Read Ebook: Magic Pretended Miracles and Remarkable Natural Phenomena by Anonymous

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called forth loud and continued applause, is this:--sulphurous acid has the property of boiling water when it is at a temperature below the freezing point; and, when poured into the heated vessel, the suddenness of the evaporation occasions a degree of cold sufficient to freeze water.

Liquid carbonic acid takes a high position for its freezing qualities. Mr. Adams, of Kensington, manufactures this curious liquid as an article of commerce, and has, occasionally, as much as nine gallons of it in store. In drawing it from its powerful reservoirs, it evaporates so rapidly as to freeze, and it is then a light porous mass, like snow. If a small quantity of this is drenched with ether, the degree of cold produced is even more intolerable to the touch than boiling water; a drop or two of the mixture producing blisters, just as if the skin had been burned! Mr. Adams states that, in eight minutes he has frozen a mass of mercury weighing ten pounds.

In one department of knowledge--that of vapours and gases--on which chemistry casts so much light, we discover many remarkable phenomena. Few persons have resided, for example, in the fenny and swampy districts of our island, without seeing, at least occasionally, the ignis fatuus, Will-o'-the-wisp, or Jack-o'-lantern, hovering a few feet above the surface of stagnant water.

"Wild fires dancing o'er the heath,"

may be observed, indeed, at almost all times of the year, but it is chiefly in autumn, and particularly in November, that they flit in mazy circles and irregular evolutions; sometimes at the edge of a morass, over the tops of withered sedges, reeds, and brushwood; and, at others, over palings and hedgerows, or the still surface of the oozy bog.

It has been argued by some, that they are effects produced by luminous insects, as the glow-worm, the gnat, and the mole-cricket. But this theory is very unsatisfactory, and the cause which is now generally acknowledged to be the real one, is far more natural. There is a substance readily obtained, but of very offensive odour, called phosphoret of lime; and, if a piece of this be taken and dropped into a pool of water, little flames will be seen on its surface. These arise from the power of the substance to decompose water, in consequence of which, the hydrogen ascends to the surface, and ignites on coming in contact with the air.

Dr. Weissenborn has given the following interesting statements:--"In the year 1818, I was fortunate enough to get a fine view of the ignes fatui operating on an extensive scale. I was then at Schnepfenthal, in the duchy of Gotha; and in a clear November night, between eleven and twelve o'clock, when I had just undressed, the bright moonshine allured me to the window, to survey the expanse of boggy meadows, which spread two or three English miles in length, a quarter-of-a-mile from the foot of the hillock on which the house in which I then was, is standing. Through the first third of the meadows there was a winding rivulet, of the breadth of seven or eight feet, which then turns off into an artificial bed, whilst the old bed continues in the direction of the meadows, which are bounded on one side by a range of brushwood, and on the other by cultivated grounds, with marshy dells here and there. My intimate acquaintance with the locality, together with the bright moonshine, enabled me to discover every object round the meadow-ground, sufficiently well to judge of the position and direction of the luminous phenomena, the display of which I saw as soon as I had posted myself at the window. I perceived a number of reddish yellow flames on different parts of the expanse of almost level ground. I descried, perhaps, no more than six at a time, but dying away and appearing in other places so rapidly, that it was impossible to count them; but I should say, on a rough calculation, there were about twenty or twenty-five within a second. Some were small and burned dimly; others flashed with a bright flame, in a direction almost parallel with the ground, and coinciding with that of the wind, which was rather brisk. After having for some time looked with amazement at the brilliant scene, as a whole, I tried to study its details, and soon found that the flames which were nearest originated in a quagmire, the position of which I knew exactly, by a solitary cluster of willows; and I could trace a succession of flashes from that spot to a certain point of the margin of the wood across the rivulet and meadow. The distance of the two points from each other was more than half-a-mile, and the flames travelled over it, perhaps, in less than a second. The first flash was not always observed in the immediate neighbourhood of the quagmire; but the succession of flames lay always in the same straight line, and in the direction of the wind; whilst other sets were observed, though not with the same distinctness, in the more distant parts of the meadow-ground.

"After about an hour, a bank of mist began to overspread the meadows, but I saw the light still glimmering through it, whilst I dressed myself, in order to examine the phenomenon in its laboratory. However, when I reached the meadows, the atmospheric conditions which gave rise to the ignes fatui had ceased to exist." Weissenborn then expresses his belief that the phosphoric hydrogen gas, exhaled by certain swamps, is kindled into flame by coming in contact with the atmospheric air; but, as the hydrogen is not saturated with phosphorus, there is a certain electric condition of the atmosphere necessary to cause the combustion. Thus, under common circumstances, the gas is evolved and dissipated without being observed; but when the state of the atmosphere is competent to effect its combustion, the proper degree of electrical tension is lost at the place where the explosion is effected; and, until it is restored, or the gas comes in contact with that layer of the atmosphere which possesses the requisite degree of electrical tension, a considerable body of bog gas may collect, and be carried in the direction of the wind, so as to give rise to a sort of quick fire, with occasional flashes; in those places of the stream of gas where there happens to be a considerable volume of it. The lights, which still frequently excite apprehensions in Wales, and are popularly termed "corpse candles," have the same origin as the "ignes fatui."

