In the Appendix to Dr. Priestley’s third volume of Experiments and Observations on Air, Mr. Warltire gives an account of some very remarkable ignes fatui, which he observed on the road to Bromsgrove, about five miles from Birmingham. The time of observation was the 12th of December, 1776, before daylight. Many of these lights were playing in an adjacent field, in different directions; from some of which suddenly sprang up bright branches of light, somewhat resembling the explosion of a rocket that contained many brilliant stars, if the discharge was upwards, instead of the usual direction; and the hedge, and trees on each side of the hedge, were illuminated. This appearance continued but a few seconds, and then the jack-with-a-lantern played as before. Mr. Warltire was not near enough to observe if the apparent explosion was attended with any report.
Cronstedt gives it as his opinion, that ignes fatui, as well as falling stars, are owing to collections of inflammable air raised to a great height in the atmosphere. But, with regard to the latter, the vast height at which they move, evidently shews that they cannot be the effect of any gravitating vapour whatever; for the lightest inflammable air is one-twelfth of that of the common atmosphere: and we have no reason to believe, that at the distance of forty or fifty miles from the earth, the latter has near one-twelfth of its weight at the surface. From the account given by Mr. Warltire, we should be apt to conclude, that there is a strong affinity betwixt the ignes fatui and fireballs, insomuch that the one might be very easily converted into the other. Electricity can assume both these appearances, as is evident in the case of points;or even when the atmosphere is violently electrified, as around the string of an electrified kite, which always will appear to be surrounded with a blue flame in the night, if the electricity be very strong. On the whole, it appears that electricity, acting upon a small quantity of atmospherical air with a certain degree of vigour, will produce an appearance resembling an ignis fatuus; with a superior force it will produce a fire-ball; and a sudden increase of electrical power might produce those sparks and apparent explosions observed by Mr. Warltire. This appearance has produced many superstitious fears in the ignorant and uneducated.
To those who have, unfortunately, been badly educated in this respect, a friendly act would be, to endeavour with sound reasoning to convince them of their error, and dissuade them from giving heed, in future, to idle, superstitious, or inconsistent stories of any kind; advising them to furnish themselves with such knowledge, as may have a tendency to produce true pleasure and happiness through life, and which, when dying, they can reflect upon without uneasiness. “The natural offspring of prevailing superstition is infidelity. Of the truth of this, the present times afford us a lamentable example. Where ignorance and fear once ruled supreme, there has rash philosophy but too successfully planted presumption and atheism. ’Tis the diffusion of pure and solid knowledge, which alone can preserve us from the dominion of these opposite tyrants. How should this consideration increase our zeal and stimulate our endeavours! The immediate sphere of our action may be circumscribed, but our exertions will not on that account be entirely lost. In that circumscribed sphere let us labour to root out every superstitious lying vanity, and plant pure religion and unsophisticated truth in its stead.
“How charming, how enlivening to the soul, to gaze upon the dawning beams of opening light, to behold them irradiate that dismal gloom of intellectual darkness, which long overwhelmed the millions of mankind: how supremely pleasing, to view them wider and wider spreading their invigorating influence: how rapturously transporting, to contemplate the resplendent prospect of pure and perfect day!
“——————Power supreme!O everlasting King! to thee we kneel,To thee we lift our voice!”—
“O spread thy benign, thy vivifying light over the dwellings of the sons of men; dispel the yet impending mists of ignorance and superstition: and, O preserve us from the dismal gulf of infidelity and atheism; let thy truth run and prevail gloriously; let pure celestial wisdom overspread the earth as the waters cover the sea!—Then shall millions kneelbefore thee with grateful and enraptured hearts; then shall they rejoice to sing the praises of thee, their Benefactor, their Father, and their God: then shall this vale of tears be filled with the mansions of joy and gladness, and become a blissful foretaste of those regions, where thy saints, crowned with unfading glory and felicity, surround thy throne with never-ceasing hallelujahs!”
SeeNaylor on Vulgar Superstitions.
CURIOSITIES RESPECTING VARIOUS PHENOMENA OR APPEARANCES IN NATURE.—(Continued.)
Extraordinary Properties and Effects of Lighting—Thunder Rod—Fire Balls—Terrible Effects of Electrified Clouds—Surprising Effects of extreme Cold—Astonishing Expansive Force of Freezing.
Extraordinary Properties and Effects of Lighting—Thunder Rod—Fire Balls—Terrible Effects of Electrified Clouds—Surprising Effects of extreme Cold—Astonishing Expansive Force of Freezing.
