A philosopher of the East, with a richness of imagery truly oriental, describes the Atmosphere as “a spherical shell which surrounds our planet to a depth which is unknown to us, by reason of its growing tenuity, as it is released from the pressure of its own superincumbent mass. Its upper surface cannot be nearer to us than 50, and can scarcely be more remote than 500, miles. It surrounds us on all sides, yet we see it not; it presses on us with a load of fifteen pounds on every square inch of surface of our bodies, or from seventy to one hundred tons on us in all, yet we do not so much as feel its weight. Softer than the softest down, more impalpable than the finest gossamer, it leaves the cobweb undisturbed, and scarcely stirs the lightest flower that feeds on the dew it supplies; yet it bears the fleets of nations on its wings around the world, and crushes the most refractory substances with its weight. When in motion, its force is sufficient to level the most stately forests and stable buildings with the earth—to raise the waters of the ocean into ridges like mountains, and dash the strongest ships to pieces like toys. It warms and cools by turns the earth and the living creatures that inhabit it. It draws up vapours from the sea and land, retains them dissolved in itself or suspended in cisterns of clouds, and throws them down again as rain or dew when they are required. It bends the rays of the sun from their path to give us the twilight of evening and of dawn; it disperses and refracts their various tints to beautify the approach and the retreat of the orb of day. But for the atmosphere sunshine would burst on us and fail us at once, and at once remove us from midnight darkness to the blaze of noon. We should have no twilight to soften and beautify the landscape; no clouds to shade us from the searching heat; but the bald earth, as it revolved on its axis, would turn its tanned and weakened front to the full and unmitigated rays of the lord of day. It affords the gas which vivifies and warms our frames, and receives into itself that which has been polluted by use and is thrown off as noxious. It feeds the flames of life exactly as it does that of the fire—it is in both cases consumed and affords the food of consumption—in both cases it becomes combined with charcoal, which requires it for combustion and is removed by it when this is over.”

UNIVERSALITY OF THE ATMOSPHERE.

It is only the girdling, encircling air that flows above and around all that makes the whole world kin. The carbonic acid with which to-day our breathing fills the air, to-morrow makes its way round the world. The date-trees that grow round the falls of the Nile will drink it in by their leaves; the cedars of Lebanon will take of it to add to their stature; the cocoa-nuts of Tahiti will grow rapidly upon it; and the palms and bananas of Japan will change it into flowers. The oxygen we are breathing was distilled for us some short time ago by the magnolias of the Susquehanna; the great trees that skirt the Orinoco and the Amazon, the giant rhododendrons of the Himalayas, contributed to it, and the roses and myrtles of Cashmere, the cinnamon-tree of Ceylon, and the forest, older than the Flood, buried deep in the heart of Africa, far behind the Mountains of the Moon. The rain we see descending was thawed for us out of the icebergs which have watched the polar star for ages; and the lotus-lilies have soaked up from the Nile, and exhaled as vapour, snows that rested on the summits of the Alps.—North-British Review.

THE HEIGHT OF THE ATMOSPHERE.

The differences existing between that which appertains to the air of heaven (the realms of universal space) and that which belongs to the strata of our terrestrial atmosphere are very striking. It is not possible, as well-attested facts prove, perfectly to explain the operations at work in the much-contested upper boundaries of our atmosphere. The extraordinary lightness of whole nights in the year 1831, during which small print might be read at midnight in the latitudes of Italy and the north of Germany, is a fact directly at variance with all we know according to the researches on the crepuscular theory and the height of the atmosphere. The phenomena of light depend upon conditions still less understood; and their variability at twilight, as well as in the zodiacal light, excite our astonishment. Yet the atmosphere which surrounds the earth is not thicker in proportion to the bulk of our globe than the line of a circle two inches in diameter when compared with the space which it encloses, or the down on the skin of a peach in comparison with the fruit inside.

COLOURS OF THE ATMOSPHERE.

Pure air is blue, because, according to Newton, the molecules of the air have the thickness necessary to reflect blue rays. When the sky is not perfectly pure, and the atmosphere is blended with perceptible vapours, the diffused light is mixed with a large proportion of white. As the moon is yellow, the blue of the air assumes somewhat of a greenish tinge, or, in other words, becomes blended with yellow.—Letter from Arago to Humboldt; Cosmos, vol. iii.

BEAUTY OF TWILIGHT.

This phenomenon is caused by the refraction of solar light enabling it to diffuse itself gradually over our hemisphere, obscured by the shades of night, long before the sun appears, even when that luminary is eighteen degrees below our horizon. It is towards the poles that this reflected splendour of the great luminary is longest visible, often changing the whole of the night into a magic day, of which the inhabitants of southern Europe can form no adequate conception.

HOW PASCAL WEIGHED THE ATMOSPHERE.

Pascal’s treatise on the weight of the whole mass of air forms the basis of the modern science of Pneumatics. In order to prove that the mass of air presses by its weight on all the bodies which it surrounds, and also that it is elastic and compressible, he carried a balloon, half-filled with air, to the top of the Puy de Dome, a mountain about 500 toises above Clermont, in Auvergne. It gradually inflated itself as it ascended, and when it reached the summit it was quite full, and swollen as if fresh air had been blown into it; or, what is the same thing, it swelled in proportion as the weight of the column of air which pressed upon it was diminished. When again brought down it became more and more flaccid, and when it reached the bottom it resumed its original condition. In the nine chapters of which the treatise consists, Pascal shows that all the phenomena and effects hitherto ascribed to the horror of a vacuum arise from the weight of the mass of air; and after explaining the variable pressure of the atmosphere in different localities and in its different states, and the rise of water in pumps, he calculates that the whole mass of air round our globe weighs 8,983,889,440,000,000,000 French pounds.—North-British Review, No. 2.

It seems probable, from many indications, that the greatest height at which visible clouds ever exist does not exceed ten miles; at which height the density of the air is about an eighth part of what it is at the level of the sea.—Sir John Herschel.

VARIATIONS OF CLIMATE.