At the village of Wigmore, in Herefordshire, there are fields which may be, and two houses which really are, illuminated with a natural gas. This vapour, with which the subjacent strata seem to be charged, is obtained in the following manner:--a hole is made in the cellar of the house, or other locality, with an iron rod; a hollow tube is then placed therein, fitted with a burner similar to those used for ordinary gas-lights, and immediately on applying a flame to the jet, a soft and brilliant light is obtained, which may be kept burning at pleasure. The gas is very pure, quite free from any offensive smell, and does not stain the ceilings, as is generally the case with the manufactured article. Besides lighting rooms, etc., it has been used for cooking; and, indeed, seems capable of the same applications as prepared carburetted hydrogen. There are several fields in which the phenomenon exists, and children are seen boring holes and setting the gas on fire for amusement. It is now several months since the discovery was made; and a great many of the curious have visited, and still continue to visit, the spot.

If the Chinese are not manufacturers, they are, nevertheless, gas consumers and employers on a large scale; and have evidently been so, ages before the knowledge of its application was acquired by Europeans. Beds of coal are frequently pierced by the borers of salt water; and the inflammable gas is forced up in jets twenty or thirty feet in height. From these fountains, the vapour has been conveyed to the salt-works in pipes, and there used for the boiling and evaporation of the salt; other tubes convey the gas intended for lighting the streets, and the larger apartments and kitchens. As there is still more gas than is required, the excess is conducted beyond the limits of the salt-works, and forms separate chimneys or columns of flame.

A singular counterpart to this employment of natural gas, is witnessed in the valley of the Kanawha, in Virginia. The origin, the means of supply, the application to all the processes of manufacturing salt, and of the appropriation of the surplus for the purposes of illumination, are remarkably alike at such distant points as China and the United States.

It has sometimes been stated of a departed person, that a luminous appearance was observed to rest upon, and occasionally to surround, a corpse. Such an effect has been described as supernatural--a Divine attestation to extraordinary excellence; and, doubtless, Roman Catholics have made the most of such circumstances in reference to those whom they have denominated saints, and to whom a place has been assigned in their calendar. And yet there was no departure in any such instance from the ordinary laws of nature. Sir H. Marsh, in an essay on "The Evolution of Light from the Human Subject," states, that electric sparks have been known to issue from the skin of some individuals when rubbed lightly and quickly with a linen cloth. Not only has this physician heard of such cases, but two had actually come under his observation.

He was led to consider the subject by the following statement made to him. "About an hour and-a-half before my sister's death, we were struck by appearances proceeding from her head, in a diagonal direction. She was, at the time, in a half-recumbent position, and perfectly tranquil. The light was pale as the moon, but quite evident to mamma, myself, and sisters, who were watching over her at the time. One of us, at first, thought that it was lightning; till, shortly after, we fancied we perceived a sort of tremulous glimmer playing round the head of the bed; and then, recollecting that we had read something of a similar nature having been observed previous to dissolution, we had candles brought into the room, fearing our dear sister would perceive it, and that it might disturb the tranquillity of her last moments."

On these, and similar facts, Dr. Marsh remarks: "Disease is but a step toward dissolution, in which the vital powers are impaired; and, unless the malady be checked, by the use of proper means, a period will quickly approach when the chemical action will entirely prevail over the whole frame. Phosphorescent matter may be generated in organic bodies at a period of incipient decomposition; and when we consider that phosphuretted hydrogen undergoes spontaneous combustion, when brought in contact with the oxygen of the atmosphere, and that the component parts of which this gas is formed exist in the body in great abundance, an easy solution is at hand, accounting for the luminous appearances which have been witnessed in dissecting-rooms, in burial-grounds, and in marine substances, as well as on the approach of dissolution."