Extraordinary Properties and Effects of Lightning.—A very surprising property of lightning of the zigzag kind, especially when near, is, its seeming omnipresence. If two persons are standing in a room looking different ways, and a loud clap of thunder, accompanied with zigzag lightning, happens, they will both distinctly see the flash, not only by that indistinct illumination of the atmosphere which is occasioned by fire of any kind, but the very form of the lightning itself, and every angle it makes in its course, will be as distinctly perceptible as if both had looked directly at the cloud from whence it proceeded. If a person happened at that time to be looking on a book, or other object which he held in his hand, he would distinctly see the form of the lightning between him and the object at which he looked. This property seems peculiar to lightning, and to belong to no other kind of fire whatever. In August 1763, a most violent storm of thunder, rain, and hail, happened at London, which did damage in the adjacent country to the amount of £50,000. Hailstones fell of an immense size, from two to ten inches in circumference, but the most surprising circumstance attendingthe hurricane was, the sudden flux and reflux of the tide in Plymouth pool, exactly corresponding with the like agitation in the same place, at the time of the great earthquake at Lisbon. Instances have also occurred where lightning, by its own proper force, without any assistance from those less common agitations of the atmosphere or electric fluid, has thrown stones of immense weight to considerable distances; torn up trees by the roots, and broke them in pieces; shattered rocks; beat down houses, and set them on fire, &c. The following singular effect of lightning, upon a pied bullock, is recorded in the sixty-sixth volume of the Philosophical Transactions.—
“In the evening of Sunday the 28th of August, 1774, there was an appearance of a thunder storm, but we heard no report. A gentleman who was riding near the marshes not far from this town, (Lewes) saw two strong flashes of lightning running along the ground of the marsh, at about nine o’clockP. M.On Monday morning, when the servants of Mr. Roger, a farmer at Swanborough, went into the marsh to fetch the oxen to their work, they found one of them, a four-year-old steer, standing up, to appearance much burnt, and so weak as to be scarcely able to walk. The animal seemed to have been struck by lightning in a very extraordinary manner. He was of a white and red colour; the white in large marks, beginning at the rump bone, and running in various directions along both sides; the belly was all white, and the whole head and horns white likewise. The lightning, with which he must have been undoubtedly struck, fell upon the rump bone, which was white, and distributed itself along the sides in such a manner as to take off all the hair from the white marks as low as the bottom of the ribs, but so as to leave a list of white hair, about half an inch broad, all round where it joined to the red, and not a single hair of the red appears to have been touched. The whole belly was unhurt, but the end of the sheath of the penis had the hair taken off; it was also taken off from the dewlap: the horns and the curled hair on the forehead were uninjured; but the hair was taken off from the sides of the face, from the flat part of the jaw-bones, and from the front of the face, in stripes. There were a few white marks on the side and neck, which were surrounded with red; and the hair was taken off from them, leaving half an inch of white adjoining to the red. The farmer anointed the ox with oil for a fortnight; the animal purged very much at first, and was greatly reduced in flesh, but afterwards recovered.” In another account of this accident, the author supposes that the bullock had been lying down at the time he was struck; which shews the reason that the under parts were not touched. “The lightning, conducted by the whitehair, from the top of the back down the sides, came to the ground at the place where the white hair was left entire.”
The author of this account says, that he inquired of Mr. Tooth, a farrier, whether he ever knew of a similar accident; and that he told him “the circumstance was not new to him; that he had seen many pied bullocks struck by lightning in the same manner; that the texture of the skin under the white hair was always destroyed, though looking fair at first; but after a while it became sore, throwing out a putrid matter in pustules, like the small-pox with us, which in time falls off, when the hair grows again, and the bullocks receive no farther injury;” which was the case with the bullock in question. In a subsequent letter, however, the very same author informs us, that he had inquired of Mr. Tooth, “whether he ever saw a stroke of lightning actually fall upon a pied bullock, so as to destroy the white hair, and shew evident marks of burning, leaving the red hair uninjured? He said he never did; nor did he recollect any one that had. He gave an account, however, of a pied horse, belonging to himself, which had been struck dead by lightning in the night time.” The explosion was so violent, that Mr. Tooth imagined his house had been struck, and therefore immediately got up. On going into the stable, he found the horse almost dead, though it kept on its legs near half an hour before it expired. The horse was pied white on the shoulder, and greatest part of the head, viz. the forehead and nose, where the greatest force of the stroke came. “The hair was not burnt nor discoloured, only so loosened at the root, that it came off with the least touch. And this is the case, according to Mr. Tooth’s observation, with all that he has seen or heard of, viz. the hair is never burnt, but the skin always affected. In the horse, all the blood in the veins under the white parts of the head was quite stagnated, though he could perceive it to flow in other parts as usual; and the skin, together with one side of the tongue, was parched and dried up to a greater degree than he had ever seen before.” Another instance is mentioned of this extraordinary effect of lightning upon a bullock, in which even the small red spots on the sides were unaffected; and in this, as well as the former, the white hair on the under part of the belly, and on the legs, was left untouched.
One very singular effect of lightning is, that it has been observed to kill alternately, that is, supposing a number of people standing in a line; if the first person was killed, the second would be safe; the third would be killed, and the fourth safe; the fifth killed, &c. Effects of this kind are generally produced by the most violent kind of lightning; namely, that which appears in the form of balls, whichfrequently divide themselves into several parts before they strike. If one of these parts of a fire-ball strike a man, another will not strike the person who stands immediately close to him; because there is always a repulsion between bodies electrified the same way. Now, as these parts into which the balls break have all the same kind of electricity, it is evident that they must for that reason repel one another, and this repulsion is so strong, that a man may be interposed within the stroke of two of them, without being hurt by either.
Thunder Rod.—Dr. Franklin has demonstrated the identity of thunder with the electric explosion. He availed himself of many curious discoveries which he had made of electrical laws: in particular, having observed that electricity was drawn off at a great distance, and without the least violence of action, by a sharp metallic point, he proposed to philosophers to erect a tall mast or pole on the highest part of a building, and to furnish the top of it with a fine metallic point, properly insulated, with a wire leading to an insulated apparatus for exhibiting the common electrical appearances. To the whole of this contrivance he gave the name ofThunder Rod, which it still retains. He had not a proper opportunity of doing this himself, at the time of his writing his dissertation in a letter from Philadelphia to the Royal Society of London; but the contents were so scientific, and so interesting, that in a few weeks they were known over all Europe. His directions were followed in many places. In particular, the French academicians, encouraged by the presence of their monarch, and the great satisfaction which he expressed at the repetition of Dr. Franklin’s most instructive experiments, which discovered and made known the theory of positive and negative electricity, as it is now received, were eager to execute his orders, and make his grand experiment, which promised so fairly to bring this tremendous operation of nature, not only within the pole of science, but in the management of human power. But in the mean time, Dr. Franklin, impatient of delay, and perhaps incited by the honourable desire of well-deserved fame, put his own scheme in practice. His inventive mind suggested to him a method of presenting a point to a thunder cloud at a considerable distance. This was, by fixing his point on the head of a paper kite, which the wind should raise to the clouds, while the wet string that held it should serve for a conductor of the electricity. With a palpitating heart, Dr. Franklin, unknown to his neighbours, and accompanied only by his son, went into the fields, and sent up his messenger that was to bring him news from the heavens. He obtained only a few sparks from his apparatus that day;but returned to his house in a state of perfect satisfaction with his success. We may justly consider this as one of the greatest of philosophical discoveries, and as doing the highest honour to the inventor; for it was not a suggestion from an accidental observation, but arose from a scientific comparison of facts, and a sagacious application of the doctrine of positive and negative electricity; a doctrine wholly Dr. Franklin’s, and the result of the most acute and discriminating observation. It was this alone, that suggested the whole; and, by explaining to his satisfaction the curious property of sharp points, gave him the courage to handle the thunderbolt of the heavens. It is now a point fully ascertained, that thunder and lightning are the electric snap and spark, as much superior to our puny imitations as we can conceive from the immense extent of the instruments in the hands of Nature.
