Progress of Science. (continued 2)

Identity of Heat and Motion.

George Stephenson’s remark, that the sun is the agent that drives our locomotives, has attained a wider and more definite meaning from modern investigations. It is now known, not only that heat and motion are mysteriously related, but that they are the same thing. From the researches of Mayer and Joule, Thomson and Rankine, it is ascertained that so much heat can be converted into so much motion, and the motion reconverted into the original quantity of heat. Sir William Armstrong says that a degree of Fahrenheit in a pound of water is the same thing as the force required to lift 772 pounds a foot high, thus testifying to the final and exact establishment of the largest generalization which modern science has made; and among the many fruits which cannot but flow from the discovery, one of the earliest is its application, by Sir William Armstrong himself, to test the waste of power in artillery practice, by observing the heat called forth in the shot. Every degree of temperature added to the projectile is part of the force intended to destroy the target; and if it is asked what material makes the most effective cannon-ball, it is only necessary to ascertain what substance will keep coolest when it strikes the mark. It is observable that the convertibility of heat and motion opens up a new light into the ultimate constitution of matter. The marvellous experiments of Professor Tyndall on the power of the minutest films of gas and vapour to absorb heat, as a dark glass stops light, are equally interesting as valuable contributions to meteorology, and as a new mode of probing the molecular condition of the gases themselves. The laws of the variation of atmospheric temperature were unfathomable until it was discovered that the habitable quality of the earth depends on the floating vapour which clothes it, and which keeps it warm in exactly the same way as the coverings by which we protect our bodies from the inclemency of the weather; but the significance of these experiments goes far beyond the limits of a single branch of science, and again we seem to be hovering on the verge of large revelations as to the ultimate arrangement of the particles of matter.

It is in the development of new powers of testing the infinitesimal, and carrying research immeasurably beyond the coarse limits of microscopic vision, that the strength of recent effort has been displayed. The most startling result of this form of investigation is the insight which has been gained into the materials and the condition of the luminous atmosphere of the sun. It could scarcely have been anticipated that the nature of a body separated from us by millions of miles should have been discovered by experiments which deal with qualities hidden in the inconceivably minute dimensions which express the form and distances of what, for want of better knowledge, may still be termed the ultimate atoms of material substances; and yet it was by testing the light-stopping power of thin films of different vapours, that philosophers have felt themselves entitled to say that some of the same substances which we are familiar with on earth have contributed to the atmosphere of the sun.—Saturday Review.

Universal Source of Heat.

Dr. Percy, in his very able Treatise on Metallurgy, gives an explanation of the principle that the sun is really the source of the heat-producing power of all fuel; and we are inevitably reminded of the question with which George Stephenson puzzled Buckland. “Now, Buckland,” said Stephenson, as they were looking at a train in motion, “can you tell me what is the power that is driving that train?” “Well,” said the other, “I suppose it is one of your big engines.” “But what drives the engine?” “Oh! very likely a canny Newcastle driver.” “What do you say to the light of the sun?” “How can that be?” asked the Doctor. “It is nothing else,” said the engineer: “it is light bottled up in the earth for tens of thousands of years; light, absorbed by plants and vegetables, being necessary for the condensation of carbon during the process of their growth, if it be not carbon in another form,—and now, after being buried in the earth for long ages in fields of coal, that latent light is again brought forth and liberated, made to work, as in that locomotive, for great human purposes.” Dr. Percy explains the process by which this light or heat is stored, and discusses the question of fuel in all its forms and branches. We find under this head, inter multa alia, an account of the manufacture of the peat-bricks in South Bavaria, which have for some years past been used for the boilers of locomotives; again, an explanation of the failure of Mr. Vignoles’s process of manufacturing iron in Ireland by means of peat charcoal, in consequence of the value of the raw material so much exceeding his estimate; besides an elaborate discussion on that litigated question so differently judged by different tribunals, and still undecided—“What is or is not coal?”

Inequalities of the Earth’s Surface.

The earth is a spherical body, or, more correctly, an elliptic spheroid. Its surface, therefore, may be considered equidistant from its centre point within, and of uniform curvature. This is so as regards the ocean, which is

“Unchangeable save to its wild waves’ play;”

but the surface of the land is very diversified. In parts it is spread out into plains; in others, into easy undulations. Here and there it rises into hills, with valleys and extensive basins between them; while at places chains of mountains appear at varying altitudes, some of which penetrate the clouds.

Although the irregularities of the small portion of land which we can see at one view seem very considerable, and more especially the largest mountains, yet these protuberances are insignificant when compared to the magnitude of the earth itself.

Mount Everest, in Nepaul, is the loftiest point of the Himalaya chain, and the highest mountain in the world. It rises 29,002 feet—equal to 5·49 miles,—above the level of the sea. This height is only

( 7912·40 ———— 5·49 ) 1 ———— 1441

part of the earth’s diameter; or equal to 1 inch placed on a globe

( 1441 —— 12 = )

120 feet in diameter. It therefore bears the same proportion to the diameter of the earth that a grain of sand, the ninetieth part of an inch in diameter, does to a globe

( 1441 —— 90 = )

16 inches in diameter.

“If we would construct a correct model of our earth, with its seas, continents, and mountains, on a globe 16 inches in diameter, the whole of the land, with the exception of a few prominent points and ridges, must be comprised on it within the thickness of thin writing paper; and the highest hills would be represented by the smallest visible grains of sand.”[17]

Astronomers have measured the distances and weighed the masses of the planets, yet the height of the atmosphere and the depths of the ocean are unsolved problems. The bottom of “blue water” is almost as unknown to us as the interior of the earth. It is a common opinion that the greatest depths of the sea are about equal to the greatest heights of the mountains. Attempts have been repeatedly made to sound out its depths, but no reliance can be placed on any reports of soundings beyond 8000 or 10,000 feet. One ran out his sounding-line 34,000 feet, and did not touch bottom; another 39,000 feet with the same result; one reported bottom at 49,000 feet, another at 50,000 feet. But there are no such depths. There are currents and counter-currents in the ocean, as in the air, which operate upon the bight of the sounding-line, and cause it to run out after the weight has reached the bottom, so that the shock cannot be felt.

The oceanic circulation is as complete as that of the atmosphere, and is possibly subject to, or governed by, the same laws; and there appears to be a law of descent through “blue water,” the same as there is a law of ascent through “blue air.” The one increases in density downwards as the other decreases in density upwards; and the development of this law proves that the sea is not so deep as reports made it.