The Arabs are well known as believers in wonders; and of one of their magicians, named Sadoomeh, the following story is told. "In order to give one of his friends a treat, he took him to the distance of about half-an-hour's walk into the desert, on the north of Cairo, where they both sat down upon the pebbly and sandy plain; and the magician having uttered a spell, they suddenly found themselves in the midst of a garden, like one of the gardens of Paradise, abounding with flowers and fruit-trees of every kind, springing up from a soil covered with verdure brilliant as the emerald, and irrigated by numerous streamlets of the purest water. A repast of the most delicious viands and fruit was spread before them by invisible hands; and they both ate and drank to satiety, taking copious draughts of the various wines. At length the magician's guest sank into a deep sleep, and when he awoke he found himself again in the pebbly and sandy plain, with Sadoomeh still by his side." "The reader will probably attribute this vision," says Mr. Lane, who relates the tale, "to a dose of opium or some similar drug; and such I suppose to have been the means employed; for I cannot doubt the integrity of the narrator, though he would not admit such an explanation; regarding the whole as an affair of magic, 'jinn,' or genii."

A story of Gassendi, one of the most distinguished of naturalists, mathematicians, and philosophers of France, in the sixteenth century, will place this solution in a still clearer light. As he was taking a morning walk near Deigne, in Provence, his ears were assailed by repeated exclamations of "A sorcerer! a sorcerer!" On glancing behind him, he beheld a mean and simple-looking man, with his hands tied, whom a mob of the country-people were hurrying to prison. Gassendi's character and learning had given him great authority with them, and he desired to be left alone with the man. They immediately surrendered him, and Gassendi said to him, in private, "My friend, you must tell me sincerely, whether you have made a compact with the devil or not: if you confess it, I will give you your liberty immediately; but, if you refuse to tell me, I will give you immediately into the hands of a magistrate." The man answered, "Sir, I will own that I go to a meeting of wizards every day. One of my friends has given me a drug, which I take to effect this, and I have been received as a sorcerer these three years." He then described the proceedings of these meetings, and spoke of the different devils, as if he had been all his life acquainted with them. "Show me," said Gassendi, "the drug which you take to attend this infernal meeting, for I intend to go there with you to-night." The man replied, "As you please, Sir; I will take you at midnight, as soon as the clock strikes twelve." Accordingly, he met Gassendi at the appointed hour, and, showing him two boluses, each of the size of a walnut, he desired him to swallow one, as soon as Gassendi had seen him swallow the other, and then they lay down together on a goat-skin. The man soon fell asleep, but Gassendi remained awake and watched him, and perceived that he was greatly disturbed in his slumbers, and writhed and twisted his body about, as if he had been troubled by bad dreams. At the expiration of five or six hours he awoke, and said to Gassendi, "I am sure, Sir, you ought to be satisfied with the manner in which the great goat received you; he conferred on you a high honour when he permitted you to kiss his tail the first time he ever saw you." It was thus apparent that the deleterious opiate had operated upon his imagination. Gassendi, compassionating his weakness and credulity, took pains to convince him of his self-delusion; and, showing him the bolus, he gave it to a dog, who soon fell asleep, and suffered great convulsions. The poor fellow was set at liberty to undeceive his brethren, who had, like him, been lulled by the noxious drug into imagining themselves sorcerers.

In India there is a native plant, which, after it has flowered, is dried and sold in the bazaars of Calcutta, for smoking. The Hindoos call it "ganpah," and they give the name of "bang" or "subjee" to the large leaves and capsules which they use for the same purpose. The plant is a species of hemp; the smoking of which is considered so delightful, according to Dr. Thomson, as to have been denominated by such epithets as "Assuager of sorrow," "Increaser of pleasure," "Cementer of friendship," "Laughter-mover," and others of the same kind.

On the same authority it is stated, that in Nepaul, the resin only is used; in some places it is collected by native coolies, walking through the fields of hemp at the time the plants give forth the resin, which, adhering to the skin, is scraped off from it, and kneaded into balls. It is taken in doses, from a grain to two grains, and causes a delightful delirium. When repeated, however, it is followed by catalepsy, or that state of insensibility which allows the body to be moulded into any form like a Dutch-jointed doll, the limbs remaining in the position in which they were placed, though contrary to the law of gravity, and continuing so for many hours.

We are well acquainted with various means of acting in an extraordinary manner on the human frame. The writer, in common with multitudes, has witnessed, for example, the operation of nitrous oxide, often called "the laughing-gas." It acts, however, very differently on different persons; some laugh immoderately, others become depressed, others assume the airs of vanity and importance which accord with their most cherished dispositions; and some can only be forcibly restrained from deeds of great violence. It is certainly a most singular sight to see a person laughing most boisterously, or strutting with all the hauteur of a newly-made potentate, suddenly subside as the action of the gas ceases, into a very unobtrusive individual.

