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minated by pointed pieces of charcoal, instead points are plunged into them, and inflamed of balls. When globe of this kind has been when they are brought near each other upon the exhausted and filled with sulphureted hydrogen, surface. on taking the Voltaic spark in it, the sulphur is 224. Some of the most pleasing effects of the separated, and deposited on the interior of the Voltaic apparatus result from its action on meglobe, and produces, during its separation, a tals; if these substances, in thin leaves, are made very beautiful appearance.
the medium of communication between the op217. Some other compound gases are similarly posite ends of a powerful battery, they inflame, affected; phosphorus separates from phosphu- and by continuing the contact may be made to reted hydrogen, and arsenic from arsenureted burn with great brilliance. The best method of hydrogen.
performing these experiments, is to suspend the 218. With the most powerful Voltaic batteries metallic leaves to a bent wire proceeding from the striking distance of the spark, or interval at one extremity of the battery, and to bring in which it passes from one conductor to another, contact with them a broad metal plate connected is very considerable. Mr. Children measured with the opposite extremity; the brilliancy of this effect by means of a micrometer, attached the effect may be increased by covering the plate to two polished points of platina, which were with gilt foil. Gold leaf burns with a vivid inserted in a receiver containing very dry air. white light tinged with blue, and produces a dark With 1250 pairs of plates the points were brown oxide. Silver leaf emits a brilliant emebrought within one-fifteenth of an inch of each rald-green light, and leaves an oxide of a dark other before the spark took place. With a large gray color. Copper produces a bluish-white apparatus employed at the London Institution, light attended by red sparks; its oxide is dark which extends to 2000 pairs of four-inch plates, brown. Tin exhibits nearly similar phenomena; points of charcoal were brought within a thirtieth its oxide is of a lighter color. Lead burns with or fortieth of an inch of each other before any a beautiful purple light; and zinc with a brillight was evolved ; but, when the points of char- liant white light, inclining to blue, and fringed coal had become intensely ignited, a stream of with red. For the distinct appearance of these light continued to play between them when colors it is essential to make the contacts with they were gradually withdrawn even to the dis- the metal; for, if charcoal be used, the brilliant tance of nearly four inches. The stream of light white light it evolves absorbs the colors prowas in the form of an arch, broad in the middle and duced by the combustion of the metals. tapering towards the charcoal points; it was ac 225. If a fine iron wire be connected with companied by intense heat, and immediately ig- one extremity of a powerful battery, and its end nited any substance introduced into it; frag- be brought to touch the surface of some quickments of diamond, and points of plumbago silver connected with the other extremity, a vivid disappeared, and seemed to evaporate, even combustion both of the wire and the quicksilver when the experiment was made in an exhausted results, and a very brilliant effect is produced. receiver; though they did not appear to have 226. If a fine iron wire of moderate length been fused. Thick platina wire melted rapidly, be made the medium of connexion between the and fell in large globules; the sapphire, quartz, extremities of the battery, it becomes ignited, magnesia, and lime, were distinctly fused. and may be fused into balls; or if a platina
219. In rarefied air, the discharge took place wire is employed, it may be kept at a red, or at a greater distance, and the beam of light was even white, heat, for a considerable length of made to pass through an interval of six or seven time; which seems to prove that some power inches.
is continually circulating through it; but how220. These phenomena may be exhibited on a ever powerful the battery, wires are never dissmaller scale by means of 100 pairs of plates, persed by it, as they are by the action of a of six inches square, an apparatus which is well charged surface. suited for all experiments of fusion and ig 227. If the slender wire be inserted in any nition.
fluid, and then introduced into the Voltaic cir221. The arched form of the stream of light, cuit, the fluid may be made to boil. passing between two charcoal points, is often 228. It has been noticed, that, if any two very perceptible when the distance of the points wires of different thicknesses are taken, on either does not exceed half an inch.