History informs us that many of the countries of Europe which now possess very mild winters, at one time experienced severe cold during this season of the year. The Tiber, at Rome, was often frozen over, and snow at one time lay for forty days in that city. The Euxine Sea was frozen over every winter during the time of Ovid, and the rivers Rhine and Rhone used to be frozen over so deep that the ice sustained loaded wagons. The waters of the Tiber, Rhine, and Rhone, now flow freely every winter; ice is unknown in Rome, and the waves of the Euxine dash their wintry foam uncrystallised upon the rocks. Some have ascribed these climate changes to agriculture—the cutting down of dense forests, the exposing of the unturned soil to the summer’s sun, and the draining of great marshes. We do not believe that such great changes could be produced on the climate of any country by agriculture; and we are certain that no such theory can account for the contrary change of climate—from warm to cold winters—which history tells us has taken place in other countries than those named. Greenland received its name from the emerald herbage which once clothed its valleys and mountains; and its east coast, which is now inaccessible on account of perpetual ice heaped upon its shores, was in the eleventh century the seat of flourishing Scandinavian colonies, all trace of which is now lost. Cold Labrador was named Vinland by the Northmen, who visited it A.D. 1000, and were charmed with its then mild climate. The cause of these changes is an important inquiry.—Scientific American.

AVERAGE CLIMATES.

When we consider the numerous and rapid changes which take place in our climate, it is a remarkable fact, that the mean temperature of a place remains nearly the same. The winter may be unusually cold, or the summer unusually hot, while the mean temperature has varied even less than a degree. A very warm summer is therefore likely to be accompanied with a cold winter; and in general, if we have any long period of cold weather, we may expect a similar period at a higher temperature. In general, however, in the same locality the relative distribution over summer and winter undergoes comparatively small variations; therefore every point of the globe has an average climate, though it is occasionally disturbed by different atmospheric changes.—North-British Review, No. 49.

THE FINEST CLIMATE IN THE WORLD.

Humboldt regards the climate of the Caspian Sea as the most salubrious in the world: here he found the most delicious fruits that he saw during his travels; and such was the purity of the air, that polished steel would not tarnish even by night exposure.

THE PUREST ATMOSPHERES.

The cloudless purity and transparency of the atmosphere, which last for eight months at Santiago, in Chili, are so great, that Lieutenant Gilliss, with the first telescope ever constructed in America, having a diameter of seven inches, was clearly able to recognise the sixth star in the trapezium of Orion. If we are to rely upon the statements of the Rev. Mr. Stoddart, an American missionary, Oroomiah, in Persia, seems to be, in so far as regards the transparency of the atmosphere, the most suitable place in the world for an astronomical observatory. Writing to Sir John Herschel from that country, he mentions that he has been enabled to distinguish with the naked eye the satellites of Jupiter, the crescent of Venus, the rings of Saturn, and the constituent members of several double stars.

SEA-BREEZES AND LAND-BREEZES ILLUSTRATED.

When a fire is kindled on the hearth, we may, if we will observe the motes floating in the room, see that those nearest the chimney are the first to feel the draught and to obey it,—they are drawn into the blaze. The circle of inflowing air is gradually enlarged, until it is scarcely perceived in the remote parts of the room. Now the land is the hearth, the rays of the sun the fire, and the sea, with its cool and calm air, the room; and thus we have at our firesides the sea-breeze in miniature.

When the sun goes down, the fire ceases; then the dry land commences to give off its surplus heat by radiation, so that by nine or ten o’clock it and the air above it are cooled below the sea temperature. The atmosphere on the land thus becomes heavier than that on the sea, and consequently there is a wind seaward, which we call the land-breeze.—Maury.

SUPERIOR SALUBRITY OF THE WEST.

All large cities and towns have their best districts in the West;38 which choice the French savans, Pelouze, Pouillet, Boussingault, and Elie de Beaumont, attribute to the law of atmospheric pressure. “When,” say they, “the barometric column rises, smoke and pernicious emanations rapidly evaporate in space.” On the contrary, smoke and noxious vapours remain in apartments, and on the surface of the soil. Now, of all winds, that which causes the greatest ascension of the barometric column is the east; and that which lowers it most is the west. When the latter blows, it carries with it to the eastern parts of the town all the deleterious gases from the west; and thus the inhabitants of the east have to support their own smoke and miasma, and those brought by western winds. When, on the contrary, the east wind blows, it purifies the air by causing to ascend the pernicious emanations which it cannot drive to the west. Consequently, the inhabitants of the west receive pure air, from whatever part of the horizon it may arrive; and as the west winds are most prevalent, they are the first to receive the air pure, and as it arrives from the country.

FERTILISATION OF CLOUDS.

As the navigator cruises in the Pacific Ocean among the islands of the trade-wind region, he sees gorgeous piles of cumuli, heaped up in fleecy masses, not only capping the island hills, but often overhanging the lowest islet of the tropics, and even standing above coral patches and hidden reefs; “a cloud by day.” to serve as a beacon to the lonely mariner out there at sea, and to warn him of shoals and dangers which no lead nor seaman’s eye has ever seen or sounded. These clouds, under favourable circumstances, may be seen gathering above the low coral island, preparing it for vegetation and fruitfulness in a very striking manner. As they are condensed into showers, one fancies that they are a sponge of the most exquisite and delicately elaborated material, and that he can see, as they “drop down their fatness,” the invisible but bountiful hand aloft that is pressing and squeezing it out.—Maury.

BAROMETRIC MEASUREMENT.

We must not place too implicit a dependence on Barometrical Measurements. Ermann in Siberia, and Ross in the Antarctic Seas, have demonstrated the existence of localities on the earth’s surface where a permanent depression of the barometer prevails to the astonishing extent of nearly an inch.

GIGANTIC BAROMETER.

In the Great Exhibition Building of 1851 was a colossal Barometer, the tube and scale reaching from the floor of the gallery nearly to the top of the building, and the rise and fall of the indicating fluid being marked by feet instead of by tenths of inches. The column of mercury, supported by the pressure of the atmosphere, communicated with a perpendicular tube of smaller bore, which contained a coloured fluid much lighter than mercury. When a diminution of atmospheric pressure occurred, the mercury in the large tube descended, and by its fall forced up the coloured fluid in the smaller tube; the fall of the one being indicated in a magnified ratio by the rise in the other.

THE ATMOSPHERE COMPARED TO A STEAM-ENGINE.

In this comparison, by Lieut. Maury, the South Seas themselves, in all their vast intertropical extent, are the boiler for the engine, and the northern hemisphere is its condenser. The mechanical power exerted by the air and the sun in lifting water from the earth, in transporting it from one place to another, and in letting it down again, is inconceivably great. The utilitarian who compares the water-power that the Falls of Niagara would afford if applied to machinery is astonished at the number of figures which are required to express its equivalent in horse-power. Yet what is the horse-power of the Niagara, falling a few steps, in comparison with the horse-power that is required to lift up as high as the clouds and let down again all the water that is discharged into the sea, not only by this river, but by all the other rivers in the world? The calculation has been made by engineers; and according to it, the force of making and lifting vapour from each area of one acre that is included on the surface of the earth, is equal to the power of thirty horses; and for the whole of the earth, it is 800 times greater than all the water-power in Europe.

