tables still present so many gaps that it is impossible to comprehend the wholeness of the plan which has presided over the grouping