If (says Dr. Franklin,) a conductor, one foot thick, and five feet long, will produce such snaps as agitate the whole human frame, what may we not expect from a surface of ten thousand acres of electrified clouds? How loud must be the explosion! how terrible the effects!
To this wonderful discovery, Dr. Darwin alludes in the following lines:—
Led by the phosphor light, with daring treadImmortal Franklin sought the fiery bed;Where, nurs’d in night, incumbent tempest shroudsThe seeds of thunder in circumfluent clouds,Besieg’d with iron points his airy cell,And pierc’d the monster slumb’ring in his shell.
Fire Balls,—are a kind of luminous bodies, commonly appearing at a great height above the earth, with a splendour surpassing that of the moon, and sometimes equalling her apparent size. They generally proceed in this hemisphere from north to south with vast velocity, frequently breaking into several smaller ones, sometimes vanishing with a report, and sometimes not. These luminous appearances, no doubt, constitute one branch of the ancient prodigies, or blazing stars. They sometimes resemble comets, in being attended with a train; but frequently they appear with a round well-defined disk. The first of these, of which we have any accurate account, was observed by Dr. Halley and others, at different places, in 1719. From the slight observations they could take of its course among the stars, its perpendicular height was computed at about seventy miles from the surface of the earth. The height of others has also been computed, and found to be various; though in general it is supposed to be beyond the limits assigned to our atmosphere, or where it loses its refractive power. The most remarkable of these onrecord appeared on the 18th of August, 1783, about nine o’clock in the evening. It was seen to the northward of Shetland, and took a southerly direction for an immense space, being observed as far as the southern provinces of France and Rome. During its course, it appears frequently to have changed its shape; sometimes appearing in the form of one ball, sometimes two or more; sometimes with a train, sometimes without one. It passed over Edinburgh nearly in the zenith, and had then the appearance of a well-defined round body, extremely luminous, and of a greenish colour; the light which it diffused on the ground giving likewise a greenish cast to objects. After passing the zenith, it was attended by a train of considerable length, which, continually augmenting, at last obliterated the head entirely; so that it looked like a wedge, flying with the obtuse end foremost. The motion was not apparently swift, by reason of its great height; though in reality it must have moved with great rapidity, on account of the vast space it travelled over in a short time. In other places its appearance was very different. At Greenwich, we are told, that “two bright balls, parallel to each other, led the way, the diameter of which appeared to be about two feet; these were followed by an expulsion of eight others, not elliptical, seeming gradually to fall to pieces, for the last was small. Between each two balls a luminous serrated body extended, and at the last a blaze issued, which terminated in a point. Minute particles dilated from the whole. The balls were tinted first by a pure bright light, then followed a delicate yellow, mixed with azure, red, green, &c. which, with a coalition of bolder tints, and a reflection from the other balls, gave the most beautiful rotundity and variation of colours, that the human eye could be charmed with. The sudden illumination of the atmosphere, and the form and singular transition of this bright luminary, contributed much to render it awful: nevertheless, the amazingly vivid appearance of the different balls, and other rich connecting parts, not very easy to delineate, gave an effect equal to the rainbow in the zenith of its glory.”
Terrible Effects of Electrified Clouds.—The most extraordinary instance of this kind perhaps on record, happened in the island of Java, in the East Indies, in August, 1772. On the 11th of that month, at midnight, a bright cloud was observed covering a mountain in the district calledCheribou, and at the same time several reports were heard like those of a gun. The people who dwelt on the upper parts of the mountain, not being able to fly fast enough, a great part of the cloud, almost three leagues in circumference, detached itself under them, and was seen at a distance, rising and fallinglike the waves of the sea, and emitting globes of fire so luminous, that the night became as clear as day. The effects of it were astonishing: every thing was destroyed for seven leagues round; the houses were demolished; plantations were buried in the earth; and two thousand one hundred and forty people lost their lives, besides fifteen hundred head of cattle, and a vast number of horses, goats, &c.
Another instance of a very destructive cloud, the electric qualities of which at present can scarcely be doubted, is related by Mr. Brydone, in his Tour through Malta. It appeared on the 29th of October, 1757. “About three-quarters of an hour after midnight, there was seen, to the south-west of the city of Valetta, a great black cloud, which, as it approached, changed its colour, till at last it became like a flame of fire mixed with black smoke. A dreadful noise was heard on its approach, which alarmed the whole city. It passed over the port, and came first on an English ship, which in an instant was torn in pieces, and nothing left but the hull; part of the masts, sails, and cordage, were carried to a considerable distance with the cloud. The small boats and selloques, that fell in its way, were all broken to pieces and sunk. The noise increased, and became more frightful. A sentinel, terrified at its approach, ran into his box; but both he and it were lifted up and carried into the sea, where he perished. It then traversed a considerable part of the city, and laid in ruins almost every thing that stood in its way. Several houses were laid level with the ground, and it did not leave one steeple in its passage. The bells of some of them, together with the spires, were carried to a considerable distance; the roofs of the churches demolished and beat down, &c. It went off at the north-east point of the city, and, demolishing the lighthouse, is said to have mounted up into the air with a frightful noise, and passed over the sea to Sicily, where it tore up some trees, and did other inconsiderable damage; but nothing material, as its fury had been spent at Malta. The number of killed and wounded amounted to near two hundred; and the loss of shipping, &c. was very considerable.”—The effects of thunder storms, and the vast quantity of electric matter formed in the clouds which produce these storms, are so well known, that it is superfluous to mention them. It appears, however, that even these clouds are not so highly electrified as to produce their fatal effects on those who are immersed in them. It is only the discharge of part of their electricity upon such bodies as are either not electrified at all, or not so highly electrified as the cloud, that does all the mischief. We have, however, only the following instance on record, of any persons’ being immersed in the body of a thunder cloud. Professor Saussure, and young Mr. Jalabert, when travelling over one of the highAlps, were caught among clouds of this kind; and, to their astonishment, found their bodies so full of electrical fire, that spontaneous flashes darted from their fingers with a crackling noise, and the same kind of sensation as when strongly electrified by art.