HOW DOES THE RAIN-MAKING VAPOUR GET FROM THE SOUTHERN INTO THE NORTHERN HEMISPHERE?

This comes with such regularity, that our rivers never go dry, and our springs fail not, because of the exact compensation of the grand machine of the atmosphere. It is exquisitely and wonderfully counterpoised. Late in the autumn of the north, throughout its winter, and in early spring, the sun is pouring his rays with the greatest intensity down upon the seas of the southern hemisphere; and this powerful engine, which we are contemplating, is pumping up the water there with the greatest activity; at the same time, the mean temperature of the entire southern hemisphere is about 10° higher than the northern. The heat which this heavy evaporation absorbs becomes latent, and with the moisture is carried through the upper regions of the atmosphere until it reaches our climates. Here the vapour is formed into clouds, condensed and precipitated; the heat which held their water in the state of vapour is set free, and becomes sensible heat; and it is that which contributes so much to temper our winter climate. It clouds up in winter, turns warm, and we say we are going to have falling weather: that is because the process of condensation has already commenced, though no rain or snow may have fallen. Thus we feel this southern heat, that has been collected by the rays of the sun by the sea, been bottled away by the winds in the clouds of a southern summer, and set free in the process of condensation in our northern winter.

Thus the South Seas should supply mainly the water for the engine just described, while the northern hemisphere condenses it; we should, therefore, have more rain in the northern hemisphere. The rivers tell us that we have, at least on the land; for the great water-courses of the globe, and half the fresh water in the world, are found on the north side of the equator. This fact is strongly corroborative of this hypothesis. To evaporate water enough annually from the ocean to cover the earth, on the average, five feet deep with rain; to transport it from one zone to another; and to precipitate it in the right places at suitable times and in the proportions due,—is one of the offices of the grand atmospherical machine. This water is evaporated principally from the torrid zone. Supposing it all to come thence, we shall have encircling the earth a belt of ocean 3000 miles in breadth, from which this atmosphere evaporates a layer of water annually sixteen feet in depth. And to hoist up as high as the clouds, and lower down again, all the water, in a lake sixteen feet deep and 3000 miles broad and 24,000 long, is the yearly business of this invisible machinery. What a powerful engine is the atmosphere! and how nicely adjusted must be all the cogs and wheels and springs and compensations of this exquisite piece of machinery, that it never wears out nor breaks down, nor fails to do its work at the right time and in the right way!—Maury.

THE PHILOSOPHY OF RAIN.

To understand the philosophy of this beautiful and often sublime phenomenon, a few facts derived from observation and a long train of experiments must be remembered.

1. Were the atmosphere every where at all times at a uniform temperature, we should never have rain, or hail, or snow. The water absorbed by it in evaporation from the sea and the earth’s surface would descend in an imperceptible vapour, or cease to be absorbed by the air when it was once fully saturated.

2. The absorbing power of the atmosphere, and consequently its capability to retain humidity, is proportionally greater in warm than in cold air.

3. The air near the surface of the earth is warmer than it is in the region of the clouds. The higher we ascend from the earth, the colder do we find the atmosphere. Hence the perpetual snow on very high mountains in the hottest climate.

Now when, from continued evaporation, the air is highly saturated with vapour, though it be invisible and the sky cloudless, if its temperature is suddenly reduced by cold currents descending from above or rushing from a higher to a lower latitude, its capacity to retain moisture is diminished, clouds are formed, and the result is rain. Air condenses as it cools, and, like a sponge filled with water and compressed, pours out the water which its diminished capacity cannot hold. What but Omniscience could have devised such an admirable arrangement for watering the earth?

INORDINATE RAINY CLIMATE.

The climate of the Khasia mountains, which lie north-east from Calcutta, and are separated by the valley of the Burrampooter River from the Himalaya range, is remarkable for the inordinate fall of rain—the greatest, it is said, which has ever been recorded. Mr. Yule, an English gentleman, established that in the single month of August 1841 there fell 264 inches of rain, or 22 feet, of which 12½ feet fell in the space of five consecutive days. This astonishing fact is confirmed by two other English travellers, who measured 30 inches of rain in twenty-four hours, and during seven months above 500 inches. This great rain-fall is attributed to the abruptness of the mountains which face the Bay of Bengal, and the intervening flat swamps 200 miles in extent. The district of the excessive rain is extremely limited; and but a few degrees farther west, rain is said to be almost unknown, and the winter falls of snow to seldom exceed two inches.

HOW DOES THE NORTH WIND DRIVE AWAY RAIN?

We may liken it to a wet sponge, and the decrease of temperature to the hand that squeezes that sponge. Finally, reaching the cold latitudes, all the moisture that a dew-point of zero, and even far below, can extract, is wrung from it; and this air then commences “to return according to his circuits” as dry atmosphere. And here we can quote Scripture again: “The north wind driveth away rain.” This is a meteorological fact of high authority and great importance in the study of the circulation of the atmosphere.—Maury.

SIZE OF RAIN-DROPS.

The Drops of Rain vary in their size, perhaps from the 25th to the ¼ of an inch in diameter. In parting from the clouds, they precipitate their descent till the increasing resistance opposed by the air becomes equal to their weight, when they continue to fall with uniform velocity. This velocity is, therefore, in a certain ratio to the diameter of the drops; hence thunder and other showers in which the drops are large pour down faster than a drizzling rain. A drop of the 25th part of an inch, in falling through the air, would, when it had arrived at its uniform velocity, only acquire a celerity of 11½ feet per second; while one of ¼ of an inch would equal a velocity of 33½ feet.—Leslie.

RAINLESS DISTRICTS.

In several parts of the world there is no rain at all. In the Old World there are two districts of this kind: the desert of Sahara in Africa, and in Asia part of Arabia, Syria, and Persia; the other district lies between north latitude 30° and 50°, and between 75° and 118° of east longitude, including Thibet, Gobiar Shama, and Mongolia. In the New World the rainless districts are of much less magnitude, occupying two narrow strips on the shores of Peru and Bolivia, and on the coast of Mexico and Guatemala, with a small district between Trinidad and Panama on the coast of Venezuela.