of which a certain battery can produce ignition, 222. From the low intensity of the most a greater length of the thickest wire will be powerful Voltaic apparatus, but little attention ignited than of that which is thinner. This to insulation is required in the transmission of effect may probably arise from the cooling inits effects. The conductors employed for this fluence of the air, for the surface of the thin purpose consist of copper wires passed through wire is most extensive in proportion to its quana short piece of glass tube, which serves as an tity of metal; and that the surrounding medium insulator to hold them by. Such conductors has an influence on the degree of ignition may are represented attached to the battery, and be proved by another experiment. placed on a glass plate to inflame gunpowder, 229. Stretch a fine wire of platina, withinat fig. 2.
side a glass receiver, placed upon an air-pump, 223. As the charcoal points usually become so that the air surrounding the wire may be reignited when the battery has moderate power, moved or restored at pleasure. Ignite the wire almost any combustible substance may be in- to a dull red heat, by connecting its opposite flamed, if placed between them. Oils, alcohol, extremities with the wires from a Voltaic batether, and "naphtha, are decomposed when the tery, of sufficient power for that purpose.
Rarefy the air by the action of the pump; and two inches square, be compared with another as the rarefaction proceeds, the ignition of the battery of thirty plates, of six inches square, wire will become more vivid, until at length it charged with diluted acid of the same strength; obtains a glowing white heat. Admit air into there will be no material difference in the shock the receiver, and the wire will lose its intense they produce, or the quantity of water they deheat, and appear more dull than at first. Rarefy compose in a given time; but the small battery the air again, the ignition will increase. Restore will not melt wire, or burn metals, and will it to its original density, it will again diminish. scarcely produce a spark between two points of These effects may be repeated many times, and charcoal; whilst the large battery will evolve a will maintain the same proportion to each other, brilliant light between the charcoal points, though they are less intense at each repetition. deflagrate metallic leaves with rapidity, and
230. The power of a Voltaic apparatus in- ignite several inches of wire. creases with the number of plates it contains, 235. This remarkable fact, which appears to within certain limits, but the limit is different have been first noticed by the French chemists, for the various effects it produces, and varies is susceptible of some explanation (on the also with the manner of employing the appa- supposition that the phenomena are electrical). ratus.
If a Leyden jar, for instance, having a square 231. The effects have been stated by Volta to foot of coated surface, be applied to an electrical be in the simple ratio of the numbers, but very machine with another jar, whose coated surface limited series only had been put together at the is equal to four square feet; after a certain numtime this statement was made, and there appears ber of turns of the machine, they will both be to be a loss of power when very extensive ar- charged, and to the same intensity, for they will rangements are employed. The pure electrical equally affect an electrometer. But the large effects, and the force of the shock, are found to jar will contain four times the quantity of elecincrease with the number, and an arrangement tricity that the small one does, and will fuse of 1500 may be employed. The power of che- sixteen times the quantity of wire. mical decomposition, and transfer, also continues 236. Now, suppose an imperfect conductor, to increase with the number when the battery is capable of transmitting only such a quantity of excited by dilute acid; but, if it be charged with electricity as is adequate to the charge of half a river water, the power does not increase after square foot; and it is obvious either of the jars 400 or 500 plates. The powers of ignition have before mentioned would produce the same effect increased in exact proportion to the numbers on such a substance; for they both contain more within the limit of 100 plates, beyond that than it can transmit, and its conducting power, limit there appears to be a loss of power; for which remains the same in both cases, limits the Sir H. Davy found that 100 plates ignited three effect that can be produced by either. It is inches of platina wire, one-seventieth of an consequently found, that, if several different inch diameter, and 1000 similar plates, charged sized jars are charged to the same degree, the in the same way, ignited only thirteen inches. shock is nearly equally painful when received
232. The French chemists have investigated from either of them. dhe ratio of increase for different numbers of 237. Mr. Cavendish has stated, that 'iron plates, as indicated by the quantity of gas wire conducts 400,000,000 times better than rain liberated by the decomposition of water; and or distilled water; that is, the electricity meets they announce that the increase is as the cube with no more resistance in passing through a poot of the number of plates. The apparatus piece of iron wire 400,000,000 inches long, than they employed, was arranged in the form of through a column of water of the same diameter troughs of a particular construction, being part only one inch long. Sea water, or a solution of of a large apparatus constructed by order of the one part of salt in thirty of water, conducts 100 French government. Sir H. Davy states, that times, and a saturated solution of sea salt about he has made similar experiments with the large 720 times better than rain water. It is therecombination of porcelain troughs, employed in fore probable, that the power excited by a Volthe Royal Institution, and the results he ob- taic apparatus, with plates of two inches square, tained indicate an increase nearly as the squares is in quantity equal or superior to the conducting of the numbers.