We may now briefly allude to one of the most extraordinary applications of the present times. The late sir Humphry Davy made many experiments on the effects of various gases on the human lungs. He found, in his own person, that the inhalation of nitrous oxide removed head-ache, and greatly assuaged the pain of cutting a wisdom-tooth. In his works, edited by Dr. John Davy, is the following passage:--

"As nitrous oxide, in its extensive operation, appears capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place." Here is the germ of the recent application of ether.

"Experience has fully shown that the brain may be acted on so as to annihilate, for the time, what may be termed the faculty of feeling pain; the organ of general sense may be lulled into profound sleep, while the organ of special sense, and the organ of intellectual function remain wide awake, active, and busily employed. The patient may feel no pain under very cruel cutting, and yet he may see, hear, taste, and smell, as well as ever, to all appearance; and he may also be perfectly conscious of everything within reach of his observation--able to reason on such events most lucidly, and able to retain both the events and the reasoning in his memory afterwards. We have seen a patient following the operator with her eyes most intelligently and watchfully, as he shifted his place near her, lifted his knife, and proceeded to use it; wincing not at all during its use; answering questions by gesture, very readily and plainly; and, after the operation was over, narrating every event as it occurred; declaring that she knew and saw all; stating that she knew and felt that she was being cut, and yet that she felt no pain whatever. Patients have said, quietly, 'You are sawing now,' during the use of the saw in amputation; and afterwards they have declared most solemnly, that though quite conscious of that part of the operation, yet they felt no pain. We have seen a patient enduring amputation of a limb without any sign of suffering, opening her eyes during the performance, at its most painful part, descrying a country practitioner at some distance--under whose care she had formerly been, and whom she had not seen for some considerable time--addressing him by name, and requesting that he might not leave town without seeing her."

Since the period to which the writer just quoted refers, Dr. Simpson, of Edinburgh, has discovered a substitute for sulphuric ether--chloroform, or the perchloride of formyle. It is stated to possess over sulphuric ether the following advantages:--1. A greatly less quantity of chloroform than of ether is requisite to produce the desired effect. 2. Its action is much more rapid and complete, and generally more enduring. 3. The inhalation and influence of chloroform are far more agreeable and pleasant than those of ether. 4. The use of chloroform is less expensive than that of ether. 5. Its odour is not unpleasant; nor does it exhale in a disagreeable form from the lungs of the patient, as so generally happens with sulphuric ether. 6. Being required in much less quantity, it is much more portable and transmissible than sulphuric ether. 7. No special kind of inhaler or instrument is necessary for its exhibition. A little of the liquid diffused upon the interior of a hollow-shaped sponge, or on a pocket-handkerchief, or a piece of linen or paper, or held over the mouth and nostrils, so as to be fully inhaled, generally suffices, in about a minute or two, to produce the effect. This agent, however, requires to be used to annul pain under the direction of a judicious medical practitioner; it may otherwise be productive of serious consequences.

A prodigious force often arises from chemical affinity. Of this, gunpowder presents a familiar instance. It is formed of nitre, sulphur, and charcoal, which, in the ordinary state, are only combined mechanically; but no sooner is this compound ignited, than these substances are brought, by chemical action, into such close contact, as to evolve a mighty and destructive power. It seemed likely to be thrown into the shade by the discovery of gun-cotton as an explosive agent, which excited extraordinary interest throughout Europe. On projectile experiments being made, a gun, charged with thirty grains of prepared cotton, propelled an equal charge of shot, with greater force and precision, at a distance of forty yards, than were gained by the same gun loaded with a hundred-and-twenty grains of gunpowder. A rifle, charged with fifty-four and-a-half grains of gunpowder, sent a ball through seven boards, half-an-inch in thickness, at a distance of forty yards; the same rifle, charged with forty grains of gun-cotton, caused the ball to enter the eighth board. Another rifle, which had been used for elephant-shooting, and consequently carried a much larger ball, charged with forty grains of gun-cotton, forced the ball through eight boards, at a distance of ninety yards. In no case was the discharge accompanied by a greater recoil than usual; and the reports were not louder than those accompanying the discharge of guns and rifles loaded with gunpowder. According to the specification of the patentee, M. Sch?nbein, cotton is preferred for this purpose, freed from extraneous matters; and it is considered desirable to operate on the clean fibres of the cotton in a dry state, by means of nitric and sulphuric acids. These are mixed together in the proportion of one measure of nitric acid to three measures of sulphuric acid, in any suitable or convenient vessel not liable to be affected by the acids. A great degree of heat being generated by the mixture, it is left to cool until its temperature falls to sixty or fifty degrees Fahrenheit. The cotton is then immersed in it; and, in order that it may become thoroughly saturated with the acids, it is stirred with a rod of glass, or other material, not affected by the acids. The cotton should be introduced in as open a state as practicable. The acids are then poured or drawn off, and the cotton gently pressed by a presser of glazed earthenware, to take out the acids, after which it is covered up in the vessel, and allowed to stand for about an hour. It is subsequently washed in a continuous flow of water, until the presence of the acids is not indicated by the ordinary test of litmus paper. To remove any uncombined portions of the acids which may remain after the cleansing process, the patentee dips the cotton in a weak solution of carbonate of potash, composed of one ounce of carbonate of potash to one gallon of water, and partially dries it by pressing, as before. The cotton is then highly explosive, and may be used in that state; but, to increase its explosive power, it is dipped in a weak solution of nitrate of potash, and, lastly, dried in a room heated by hot air, or steam, to about one hundred and fifty degrees Fahrenheit.