Among the awful phenomena of nature, none have excited more terror than lightning and thunder. Some of the profligate Roman emperors, of whom history records that they procured themselves to be deified, confessed, by their trembling and hiding themselves, when they heard the thunder, that there was a divine power greater than their own—Cœla tonantem Jovem. The greatest security against the terrors of a thunder-storm, although no certain one against its effects, is that life of piety and virtue, which is the best guardian of every earthly blessing. The good man, who knows that every event is under the direction of an overruling Providence, and that this life is only a part of his existence, introductory to the blissful scenes of immortality, will behold the terrors of the storm with unshaken resolution: grateful to the Supreme Being, if permitted to escape from the danger; and acquiescing in the Divine Will, if thus to be conveyed, by an easy and instantaneous passage, to that heaven where his conversation had long been, and to that God with whom he delighted to walk.
These sentiments are beautifully expressed in the following lines, written in a midnight thunder-storm, by the celebrated Mrs. Carter, and addressed to a lady:—
Let coward guilt with pallid fearTo shelt’ring caverns fly,And justly dread the vengeful fateThat thunders thro’ the sky:Protected by that hand, whose lawThe threat’ning storms obey,Intrepid virtue smiles secure,As in the blaze of day.In the thick cloud’s tremendous gloom,The lightning’s lurid glare,It views the same All-gracious Pow’r,That breathes the vernal air.Thro’ nature’s ever-varying scene,By diff’rent ways pursu’d,The one eternal end of Heav’nIs universal good.The same unchanging mercy rulesWhen flaming ether glows,As when it tunes the linnet’s voice,Or blushes in the rose.By reason taught to scorn those fearsThat vulgar minds molest,Let no fantastic terrors breakMy dear Narcissa’s rest.Thy life may all the tend’rest careOf Providence defend,And delegated angels roundTheir guardian wings extend.When thro’ creation’s vast expanseThe last dread thunders roll,Untune the concord of the spheres,And shake the rising soul;Unmov’d may’st thou the final stormOf jarring worlds survey,That ushers in the glad sereneOf everlasting day.
The following lines on the same subject were written by Mrs. Chapone:—
In gloomy pomp, whilst awful midnight reigns,And wide o’er earth her mournful mantle spreads;Whilst deep-voiced thunders threaten guilty heads,And rushing torrents drown the frighted plains;And quick-glanc’d lightnings, to my dazzled sight,Betray the double horrors of the night:A solemn stillness creeps upon my soul,And all its powers in deep attention die;My heart forgets to beat; my stedfast eyeCatches the flying gleam; the distant roll,Advancing gradual, swells upon my earWith louder peals, more dreadful as more near.Awake, my soul, from thy forgetful trance!The storm calls loud, and meditation wakes:How at the sound pale superstition shakes,Whilst all her train of frantic fears advance!Children of darkness, hence! fly far from me!And dwell with guilt and infidelity!But come, with look compos’d and sober pace,Calm Contemplation, come! and hither leadDevotion, that on earth disdains to tread;Her inward flame illumes her glowing face,Her upcast eye, and spreading wings, prepareHer flight for heaven, to find her treasure there.She sees, enraptur’d through the thickest gloom,Celestial beauty beam, and ’midst the howlOf warring winds, sweet music charms her soul;She sees, while rifted oaks in flames consume,A Father God, that o’er the storm presides,Threatens to save,—and loves when most he chides.
Surprising Effects of Extreme Cold.—By extreme degrees of cold, trees are burst, rocks rent, and rivers and lakes frozen several feet deep: metallic substances blister theskin like red-hot iron: the air, when drawn in by respiration, hurts the lungs, and excites a cough: even the effects of fire in a great measure seem to cease; and metals, though kept for a considerable time before a strong fire, will still freeze water when thrown upon them. When the French mathematicians wintered at Tornea, in Lapland, the external air, when suddenly admitted into their rooms, converted the moisture of the air into whirls of snow; their breasts seemed to be rent when they breathed it; the contact of it was intolerable to their bodies; and the spirit of wine, which had not been highly rectified, burst some of their thermometers by the congelation of the aqueous parts.
Extreme cold very often proves fatal to animals, in countries where the winters are very severe. Thus seven thousand Swedes perished at once, in attempting to pass the mountains which divide Norway from Sweden. It is not necessary, indeed, that the cold, in order to prove fatal to human life, should be so very intense as has been just mentioned. There is only requisite a degree somewhat below 32° of Fahrenheit, accompanied with snow or hail, from which shelter cannot be obtained. The snow which falls upon the clothes, or the uncovered parts of the body, then melts, and, by a continual evaporation, carries off the animal heat to such a degree, that a sufficient quantity is not left for the support of life. In such cases, the person first feels himself extremely chill and uneasy; he begins to grow listless, unwilling to walk or use exercise to keep himself warm; and at last turns drowsy, sits down to refresh himself with sleep, but wakes no more.
