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eggs of insects and the seeds of plants, the latter provided with light hairy or feathery appendages, by means of which they are wafted through the air during long autumnal wanderings. Even the fertilizing dust or pollen from the anthers of the male flowers, in species where the sexes are separated, is carried over land and sea, by winds and by the agency of winged insects, to the solitary female plant on other shores.

Thus, wherever the glance of the inquirer into Nature penetrates, he sees the continual dissemination of life, either fully formed or in the germ. If the aerial ocean, in which we are submerged, and above the surface of which we cannot rise, be indispensable to the existence of organized beings, they also require a more substantial aliment, which they can find only at the bottom of this gaseous ocean. This bottom is of two kinds; the smaller portion consisting of water, which may perhaps have been formed thousands of years ago by electric agencies from gaseous substances, and which is now incessantly undergoing decomposition in the laboratories of Nature, in the clouds, and in the pulsating vessels of animals and plants. Organic forms also descend deep below the surface of the earth, wherever rain or surfacewater can percolate, either by natural cavities or by mines or other excavations made by man. The subterranean cryptogamic Flora was an object of my scientific research in the early part of my life. Thermal springs of very high temperature nourish small Hydropores, Confervae and Oscillatoria. At Bear Lake, near the Arctic Circle, Richardson saw the ground, which continues frozen throughout the summer at a depth of twenty inches, covered with flowering plants. We do not yet know where life is most abundant-whether on continents or in the unfathomed depths of the ocean.

Through the excellent work of Ehrenberg-" über das Verhalten des kleinsten Lebens"-we have seen the sphere of organic life extend, and its horizon widen before our eyes, both in the tropical parts of the ocean and in the fixed or floating masses of ice of the Antarctic seas. Siliciousshelled Polygastrica, and even Coscinodiscae, with their green ovaries, have been found alive enveloped in masses of ice only twelve degrees from the Pole; the small black Glacier Flea (Desoria glacialis) and Podurellae inhabit the narrow tubular holes examined by Agassiz in the Swiss On the Economy of Animalcule Existence.

glaciers. Ehrenberg has shown that on several microscopic Infusoria (Synedra locconeis) others live as parasites, and that in the Gallionellæ such is their prodigious power of development or capability of division, that in the space of four days an animalcule, invisible to the naked eye, can form two cubic feet of the Bilin polishing slate. In the sea, gelatinous worms, living or dead, shine like stars, and by their phosphoric light change the surface of the ocean into a sea of fire. Ineffaceable is the impression made on my mind by the calm nights of the Torrid Zone on the waters of the Pacific. I still see the dark azure of the firmament, the constellation of the Ship near the zenith, and that of the Cross declining towards the horizon, shedding through the perfumed air their soft and planetary lustre; while bright furrows of flashing light marked the track of the dolphins through the midst of the foaming waves.-HUMBOLDT.

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LUMINOSITY OF THE OCEAN.

The luminosity of the ocean is one of those superb natural phenomena which continue to excite our admiration even when we have seen them recur every night for months. The sea is phosphorescent in every zone; but those who have not witnessed the phenomenon within the tropics, and especially in the Pacific, have only an imperfect idea of the grand and majestic spectacle which it affords. When a man-of-war, impelled by a fresh breeze, cuts the foaming waves, the voyager, standing at the ship's side, feels as if he never could be satisfied with gazing on the spectacle which presents itself to his view. Every time that in the rolling of the vessel her side emerges from the water, blue or reddish streams of light appear to dart upwards like flashes of lightning from her keel. Nor can I describe the splendour of the appearance presented on a dark night, in the tropic seas, by the sports of a troop of porpoises. As they dart through the rolling waters, following each other in long winding lines, one sees their mazy track marked by intense and sparkling light. In the Gulf of Cariaco, between Cumana and the Peninsula of Maniguarey, I have stood for hours enjoying this spectacle. Le Gentil and the elder Forster attributed the flashing to the electric friction excited by the ship in moving through the water, but the present

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state of our knowledge does not permit us to receive this as a valid explanation. Perhaps there are few natural subjects of observation which have been so long and so much debated, as the luminosity of the waters of the sea. What we know

with certainty on the subject may be reduced to the following simple facts. There are several luminous animals which, when alive, give out at pleasure a faint phosphoric light. The luminous appearance of the sea is due partly to living animals, such as are spoken of above, and partly to organic fibres and membranes derived from the destruction of these

living torch-bearers. The first of these causes is undoubtedly the most usual and most extensive. In proportion as travellers engaged in the investigation of natural phenomena have become more zealous in their researches, and more experienced in the use of excellent microscopes, we have seen in our zoological systems the groups of mollusca and infusoria, which become luminous either at pleasure or when excited by external stimulus, increase more and more.-HUMBOLDT.