The advantages and disadvantages of this substance have thus been stated by professor Brande:--"The disadvantages are, that the effects are less regular than those of gunpowder; that it is more dangerous, because inflaming at a lower temperature; that it does not take fire when compressed in tubes; that it burns slowly in all kinds of cartridges; that guns and pistols must be altered to admit of its use; that it is not adapted for the use of the army; that the barrel of the gun is moistened by the water produced during combustion. The advantages, on the other hand, may be stated as follows:--Its extreme cleanliness, leaving no residue after combustion; its freedom from all bad smell; the facility and the safety of its preparation; the possessing treble the force of gunpowder; its explosion producing no smoke, and less noise than that of gunpowder; its filamentary nature admitting of its being used over head in mining operations; its not being liable to the accidents of leakage; its occasioning very little recoil."--Every benevolent mind must wish to hear no more of "the confused noise of battle and of garments rolled in blood;" and that the time may soon arrive when men shall "beat their swords into ploughshares, and their spears into pruning-hooks;" when "they shall learn war no more," but yield themselves heartily and devotedly to the benignant sway of the Prince of peace. There seems, however, no reason to conclude that gun-cotton will be employed for any hostile purpose, the Board of Ordnance having definitely decided against its adoption in the military and naval services. The principal objection to it is, the very low temperature at which it explodes. The mere heating of a gun, from a number of charges successively fired, has been proved sufficient to cause an instant explosion of gun-cotton.

In mining, it is likely to be of great use. In the slate-quarries at Penrhyns it has been found far superior to gunpowder. A huge mass of sixty tons' weight, for instance, was gently pushed from its firmly compacted bed by the explosion of only eight ounces of cotton, while the slate was not splintered. In other great works it will also be of service. In a cutting on the Syston and Peterborough railway, not far from Stamford, experiments showed the average powers of the gun-cotton to be in the proportion of one to six of gunpowder; so that, in a hard freestone foundation, about five feet thick, and with an entire depth of twenty-eight feet, where six holes were necessary for gunpowder, only one was required for gun-cotton. In all blasting operations, whether in open cuttings, tunnels, or deep mines, a great saving of time, labour, and cost, is thus likely to be effected.

Light and its phenomena--Magic pictures--The optical paradox--Chinese metallic mirrors--Effect of an optical instrument on a superstitious mind--Origin of photography--The Talbotype--The Daguerreotype--Sunlight pictures.

The cause of those sensations which we refer to the eyes, or that which produces the sense of seeing, is light. The phenomena of vision have always been regarded as among the most interesting branches of natural science. The knowledge of the laws which regulate the phenomena of light, constitutes the science of optics, which explains the cause of many most striking illusions.

The writer has often seen a singular transformation effected by an ingenious device, called the optical paradox: thus an eagle may be changed into a lion, and a dog into a cat.

For this purpose, a wooden three-sided box must be prepared, and through the open part may slide the various drawings to be used, as B. Connected with this, there must be a pillar, C, and a horizontal bar holding a tube, D, having in it a glass placed exactly over the centre. The change is partly dependent on the glass, the sides of which are flat and diverge from its hexagonal base upwards, to a point in the axis of the glass, like a pyramid, E, forming an isosceles triangle. All that is now necessary to the completion of the change, is in the border of the drawing, in which the various parts required for the new figure are cleverly introduced; so that when the distance of the glass from the eye is rightly adjusted, each angular side will take up its portion from the border, and present to the eye the various parts in an entire figure. The shape of the glass prevents the appearance of any particular figure in the centre, as the eagle, for instance; while the lion, arranged in portions and drawn on the circle of refraction at six different parts of the border, yet artfully disguised by blending with it, the transformation will be completely produced.