An instance of this was seen not many years ago at Terra del Fuego; where Dr. Solander, with some others, having taken an excursion up the country, the cold was so intense, that one of their number died. The Doctor himself, though he had warned his companions of the danger of sleeping in that situation, yet could not be prevented from making that dangerous experiment himself; and though he was awaked with all possible expedition, his body was so much shrunk in bulk, that his shoes fell off his feet, and it was with the utmost difficulty that he was recovered.
In those parts of the world where vast masses of ice are produced, the accumulation of it, by absorbing the heat of the atmosphere, occasions an absolute sterility in the adjacent countries, as is particularly the case with the island of Iceland; where the vast collections of ice floating out from the Northern Ocean, and stopped on that coast, are sometimes several years in thawing. Indeed, where great quantities of ice are collected, it would seem to have a power like fire, of both augmenting its own intenseness and that of the adjacent bodies.
Astonishingly Expansive Force of Freezing Water.—Although cold, in general, contracts most bodies, and heat expands them, yet there are some instances to the contrary, especially in the extreme cases or states of these qualities of bodies. Thus, though iron, in common with other bodies, expands with heat; yet, when melted, it is always found to expand in cooling again. Thus also, though water expands gradually as it is heated, and contracts as it cools, yet in the act of freezing it suddenly expands again, and that with an enormous force, capable of rending rocks, or bursting the very thick shells of metal, &c. A computation of the force of freezing water, has been made by the Florentine academicians, from the bursting of a very strong brass globe or shell by freezing water in it; when, from the known thickness and tenacity of the metal, it was found that the expansive power of a spherule of water only one inch in diameter, was sufficient to overcome a resistance of more than twenty-seven thousand pounds, or thirteen tons and a half.
Such a prodigious effect of expansion, almost double that of the most powerful steam-engines, and exerted in so small a mass, seemingly by the force of cold, was thought a very material argument in favour of those who supposed that cold, like heat, is a positive substance. Dr. Black’s discovery of latent heat, however, has afforded a very easy and natural explication of this phenomenon. He has shewn, that, in the act of congelation, water is not cooled more than it was before, but rather grows warmer: that as much heat is discharged and passes from a latent and a sensible state, as, had it been applied to water in its fluid state, would have heated it to 135°. In this process, the expansion is occasioned by a great number of minute bubbles suddenly produced. Formerly these were supposed to be cold in the abstract, and to be so subtile, that, insinuating themselves into the substances of the fluid, they augmented its bulk, at the same time that, by impeding the motion of its particles upon each other, they changed it from a fluid to a solid. But Dr. Black shews, that these are only air extricated during the congelation; and to the extrication of this air he ascribes the prodigious expansive force exerted by freezing water. The only question, therefore, is, by what means this air comes to be extricated, and to take up more room than it naturally does in the fluid? To this it may be answered, that perhaps part of the heat, which is discharged from the freezing water, combines with air in its unelastic state, and, by restoring its elasticity, gives it that extraordinary force; as is seen in the case of air suddenly extricated in the explosion of gunpowder. The degree of expansion of water, in the state of ice, is by some authors computed at one tenth of its volume. Oil and quicksilvershrink and contract after freezing. Mr. Boyle relates several experiments of vessels made of metals, very thick and strong; in which, when filled with water, closely stopped, and exposed to the cold, the water being expanded in freezing, and not finding either room or vent, burst the vessels. A strong barrel of a gun, with water in it, close stopped and frozen, was rent the whole length. Huygens, to try the force with which it expands, filled a cannon with it, whose sides were an inch thick, and then closed up the mouth and vent, so that none could escape; the whole being exposed to a strong freezing air, the water froze in about twelve hours, and burst the piece in two places. Hence mathematicians have computed the force of the ice upon this occasion; and they say, that such a force would equal twenty-seven thousand seven hundred and twenty pounds.
Major Edward Williams, of the Royal Artillery, made many experiments on the force of freezing water, at Quebec, in 1784-1785. He filled all sizes of bomb shells with water, then plugged the fuze-hole close up, and exposed them to the strong freezing air of the winter in that climate; sometimes driving in the iron plugs as hard as possible with a sledge hammer; and yet they were all thrown out by the sudden expansion of the water in the act of freezing, like a ball shot by gunpowder, sometimes to the distance of between four and five hundred feet, though they weighed near three pounds; and when the plugs were screwed in, or furnished with hooks or barbs to lay hold of the inside of the shell by, so that they could not possibly be forced out, in this case the shell was always split in two, though the thickness of the metal of the shell was about an inch and three-quarters. Through the circular crack, round about the shells, where they burst, there stood out a thin film or sheet of ice, like a fin; and in the cases where the plugs were projected by freezing water, there suddenly issued out from the fuze-hole a bolt of ice of the same diameter, and stood over it to the height sometimes of eight inches and a half.
CURIOSITIES RESPECTING VARIOUS PHENOMENA, OR APPEARANCES IN NATURE.—(Continued.)
Water Spout—Fata Morgana—Fairy Rings—Sheet of Phosphoric Fire—Phosphorus.
Water Spout—Fata Morgana—Fairy Rings—Sheet of Phosphoric Fire—Phosphorus.
Water Spout.—This extraordinary meteor is most frequently observed at sea. It generally begins by a cloud, which appears very small, and which is called, by sailors, the Squall. This augments in a little time into an enormous cloud of a cylindrical form, or that of a cone on its apex, and produces a noise like the roaring of an agitated sea, sometimes accompanied with thunder and lightning, and also large quantities of rain or hail, sufficient to inundate large vessels; and to carry away in their course, (when they occur by land,) trees, houses, and every thing that opposes their impetuosity. Sailors, dreading the fatal consequences of water-spouts, endeavour to dissipate them by firing a cannon into them just before they approach the ship. We shall give an account of one, as described by M. Tournefort, in his Voyage to the Levant.
WATER SPOUTS.—Page 663.