There is a set of currents in the sea by which its waters are conveyed from place to place through regular and certain channels, traversing from one ocean to the other with the regularity of the machinery of a watch. The chief motive power of marine currents is caused by heat. But an active agency in the system of circulation is derived from the salts of the sea-water, by winds, marine plants, and animals. These give the ocean great dynamical force.

The only reliable deep-sea soundings are those obtained by Brooke’s plummet; and the greatest depths at which the bottom of the sea has been reached with this plummet are in the North Atlantic Ocean, and do not show it to be deeper than 25,000 feet, the deepest place being immediately to the south of the Grand Banks of Newfoundland. Thus, from the top of Mount Everest to the deepest reliable sea bottom reached by sounding, we have a vertical height of nearly 10¼ miles, equal to

( 7912·40 ———— 10·23 ) 1 —— 773

rd part of the earth’s diameter.—

The Builder.

Chemistry of the Sea.

The specific gravity of Sea-water varies of course with the proportion of salts and the degree of heat it receives from the sun, or by the intermixture of currents of various temperatures; but in our own latitudes it is about 1·028—that is, a given volume of pure distilled water weighing 1000 grains, the same volume of sea-water weighs 1028 grains. Many useful substances are daily extracted from the sea for the use of man, among which we may mention pure water for the use of ships, salt, iodine, bromine, &c. Many attempts have been made to purity sea-water in order to render it potable, not only for supplying ships, but for the use of maritime towns and villages, where pump-water is often brackish, and where the inhabitants are frequently obliged to have recourse to rain-water. Now, when sea-water is submitted to congelation, it abandons its salt almost completely—a fact which appears to have been discovered many years ago by Chevalier Lorgna, who found that a mixture of three parts of pounded ice and two parts of common salt produced a cold of about 4° below the zero of a Fahrenheit thermometer, and that such a mixture caused sea-water to freeze rapidly. A mixture of various chemical salts in proper proportions produces a similar degree of cold. Lately, the cold produced by the evaporation of ether has been proposed for the same purpose. The purification is complete if the ice thus formed be melted and frozen again. In the Polar regions the ice formed from salt-water is more or less opaque, except it be in very small pieces, when it transmits light of a bluish green shade. When melted, it produces sometimes perfectly fresh water, and at other times water slightly brackish. The fresh-water ice resulting from rain or melted snow, as seen floating in the Arctic seas, is distinguished from the salt-water ice by its black appearance, especially when in small pieces, and by its transparency when removed from the water into the air. Its transparency is so great, when compared with sea-ice, that Dr. Scoresby used to amuse his sailors by cutting large lenses out of this fresh-water ice, and using them as burning-glasses to light the men’s pipes. Their astonishment was increased by observing that the ice did not melt, while the solar rays emerging from it were so hot that the hand could not be kept more than a second or two at the focus.—Macmillan’s Magazine.

The Sea: its Perils.

On the surface of the globe there is nowhere to be found so inhospitable a desert as the “wide blue sea.” At any distance from land there is nothing in it for man to eat, nothing in it that he can drink. His tiny foot no sooner rests upon it, than he sinks into his grave: it grows neither flowers nor fruits; it offers monotony to the mind, restless motion to the body; and when, besides all this, one reflects that it is to the most fickle of the elements, the wind, that vessels of all sizes are to supplicate for assistance in sailing in every direction to their various destinations, it would almost seem that the ocean was divested of its charms, and armed with storms, to prevent our being persuaded to enter its dominions.

But though the situation of a vessel in a heavy gale of wind appears indescribably terrific, yet, practically speaking, its security is so great, that it is truly said that ships seldom or never founder in deep water, except from accident or inattention. How ships manage to get across that still region, that ideal line, which separates the opposite trade-winds from each hemisphere; how a small box of men manages, unlabelled, to be buffeted for months up one side of a wave and down another; how they ever get out of the abysses into which they sink; and how, after such pitching and tossing, they reach in safety the very harbour in their native country from which they originally departed—can and ought only to be accounted for, by acknowledging how truly it has been written, that “the Spirit of God moves upon the face of the waters.”

It is not, therefore, from the ocean itself that man has so much to fear: the earth and the water each afford to man a life of considerable security, yet there exists between these two elements an everlasting war, into which no passing vessel can enter with impunity; for of all the terrors of this world, there is surely no one greater than that of being on a lee-shore in a gale of wind, and in shallow water. On this account it is natural enough that the fear of land is as strong in the sailor’s heart as is his attachment to it; and when, homeward bound, he day after day approaches his own latitude, his love and his fears of his native shores increase as the distance between them diminishes. Two fates, the most opposite in their extremes, are shortly to await him. The sailor-boy fancifully pictures to himself that in a few short hours he will be once again nestling in his mother’s arms. The able seaman better knows that it may be decreed for him, as it has been for thousands, that in gaining his point he shall lose its object—that England, with all its virtue, may fade before his eyes, and,

Nor can it be regarded as improbable that in the beds of the present seas the edifices and works of nations, whose history is altogether unknown to existing generations, are embedded and preserved:

Limitations of Astronomy.

These limitations are great. Ages before the existence of scientific astronomy, the question was put to the patriarch Job, “Canst thou bind the sweet influences of Pleiades, or loose the bands of Orion; canst thou bring forth Mazzaroth in his season? or canst thou guide Arcturus with his sons?” And when Job in his heart, if not with his lips, answered the Almighty, No, he answered for all his successors as well as for himself. Astronomical problems accumulate unsolved on our hands, because we cannot, as mechanicians, chemists, or physiologists, experiment upon the stars. Are they built of the same materials as our planet? Are they inhabited? Are Saturn’s rings solid or liquid? Has the moon an atmosphere? Are the atmospheres of the planets like ours? Are the light and heat of the sun begotten of combustion? and what is the fuel which feeds his unquenchable fires? These are but a few of the questions which we ask, and variously answer, but leave in reality unanswered, after all. A war of words regarding the revolution of the moon round her axis may go on to the end of time, because we cannot throw our satellite out of gearing, or bring her to a momentary stand-still; and the problem of the habitability of the stars awaits in vain an experimentum crucis.