It is easy for an ignorant and superstitious mind to confound a very harmless and simple instrument with one of magical power. We have an example of this in Dodwell's description of his residence at Athens. On his first admission within the venerable walls of the Acropolis, it was necessary to offer a small present to the disdar, or Turkish governor, and an additional sum to make drawings and observations without being molested by the servants of the garrison. The disdar proved to be a man of bad faith and insatiable rapacity, and, after experiencing numerous vexations from the mercenary Turk, Dodwell was at length released from his importunities by a singular circumstance. As he was one day engaged in drawing the Parthenon, with the aid of his camera obscura, the disdar, whose surprise was excited by the novelty of the sight, asked, with a sort of fretful inquietude, what new conjuration he was performing with that extraordinary machine. Dodwell endeavoured to explain it, by putting in a clean sheet of paper, and making him look at the instrument; but he no sooner saw the Temple of Minerva reflected on the paper in all its lines and colours, than he imagined the effect was produced by some magical process; his astonishment appeared mingled with alarm, and, stroking his long black beard, he repeated several times the words Allah, Masch-Allah--a term of admiration with the Turks, signifying that which is made by God.

Again he looked into the camera obscura, with a kind of cautious diffidence, and, at that moment, some of his soldiers happening to pass before the reflecting-glass, were beheld by the astonished disdar walking upon the paper. He now became outrageous; he assailed Dodwell with various opprobrious epithets, one of which was Bonaparte--the appellation being at the time synonymous to that of magician, or of any one supposed to be endowed with supernatural talents--and declared that, if Dodwell chose, he might take away all the stones in the temple, but that he would not permit his soldiers to be conjured into a box. "When I found," says Dodwell, "that it was no use to reason with his ignorance, I changed my tone, and told him that, if he did not leave me unmolested, I would put him into my box; and that he should find it a very difficult matter to get out again. His alarm was now visible; he immediately retired, and ever after stared at me with a mixture of apprehension and amazement. When he saw me come to the Acropolis, he carefully avoided my approach; and never afterwards gave me any further molestation."

The portable camera obscura, represented by the diagram, has often yielded much pleasure in the domestic circle, while the larger ones, which are publicly exhibited, are highly interesting. No person, perhaps, has witnessed the neatness of outline, the precision of form, the truth of colouring, and the sweet gradations of tint, thus apparent, without regretting that an imagery so exquisite and faithful to nature could not be made to fix itself permanently on the tablet of the machine. Yet, in the estimation of all, such a wish seemed destined to take its place among other dreams of beautiful things; the splendid but impracticable conceptions in which men of science and ardent temperament have sometimes indulged. Such a dream, however, has been realized of late.

"The subjects are 'The Entrance Gateway of Queen's College, Oxford;' 'The Ladder,' in which we have three figures from the life; and 'A View of the Author's Residence, Lacock Abbey, in Wiltshire.' In the first of these, the truth-telling character of photographic pictures is pleasingly shown. It appears, by the turret clock, that the view was taken a little after two, when the sun was shining obliquely upon the building. The story of every stone is told, and the crumbling of its surface under the action of atmospheric influences is distinctly marked. The figures in 'The Ladder' are prettily arranged, but the face of the boy is distorted, from the circumstance of its being so very near the edge of the field of view embraced by the lens of the camera obscura. In looking at this photograph, we are led at once to reflect on the truth to nature observed by Rembrandt, in the disposition of his lights and shadows. We have no violent contrasts; even the highest lights and the deepest shadows seem to melt into each other, and the middle tints are but the harmonizing gradations. Without the aid of colour, with simple brown and white, so charming a result is produced, that, looking at the picture from a little distance, we are almost led to fancy that the introduction of colour would add nothing to its charm."

The following is the patent process for obtaining a negative picture:--Take a sheet of paper, with a smooth surface, and a close and even texture, and without the water-mark, and wash one side of it, by means of a soft camel's-hair brush, with a solution composed of one hundred grains of crystallized nitrate of silver dissolved in six ounces of distilled water, having previously marked with a cross the side which is to be washed. When the paper has been dried cautiously at the fire, or spontaneously in the dark, immerse it for a few minutes in a solution of iodide of potassium, consisting of five hundred grains to one pint of distilled water. The paper is then to be dipped in water, and then dried, by applying blotting-paper to it lightly, and afterwards exposing it to the heat of a fire, or allowing it to dry spontaneously. The paper thus prepared is called iodized paper, and may be kept for any length of time in a portfolio not exposed to light. When a sheet of paper is required for use, wash it with the following solution, which we shall call No. 1; take one hundred grains of nitrate of silver, dissolved in two ounces of distilled water, and add to this one-third of its volume of strong acetic acid. Make another solution, No. 2, by dissolving crystallized gallic acid in cold distilled water, and then mix the two solutions together in equal proportions, and in no greater quantity than is required for immediate use, as it will not keep long without spoiling. This mixture, called gallo-nitrate of silver, by the patentee, is then to be spread, by a soft camel's-hair brush, on the marked side of the iodized paper; and, after allowing the paper to remain half-a-minute to absorb the solution, it should be dipped in distilled water and dried lightly; first with blotting-paper, and then by holding the paper at a considerable distance from the fire. When dry, the paper is ready, and it is advisable to use it within a few hours.