capacity of most aqueous fluids, and conse233. The result of every experiment of the quently no increased effect can be produced on kind must be uncertain if a series of minute such Auids by larger plates, which increase the attentions are not observed, which appear to quantity of that power, but not its intensity. have been overlooked in those already instituted. But if a conductor be presented to the large The vessels employed for the decomposition plates, which is capable of receiving the increased should be of the same size and form; the wires quantity furnished, the effect must necessarily be of the same length and thickness, and placed at greater on such conductors, in proportion to the equal distances from each other, in a fuid of increased impulse it may be supposed to reEniform conducting power.
ceive. These facts are capable of easy illustra234. When the size of the plates is increased, tion. their effects on perfect conductors, such as 238. Let two wires, proceeding from the exmetals, charcoal, and strong acid solutions, are tremities of a battery of fifty or 100 plates of greatly augmented ; but their action on imper- two inches square, be plunged in separate glasses fect conductors, as water, and various weak of water, if the glasses are connected by putting saline solutions, remains unaltered. If a bat- a finger into each of them, a shock will be felt tery, for instance, of thirty pairs of plates of at the moment of contact. Connect the water
in the glasses by some fibres of moistened cot- recently advanced an opinion contrary to mine ton, or by an inverted syphon filled with water; and have endeavoured to prove that the heart, on repeating the contact with this arrangement, together with the other muscles of organic life, either no shock, or a very slight one will be felt. do not differ, as to their susceptibility to the Make a similar experiment with another battery galvanic influence, from the different muscles of of the same extent, but with plates of six inches animal life. I shall begin by a detail of the obsquare. The shock will be nearly as great when servations I have made on animals with red and the glasses are connected by moistened fibres, cold blood. as when no connexion exists between them; and 243. (1.) 'In several experiments made on whilst the circuit exists through the moistened frogs, I coated the brain, on the one hand with fibres, and the human body, if a third circuit be lead, and the heart and muscles of the inferior formed through a fine wire, several inches of it extremities, on the other, with a long lamına of may be ignited. The imperfect conductors zinc, the upper end of which touched the heart, being incapable of conducting more than a and the lower end the muscles. Having, by the small portion of the power excited by the large means of silver, established a communication plates.
between the coatings of the muscles and those of 239. Whatever be the cause of the power of the the brain, the movements of the limbs constantly Voltaic apparatus, the quantity of that power ex- followed; but I could not perceive any accelecited by any given number of plates under similarration in the contractions of the heart, when it circumstances, will be in direct proportion to still continued to beat; and, when its action had the size of the plates ; and if the power be elec- entirely ceased, it did not display the smallest tricity, or should obey the same law that operates movement. Whichever may be the voluntary with charged surfaces, the comparative action of muscle that is coated at the same time with the different sized batteries, containing the same heart, with a view to a comparison of the phenumber of plates, should be, with regard to their nomena they exhibit at the moment of the power of igniting wire, in the proportion of the metallic communication, there is constantly a square of the increased surface; thus if two marked and decided difference. batteries are taken, one containing fifty plates of 244. (2.) • In the case of other frogs, I coated, twenty square inches surface, and the other with a common metallic wire, on the one hand, fifty plates of forty square inches, the latter the cervical part of the spinal marrow, in the ought to ignite four times the length of wire upper region of the heart, to the end that the the former can ignite. From some experiments coating might be above the part where the nerves with plates of four inches square, and others which proceed from the great intercostal nerve, with plates of eight inches square, made many and thence to the heart, originate ; and, on the years since, it has been stated by Dr. Wilkinson, other hand, the heart, and any one of the volun
that the power of ignition, in batteries of the tary muscles. I constantly noticed a result same total surface, but with plates of different similar to the one which attended the preceding sizes, increases in the proportion of the squares experiment, whenever the communication was of the surfaces of the elementary plates, singly established. There were invariably violent agitaken in each.' It was afterwards shown by Mr. tations in the voluntary muscles, without any Harrison of Kendal, that when the total surfaces visible alteration in the contractile movements are not equal, the rate of ignition must be as the of the heart. sixth power of the diameters of the elementary 245. (3.) I endeavoured to denudate the plates, or as the cubes of their respective sur nerves which lead to the heart of frogs. Several faces.