These phenomena are the great terror of sailors, who endeavourto dissipate them by firing cannon into them.
“The first of these (says this traveller) that we saw, was about a musket-shot from our ship. There we perceived the water begin to boil, and to rise about a foot above its level. The water was agitated, and whitish; and above its surface there seemed to stand a smoke, such as might be imagined to come from wet straw before it begins to blaze. It made a sort of a murmuring sound, like that of a torrent heard at a distance, mixed, at the same time, with a hissing noise, like that of a serpent: shortly after we perceived a column of this smoke rise up to the clouds, at the same time whirling about with great rapidity. It appeared to be as thick as one’s finger; and the former sound still continued. When this disappeared, after lasting for about eight minutes, upon turning to the opposite quarter of the sky, we perceived another, which began in the manner of the former; presently after, a third appeared in the west; and instantly beside it, still another arose. The most distant of these three could not be above a musket-shot from the ship. They all appeared like so many heaps of wet straw set on fire, and continued to smoke, and to make the same noise as before. We soonafter perceived each, with its respective canal, mounting up in the clouds; and spreading, where it touched the cloud, like the mouth of a trumpet; making a figure (to express it intelligibly) as if the tail of an animal was pulled at one end by a weight. These canals were of a whitish colour, and so tinged, as I suppose, by the water which was contained in them; for, previous to this, they were apparently empty, and of the colour of transparent glass. These canals were not straight, but bent in some parts, and far from being perpendicular, by rising in their clouds with a very inclined ascent.
“But what is very remarkable, the spouts crossed each other, in the form of a St. Andrew’s cross. In the beginning they were all about as thick as one’s finger, except at the top, where they were broader, and two of them disappeared; but shortly after, the last of the three increased considerably, and its canal, which was at first so small, soon became as thick as a man’s arm, then as his leg, and at last thicker than his whole body. We saw distinctly, through this transparent body, the water, which rose up with a kind of spiral motion; and it sometimes diminished a little of its thickness, and again resumed the same, sometimes widening at top, and sometimes at the bottom, exactly resembling a gut filled with water, pressed with the fingers to make the fluid rise or fall; and I am well convinced that this alteration in the spout was caused by the wind, which pressed the cloud, and compelled it to give up its contents. After some time its bulk was so diminished as to be no thicker than a man’s arm again, and thus swelling and diminishing, it at last became very small. In the end, I observed the sea which was raised about it to resume its level by degrees, and the end of the canal that touched it to become as small as if it had been tied round with a cord; and this continued till the light, striking through the cloud, took away the view. I still, however, continued to look, expecting that its parts would join again, as I had before seen in one of the others, in which the spout was more than once broken, and yet the parts again came together; but I was disappointed, for the spout appeared no more.”
In the Philosophical Transactions, (volume xxii. and xxiii.) we have descriptions of several of these phenomena: their effects, in some instances, are probably much exaggerated. One at Topsham is said to have cut down an apple-tree, several inches in diameter: another, we are told, seemed to be produced by a concourse of winds, turning like a screw, the clouds dropping into it: it threw trees and branches about with a gyratory motion.—One in Deeping Fen, Lincolnshire, was first seen moving across the land and water of the fen: it raised the dust, broke some gates, and destroyed a field of turnips: it vanished with an appearance of fire.—Dr.Franklin supposes that a vacuum is made by the rotatory motion of the ascending air, as when water is running through a funnel, and that the water of the sea is thus raised. But Dr. Young says, no such cause could do more than produce a slight rarefaction of the air, much less raise the water to the height of thirty or forty feet, or more.
THE FATA MORGANA, As observed in the harbour of Messina.—Page 665.
THE FATA MORGANA, As observed at Reggio.—Page 666.
Professor Wolke describes a water-spout, which passed immediately over the ship in which he was sailing, in the gulf of Finland: it appeared to be twenty-five feet in diameter, consisting of drops about the size of cherries. The sea was agitated round its base, through a space of about one hundred and thirty feet in diameter. One of the latest accounts of the phenomenon of a water-spout, is that read to the Royal Society in the year 1803, from a letter written to Sir Joseph Banks, by Captain Ricketts, of the royal navy. In the month of July, 1800, Captain Ricketts was called on deck, on account of the rapid approach of a water-spout, among the Lipari islands. It had the appearance of a viscid fluid, tapering in its descent, proceeding from the cloud to join the sea. It moved at the rate of about two miles an hour, with a loud sound of rain. It passed the stern of the ship, and wetted the afterpart of the main-sail: hence it was inferred, that water-spouts are not continuous columns of water; and subsequent observations confirmed the opinion. In November, 1801, about twenty miles from Trieste, a water-spout was seen eight miles to the south; round its lower extremity was a mist, about twelve feet high, somewhat in the form of an Ionian capital, with very large volutes, the spout resting obliquely on its crown. At some distance from this spout the sea began to be agitated, and a mist rose to the height of about four feet; then a projection descended from the black cloud that was impending, and met the ascending mist about twenty feet above the sea; the last ten yards of the distance were described with very great rapidity. A cloud of a light colour appeared to ascend in this spout, something like quicksilver in a tube. The first spout then snapped at about one-third of its height, the inferior part subsiding gradually, and the superior curling upwards. Several other projections from the cloud appeared, with corresponding agitations of the water below, but not always in spots vertically under them: seven spouts in all were formed; two other projections being re-absorbed. Some of the spouts were not only oblique, but curved: the ascending cloud moved most rapidly in those which were vertical: they lasted from three to five minutes, and their dissipation was attended by no fall of rain.