The paper, which is highly sensitive to light, must now be placed in the camera obscura, in order to receive on its marked surface a distinct image of the landscape or person whose picture is required. After remaining in the camera from ten seconds to several minutes, according to the intensity of the light, it is taken out of the camera in a dark room. If the object has been strongly illuminated, or if the paper has been long in the camera, a sensible picture will be seen on the paper; but, if the time of exposure has been short, or the illumination feeble, the paper will "appear entirely blank." An invisible image, however, is impressed on the paper, and may be rendered apparent by the following process:--Take some of the gallo-nitrate of silver, and, with a soft camel's-hair brush, wash the paper all over with this liquid, then hold it before a gentle fire, and, in a short time, the image will begin to appear; and those parts upon which the light has acted most strongly will become brown or black, while the others remain white. The image continues to grow more and more distinct for some time, and, when it becomes sufficiently so, the operation must be terminated, and the picture fixed. In order to effect this, the paper must be dipped first into water, then partly dried by blotting-paper, and afterwards washed with a solution of bromide of potassium, consisting of one hundred grains of the salt, dissolved in eight or ten ounces of water. The picture is then finally washed in water and dried as before. In place of bromide of potassium, a strong solution of common salt may be used.

A singular result of the application of this invention occurred to an accomplished traveller, who ascended Mount Etna, in order to obtain representations of that remarkable volcano. No sooner was the camera fixed on the edge of the crater, and the sensitive paper introduced, than a partial irruption took place, and the traveller had to fly for his life. On the cessation of the irruption, he returned; doubtless, with the expectation of merely collecting the fragments of his valuable instrument; when, to his great astonishment and delight, he discovered not only that his camera was absolutely uninjured, but that it contained an admirable representation of the crater and the irruption.

A brief account of the process of the Daguerreotype may now be given. A plate of silvered copper, about as thick as a shilling, is well cleaned and polished by rubbing it with cotton, fine pumice powder, and dilute nitric acid, and afterwards exposed to the heat of a spirit-lamp, placed below it, till a strong white coating is formed on the polished surface. On the plate being cooled suddenly by means of a cold slab of stone or of metal, the white coating is removed by repeatedly polishing it with dry pumice and cotton, and then three times more with the dilute nitric acid and pumice powder.

A careful cleaning being thus given to the plate, it is placed in a box containing iodine, till it becomes visibly covered with a golden film of that substance, which must neither be pale nor purple. It is then placed in the camera till a distinct picture of whatever appears before it is formed upon the surface; it remains there for a period depending on the intensity of the light, and is then removed to a metallic box, having in it a cup containing at least three ounces of mercury. Placed below the cup is a spirit-lamp, which throws off the mercurial vapour; and, in exact proportion as this vapour deposits itself on the parts of the plate which have been acted upon by the light, is the picture developed on the surface of the plate, by the adhesion of the white mercurial vapour to the different parts which had been impressed by the light. As soon as the picture appears complete, the plate is placed in a trough of sheet-copper, containing either a saturated solution of common salt, or a weak solution of hyposulphite of soda. Thus, the coating of iodine will be dissolved, the yellow colour quite disappearing; hot, but not boiling, distilled water is then poured over the plate, and any drops which remain are removed by blowing upon them.

The picture being now finished, is preserved from dust by placing it in a frame, and covering it with glass. In every successful operation, the picture is almost as perfect in its details as that of the camera obscura itself; but, as the light of the sun is only white, there can be, of course, none of the varied tints of nature. The shades are supplied by the black polish of the metallic surface which, when it reflects a luminous object, the white vapour of the mercury appears in shade, and thus gives us either a positive or a negative picture, according to the light in which it is viewed.

M. Regnault has laid before the Academy of Sciences, at Paris, some photographic specimens on paper, obtained by M. Blanquart-Evrard, by a modification of the usual process. In the preparations hitherto described, one part of the process presented serious difficulties, namely, that of the use of gallic acid in order to produce the impression. It happened frequently, that a proof taken in too mild a light, or of too large dimensions, could not receive the necessary force before disappearing, as it may be said, under the uniform colour produced by the mixture of the gallic acid with the aceto-azotate of silver, with which the paper is imbued. After having ascertained that the gallic acid produces this uniform colour on the impression, only because it is combined in small quantity with the aceto-azotate of silver, M. Blanquart-Evrard removes all the difficulty. After taking the proof from the camera obscura, he plunges it into a vessel of large dimensions, covered with a layer of one centim?tre of gallic acid of cold saturation. The bath is agitated during the immersion; and the action may be thus prolonged until the impression has obtained the necessary force to secure a good result. The proof is then washed, and the gallic acid is replaced by a solution of bromure of potassium, or chloruret of sodium, in which it is left for about a quarter-of-an-hour.