DESCRIPTION OF A TROPICAL STORM.

The day broke with an unwonted gloom, overshadowing everything; a dense black haze rested like a high wall round the horizon; while the upper sky, so long without a single speck, was stained all over with patches of shapeless clouds flying in different directions. The sun rose attended by vapours and clouds, which concealed him from our sight. The sea-wind, which used to begin gently, and then gradually increase to a pleasant breeze, came on suddenly, and with great violence; so that the waves curled and broke into a white sheet of foam, extending as far as the eye could reach. The whole sea looked bleak and stormy under the portentous influence of an immense mass of dark clouds, rising slowly in the western quarter, till they reached nearly to the zenith, where they continued like a mantle during the whole day. The ships which heretofore had lain motionless on the smooth surface of the bay, were now rolling and pitching, with their cables stretched out to sea-ward; while the boats that used to skim along from the shore to the vessels at anchor, were seen splashing through the waves under a reefed sail, or struggling hard with their oars to avoid being driven into the surf which was breaking and roaring furiously

along the coast. The flags that were wont to be idly asleep for weeks together, by the sides of the masts on the batteries, now stood stiffly out in the storm. Innumerable sea-birds, continued during all the day, wheeling and screaming round the rock on which the town stood, as if in terror at this sudden change. The dust of six months' hot weather, raised into high pyramids, was forced by furious gusts of wind into the innermost corners of the houses. Long before sunset, it seemed as if the day had closed, owing to the darkness caused by the dust in the air, and to the sky being overcast in every part by unbroken masses of watery clouds. Presently lightning was observed amongst the hills; followed, shortly afterwards, by a storm exceeding in violence anything I ever met with in other parts of the world. During eight hours, deluges of rain never ceased pouring down for a moment; the steep streets of the town soon became the channels of streams of such magnitude as to sweep away large stones; rendering it everywhere dangerous, and in some parts impossible to pass. The rain found its way through the roofs, and drenched every part of the houses; the deep rumbling noise of the torrents in the streets was never interrupted; the deafening loudness of the thunder became exceedingly distracting; while flashes of forked lightning, playing in the most brilliant manner without ceasing from the zenith to the horizon on all sides, and clinging, as it were to the rock, were at once beautiful and terrific.-CAPTAIN BASIL HALL.

SCIENTIFIC AERIAL VOYAGE.

M. Barral, a chemist of some distinction at Paris, and M. Bixio, a Member of the Legislative Assembly, resolved upon making a grand experiment with a view to observe and record the meteorological phenomena of the strata of the atmosphere, at a greater height and with more precision than had hitherto been accomplished. MM. Arago and Regnault undertook to supply the aerial voyagers with a programme of the proposed performance, and instruments suited to the projected observations. M. Arago prepared the programme, in which was stated clearly what observations were to be made at every stage of the ascensional movement.

The precious instruments by which these observations were to be made were prepared, and in some cases actually

fabricated and graduated by the hands of M. Regnault himself. To provide the balloon and its appendages, recourse was had to some of those persons who have followed the fabrication of balloons as a sort of trade for the purposes of exhibition. It has since been proved that the balloon was old and worn, and that it ought not to have been supplied for such an occasion. It was obviously patched, and it is now known that two sempstresses were employed during the preceding day in mending it, and some stitching even was found necessary after it had arrived at the Observatory. The net-work which included and supported the car was new, and not originally made with a view to the balloon it enclosed, the consequence of which will be presently seen.

On the morning of Saturday, the instruments being duly deposited in the car, the two enterprising voyagers placed themselves in it, and the balloon, which previously had been held down by the strength of twenty men, was liberated, and plunged into the clouds, and was withdrawn from the anxious view of the distinguished persons assembled in the garden of the Observatory. While passing through this dense cloud, the voyagers carefully observed the barometer, and knew by the rapid fall of the mercury that they were ascending with a great velocity. Fifteen minutes elapsed before they emerged from the cloud; when they did so, however, a glorious spectacle presented itself. The balloon, emerging from the superior surface of the cloud, rose under a splendid canopy of azure, and shone with the rays of a brilliant sun. The cloud which they had just passed was soon several thousand feet below them. From the observations taken with the barometer and thermometer, it was afterwards found that the thickness of the cloud through which they had passed was 9800 feet a little less than two miles. On emerging from the cloud, our observers examined the barometer, and found that the mercury had fallen to the height of 18 inches; the thermometer showed a temperature of 45 degrees Fahr. The height of the balloon above the level of the sea was then 14,200 feet. At the moment of emerging from the cloud, M. Barral made a polariscopic observation, which established a fact foreseen by M. Arago, that the light reflected from the surface of the clouds was unpolarized light. The continued and somewhat considerable fall of the barometer informed the observers that their ascent still continued to be rapid. The rain which had previously fallen, and which wetted the

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