The astronomer, accordingly, must be content to be the chronicler of a spectacle, in which, except as an on-looker, he takes no part. Like the sailor at the mast-head in his solitary night-watch, he must see, as he sails through space in his small earthly bark, that nothing escapes his view within the vast visible firmament. But he stands, as it were, with folded arms, occupied solely in wistfully gazing over the illimitable ocean, where the nearest vessel, like his own, is far beyond summons or signal, and the greatest appears but as a speck on the distant horizon. His course lies out of the track of every other vessel; and year after year he repeats the same voyage, without ever practically altering his relation to the innumerable fleets which navigate those seas.—Professor George Wilson, on the Physical Sciences, &c.

Distance of the Earth from the Sun.

Mr. Hind, the astronomer, in a communication to the Times, September 17, 1863, observes: “It may occasion surprise to many who are accustomed to read of the precision now attained in the science and practice of Astronomy, when it is stated that there are strong grounds for supposing the generally received value of that great unit of celestial measures—the mean Distance of the Earth from the Sun—to be materially in error; and that, in fact, we are nearer to the central luminary by some 4,000,000 miles than for many years past has been commonly believed. The results of various researches during the last ten years appear, however, to point to the same conclusion.”

Mr. Hind then proceeds to describe the actual state of our knowledge respecting it, extending through two entire columns of the above Journal. We have only space for the results:

“To recapitulate briefly: a diminution in the measure of the sun’s distance now adopted is implied by—1st, the theory of the moon, as regards the parallactic equation, agreeably to the researches of Professor Hansen and the Astronomer Royal; 2nd, the lunar equation in the theory of the earth, newly investigated by M. Le Verrier; 3rd, the excess in the motion of the node of the orbit of Venus beyond what can be due to the received values of the planetary masses; 4th, the similar excess in the motion of the perihelion of Mars, also detected within the past few years by the same mathematician; 5th, the experiments of M. Foucault on the velocity of light; and 6th, the results of observations of Mars when near the earth about the opposition of 1862.

“Subjoined are a few of the numerical changes which will follow upon the substitution of M. Le Verrier’s solar parallax (8´´·95) for that of Professor Encke, on which reliance has so long been placed. The earth’s mean distance from the sun becomes 91,328,600 miles, being a reduction of 4,036,000. The circumference of her orbit, 599,194,000 miles, being a diminution of 25,360,000. Her mean hourly velocity, 65,460 miles. The diameter of the sun 850,100 miles, which is smaller by nearly 38,000. The distances, velocities, and dimensions of all the members of the planetary system of course require similar corrections if we wish to express them in miles; in the case of Neptune, the mean distance is diminished by 30 times the amount of correction to that of the earth, or about 122,000,000 miles. The velocity of light is decreased by nearly 8000 miles per second, and becomes 183,470 if based upon astronomical data alone. These numbers will illustrate the great importance that attaches to a precise knowledge of the sun’s parallax, in our appreciation of the various distances and dimensions in the solar system.

“The evidence which has been adduced since the publication of M. Le Verrier’s investigations, would rather induce us to adopt a diminished measure of the earth’s distance from the sun, as the most probable solution of the difficulty.

“M. Léon Foucault, of Paris, has succeeded in measuring the absolute velocity of light by means of the ‘turning mirror’—an experimental determination of no little interest and significance. He concludes that it cannot differ much from 298,000,000 of French metres per second, or 185,170 English miles, which is a notable diminution upon the velocity previously derived from astronomical data alone. The time which light requires to travel from the sun to the earth is known with great precision; at the mean distance of the latter it is rather less than 8´ 18´´, and if this number be combined with M. Foucault’s measure of the velocity, it will be evident that the received distance is too great by about one-thirtieth part—that light, in fact, has not so far to travel before it reaches the earth as generally supposed. The corresponding solar parallax is 8´ 86´´, which approaches much nearer to M. Le Verrier’s theoretical value than to the one depending on the transits of 1761 and 1769. So curious a corroboration of the former deserves especial remark.”

Blue Colour of the Sky.

Mr. Glaisher, in his Report of Scientific Balloon ascents made by him and Mr. Coxwell, in 1863, remarks that the Colour of the Sky in 1862 was of a deeper blue generally than in 1863. On the 31st of March the sky was of a deep Prussian blue, and on the 18th of April it was of a faint blue only, exhibiting another great contrast to the appearance of last year. Sir Isaac Newton considers this colour as a “blue of the first order, though very faint and little, for all vapours, when they begin to condense and coalesce into small parcels, become first of that bigness, whereby such an azure must be reflected.” Professor Clausius considers the vapours to be vesicles or bladders, and ascribes the blue colour of the first order to reflection from the thin pellicle of water. In reference to these opinions the following facts are important:—1. The azure colour of the sky, though resembling the blue of the first order when the sky is viewed from the earth’s surface, becomes, as observed by Mr. Glaisher in his balloon ascents, an exceedingly deep Prussian blue, as we ascend to the height of five or six miles, which is a deep blue of the second or third order. 2. The maximum polarizing angle of the atmosphere being 45 deg. is that of air, and not that of water, which is 55 deg. 3. At the greatest height to which Mr. Glaisher ascended—namely, at the height of five, six, and seven miles, where the blue is the brightest—“the air is almost deprived of moisture.”

Hence it follows that the exceedingly deep Prussian blue cannot be produced by vesicles of water, but must be caused by reflection from the molecules of air, whose polarizing angle is 45 deg. The faint blue which the sky exhibits at the earth’s surface is therefore not the blue of the first order, and is merely the blue of the second or third order, rendered paler by the light reflected from the aqueous vapour in the lower regions of the atmosphere.

Mr. Glaisher speaks of the curious changes in colour that he and Mr. Coxwell experienced in ascending, and remarked that they could now easily go a mile higher without turning quite so blue as before. In one descent they very nearly got into the sea, and only escaped that fate by coming down at the rate of four miles in two minutes.

Beauty of the Sky.

It is a strange thing how little in general people know about the Sky. It is the part of creation in which Nature has done more for the sake of pleasing man, more for the sole and evident purpose of talking to him and teaching him, than in any other of her works, and it is just the part in which we least attend to her. There are not many of her other works in which some more material or essential purpose than the mere pleasing of man is not answered by every part of their organization; but every essential purpose of the sky might, as far as we know, be answered, if once in three days, or thereabouts, a great black ugly rain-cloud were broken up over the blue, and everything well watered, and so all left blue again till next time, with perhaps a film of morning and evening mist for dew. But, instead of this, there is not a moment of any day of our lives when Nature is not producing scene after scene, picture after picture, glory after glory, and working still upon such exquisite and constant principles of the most perfect beauty, that it is quite certain it is all done for us, and intended for our perpetual pleasure.—John Ruskin.