grayish filaments, scarcely perceptible, with the 240. It appears also from some experiments nature of which I must acknowledge I am not with large plates, mentioned by Sir H. Davy, that positively acquainted, were coated with a methe power of ignition, for equal number of plates, tallic substance, at the same time that the heart probably increases in a higher proportion than was made to rest on a substance of a similar the squares of their surfaces; for twenty double nature. When the communication was estabplates, each exposing a surface of eight square lished by the means of a third metal, not the feet, ignited more than sixteen times as much smallest sensible effect was to be perceived.' wire as twenty double plates, having each a sur 246 Dr. Wilson Philip has made some face of two square feet.
curious experiments on the influence of the 241. Several curious galvanic experiments Voltaic battery in obviating the effects of the and observation: have been published by M. ivision of the eight pairs of nerves.
In some Bichat, author of a very celebrated work on experiments in which the nerves of the eighth anatomy. In speaking of the influence of the pair were divided in the neck of a rabbit, and destruction of the brain on that of the heart, the ends not displaced, and the animal was after having proved, conformably to observation allowed to live some hours, it was found that food and experience, that it is not immediately by the swallowed immediately before the division of interruption of the cerebral action that the heart the nerves, was considerably digested, even when ceases to act, he confirms this fundamental datum the divided ends of the nerves had separated of physiology and pathology, by a series of gal- to the distance of a quarter of an inch from each vanic experiments, which demonstrate that the other. heart is in all cases independent of the brain. 247. In other experiments in which, after the
242. “These experiments,' he observes, 'were division of the nerves, the divided ends had been made by me with the most scrupulous attention, turneri completely away from each other, little because several very respectable authors have or no perfectly digested food, when the animal
was allowed to live some hours, was found in 253. • Experiment I.-A large incision was made the stomach: and the longer the animal lived, into the nape of the neck, close below the occiput. the smaller was the proportion of digested food The posterior half of the atlas vertebra was then in the stomach, the great mass having the ap- removed by bone forceps, when the spinal marrow pearance of masticated food, which was not was brought into view. A considerable incision sensibly lessened in quantity, however long the was at the same time made in the left hip, through animal lived. In an experiment in which, under the great gluteal muscle, so as to bring the some circumstances, the stomach was exposed, sciatic nerve into sight; and a small cut was from the time of the division of the nerves, lo made in the heel. From neither of these did the influence of a Voltaic battery sent through any blood flow. The pointed rod connected the lower portion of the divided nerves, its con with one end of the battery was now placed in lents were apparently as much changed as they contact with the spinal marrow, while the other would have been in the same time in the healthy rod was applied to the sciatic nerve. Every animal. The change was also of the same kind, muscle of the body was immediately agitated the contents of the stomach assuming a dark with convulsive movements, resembling a violent color, and those of the pyloric end being more shuddering from cold. The left side was most uniform, and of a firmer consistence than those of powerfully convulsed at each renewal of the the central and cardiac portions of the stomach, electric current. On moving the second rod while the whole contents became less in quantity. from the hip to the heel, the knee being pre
248. The division of the nerves, in both ways, viously bent, the leg was thrown out with such produced ditficulty of breathing and efforts to violence as nearly to overturn one of the assisvomit; neither of which occurred, when the tants, who in vain attempted to prevent its extenstomach and lungs were brought under the in- sion. fluence of a Voltaic battery, sent through the 254. “Experiment II.— The left phrenic nerv? lower portion of the divided nerves.