ALL THE RAIN IN THE WORLD.

The Pacific Ocean and the Indian Ocean may be considered as one sheet of water covering an area quite equal in extent to one half of that embraced by the whole surface of the earth; and the total annual fall of rain on the earth’s surface is 186,240 cubic imperial miles. Not less than three-fourths of the vapour which makes this rain comes from this waste of waters; but, supposing that only half of this quantity, that is 93,120 cubic miles of rain, falls upon this sea, and that that much at least is taken up from it again as vapour, this would give 255 cubic miles as the quantity of water which is daily lifted up and poured back again into this expanse. It is taken up at one place, and rained down at another; and in this process, therefore, we have agencies for multitudes of partial and conflicting currents, all, in their set strength, apparently as uncertain as the winds.

The better to appreciate the operation of such agencies in producing currents in the sea, imagine a district of 255 square miles to be set apart in the midst of the Pacific Ocean as the scene of operations for one day; then conceive a machine capable of pumping up in the twenty-four hours all the water to the depth of one mile in this district. The machine must not only pump up and bear off this immense quantity of water, but it must discharge it again into the sea on the same day, but at some other place.

All the great rivers of America, Europe, and Asia are lifted up by the atmosphere, and flow in invisible streams back through the air to their sources among the hills; and through channels so regular, certain, and well defined, that the quantity thus conveyed one year with the other is nearly the same: for that is the quantity which we see running down to the ocean through these rivers; and the quantity discharged annually by each river is, as far as we can judge, nearly a constant.—Maury.

AN INCH OF RAIN ON THE ATLANTIC.

Lieutenant Maury thus computes the effect of a single Inch of Rain falling upon the Atlantic Ocean. The Atlantic includes an area of twenty-five millions of square miles. Suppose an inch of rain to fall upon only one-fifth of this vast expanse. It would weigh, says our author, three hundred and sixty thousand millions of tons: and the salt which, as water, it held in solution in the sea, and which, when that water was taken up as vapour, was left behind to disturb equilibrium, weighed sixteen millions more of tons, or nearly twice as much as all the ships in the world could carry at a cargo each. It might fall in an hour, or it might fall in a day; but, occupy what time it might in falling, this rain is calculated to exert so much force—which is inconceivably great—in disturbing the equilibrium of the ocean. If all the water discharged by the Mississippi river during the year were taken up in one mighty measure, and cast into the ocean at one effort, it would not make a greater disturbance in the equilibrium of the sea than would the fall of rain supposed. And yet so gentle are the operations of nature, that movements so vast are unperceived.

THE EQUATORIAL CLOUD-RING.

In crossing the Equatorial Doldrums, the voyager passes a ring of clouds that encircles the earth, and is stretched around our planet to regulate the quantity of precipitation in the rain-belt beneath it; to preserve the due quantum of heat on the face of the earth; to adjust the winds; and send out for distribution to the four corners vapours in proper quantities, to make up to each river-basin, climate, and season, its quota of sunshine, cloud, and moisture. Like the balance-wheel of a well-constructed chronometer, this cloud-ring affords the grand atmospherical machine the most exquisitely arranged self-compensation. Nature herself has hung a thermometer under this cloud-belt that is more perfect than any that man can construct, and its indications are not to be mistaken.—Maury.

“THE EQUATORIAL DOLDRUMS”

is another of these calm places. Besides being a region of calms and baffling winds, it is a region noted for its rains and clouds, which make it one of the most oppressive and disagreeable places at sea. The emigrant ships from Europe for Australia have to cross it. They are often baffled in it for two or three weeks; then the children and the passengers who are of delicate health suffer most. It is a frightful graveyard on the wayside to that golden land.

BEAUTY OF THE DEW-DROP.

The Dew-drop is familiar to every one from earliest infancy. Resting in luminous beads on the down of leaves, or pendent from the finest blades of grass, or threaded upon the floating lines of the gossamer, its “orient pearl” varies in size from the diameter of a small pea to the most minute atom that can be imagined to exist. Each of these, like the rain-drops, has the properties of reflecting and refracting light; hence, from so many minute prisms, the unfolded rays of the sun are sent up to the eye in colours of brilliancy similar to those of the rainbow. When the sunbeams traverse horizontally a very thickly-bedewed grass-plot, these colours arrange themselves so as to form an iris, or dew-bow; and if we select any one of these drops for observation, and steadily regard it while we gradually change our position, we shall find the prismatic colours follow each other in their regular order.—Wells.

FALL OF DEW IN ONE YEAR.

The annual average quantity of Dew deposited in this country is estimated at a depth of about five inches, being about one-seventh of the mean quantity of moisture supposed to be received from the atmosphere all over Great Britain in the year; or about 22,161,337,355 tons, taking the ton at 252 imperial gallons.—Wells.

GRADUATED SUPPLY OF DEW TO VEGETATION.

Each of the different grasses draws from the atmosphere during the night a supply of dew to recruit its energies dependent upon its form and peculiar radiating power. Every flower has a power of radiation of its own, subject to changes during the day and night, and the deposition of moisture on it is regulated by the peculiar law which this radiating power obeys; and this power will be influenced by the aspect which the flower presents to the sky, unfolding to the contemplative mind the most beautiful example of creative wisdom.39

WARMTH OF SNOW IN ARCTIC LATITUDES.

The first warm Snows of August and September (says Dr. Kane), falling on a thickly-bleached carpet of grasses, heaths, and willows, enshrine the flowery growths which nestle round them in a non-conducting air chamber; and as each successive snow increases the thickness of the cover, we have, before the intense cold of winter sets in, a light cellular bed covered by drift, seven, eight, or ten feet deep, in which the plant retains its vitality. Dr. Kane has proved by experiments that the conducting power of the snow is proportioned to its compression by winds, rains, drifts, and congelation. The drifts that accumulate during nine months of the year are dispersed in well-defined layers of different density. We have first the warm cellular snows of fall, which surround the plant; next the finely-impacted snow-dust of winter; and above these the later humid deposits of spring. In the earlier summer, in the inclined slopes that face the sun, as the upper snow is melted and sinks upon the more compact layer below it is to a great extent arrested, and runs off like rain from a slope of clay. The plant reposes thus in its cellular bed, safe from the rush of waters, and protected from the nightly frosts by the icy roof above it.

IMPURITY OF SNOW.