Influence of High Temperatures in Balloon Ascents.

Professor Owen has remarked the importance of the influences of very high distances on the human frame, which is adapted of course to a very different medium. The fact which Mr. Glaisher mentions as to his feeling a greater power of resisting the influence of very high temperatures is interesting in physiology, and in relation to the series of facts with which we are acquainted. We know that our lungs adapt themselves to atmospheres of different degrees of gravity, so that there are people who live habitually on high mountains, and feel no such difficulty in breathing as is felt at once when the inhabitant of a plain or low country comes up to these elevations. Now that depends upon the greater proportion of the minute cells of the lungs which are open and receive an attenuated atmosphere, in proportion to the minute cells that are occupied by a quantity of mucus. Those on the plain do not make so large a use of their breathing apparatus as those who live at great altitudes. Hence more cells, occupied by mucus, will be taken up, and opened to free course and play; and Professor Owen has no doubt that is the solution of the interesting fact mentioned by Mr. Glaisher. Physiologists are all agreed that one condition of longevity is the capacity of the chest; and therefore it is hoped the increased breathing capacity acquired by Mr. Glaisher and Mr. Coxwell will tend to the prolongation of their lives.

Value of Meteorological Observations, Telegraphy, and Forecasts.

The establishment of a Meteorological Department by the Board of Trade is understood to have originated with the late Prince Consort, who suggested that the more methodical observation of the phenomena of the Weather might be rendered conducive to the saving of many valuable lives. The plan had worked to February, 1861, when the Secretary of the Board of Trade wrote to the Royal Society concerning the new features which the operations of the Meteorological Department had assumed; and expressing an anxiety to know whether the science of meteorology was now in such a state as to admit of a permanent reliable system of storm-signals and daily weather forecasts; also, whether the progress and useful application of meteorological science would be more efficiently promoted by devoting the money voted by Parliament to the original objects contemplated—viz., the collection, tabulation, and discussion of meteorological phenomena, or by devoting it to the system of telegraphy and weather forecasts. The Secretary of the Royal Society, after the lapse of a month, replied, on behalf of the President and Council, to the effect that they were assured by Admiral Fitzroy that the original objects for which the Meteorological Department was formed were still kept in view. “In the forewarnings of storms,” adds Dr. Sharpey, “much must as yet undoubtedly be viewed as in a great measure tentative; but there is one class of cases on which such premonitory information is entitled to be regarded as resting on more assured scientific relations. Admiral Fitzroy considers that he has satisfactorily established the occasional occurrence of storms of a cyclonic character, of very limited diameter, not much exceeding perhaps that of the British islands themselves, and originating in their vicinity. The practice of forewarning is specially suited to such storms. They are characterized by great violence, and by frequent and rapid changes in the direction of the wind. The key to their comprehension is supplied by the telegraphic reports, which convey to the central office a knowledge of the various simultaneous directions of the wind in different localities; and, when once comprehended, they are particularly suited for forewarning, inasmuch as, in its general course, the advance of the cyclone is steady in direction and moderate in rate.

“In connexion with this subject the President and Council revert with satisfaction to a reply by Sir John Herschel to the Royal Commission on Lights, Buoys, and Beacons, that ‘the most important meteorological information which could be telegraphed would be information first received by telegraph of a cyclone actually in progress at a great distance, and working its way towards the locality. There is no doubt that the progress of a cyclone may be telegraphed, and might secure many a ship from danger by forewarning.’ It is obvious that this remark, which refers to the approach of a distant cyclone, is equally applicable to cyclones originating in or near our islands, the existence of which has been made known by the system of telegraphy which Admiral Fitzroy has established.

“With respect to the ‘forecasts of the state of the weather,’ which are published in the newspapers, the President and Council learn from Admiral Fitzroy that they really occasion no cost to Government, and scarcely fall, therefore, within the questions submitted for reply; moreover, the President and Council have no data whereon to rest a conclusion in regard to the degree of reliance to which these last-named forecasts may be entitled.”

Weather Signs.

A few of the more marked Signs of Weather—useful alike to seaman, farmer, and gardener, are the following:

Whether clear or cloudy—a rosy sky at sunset presages fine weather:—a red sky in the morning bad weather, or much wind (perhaps rain):—a grey sky in the morning, fine weather:—a high dawn, wind:—a low dawn, fair weather.

Soft-looking or delicate clouds foretell fine weather, with moderate or light breezes:—hard edged, oily-looking clouds,—wind. A dark, gloomy, blue sky is windy;—but a light bright blue sky indicates fine weather. Generally, the softer clouds look, the less wind (but perhaps more rain) may be expected;—and the harder, more “greasy,” rolled, tufted, or ragged,—the stronger the coming wind will prove. Also—a bright yellow sky at sunset presages wind; a pale yellow, wet:—and thus by the prevalence of red, yellow, or grey tints, the coming weather may be foretold very nearly:—indeed, if aided by instruments, almost exactly.

Small inky-looking clouds foretell rain:—light scud clouds driving across heavy masses show wind and rain, but if alone, may indicate wind only.

High upper clouds crossing the sun, moon, or stars, in a direction different from that of the lower clouds, or the wind then felt below, foretell a change of wind.

After fine clear weather, the first signs in the sky of a coming change are usually light streaks, curls, wisps, or mottled patches of white distant clouds, which increase and are followed by an overcasting of murky vapour that grows into cloudiness. This appearance, more or less oily or watery, as wind or rain will prevail, is an infallible sign.

Usually the higher and more distant such clouds seem to be, the more gradual but general the coming change of weather will prove.

Light, delicate, quiet tints or colours, with soft, undefined forms of clouds, indicate and accompany fine weather; but gaudy, or unusual hues, with hard, definitely outlined clouds, foretell rain and probably strong wind. Misty clouds forming, or hanging on heights, show wind and rain coming—if they remain, increase, or descend. If they rise or disperse, the weather will improve or become fine.

When sea birds fly out early and far to seaward, moderate wind and fair weather may be expected.