The chromatype, discovered by Mr. Hunt, consists in washing good letter-paper with the following solution:--

Bi-chromate of potash 10 grains Sulphate of copper 20 grains Distilled water 1 ounce

Papers prepared with this are of a pale yellow colour; they may be kept for any length of time without injury, and are always ready for use. For copying botanical specimens or engravings, nothing can be more beautiful. After the paper has been exposed to the influence of sunshine, with the objects to be copied superposed, it is washed over in the dark with a solution of nitrate of silver of moderate strength. As soon as this is done, a very vivid positive picture makes its appearance; and all the fixing these photographic pictures require is, well washing in pure water.

M. Niepc? de St. Victor finds that, if a sheet of paper on which there is writing, printed characters, or a drawing, be exposed for a few minutes to the vapour of iodine, and there be applied immediately afterwards a coating of starch, moistened by slightly acidulated water, a faithful tracing of the writing, printing, or drawing, will be obtained. M. Niepc? has also discovered that a great number of substances, such as nitric acid, chlorurets of lime and mercury, act in a similar manner; and that various vapours, particularly those of ammonia, have the effect of vivifying the images which are obtained by photography.

Heat, the cause of many wonders--Its universal diffusion and application--Story of a burning-glass--The Augustine friars and the Jesuits--Impostures as to the endurance of heat--Burning mirrors--The blow-pipe--The Giants' Causeway--Application of currents of heated air--Travelling by steam.

Heat is everywhere present: every body that exists contains it in quantity to which we can assign no limits. The endless variety of forms which are spread over and beautify the surface of the globe, are to be traced to its influence. Without it, the land and the water would fall into one formless and impenetrable mass, and the air now essential to life, prove absolutely poisonous. We shall find in connexion with it, therefore, many extraordinary phenomena.

When Labat the Jesuit visited the Peruvians, he took the naked arm of one of them, and, concentrating on it the rays of the sun by means of a powerful lens, soon made him cry out with pain, while the others looked on with wonder, not unmixed with indignation. How could this effect be produced? was instantly the question; and, as promptly, the cause was declared to be infernal. In vain did Labat assert that it was merely natural. The Peruvians made many attempts to obtain possession of the lens in order to destroy it, and deliver themselves from the power of that which they regarded as able to bring upon them the vengeance of the gods.

The Jesuit avoided entering the lists of controversy with the Augustine friar, but arrested his triumph by asking him if he would see one of his friars, who pretended to be nothing more than a Jesuit, and one of the Augustine friars who religiously performed the three vows, show instantly which of them would be readier to obey his superior?

Other instances of endurance are merely pretended. In country places, a conjurer sometimes appears in the streets, professing that he is able to eat fire; and yet he only rolls together a ball of flax or hemp, lights it, rolls round it some more of the same material, slips it cunningly into his mouth, and breathes through it to revive the flame; and so long as he inspires the air through the nostrils, and not through the mouth, he suffers no injury. A performer, named Richardson, in the seventeenth century, pretended to pour melted lead upon his tongue; but it is probable that he used the fusible metal formed of bismuth, tin, and lead, which melts at a low temperature, and which the writer has seen fused on a card, and poured into the hand with impunity by a person accustomed to handle hot substances.

Not many years ago, a man named Chaubert professed to be incombustible; but it has been proved that the human body is capable of bearing a very high degree of heat. Men of unquestionable integrity have surpassed all his wonders. Sir Charles Blagden exposed himself in a heated room where the heat was one or two degrees above 260?, and remained eight minutes in this situation. Eggs and a beef-steak were placed on a tin frame, near the thermometer, and in the space of twenty minutes the eggs were roasted quite hard, and in forty-seven minutes the steak was not only dressed, but almost dry. Another beef-steak, similarly placed, was rather over-done in thirty-three minutes. Chantrey, the celebrated sculptor, accompanied by five or six friends, also entered a furnace, and, after remaining two minutes, brought out a thermometer which stood at 320?. Some pain was experienced in this experiment, but it placed beyond all doubt that the human body has a remarkable power of enduring heat. Chaubert excited much wonder by taking phosphorus into his mouth; but, as that substance, when deprived of air, will not burn, he always closed his lips, and retired to eject the phosphorus immediately afterwards.

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