“The effects of this inhalation, as indicated by the patient’s own recollection,” says a writer in the North British Review, “are very various. In general they are somewhat as follows:—A pleasing sense of soothing succeeds the first irksomeness of the pungent vapour—a soothing of both mind and body. Ringing in the ears takes place, with some confusion of sight and intellectual perception. The limbs are felt cold and powerless; the hands and feet first, then the knees; and the feeling is as if these parts had ceased to be peculiar property, and dropped away. This sensation may gradually creep over the whole frame; the patient becoming, in more senses than one, truly etherealized; reduced to the condition of no body and all soul. The objects around are either lost sight of or strangely perverted; fancied shadows flit before the eyes, and then a dream sets in—sometimes calm and placid, sometimes active and bustling, sometimes very pleasurable, sometimes frightful, as a nightmare. Emerging, the figures and scenes shift rapidly, and grow fainter and fainter; present objects are caught by the eye once more, the ringing of the ears is heard again, consciousness and self-control return, a tendency to excited talking is very manifest, movement is unsteady, and, both in mind and body, a kind of intoxication is declared. It is, however, of a light and airy kind; very pure, very pleasant, and very passing, and, when gone, leaving very little trace behind.
“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. Schönbein, 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 (as a granulated substance is) 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.
CHAPTER VI.
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.
Magic pictures have been produced, which, when seen in a certain point through a glass, exhibit an object different from that be held by the naked eye. Niceron tells us that he executed at Paris, and deposited in the library of the Minimes of the Place Royale, a picture of this kind; when seen by the naked eye, it represented fifteen portraits of Turkish sultans, but, when viewed through the glass, it was a portrait of Louis XIII.