When they hang about the land, or over it, sometimes flying inland, expect a strong wind with stormy weather. As many creatures besides birds are affected by the approach of rain or wind, such indications should not be slighted by an observer who wishes to foresee weather or compare its variations. There are other signs of a coming change in the weather known less generally than may be desirable, and therefore worth notice; such as, when birds of long flight, rooks, swallows, or others, hang about home and fly up and down or low, rain or wind may be expected. Also when animals seek sheltered places, instead of spreading over their usual range; when pigs carry straw to their sties; when smoke from chimneys does not ascend readily (or straight upwards during calm), an unfavourable change is probable.

Dew is an indication of fine weather, so is fog. Neither of these two formations occur under an overcast sky, or when there is much wind. One sees fog occasionally rolled away as it were by wind, but seldom or never formed while it is blowing.

Remarkable clearness of atmosphere near the horizon: distant objects, such as hills unusually visible, or raised (by refraction), and what is called “a good hearing day,” may be mentioned among signs of wet, if not wind, to be expected.

More than usual twinkling of the stars; indistinctness or apparent multiplication of the moon’s horns; halos; “winddogs,” and the rainbow; are more or less significant of increasing wind, if not approaching rain, with or without wind.

Mr. Glaisher remarks, in the account of one of his recent balloon ascents:—“It would also seem that, when the sky is overcast and no rain falling, the Sun is shining on its upper surface, and both these conclusions agree with all my own experiences. That double strata or layers of clouds are indications of rain is shown by my recent observations; but it is one of those facts which have so far attracted the attention of some observers of nature as even to have passed into proverbs. My friend, Mr. Sopwith, tells me that in the mining districts, where he has resided so much, it is a common saying that ‘it will be rain to-day; the clouds is twee ply thick;’ by which, in their homely phrase, they clearly express that their expectations of rain are based on the observance of one range of clouds flying in the air at a higher elevation than another.”

It has been well observed that the old lunar theory, still implicitly received by country-folks, and held by many ladies as a fact of direct experience—the theory that weather is apt to change at the moon’s quarters, clearly applies rather to the earth than to any particular spot on it. And all the various complicated forms of that theory, invented to supply its apparent failures—such as that a change from fine to wet may be expected if the new quarter is entered on after midnight, and vice versâ for a post-meridian change,—are liable to the same objection.

The late Marshal Bugeaud, says the Emancipation, when only a captain, during the Spanish campaign under Napoleon I., once read in a manuscript which by chance fell into his hands, that from observations made in England and Florence during a period of fifty years, the following law respecting the Weather had been proved true:—‘Eleven times out of twelve the weather remains the same during the whole moon as it is on the fifth day, if it continues unchanged over the sixth day; and nine times out of twelve like the fourth day, if the sixth resembles the fourth.’ From 1815 to 1830 M. Bugeaud devoted his attention to agriculture; and guided by the law just mentioned, avoided the losses in hay time and vintage which many of his neighbours experienced. When Governor of Algiers, he never entered on a campaign till after the sixth day of the moon. His neighbours at Excideuil and his lieutenants in Algeria would often exclaim, ‘How lucky he is in the weather.’ What they regarded as mere chance was the result of observation. In counting the fourth and sixth days, he was particular in beginning from the exact time of new moon, and added three-quarters of an hour for each day for the greater length of the lunar as compared with the solar day.

Mr. Shepherd, C.E., appears to prefer the planet Jupiter to the moon, and has discovered an elaborate law for the variations of our English weather, except so far as the principle is affected by comets.

Mr. Shepherd is not quite without even higher authority. Sir John Herschel has publicly intimated his suspicion that the periodic expansion in the Sun’s spots had some close connexion with the extraordinarily wet summer of 1860, and in his article on Meteorology in the Encyclopædia Britannica, the same eminent authority has connected this periodic change in the Sun’s spots, which takes place in about twelve years, with the periodic time of Jupiter’s revolution round the sun (which is nearly the same in length), so that here we have an eminent astronomer half conceding the same very dubious principle—that causes which affect equally, if not the whole earth, at least all places which, in the diurnal rotation, are brought into the same relative position towards the sun or the planet, are the principal influences which determine our local weather.

Yet, if this be so, how does it happen that the year 1860, which was abnormally wet in Europe, was abnormally dry in many other parts of the world? If Mr. Shepherd be right in connecting this fact with the orbital position of Jupiter, or Sir John Herschel in connecting it with the large spots on the Sun, it would scarcely have merely affected the local distribution of heat; or, if it could, the means by which these causes rob England to burn India remain as dark as before.—Paper in the Spectator newspaper.

Barometer for Farmers.

In one of his letters, Humboldt says that a Barometer should be considered as necessary on a farm as a plough: but farmers generally prefer to trust in the moon and other exploded nonsense to purchasing a reliable instrument that would repay them tenfold. A substitute, called Leoni’s Prognosticator, consists of a vial full of a clear liquid, in which swims a snowy substance. In fine weather that substance lies on the bottom, but before a storm it rises to the surface, with a tendency to the side opposite the quarter from which the storm is coming. The substances used are kept secret. An ordinary barometer indicates the density of the atmosphere. Leoni’s instrument evidently indicates its electric state, and for that reason we are of opinion that it is a better instrument to prognosticate the weather. The following is a substitute that will not cost more than 1s., and for aught we know it may be the identical thing itself. Dissolve some camphor in alcohol and throw into the solution some soda; the camphor will be precipitated in snowy flakes; collect these by passing the mixture through a filter and put them in a vial with clear alcohol, in which as much camphor as it would take has been dissolved. Cork it, place it where it will not be disturbed, and examine it every morning and night. This is termed a Storm-glass.

Icebergs and the Weather.

The intimate relation existing between the Climates of particular seasons, and the discharge of Icebergs from the great Arctic glaciers has long been perfectly understood and described by both British and American naval officers. But the quantity of ice annually released in the shape of bergs is so insignificant, majestic as those frozen masses are, in proportion to the quantity remaining behind, and to that annually engendered over the vast area of the Arctic continental icefields, that any difference in the amount of “average” annual discharge cannot materially disturb the balance. Nor is the disengagement of the bergs, when viewed on a large scale, a process depending on variable conditions. The slow downward descent of glaciers towards the ocean (which is now fully recognised as the result of a well-known law) is dependent on forces of such vast magnitude and in such constant operation as to admit of no perceptible modification owing to local atmospheric influences.