It is believed that in ascending mountains difficult breathing is sooner felt upon snow than upon rock; and M. Boussingault, in his account of the ascent of Chimborazo, attributes this to the sensible deficiency of oxygen contained in the pores of the snow, which is exhaled when it melts. The fact that the air absorbed by snow is impure, was ascertained by De Saussure, and has been confirmed by Boussingault’s experiments.—Quarterly Review, No. 202.

SNOW PHENOMENON.

Professor Dove of Berlin relates, in illustration of the formation of clouds of Snow over plains situated at a distance from the cooling summits of mountains, that on one occasion a large company had gathered in a ballroom in Sweden. It was one of those icy starlight nights which in that country are so aptly called “iron nights.” The weather was clear and cold, and the ballroom was clear and warm; and the heat was so great, that several ladies fainted. An officer present tried to open a window; but it was frozen fast to the sill. As a last resort, he broke a pane of glass; the cold air rushed in, and it snowed in the room. A minute before all was clear; but the warm air of the room had sustained an amount of moisture in a transparent condition which it was not able to maintain when mixed with the colder air from without. The vapour was first condensed, and then frozen.

ABSENCE OF SNOW IN SIBERIA.

There is in Siberia, M. Ermann informs us, an entire district in which during the winter the sky is constantly clear, and where a single particle of snow never falls.—Arago.

ACCURACY OF THE CHINESE AS OBSERVERS.

The beautiful forms of snow-crystals have long since attracted Chinese observers; for from a remote period there has been met with in their conversation and books an axiomatic expression, to the effect that “snow-flakes are hexagonal,” showing the Chinese to be accurate observers of nature.

PROTECTION AGAINST HAIL AND STORMS.

Arago relates, that when, in 1847, two small agricultural districts of Bourgoyne had lost by Hail crops to the value of a million and a half of francs, certain of the proprietors went to consult him on the means of protecting them from like disasters. Resting on the hypothesis of the electric origin of hail, Arago suggested the discharge of the electricity of the clouds by means of balloons communicating by a metallic wire with the soil. This project was not carried out; but Arago persisted in believing in the effectiveness of the method proposed.

Arago, in his Meteorological Essays, inquires whether the firing of cannon can dissipate storms. He cites several cases in its favour, and others which seem to oppose it; but he concludes by recommending it to his successors. Whilst Arago was propounding these questions, a person not conversant with science, the poet MÉry, was collecting facts supporting the view, which he has published in his Paris Futur. His attention was attracted to the firing of cannon to dissipate storms in 1828, whilst an assistant in the “Ecole de Tir” at Vincennes. Having observed that there was never any rain in the morning of the exercise of firing, he waited to examine military records, and found there, as he says, facts which justified the expressions of “Le soleil d’Austerlitz,” “Le soleil de juillet,” upon the morning of the Revolution of July; and he concluded by proposing to construct around Paris twelve towers of great height, which he calls “tours imbrifuges,” each carrying 100 cannons, which should be discharged into the air on the approach of a storm. About this time an incident occurred which in nowise confirmed the truth of M. MÉry’s theory. The 14th of August was a fine day. On the 15th, the fÊte of the Empire, the sun shone out, the cannon thundered all day long, fireworks and illuminations were blazing from nine o’clock in the evening. Every thing conspired to verify the hypothesis of M. MÉry, and chase away storms for a long time. But towards eleven in the evening a torrent of rain burst upon Paris, in spite of the pretended influence of the discharge of cannon, and gave an occasion for the mobile Gallic mind to turn its attention in other directions.

TERRIFIC HAILSTORM.

Jansen describes, from the log-book of the Rhijin, Captain Brandligt, in the South-Indian Ocean (25° south latitude) a Hurricane, accompanied by Hail, by which several of the crew were made blind, others had their faces cut open, and those who were in the rigging had their clothes torn off them. The master of the ship compared the sea “to a hilly landscape in winter covered with snow.” Does it not appear as if the “treasures of the hail” were opened, which were “reserved against the time of trouble, against the day of battle and war”?

HOW WATERSPOUTS ARE FORMED IN THE JAVA SEA.

Among the small groups of islands in this sea, in the day and night thunderstorms, the combat of the clouds appears to make them more thirsty than ever. In tunnel form, when they can no longer quench their thirst from the surrounding atmosphere, they descend near the surface of the sea, and appear to lap the water directly up with their black mouths. They are not always accompanied by strong winds; frequently more than one is seen at a time, whereupon the clouds whence they proceed disperse, and the ends of the Waterspouts bending over finally causes them to break in the middle. They seldom last longer than five minutes. As they are going away, the bulbous tube, which is as palpable as that of a thermometer, becomes broader at the base; and little clouds, like steam from the pipe of a locomotive, are continually thrown off from the circumference of the spout, and gradually the water is released, and the cloud whence the spout came again closes its mouth.

COLD IN HUDSON’S BAY.

Mr. R. M. Ballantyne, in his journal of six years’ residence in the territories of the Hudson’s Bay Company, tells us, that for part of October there is sometimes a little warm, or rather thawy, weather; but after that, until the following April, the thermometer seldom rises to the freezing point. In the depth of winter, the thermometer falls from 30° to 40°, 45°, and even 49° below zero of Fahrenheit. This intense cold is not, however, so much felt as one might suppose; for during its continuance the air is perfectly calm. Were the slightest breath of wind to rise when the thermometer stands so low, no man could show his face to it for a moment. Forty degrees below zero, and quite calm, is infinitely preferable to fifteen below, or thereabout, with a strong breeze of wind. Spirit of wine is, of course, the only thing that can be used in the thermometer; as mercury, were it exposed to such cold, would remain frozen nearly half the winter. Spirit never froze in any cold ever experienced at York Factory, unless when very much adulterated with water; and even then the spirit would remain liquid in the centre of the mass. Quicksilver easily freezes in this climate, and it has frequently been run into a bullet-mould, exposed to the cold air till frozen, and in this state rammed down a gun-barrel, and fired through a thick plank. The average cold may be set down at about 15° or 16° below zero, or 48° of frost. The houses at the Bay are built of wood, with double windows and doors. They are heated by large iron stoves, fed with wood; yet so intense is the cold, that when a stove has been in places red-hot, a basin of water in the room has been frozen solid.

PURITY OF WENHAM-LAKE ICE.