was now laid bare at the outer edge of the sterno249. When, under the foregoing circum- thyroideus muscle, from three to four inches above stances, the lungs had not been exposed to the the clavicle; the cutaneous incision having been Voltaic influence, and the animal had been al- made by the side of the sterno cleido-mastoideus. lowed to live for five or six hours, they were Since this nerve is distributed to the diaphragm, found much affected : in the rabbit which had and since it communicates with the heart through been submitted to this influence, they seemed the eighth pair, it was expected by transmitting quite healthy.
the galvanic power along it, that the respiratory 250. An account of some very interesting expe- process would be renewed. Accordingly, a riments performed by Dr. Ure, on the body of a small incision having been made under the carcriminal executed in the north, was read before tilage of the seventh rib, the point of the one the Glasgow Literary Society. The paper com- insulating rod was brought into contact with the mences with some appropriate general physiolo- great head of the diaphragm, while the other gical views relating to the application of galva- point was applied to the phrenic nerve in the Disn, in which the author notices particularly neck. This muscle, the main agent of respirathe researches of Dr. Wilson Philip on the tion, was instantly contracted, but with less force relation between Voltaic electricity and the phe- than was expected. Satisfied, from ample expenomena of life. The author gives the following rience on the living body, that more powerful detail of his experiments.
effects can be produced in galvanic excitation, 251. • The subject of these experiments was a by leaving the extreme communicating rods in middle-sized, athletic, and extremely muscular close contact with the parts to be operated on, man, about thirty years of age. He was sus- while the electric chain or circuit is completed, pended from the gallows nearly an hour, and by running the end of the wires along the top of Toade no convulsive struggle after he dropped; the plates in the last trough of either pole, the while a thief executed along with him, was vio- other wire being steadily immersed in the last lently agitated for a considerable time. He was cell of the opposite pole, I had immediate rebrought to the anatomical theatre of the Univer- course to this method. The success of it was sity of Glasgow in about ten minutes after he truly wonderful. Full, nay laborious breathing was cut down. His face had a perfectly natural instantly commenced. The chest heaved, and aspect, being neither livid nor tumefied; and fell; the belly was protruded, and again colthere was no dislocation of his neck.
lapsed, with the relaxing and retiring diaphragm. 252.' Dr. Jeffrey, the distinguished professor of This process was continued, without interruption, anatomy, having on the preceding day requested as long as I continued the electric discharges. me to perform the galvanic experiments, I sent 255. “In the judgment of many scientific gentleto his theatre with this view, next morning, my men who witnessed the scene, this respiratory exminor Voltaic battery, consisting of 270 pairs of periment was perhaps the most striking ever made four-inch plates, with wires of communication, with a philosophical apparatus. Let it also be and pointed metallic rods with insulating handles, remembered, that, for full half an hour before for the more commodious application of the this period, the body had been well nigh drained electric power.
About five minutes before the of its blood, and the spinal marrow severely police officers arrived with the body, the battery lacerated. No pulsation could be perceived was charged with a dilute nitro-sulphuric acid, meanwhile at the heart or wrist; but it may be which speedily brought it into a state of intense supposed that, but for the evacuation of the action. The dissections were skilfully executed blood, the essential stimulus of that organ, this by Mr. Marshall, under the superintendence of phenomenon might also have occurred the professor.
256. ^ Experiment III.-- The supra-orbital nerve
was laid bare in the forehead, as it issues through discharges across the breast, directly through the the supra-ciliary foramen, in the eye-brow: the heart and lungs. On the principles so well deone conducting rod being applied to it, and the veloped by Dr. Philip, and now illustrated on other to the heel, most extraordinary grimaces Clydsdale's body, we should transmit along the were exhibited every time that the electric dis- channel of the nerves, that substitute for nervous charges were made, by running the wire in my influence, or that power which may perchance hand along the edges of the last trough, from awaken its dormant faculties. Then, indeed, the 220th to the 227th pair of plates; thus fifty fair hopes may be formed of deriving extensive shocks, each greater than the preceding one, were benefit from galvanism; and of raising this wongiven in two seconds: every muscle in his coun- derful agent to its expected rank, among the mitenance was simultaneously thrown into a fearful nisters of health and life to man. action; rage, horror, despair, anguish, and 261. 'I would, however, beg leave to suggest ghastly smiles, united their hideous expression in another nervous channel, which I conceive to be the murderer's face, surpassing far the wildest a still readier and more powerful one to the action representations of a Fuseli or a Kean. At this of the heart and lungs than the phrenic nerve. period several of the spectators were forced to If a longitudinal incision be made, as is frequently leave the apartment from terror or sickness, and done for aneurism, through the integuments of one gentleman fainted.