What does materially affect climate, however, is the variation in the annual range, Equator-wards, of the great Arctic currents, which convey on their surface not only the bergs, but the vast compact fields of pack-ice, extending over areas of many thousands of square miles, and thus bringing about a reduction of temperature, infinitely in excess of that produced by the bergs.

The exceptionally boisterous and rainy summer of 1860 was due to the much increased southward range, along the eastern and southern shores of Greenland, of the Spitzbergen drift, and was alluded to by Dr. Wallich, in some observations published by him at the close of that year.

St. Swithun: his true History.

So little is really known of this good Saint, that it is tedious to wade through a mass of more or less probable conjecture.

The facts of St. Swithun’s life seem to be that he was born near Winchester about the year 800—that he became a monk, and afterwards prior of the old abbey of that city, and was chosen by King Ecgberht the Bretwalda to be tutor of his son Æthelwulf, heir to the throne of Wessex. From 852 to 863, when he died, Swithun was Bishop of Winchester. He distinguished himself as an architect by building a bridge of stone and a tower to his cathedral, and as a Minister of State both to Æthelwulf and his successor, Æthelbald. In 971, more than a century after his death, he was exhumed, and “translated” and beatified by his successor, the famous Bishop Æthelwold, in the time of Archbishop St. Dunstan. Ridiculing, with Godwin De Præsulibus, the idea taken up by Lord Campbell, that Swithun was Æthelwulf’s “Chancellor,” in the modern sense of the word, Mr. Earle (formerly Professor of Anglo-Saxon at Oxford) claims for him the credit of having had a great share in the administration of that King’s policy, and especially in the education of his youngest son, the Great Alfred. Indeed, he surmises that Swithun was Alfred’s companion in his journey to Rome in 853, though the Saxon Chronicle says nothing about it. And he also argues that Æthelwulf’s much-debated dedication of the tenth of his land as tithes to religious purposes, in the year 855 (when the Northmen first wintered in England), was due to Swithun’s advice. “This was,” he says, “the culminating point of Swithun’s policy.” Equally baseless is the hypothesis that Swithun was the “intermediary,” the “prudent counsellor and successful diplomat” who averted civil war when Æthelwulf returned from his pilgrimage to Rome, bringing with him as wife the Frankish Princess Judith. It is more certain, we think, that Swithun’s name continued to be held in affectionate reverence among the people; and this probably led to his beatification by popular consent. The formal process of canonization had not yet been introduced.—Saturday Review.

Mr. Earle discusses the legend which connects St. Swithun with forty days of rain, and decides that it is wholly without foundation. Mr. Howard, the meteorologist, many years since, by his observations, gave a sort of currency to this notion; but it has since received its quietus in the following facts, from the Greenwich observations for 20 years:—It appears that St. Swithun’s day was wet in 1841, and there were 23 rainy days up to the 24th of August; 1845, 26 rainy days; 1851, 13 rainy days; 1853, 18 rainy days; 1854, 16 rainy days; and in 1856, 14 rainy days. In 1842 and following years St. Swithun’s day was dry, and the result was, in 1842, 12 rainy days; in 1843, 22 rainy days; 1844, 20 rainy days; 1846, 21 rainy days; 1847, 17 rainy days; 1848, 31 rainy days; 1849, 20 rainy days; 1850, 17 rainy days; 1852, 19 rainy days; 1855, 18 rainy days; 1857, 14 rainy days; 1858, 14 rainy days; 1859, 13 rainy days; and in 1860, 29 rainy days. These figures show the superstition to be founded on a fallacy, as the average of 20 years proves rain to have fallen upon the largest number of days when St. Swithun’s day was dry.

No event, or natural phenomenon which could be construed into such, is alluded to by any of the various authors who wrote histories of St. Swithun. On the contrary, the weather seems to have been most propitious during his translation. How then did the popular notion about St. Swithun’s Day arise? Most probably, as Mr. Earle remarks, it was derived from primeval pagan belief regarding the meteorologically prophetic character of some day about the same period of the year as St. Swithun’s. Such adaptations, it is well known, were frequent on the supplanting throughout Europe of heathenism by Christianity. In confirmation of this view it is to be observed, that in various countries of the European continent, the same belief prevails, though differences exist as to the period of the particular day in question. Thus, in France, St. Médard’s Day, (June 8,) and the Day of St. Gervais and Protais, (June 19,) have a similar character ascribed to them. In Belgium they have a rainy saint, named St. Godeliève; whilst in Germany, among others, a character of this description is ascribed to the day of the Seven Sleepers.

Rainfall in London.

Mr. G. V. Vernon has communicated to the Literary and Philosophical Society of Manchester a Paper on the number of Days on which Rain falls annually in London, from observations made during the fifty-six years, 1807-1862. Howard’s Climate of London has been used for the years 1807 to 1831; the Philosophical Transactions for the years 1832 to 1840; and the Greenwich Observations for the years 1841 to 1862. During the entire period of fifty-six years, no month occurred in which rain did not fall.

The minimum number of days occurred in 1832, the cholera year, and 1834; the number of days being 86, 82 respectively. The maximum number occurred in 1848, the number being 223 days.

Taking the quarterly values, we find that rain falls on the greatest number of days in autumn, and the least in spring.

Taking the means of five yearly periods, there appears to be a kind of periodicity in the number of days on which rain falls; having a maximum in 1815 to 1817, and a minimum in 1845 to 1847.

The Force of Lightning.

A person may be killed by Lightning, although the explosion takes place at the distance of twenty miles, by what is called the back-stroke. Suppose that the two extremities of a cloud, highly charged with electricity, hang down towards the earth, they will repel the electricity from the earth’s surface, if it be of the same kind with their own, and will attract the other kind; and if a discharge should suddenly take place at one end of the cloud, the equilibrium will instantly be restored by a flash at that point of the earth which is under the other. Though the back-stroke is often sufficiently powerful to destroy life, it is never so terrible in its effects as the direct shot, which is frequently of inconceivable intensity. Instances have occurred in which large masses of iron and stone, and even many feet of a stone wall, have been conveyed to a considerable distance by a stroke of lightning. Rocks and the tops of mountains often bear the marks of fusion from its action, and occasionally vitreous tubes, descending many feet into banks of sand, mark the path of the electric fluid. Some years ago, Dr. Fielder exhibited several of these fulgorites in London, of considerable length, which had been dug out of the sandy plains of Silesia and Eastern Prussia. One found at Paderborn was forty feet long. Their ramifications generally terminate in pools or springs of water below the sand, which are supposed to determine the course of the electric fluid. No doubt the soil and substrata must influence its direction, since it is found by experience that places which have been struck by lightning are often struck again. A school-house in Lammer-Muir, in East Lothian, has been struck three different times.—Mrs. Somerville’s Connexion of the Sciences.