Fata Morgana.—This is a very remarkable aërial phenomenon, which is sometimes observed from the harbour ofMessina, and adjacent places, at a certain height in the atmosphere. The name, which signifies theFairy Morgana, is derived from an opinion of the superstitious Sicilians, that the whole spectacle is produced by fairies, or such like visionary invisible beings. The populace are delighted whenever it appears; and run about the streets shouting for joy, calling every body out to partake of the glorious sight. This singular meteor has been described by various authors; but the first who mentioned it with any degree of precision was Father Angelucci, whose account is thus quoted by Mr. Swinburne in his Tour through Sicily: “On the 15th of August, 1643, as I stood at my window, I was surprised with a most wonderful delectable vision. The sea that washes the Sicilian shore swelled up, and became, for ten miles in length, like a chain of dark mountains; while the waters near our Calabrian coast grew quite smooth, and in an instant appeared as one clear polished mirror, reclining against the aforesaid ridge. On this glass was depicted, inchairo scuro, a string of several thousands of pilasters, all equal in altitude, distance, and degree of light and shade. In a moment they lost half their height, and bent into arcades, like Roman aqueducts. A long cornice was next formed on the top, and above it arose castles innumerable, all perfectly alike. These soon split into towers, which were shortly after lost in colonnades, then windows, and at last ended in pines, cypresses, and other trees, even and similar. This is the Fata Morgana, which for twenty-six years I had thought a mere fable.” To produce this pleasing deception, many circumstances must concur, which are not known to exist in any other situation. The spectator must stand with his back to the east, in some elevated place behind the city, that he may command a view of the whole bay; beyond which the mountains of Messina rise like a wall, and darken the back ground of the picture. The winds must be hushed, the surface quite smoothed, the tide at its height, and the waters pressed up by currents to a great elevation in the middle of the channel. All these events coinciding, as soon as the sun surmounts the eastern hills behind Reggio, and rises high enough to form an angle of forty-five degrees on the water before the city, every object existing or moving at Reggio, will be repeated one thousand-fold upon this marine looking-glass, which, by its tremulous motion, is as it were cut into facets. Each image will pass rapidly off in succession, as the day advances, and the stream carries down the wave on which it appeared. Thus the parts of this moving picture will vanish in the twinkling of an eye. Sometimes the air is at that moment so impregnated with vapours, and undisturbed by winds, as to reflect objects in a kind of aërial screen, rising about thirty feet above the level of the sea. Incloudy heavy weather, they are drawn on the surface of the water, bordered with fine prismatical colours.
To the above account we shall add the following, given by M. Houel, whose judgment and veracity render his authority highly respectable.
“In fine summer days, when the weather is calm, there rises above the great current a vapour, which acquires a certain density, so as to form in the atmosphere horizontal prisms, whose sides are disposed in such a manner, that when they come to their proper degree of perfection, they reflect and represent successively, for some time, (like a moveable mirror,) the objects on the coast, or in the adjacent country. They exhibit by turns, the city and suburbs of Messina, trees, animals, men, and mountains. They are certainly beautiful aërial moving pictures. There are sometimes two or three prisms, equally perfect; and they continue in this state eight or ten minutes. After this, some shining inequalities are observed upon the surface of the prism, which render confused to the eye, the objects which had been before so accurately delineated, and the picture vanishes. The vapour forms other combinations, and is dispersed in the air. Different accounts have been given of this singular appearance; which for my part I attribute to a bitumen that issues from certain rocks at the bottom of the sea, and which is often seen to cover a part of its surface in the canal of Messina. The subtile parts of this bitumen being attenuated, combined, and exhaled with the aqueous globules that are raised by the air, and formed into bodies of vapour, give to this condensed vapour more consistence; and contribute, by their smooth and polished particles, to the formation of a kind of aërial crystal, which receives the light, reflects it to the eye, and transmits to it all the luminous points which colour the objects exhibited in this phenomenon, and render them visible.”
Fairy Rings,—are circles of dark green grass frequently observed in old pastures; they have long been known under the name of fairy rings, and have generally been supposed to be occasioned, in some way or other, by electricity. Dr. Wollaston has, in a late volume of the Transactions of the Royal Society, given a new and very ingenious theory, of which we shall present our readers with a brief account, premising, that Mr. Davy, in the course of his lectures at the Royal Institution, had occasion to refer to the subject, and seemed to coincide in opinion with Dr. Wollaston. That which first attracted his notice was the position of certain fungi, which are always found growing upon these circles, if examined in a proper season. The position of these fungi led him to imagine that the progressive increase from a central point wasthe probable mode of formation of the ring: hence he conjectured that the soil, which had once contributed to the support of the fungi, might be so exhausted of some peculiar pabulum necessary for their production, as to be rendered incapable of producing a second crop. The second year’s crop would, if this theory be just, appear in a small ring surrounding the original centre of vegetation; and at every succeeding year the defect of nutriment on one side, would necessarily cause the new roots to extend themselves solely in the opposite direction, and would occasion the circle of fungi continually to proceed, by an annual enlargement, from the centre outwards. An appearance of luxuriance of the grass would follow as a natural consequence, as the soil of an interior circle would always be enriched, by the decayed roots of fungi of the year’s growth. This theory is supported by some observations of Dr. Withering; and Dr. Wollaston says, by way of confirmation, that whenever two adjacent circles are found to interfere, they not only do not cross each other, but both circles are invariably obliterated between the points of contact: the exhaustion occasioned by each obstructs the progress of the other, and both are starved.—Philosophical Transactions, 1807, Part II.
Though it cannot be doubted that most fairy rings, if not all of them, have considerable relation to the running of a fungus; there, nevertheless, seems reason to conclude that electricity may likewise be concerned in their production. The electrical effect may relate to fairy rings of a different kind from those occasioned by the fungus, or it may have been antecedent to the production of the vegetable. It is a familiar effect in our experiments, that the spark proceeding from a positive conductor, breaks or radiates at about one-third of its course, and strikes the receiving conductor by a central spark surrounded by other smaller ones. The concentric rings produced upon polished metallic surfaces by the strong explosion of a battery, as first observed by Dr. Priestley, appears to be a fact of the same kind; and the forked radiations of lightning are well known. There is related, in the Philosophical Journal, volume I. 4to, some events which happened in Kensington Gardens in June, 1781, when a powerful thunder-storm passed over the western extremity of London. The explosions were very marked and distinct, and in many instances forked at the lower end, but never at the top; from which it seems proper to conclude, that the general mass of clouds, or, at least, that extremity which passed over London, was in the state called positive.