Professor Faraday attributes the purity of Wenham-Lake Ice to its being free from air-bubbles and from salts. The presence of the first makes it extremely difficult to succeed in making a lens of English ice which will concentrate the solar rays, and readily fire gunpowder; whereas nothing is easier than to perform this singular feat of igniting a combustible body by aid of a frozen mass if Wenham-Lake ice be employed. The absence of salts conduces greatly to the permanence of the ice; for where water is so frozen that the salts expelled are still contained in air-cavities and cracks, or form thin films between the layers of ice, these entangled salts cause the ice to melt at a lower temperature than 32°, and the liquefied portions give rise to streams and currents within the body of the ice which rapidly carry heat to the interior. The mass then goes on thawing within as well as without, and at temperatures below 32°; whereas pure, compact, Wenham-Lake ice can only thaw at 32°, and only on the outside of the mass.—Sir Charles Lyell’s Second Visit to the United States.

ARCTIC TEMPERATURES.

Dr. Kane, in his Second Arctic Expedition, found the thermometers beginning to show unexampled temperature: they ranged from 60° to 70° below zero, and upon the taffrail of the brig 65°. The reduced mean of the best spirit-standards gave 67° or 99° below the freezing point of water. At these temperatures chloric ether became solid, and chloroform exhibited a granular pellicle on its surface. Spirit of naphtha froze at 54°, and the oil of turpentine was solid at 63° and 65°.

DR. RAE’S ARCTIC EXPLORATIONS.

The gold medal of the Royal Geographical Society was in 1852 most rightfully awarded to this indefatigable Arctic explorer. His survey of the inlet of Boothia, in 1848, was unique in its kind. In Repulse Bay he maintained his party on deer, principally shot by himself; and spent ten months of an Arctic winter in a hut of stones, with no other fuel than a kind of hay of the Andromeda tetragona. Thus he preserved his men to execute surveying journeys of 1000 miles in the spring. Later he travelled 300 miles on snow-shoes. In a spring journey over the ice, with a pound of fat daily for fuel, accompanied by two men only, and trusting solely for shelter to snow-houses, which he taught his men to build, he accomplished 1060 miles in thirty-nine days, or twenty-seven miles per day, including stoppages,—a feat never equalled in Arctic travelling. In the spring journey, and that which followed in the summer in boats, 1700 miles were traversed in eighty days. Dr. Rae’s greatest sufferings, he once remarked to Sir George Back, arose from his being obliged to sleep upon his frozen mocassins in order to thaw them for the morning’s use.

PHENOMENA OF THE ARCTIC CLIMATE.

Sir John Richardson, in his history of his Expedition to these regions, describes the power of the sun in a cloudless sky to have been so great, that he was glad to take shelter in the water while the crews were engaged on the portages; and he has never felt the direct rays of the sun so oppressive as on some occasions in the high latitudes. Sir John observes:

The rapid evaporation of both snow and ice in the winter and spring, long before the action of the sun has produced the slightest thaw or appearance of moisture, is evident by many facts of daily occurrence. Thus when a shirt, after being washed, is exposed in the open air to a temperature of from 40° to 50° below zero, it is instantly rigidly frozen, and may be broken if violently bent. If agitated when in this condition by a strong wind, it makes a rustling noise like theatrical thunder.

In consequence of the extreme dryness of the atmosphere in winter, most articles of English manufacture brought to Rupert’s Land are shrivelled, bent, and broken. The handles of razors and knives, combs, ivory scales, &c., kept in the warm room, are changed in this way. The human body also becomes vividly electric from the dryness of the skin. One cold night I rose from my bed, and was going out to observe the thermometer, with no other clothing than my flannel night-dress, when on my hand approaching the iron latch of the door, a distinct spark was elicited. Friction of the skin at almost all times in winter produced the electric odour.

Even at midwinter we had but three hours and a half of daylight. On December 20th I required a candle to write at the window at ten in the morning. The sun was absent ten days, and its place in the heavens at noon was denoted by rays of light shooting into the sky above the woods.

The moon in the long nights was a most beautiful object, that satellite being constantly above the horizon for nearly a fortnight together. Venus also shone with a brilliancy which is never witnessed in a sky loaded with vapours; and, unless in snowy weather, our nights were always enlivened by the beams of the aurora.

INTENSE HEAT AND COLD OF THE DESERT.

Among crystalline bodies, rock-crystal, or silica, is the best conductor of heat. This fact accounts for the steadiness of temperature in one set district, and the extremes of Heat and Cold presented by day and night on such sandy wastes as the Sahara. The sand, which is for the most part silica, drinks-in the noon-day heat, and loses it by night just as speedily.

The influence of the hot winds from the Sahara has been observed in vessels traversing the Atlantic at a distance of upwards of 1100 geographical miles from the African shores, by the coating of impalpable dust upon the sails.

TRANSPORTING POWER OF WINDS.

The greatest example of their power is the sand-flood of Africa, which, moving gradually eastward, has overwhelmed all the land capable of tillage west of the Nile, unless sheltered by high mountains, and threatens ultimately to obliterate the rich plain of Egypt.

EXHILARATION IN ASCENDING MOUNTAINS.

At all elevations of from 6000 to 11,000 feet, and not unfrequently for even 2000 feet more, the pedestrian enjoys a pleasurable feeling, imparted by the consciousness of existence, similar to that which is described as so fascinating by those who have become familiar with the desert-life of the East. The body seems lighter, the nervous power greater, the appetite is increased; and fatigue, though felt for a time, is removed by the shortest repose. Some travellers have described the sensation by the impression that they do not actually press the ground, but that the blade of a knife could be inserted between the sole of the foot and the mountain top.—Quarterly Review, No. 202.

TO TELL THE APPROACH OF STORMS.

The proximity of Storms has been ascertained with accuracy by various indications of the electrical state of the atmosphere. Thus Professor Scott, of Sandhurst College, observed in Shetland that drinking-glasses, placed in an inverted position upon a shelf in a cupboard on the ground-floor of Belmont House, occasionally emitted sounds as if they were tapped with a knife, or raised a little and then let fall on the shelf. These sounds preceded wind; and when they occurred, boats and vessels were immediately secured. The strength of the sound is said to be proportioned to the tempest that follows.

REVOLVING STORMS.

By the conjoint labours of Mr. Redfield, Colonel Reid, and Mr. Piddington, on the origin and nature of hurricanes, typhoons, or revolving storms, the following important results have been obtained. Their existence in moderate latitudes on both sides the equator; their absence in the immediate neighbourhood of the equatorial regions; and the fact, that while in the northern latitudes these storms revolve in a direction contrary to the hands of a watch the face of which is placed upwards, in the southern latitudes they rotate in the opposite direction,—are shown to be so many additions to the long chain of evidence by which the rotation of the earth as a physical fact is demonstrated.