The inquiries into the chances of refuge from lightning have been attended with saving results. Here is an instance:

A few years since an awful thunderstorm occurred in the neighbourhood of Inkpen, Berkshire. Three men, named Martin, Buxey, and Palmer, were employed in mowing grass, when a storm of thunder and lightning broke over the field, and one of them suggested that they should run beneath a tree; Martin knowing that trees generally attract lightning, immediately remarked, “We had better go anywhere than under a tree.” Buxey and Palmer, however, as the storm was severe, and the hail was falling heavily at the time, ran and seated themselves beneath a large lime-tree, but Martin walked off to a cottage, and was safely sheltered. In about half-an-hour after the storm had abated, both Buxey and Palmer were found lying on the grass beneath the tree, quite dead from the lightning. The clothes of Buxey were found to be on fire, and the hair of Palmer was much scorched.

Effect of Moonlight on Vegetation.

It has been demonstrated that Moonlight has the power, per se, of awakening the Sensitive Plant, and consequently that it possesses an influence of some kind on Vegetation. It is true that the influence is very feeble, compared with that of the sun; but the action is established, and the question remains, what is the practical value of the fact? “It will immediately,” says Professor Lindley, “occur to the reader that possibly the screens which are drawn down over hothouses at night, to prevent loss of heat by radiation, may produce some unappreciated injury by cutting off the rays of the moon, which Nature intended to fall upon plants as much as the rays of the sun.”

Even artificial light is not wholly powerless. Decandolle succeeded in making crocuses expand by lamplight; and Dr. Winn, of Truro, has suggested that the oxyhydrogen lamp may be made subservient to horticulture in the dark days of winter.

An extraordinary effect of Moonlight upon the human subject occured in 1863. A boy, thirteen years of age, residing near Peckham Rye, was expelled his home by his mother for disobedience. He ran away to a corn-field close by, and on lying down in the open air, fell asleep. He slept throughout the night, which was a moonlight one. Some labourers on their way to work, next morning, seeing the boy apparently asleep, aroused him; the lad opened his eyes, but declared he could not see. He was conveyed home, and medical advice was obtained: the surgeon affirmed that the total loss of sight resulted from sleeping in the moonlight.

Contemporary Inventions and Discoveries.

Mr. Piesse, the well-known operative chemist, has thus popularly grouped some of the leading novelties of our age:

The inventions and discoveries of my time may truly be included among some of the greatest and most wonderful which the world has seen. I have not yet passed forty summers, but perfectly recollect being one of the gaping crowd that first witnessed lighting the streets with gas. Near to the Marble Arch, at the top of Oxford-street, London, stands an iron post, on which is inscribed “Here stood Tyburn Gate, 1829.” Now I well remember this Oxford-street turnpike, and the oil-lamps ‘dimly burning,’ which enabled the University coach and the eight-horse waggons to nearside the off-side gatepost; at that time all Oxford-street and the shops therein protested against ‘the light of other days,’ and became illumined with Murdoch’s gas: thus the oil-lamps passed away for ever. Tunneling Primrose Hill for the first railway into London was a fund of enjoyment to me; there I learned my first practical lesson in mineralogy—to distinguish iron pyrites from real gold nuggets, which it at times resembles. One morning the newspapers teemed with an account of the late Duke of Wellington witnessing the first electric telegram from Drayton, twelve miles from London. People flocked to Paddington, and paid a shilling to do the same; of course I was among them! It appears to me but the other day when every housewife kept her linen rags to make tinder. The bunch of matches, like a large fan, the flint and steel were in every house. What a change has the lucifer produced? After hearing Professor Brande one night deliver a popular lecture at the Royal Institution, the Secretary read a letter received that day from Paris, announcing the discoveries of Daguerre. The assertion that the picture of a camera could be fixed by the mere agency of light startled belief, yet from that hour photography took its rise. Strange discoveries now crowd upon the memory. The oxyhydrogen flame that burns the diamond and volatilizes platinum; then came the Drummond lime-light that is visible as a star sixty miles away; now followed Dobereiner’s lamp that ignites itself when you lift a latch. Electroplating becomes one of the arts of the country. A new force of nature, actinism, was recognised. Wonderfully active principles of plants—quinine, morphia, and strychnine, are discovered. The food of plants and the balance of organic nature are developed at Giessen. New metals are discovered and are practically eliminated for the use of manufacturers; and so we thus come to the present, when I now write with an aluminium pen made from tiles laid in a wall when Constantine was crowned at York.[18]

The Bayonet.

Mr. Akermann, in an elaborate series of “Notes on the Origin and History of the Bayonet,” has been unable to verify the statement that this weapon derives its name from Bayonne, the reputed place of its invention. Voltaire alludes to it in the eighth book of the Henriade. The results of the inquiry may be thus briefly recited:—That “bayonette” was the name of a knife, which may probably have been so designated either from its having been the peculiar weapon of a crossbow-man, or from the individual who first adopted it; that its first recorded use as a weapon of war occurs in the Memoirs of Puysegur, and may be referred to the year 1647; that it is first mentioned in England by Sir J. Turner, 1670-71; that it was introduced into the English army in the first half of the year 1672; that before the peace of Nimwegen Puysegur had seen troops on the Continent armed with bayonets, furnished with rings, which would go over the muzzles of the muskets; that in 1686 the device of the socket-bayonet was tested before the French king, and failed; that in 1689 Mackay, by the adoption of the ringed bayonet, successfully opposed the Highlanders at the battle of Killicrankie; lastly, that the bayonet with the socket was in general use in the year 1703.

William Cobbett, who had been a soldier, and carried the bayonet, used to call it “King George’s Toasting-fork.”

Derivation of the word Loot.

This word, which so often occurs in the account of the late Indian war, is simply the Hindustani for plunder. Noun, “loot,” plunder; verb, “lootna,” to plunder. This is one of the many examples of Hindustani words generally used in English conversation in India, which gradually came into use at home, amongst the oldest and most familiar of which is, perhaps, the slang term “that’s the cheez,” for “that’s the thing,” “cheez” Hindustani for “thing.”