the neck at the outer edge of the sterno-mastoi257. ' Experiment IV.-The last galvanic ex- deus muscle, about half way between the clavicle periment consisted in transmitting the electric and angle of the lower jaw; then, on turning power from the spinal marrow to the ulnar over the edge of this muscle, we bring into view nerve, as it passes by the internal condyle at the the throbbing carotid, on the outside of which the elbow; the fingers now moved nimbly, like par vagum and great sympathetic nerve lie tothose of a violin performer; an assistant, who gether in one sheath. Here, therefore, they may tried to close the fist, found the hand to open both be directly touched and pressed by a blunt forcibly, in spite of his efforts. When the one metallic conductor. These nerves communicate rod was applied to a slight incision in the tip of directly or indirectly with the phrenic, and the the fore-finger, the fist being previously clenched, superficial nerve of the heart is sent off from the that finger extended instantly; and, from the sympathetic. convulsive agitation of the arm, he seemed to 262. • Should, however, the phrenic nerve point to the different spectators, some of whom be taken, that of the left side is the preferable thought he had come to life!'
of the two. From the position of the heart, 258. An hour was spent in these experiments, the left phrenic differs a little in its course from when an experiment was made with the view of the right. It passes over the pericardium, coverdetermining the quantity of residual air in the ing the apex of the heart. lungs; after the detail of which, the author pro 263. While the point ofone metallic conductor ceeds as follows.
is applied to the nervous cords above described, 259. 'In deliberating on the above galvanic the other knob ought to be firmly pressed against phenomena, we are almost willing to imagine, the side of the person, immediately under the that if
, without cutting into and wounding the cartilage of the seventh rib. The skin should be spinal marrow and blood vessels in the neck, the moistened with a solution of common salt, or, pulmonary organs had been set a-playing at first what is better, a hot saturated solution of sal (as I proposed), by electrifying the phrenic nerve ammoniac, by which means the electric energy (which may be done without any dangerous in- will be more effectually conveyed through the çision), there is a probability that life night have cuticle, so as to complete the Voltaic chain. been restored. This event, however little desi 264. To lay bare the nerves above described, rable with a murderer, and perhaps contrary to requires, as I have stated, no formidable incision, law, would yet have been pardonable in one in- nor does it demand more anatomical skill, or stance, as it would have been highly honorable surgical dexterity, than every practitioner of the and useful to science. From the accurate expe- healing art ought to possess. We should always riments of Dr. Philip, it appears that the action bear in mind that the subject of experiment is of the diaphragm and lungs is indispensable at least insensible to pain; and that life is at a towards restoring the suspended action of the stake, perhaps irrecoverably gone. And assuheart and great vessels, subservient to the circu- redly, if we place the risk and difficulty of the lation of the blood.
operations in competition with the blessings and 260. • It is known that cases of death-like glory consequent on success, they will weigh as lethargy, or suspended animation from disease nothing with the intelligent and humane. It is and accidents have occurred, where life has re- possible, indeed, that two small brass knobs, turned, after longer interruption of its functions covered with cloth moistened with solution of than in the subject of the preceding experiments. sal ammoniac, pressed above and below on the It is probable, when apparent death supervenes place of the nerve and the diaphragmatic region, from suffocation with noxious gases, &c., and may suffice, without any surgical operation. It when there is no organic defect, that a judiciously may first be tried. directed galvanic experiment will, if any thing 265. • Immersion of the body in cold water acwill, restore the activity of the vital functions. celerates greatly the extinction of life arising from The plans of administering Voltaic electricity suffocation; and hence less hopes need be enterhitherto pursued in such case, are, in my humble tained of recovering drowned persons after a apprehension, very defective. No advantage, we considerable interval, than when the vital heat perceive, is likely to accrue from passing electric has been suffered to continue with little abate