IMPETUS OF A STORM.

Captain Sir S. Brown estimates, from experiments made by him at the extremity of the Brighton-Chain Pier in a heavy south-west gale, that the waves impinge on a cylindrical surface one foot high and one foot in diameter with a force equal to eighty pounds, to which must be added that of the wind, which in a violent storm exerts a pressure of forty pounds. He computed the collective impetus of the waves on the lower part of a lighthouse proposed to be built on the Wolf Rock (exposed to the most violent storms of the Atlantic), of the surf on the upper part, and of the wind on the whole, to be equal to 100 tons.

HOW TO MAKE A STORM-GLASS.

This instrument consists of a glass tube, sealed at one end, and furnished with a brass cap at the other end, through which the air is admitted by a very small aperture. Nearly fill the tube with the following solution: camphor, 2½ drams; nitrate of potash, 38 grains; muriate of ammonia, 38 grains; water, 9 drams; rectified spirit, 9 drams. Dissolve with heat. At the ordinary temperature of the atmosphere, plumose crystals are formed. On the approach of stormy weather, these crystals appear compressed into a compact mass at the bottom of the tube; while during fine weather they assume their plumose character, and extend a considerable way up the glass. These results depend upon the condition of the air, but they are not considered to afford any reliable indication of approaching weather.

SPLENDOUR OF THE AURORA BOREALIS.

Humboldt thus beautifully describes this phenomenon:

The intensity of this light is at times so great, that LowenÖrn (on June 29, 1786) recognised its coruscation in bright sunshine. Motion renders the phenomenon more visible. Round the point in the vault of heaven which corresponds to the direction of the inclination of the needle the beams unite together to form the so-called corona, the crown of the Northern Light, which encircles the summit of the heavenly canopy with a milder radiance and unflickering emanations of light. It is only in rare instances that a perfect crown or circle is formed; but on its completion, the phenomenon has invariably reached its maximum, and the radiations become less frequent, shorter, and more colourless. The crown, and the luminous arches break up; and the whole vault of heaven becomes covered with irregularly scattered, broad, faint, almost ashy-gray, luminous, immovable patches, which in their turn disappear, leaving nothing but a trace of a dark smoke-like segment on the horizon. There often remains nothing of the whole spectacle but a white delicate cloud with feathery edges, or divided at equal distances into small roundish groups like cirro-cumuli.—Cosmos, vol. i.

Among many theories of this phenomenon is that of Lieutenant Hooper, R.N., who has stated to the British Association that he believes “the Aurora Borealis to be no more nor less than the moisture in some shape (whether dew or vapour, liquid or frozen), illuminated by the heavenly bodies, either directly, or reflecting their rays from the frozen masses around the Pole, or even from the immediately proximate snow-clad earth.”

VARIETIES OF LIGHTNING.

According to Arago’s investigations, the evolution of Lightning is of three kinds: zigzag, and sharply defined at the edges; in sheets of light, illuminating a whole cloud, which seems to open and reveal the light within it; and in the form of fire-balls. The duration of the first two kinds scarcely continues the thousandth part of a second; but the globular lightning moves much more slowly, remaining visible for several seconds.

WHAT IS SHEET-LIGHTNING?

This electric phenomenon is unaccompanied by thunder, or too distant to be heard: when it appears, the whole sky, but particularly the horizon, is suddenly illuminated with a flickering flash. Philosophers differ much as to its cause. Matteucci supposes it to be produced either during evaporation, or evolved (according to Pouillet’s theory) in the process of vegetation; or generated by chemical action in the great laboratory of nature, the earth, and accumulated in the lower strata of the air in consequence of the ground being an imperfect conductor.

Arago and Kamtz, however, consider sheet-lightning as reflections of distant thunderstorms. Saussure observed sheet-lightning in the direction of Geneva, from the Hospice du Grimsel, on the 10th and 11th of July 1783; while at the same time a terrific thunderstorm raged at Geneva. Howard, from Tottenham, near London, on July 31, 1813, saw sheet-lightning towards the south-east, while the sky was bespangled with stars, not a cloud floating in the air; at the same time a thunderstorm raged at Hastings, and in France from Calais to Dunkirk. Arago supports his opinion, that the phenomenon is reflected lightning, by the following illustration: In 1803, when observations were being made for determining the longitude, M. de Zach, on the Brocken, used a few ounces of gunpowder as a signal, the flash of which was visible from the Klenlenberg, sixty leagues off, although these mountains are invisible from each other.

PRODUCTION OF LIGHTNING BY RAIN.

A sudden gust of rain is almost sure to succeed a violent detonation immediately overhead. Mr. Birt, the meteorologist, asks: Is this rain a cause or consequence of the electric discharge? To this he replies:

In the sudden agglomeration of many minute and feebly electrified globules into one rain-drop, the quantity of electricity is increased in a greater proportion than the surface over which (according to the laws of electric distribution) it is spread. By tension, therefore, it is increased, and may attain the point when it is capable of separating from the drop to seek the surface of the cloud, or of the newly-formed descending body of rain, which, under such circumstances, may be regarded as a conducting medium. Arrived at this surface, the tension, for the same reason, becomes enormous, and a flash escapes. This theory Mr. Birt has confirmed by observation of rain in thunderstorms.

SERVICE OF LIGHTNING-CONDUCTORS.

Sir David Brewster relates a remarkable instance of a tree in Clandeboye Park, in a thick mass of wood, and not the tallest of the group, being struck by lightning, which passed down the trunk into the ground, rending the tree asunder. This shows that an object may be struck by lightning in a locality where there are numerous conducting points more elevated than itself; and at the same time proves that lightning cannot be diverted from its course by lofty isolated conductors, but that the protection of buildings from this species of meteor can only be effected by conductors stretching out in all directions.

Professor Silliman states, that lightning-rods cannot be relied upon unless they reach the earth where it is permanently wet; and that the best security is afforded by carrying the rod, or some good metallic conductor duly connected with it, to the water in the well, or to some other water that never fails. The professor’s house, it seems, was struck; but his lightning-rods were not more than two or three inches in the ground, and were therefore virtually of no avail in protecting the building.

ANCIENT LIGHTNING-CONDUCTOR.