Telegram.

When this Indian term was first applied to our telegraphic messages, a considerable amount of learned disquisition was wasted in seeking its origin. Any one who has been in India must remember the curious pronunciation by natives of many English proper names, as well as of other words, for which they have no translation in Hindustani; generally abbreviating a long difficult expression, and sometimes even changing altogether the pronunciation. On the introduction of the telegraph into India, there being no Hindustani word, the natives were obliged to attempt English, and the easiest way they could manage to pronounce telegraphic message was “telegram.” This being an easy abbreviation was at once picked up and adopted by the English in India, and then came home in the same way that we got “loot” from India, and now again from China.—Correspondent of the “Daily News.”

Archæology and Manufactures.

Archæology, far from being a mere unprofitable dilettantism, has a positive money-value, one appreciable not only by the literary or scientific mind, but even by those who look exclusively to material interests—that commerce, in fine, no less than history or art, is under obligations to archæology. In the case of our pottery and earthenware manufacture,—now an important branch of our national trade—at the time when Wedgwood first began his operations, England was an importing country with regard to this article of trade, drawing her supplies from Holland, France, and Germany. About the year 1760, Wedgwood established himself in Staffordshire. The models which he selected for imitation were taken from the antique:—from the Portland Vase, Greek vases, cameos, and old coins,—but, above all, from the magnificent collection of Etruscan vases and earthenware, which was purchased about that time from Sir William Hamilton, for the British Museum. Such was the immediate improvement in classical elegance and purity of design, which the manufactures derived from these sources, that within very few years England became an exporting country in this article; and the trade was steadily developed, until, in the year 1857, the declared value of her exports nearly reached a million and a half of money. Wedgwood’s own sense of his obligation to ancient models was marked by the name he gave to the new village formed around his works in Staffordshire, which he called Etruria, in honour of them. More recently the collection of Etruscan antiquities made by the Prince of Canino, and brought to England by Signor Campanari, has marked another stage of progress in this branch of industry; and, at this moment, the best silversmiths and jewellers in London resort to the British Museum, to study these models, and copy them for reproduction. Much of the well-known Minton-ware is either copied from, or due to the study and imitation of, the Majolica ware of Mediæval Italy; whilst the smaller objects of Assyrian art, brought from Nineveh by Mr. Layard, are extensively copied by artists, and reductions of them made in Parian, in marble, or in bronze.—Address to the Cambrian Archæological Association, by Mr. C. G. Wynne, M.P.

Good Art should be cheap.

There is no hope of the diffusion of a better taste till all classes of society are familiarized with the best works of the best artists; and English manufactures will never be generally improved in design till the purchasers as well as the producers know how to appreciate what is beautiful, and till a better intuitive taste prevails in the cottage as well as in the mansion. So long as it is cheaper to reproduce familiar shapes and ornaments, so long will it be vain to expect sufficient encouragement for improvements in design. Theorists may preach for ever as to abstract beauty, but the public will buy the old-fashioned, tasteless goods, if they cost less.

We do not believe that a beautiful thing need be more expensive than an ugly thing. At any rate, this is the lesson to impress upon such of our manufacturers as may be disposed to join the art-movement of the day. It is not enough to design a novelty in really good taste—it must be at least as cheap as the monstrosity which it is meant to supersede, and, if possible, cheaper. Is it not worth while to inquire whether there may not be some deeper reason than a supposed depraved taste for the hideous colouring, so dubious and sombre, of our Manchester goods, for example? To take an instance: we believe that Hoyle’s Prints, famous throughout the world for their slates and lilacs, are dyed of those most unpicturesque hues for no other reason than that they are the most “fast” colours that can be produced. If our chemists could discover the secret of making the primitive colours equally “fast,” and if the needful pigments were no dearer, we believe that cotton printing would be revolutionized. But, meanwhile, customers in every market of the world will ask for Hoyle’s Fast Prints, in preference to the brightest and most beautiful colours, which, however charming to the eye when bran-new, would disappear in the first wash.—Saturday Review.

Imitative Jewellery.

From the profuse display of what are designated “gold chains” in the windows of jewellers’ shops, there is evidently a large demand for these articles, although the purchasers are little aware of the value of the articles. The gold coin of the realm is, in technical language, 22 carats fine—that is, it consists of 22 parts by weight of fine, or pure gold, and 2 parts by weight of copper; and gold plate, &c., is 18 carats fine—that is, it contains 18 parts by weight of gold and 6 of copper in the 24. The alloy of which a large proportion of gold chains is made contains only 8 or 10 parts by weight of fine gold in the 24 parts, the remaining 16 or 14 parts being common brass. The application of brass for this purpose is of comparatively recent date, and enables the manufacturer to adulterate gold to a much greater extent than is practicable with copper alone. This depends upon the fact that brass resembles gold in colour, and copper does not. The brassy gold chains in question are far inferior in colour to chains made of gold of 18 or 22 carats fine, and they would hardly be tolerated by many persons when seen side by side with those of the latter description. They are now manufactured on a very large scale by the aid of machinery, and so great has been the decrease in their cost of production, that the value of the labour upon certain kinds of chains has been reduced from 30s. to 3s. 6d., or even less. It is usual to deposit upon the finished chain an exceedingly thin coating of pure gold by the electrotype process. This, of course, is speedily worn off by friction, and consequently the original fine colour of the chain at the time of purchase disappears. The propriety of this practice is questionable. If the public like cheap brassy gold chains, and are satisfied with their appearance, it is their own affair, and no one has a right to say a word; but, in buying such articles, beware of the small value of the materials in comparison with gold.[19]

French Enamel.

Among the artistic triumphs in the International Exhibition of 1862 was the magnificent work in gold and enamel, by M. Payen, which is stated to have cost him several years’ labour, or the sum of 6000l. In this work the late Prince Consort evinced considerable interest when he was in Paris; and it was mainly to the Prince’s kind interference on behalf of M. Payen, that the Great Seal of England was sent to Paris, in order that it might be copied as one of the great seals of the different nations, which form the border of the work. The subject of the allegory is the Reward of Genius and Industry: this is shown on a large centre-piece on a ground of blue enamel; and the border, in which the seals of different countries are emblazoned, is formed of filigree work in gold. There was besides in the Exhibition an immense variety of works by M. Payen, including gold rings from three francs to three thousand francs each.