Five days afterwards, upon visiting Kensington Gardens, it was observed, that every part of that extensive piece of ground shewed marks of the agency of the lightning, chiefly bydiscoloration of the grass in zigzag streaks, some of which were fifty or sixty yards in length. Instances of this superficial course of the lightning along the ground, before it enters the earth, are sufficiently frequent. But the circumstance applicable to our present subject is, that several trees had been struck by the lightning. Two of them, which stood on the outside to the westward, had holes torn in the ground, close to the trunk; and round one of these trees was a space of six feet in diameter, in which the grass was very much scorched. Another tree on the west was surrounded by a faint ring of burnt or faded grass, which seemed to be occasioned by some earlier stroke, as the vegetation had begun to shoot up again. Another tree, standing on the out side to the south, was surrounded by a ring of twelve feet diameter, and eighteen inches broad. Within the ring the grass was fresh; but on the surface of the ring, the grass and the ground were much burned. To the eastward of the tree, upon the ring itself, were two holes, in which the ground had the appearance of ashes. Another tree, on the east side of the grove, had the half of a faint ring to the westward. And, lastly, a tree which stood in the middle was surrounded by a faint ring of twelve feet diameter, within which the grass was unhurt; and to the westward, at the distance of about three feet from the inner ring, was part of another similar ring, of nearly the same appearance; the verdure being unhurt in the interval between the rings.
A Sheet of Phosphoric Fire.—A curious instance of this occurred to Monsieur Peron, in his voyage from Europe to the Isle of France. Between three and four degrees north latitude, during the obscurity of a night intensely dark, the wind blowing a hurricane, and the vessel making a rapid progress, he was struck by the sudden appearance of a vast sheet of phosphoric fire, floating before the ship, and covering a considerable space. The vessel presently made its way through this inflamed part of the sea, which enabled the observant navigator to discover that this prodigious light was occasioned entirely by an immense number of small animalcules, which swam at different depths, and appeared to assume various forms. Those which were most immersed in the water, looked like great red-hot cannon balls: whilst those on the surface resembled cylinders of red-hot iron. Some of them were soon caught, and found to vary in size, from three to seven inches. All the outside surface of the animal was bristled with thick oblong tubercles, shining like so many diamonds; and these seemed to be the principal seat of its wonderful phosphorescence. The inside, also, appeared furnished with a multitude of little, narrow, oblongglands, which possessed the phosphoric virtue in a high degree.
When in a tranquil state, the colour of these brilliant inhabitants of the ocean is an opal yellow, mixed with green; but, on the slightest movement of those voluntary contractions exercised by the creature, or those which the observer can at pleasure excite by the least irritation, the animal seems to inflame, and it becomes instantly like a piece of red-hot iron of the most vivid brilliancy. When its phosphorescency declines, it assumes a succession of light elegant tints, that are very pleasing to the eye, such as red, aurora, orange, green, and azure blue; the last is particularly lively and pure. The organization of this animal, which is called the Pyrosoma Atlanticum, ranks it amongst the most singular of the zoophite tribe; whilst its extraordinary phosphoric powers render it the most beautiful that has yet been seen.
It may be not amiss to conclude this chapter with an account of that very curious substance,Phosphorus.—This singular production was accidentally discovered, in 1677, by an alchymist of Hamburgh, named Brandt, when he was engaged in searching for the philosopher’s stone. Kunkel, another chemist, who had seen the new product, associated himself with one of his friends, named Krafft, to purchase the secret of its preparation; but the latter deceiving his friend, made the purchase for himself, and refused to communicate it. Kunkel, who at this time knew nothing further of its preparation, than that it was obtained by certain processes from urine, undertook the task, and succeeded. It is on this account that the substance long went under the name of Kunkel’s phosphorus. Mr. Boyle is also considered as one of the discoverers of phosphorus. He communicated the secret of the process for preparing it, to the Royal Society of London, in 1680. It is asserted, indeed, by Krafft, that he discovered the secret to Mr. Boyle, having, in the year 1678, carried a small piece of it to London, to shew it to the royal family; but there is little probability that a man of such integrity as Mr. Boyle would claim the discovery of the process as his own, and communicate it to the Royal Society, if this had not been the case. Mr. Boyle communicated the process to Godfrey Hankwitz, an apothecary of London, who for many years supplied Europe with phosphorus, and hence it went under the name of English Phosphorus. In the year 1774, the Swedish chemists, Gahn and Scheele, made the important discovery, that phosphorus is contained in the bones of animals; and they improved the processes for procuring it.
When phosphorus is heated to the temperature of 148°, it takes fire, burns with a bright flame, and gives out a great quantity of white smoke. Phosphorus enters into combination with oxygen, azote, hydrogen, and carbon. Phosphorus is soluble in oils, and, when thus dissolved, forms what has been called liquid phosphorus, which may be rubbed on the face and hands without injury. It dissolves too in ether; and a very beautiful experiment consists in pouring this phosphoric ether in small portions, and in a dark place, on the surface of hot water. The phosphoric matches consist of phosphorus extremely dry, minutely divided, and perhaps a little oxygenized. The simplest mode of making them, is to put a little phosphorus, dried by blotting paper, into a small phial; heat the phial, and when the phosphorus is melted, turn it round, so that the phosphorus may adhere to the sides. Cork the phial closely, and it is prepared. On putting a common sulphur match into the bottle, and stirring it about, the phosphorus will adhere to the match, and will take fire when brought out into the air.
CURIOSITIES RESPECTING VARIOUS PHENOMENA, OR APPEARANCES IN NATURE.—(Continued.)