Humboldt informs us, that “the most important ancient notice of the relations between lightning and conducting metals is that of Ctesias, in his Indica, cap. iv. p. 190. He possessed two iron swords, presents from the king Artaxerxes Mnemon and from his mother Parasytis, which, when planted in the earth, averted clouds, hail, and strokes of lightning. He had himself seen the operation, for the king had twice made the experiment before his eyes.”—Cosmos, vol. ii.

THE TEMPLE OF JERUSALEM PROTECTED FROM LIGHTNING.

We do not learn, either from the Bible or Josephus, that the Temple at Jerusalem was ever struck by Lightning during an interval of more than a thousand years, from the time of Solomon to the year 70; although, from its situation, it was completely exposed to the violent thunderstorms of Palestine.

By a fortuitous circumstance, the Temple was crowned with lightning-conductors similar to those which we now employ, and which we owe to Franklin’s discovery. The roof, constructed in what we call the Italian manner, and covered with boards of cedar, having a thick coating of gold, was garnished from end to end with long pointed and gilt iron or steel lances, which, Josephus says, were intended to prevent birds from roosting on the roof and soiling it. The walls were overlaid throughout with wood, thickly gilt. Lastly, there were in the courts of the Temple cisterns, into which the rain from the roof was conducted by metallic pipes. We have here both the lightning-rods and a means of conduction so abundant, that Lichtenberg is quite right in saying that many of the present apparatuses are far from offering in their construction so satisfactory a combination of circumstances.—Abridged from Arago’s Meteorological Essays.

HOW ST. PAUL’S CATHEDRAL IS PROTECTED FROM LIGHTNING.

In March 1769, the Dean and Chapter of St. Paul’s addressed a letter to the Royal Society, requesting their opinion as to the best and most effectual method of fixing electrical conductors on the cathedral. A committee was formed for the purpose, and Benjamin Franklin was one of the members; their report was made, and the conductors were fixed as follows:

The seven iron scrolls supporting the ball and cross are connected with other rods (used merely as conductors), which unite them with several large bars, descending obliquely to the stone-work of the lantern, and connected by an iron ring with four other iron bars to the lead covering of the great cupola, a distance of forty-eight feet; thence the communication is continued by the rain-water pipes to the lead-covered roof, and thence by lead water-pipes which pass into the earth; thus completing the entire communication from the cross to the ground, partly through iron, and partly through lead. On the clock-tower a bar of iron connects the pine-apple at the top with the iron staircase, and thence with the lead on the roof of the church. The bell-tower is similarly protected. By these means the metal used in the building is made available as conductors; the metal employed merely for that purpose being exceedingly small in quantity.—Curiosities of London.

VARIOUS EFFECTS OF LIGHTNING.

Dr. Hibbert tells us that upon the western coast of Scotland and Ireland, Lightning coÖperates with the violence of the storm in shattering solid rocks, and heaping them in piles of enormous fragments, both on dry land and beneath the water.

Euler informs us, in his Letters to a German Princess, that he corresponded with a Moravian priest named Divisch, who assured him that he had averted during a whole summer every thunderstorm which threatened his own habitation and the neighbourhood, by means of a machine constructed upon the principles of electricity; that the machinery sensibly attracted the clouds, and constrained them to descend quietly in a distillation, without any but a very distant thunderclap. Euler assures us that “the fact is undoubted, and confirmed by irresistible proof.”

About the year 1811, in the village of Phillipsthal, in Eastern Prussia, an attempt was made to split an immense stone into a multitude of pieces by means of lightning. A bar of iron, in the form of a conductor, was previously fixed to the stone; and the experiment was attended with complete success; for during the very first thunderstorm the lightning burst the stone without displacing it.

The celebrated Duhamel du Monceau says, that lightning, unaccompanied by thunder, wind, or rain, has the property of breaking oat-stalks. The farmers are acquainted with this effect, and say that the lightning breaks down the oats. This is a well-received opinion with the farmers in Devonshire.

Lightning has in some cases the property of reducing solid bodies to ashes, or to pulverisation,—even the human body,—without there being any signs of heat. The effects of lightning on paralysis are very remarkable, in some cases curing, in others causing, that disease.

The returning stroke of lightning is well known to be due to the restoration of the natural electric state, after it has been disturbed by induction.

A THUNDERSTORM SEEN FROM A BALLOON.

Mr. John West, the American aeronaut, in his observations made during his numerous ascents, describes a storm viewed from above the clouds to have the appearance of ebullition. The bulging upper surface of the cloud resembles a vast sea of boiling and upheaving snow; the noise of the falling rain is like that of a waterfall over a precipice; the thunder above the cloud is not loud, and the flashes of lightning appear like streaks of intensely white fire on a surface of white vapour. He thus describes a side view of a storm which he witnessed June 3, 1852, in his balloon excursion from Portsmouth, Ohio:

Although the sun was shining on me, the rain and small hail were rattling on the balloon. A rainbow, or prismatically-coloured arch or horse-shoe, was reflected against the sun; and as the point of observation changed laterally and perpendicularly, the perspective of this golden grotto changed its hues and forms. Above and behind this arch was going on the most terrific thunder; but no zigzag lightning was perceptible, only bright flashes, like explosions of “Roman candles” in fireworks. Occasionally there was a zigzag explosion in the cloud immediately below, the thunder sounding like a feu-de-joie of a rifle-corps. Then an orange-coloured wave of light seemed to fall from the upper to the lower cloud; this was “still-lightning.” Meanwhile intense electrical action was going on in the balloon, such as expansion, tremulous tension, lifting papers ten feet out of the car below the balloon and then dropping them, &c. The close view of this Ohio storm was truly sublime; its rushing noise almost appalling.

Ascending from the earth with a balloon, in the rear of a storm, and mounted up a thousand feet above it, the balloon will soon override the storm, and may descend in advance of it. Mr. West has experienced this several times.

REMARKABLE AERONAUTIC VOYAGE.

Mr. Sadler, the celebrated aeronaut, ascended on one occasion in a balloon from Dublin, and was wafted across the Irish Channel; when, on his approach to the Welsh coast, the balloon descended nearly to the surface of the sea. By this time the sun was set, and the shades of evening began to close in. He threw out nearly all his ballast, and suddenly sprang upward to a great height; and by so doing brought his horizon to dip below the sun, producing the whole phenomenon of a western sunrise. Subsequently descending in Wales, he of course witnessed a second sunset on the same evening.—Sir John Herschel’s Outlines of Astronomy.

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