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but they did not think of any method by which (3.) Lightning is observed to strike most fretheir suppositions could be brought to the test quently into those substances that are good conof experiment. The remarks of the abbé Nollet on ductors of electricity, such as metals, water, and this subject, considering the time at which they moist substances; and to avoid those that are were made, are so striking, that we consider them non-conductors. Well deserving of a place in the memory of every (4.) Lightnings inflame combustible bodies. lover of the electrical science, and shall here re- The same is effected by electricity. cord them.
(5.) Metals are melted by a powerful charge of 18. ' If,' says he, any one should take upon electricity. This phenomenon is one of the him to prove from a well connected comparison most common effects of a stroke of lightning. of phenomena, that thunder is in the hands of (6.) The same may be observed of the fracture nature what electricity is in ours; that the won of brittle bodies, and of other expansive effects ders which we now exhibit at our pleasure, are common to both causes. little imitations of those great effects that frighten (7.) Lightning has often been known to strike us, and that the whole depends upon the same people blind. Dr. Franklin found, that the mechanism : if it can be demonstrated that a same effect is produced on animals when they cloud prepared by the action of the winds, by are subject to a strong electric charge. heat, by a mixture of exhalations, &c., is oppo (8.) Lightning destroys animal life. Dr. site to a terrestrial object; that this is the electri- Franklin killed turkies of about ten pounds fied body, and at a certain proximity to that weight, by a powerful electric shock. which is not; I avow that this idea, if it were (9.) The magnetic needle is affected in the well supported, would give me a great deal of same manner by lightning and by electricity, pleasure; and, in support of it, how many spe- and iron may be rendered magnetic by both cious reasons present themselves to a man who causes. The phenomena are therefore strictly is well acqua nted with electricity! The univer- analogous, and differ only in degree; but if an sality of the electric matter, the readiness of its electrified gun-barrel will give a spark, and pro- i action, its inflammability, and its activity in duce a loud report at two inches distance, what giving fire to other bodies, its property of striking effect may not be expected from perhaps 10,000 externally and internally even to their smallest acres of electrified cloud? And is not the difparts, the remarkable example we have of this ferent extent of these conductors, equal to the effect in the Leyden experiment, the idea which different limit of their effects ? But to ascerwe might truly adopt in supposing a greater de- tain the accuracy of these ideas, let us have regree of electric power, &c.; all these points of course to experiment. analogy, which I have been some time meditating, Pointed bodies receive and transmit electribegin to make me believe, that, by taking elec- city with facility; let, therefore, a pointed metal tricity for the model, one might form to one's rod be elevated in the atmosphere, and insulated; self, in respect to thunder and lightning, more if lightning is caused by the electricity of the perfect and more probable ideas than have clouds, such an insulated rod will be electrified hitherto been offered.'
whenever a cloud passes over it, and this elec19. It is generally admitted that the French tricity may then be compared with that obtained philosophers were the first to verify these con- in our experiments. Such were the suggestions jectures; they preceded the justly celebrated of this admirable philosopher: they soon exDr. Franklin in drawing the electric matter from cited the attention of the electricians of Europe, the clouds by means of an iron conducting rod; and having attracted the notice of the king of but, within a month after they had done so, the France, the approbation he expressed excited in American philosopher effected the same thing in several members of the French Academy a dea manner that never seems to have entered into sire to perform the experiment proposed by their minds. Speaking of the observations of Franklin, and several insulated and pointed the abbé Nollet, above quoted, Mr. Singer justly metallic rods were erected for that purpose. remarks, that thy bear no comparison with the 20. In this pursuit the most active persons acute conception, sound philosophical argu- were two French gentlemen, Messrs. D'Àlibard mest, and satisfactory experiments, by which and Delar. The former prepared his apparatus Dr. Franklin has demonstrated the identity of at Marly la Ville, five or six leagues from Paris; the electric fluid, and the cause of thunder. Dr. the latter at his own house, on some of the Franklin, says he, had observed with equal atten- highest ground in that capital. M. D'Alition the peculiarities of the natural phenomenon, bard's machine consisted of an iron rod forty and the power to which be ascribed its produc- feet long, the lower extremity of which was tion; he enumerated the following as their lead- brought into a sentry-box, where the rain could ing features of resemblance:
not come; while on the outside it was fastened (1.) The zigzag form of lightning corresponds to three wooden posts by long silken strings de. exactly in appearance with an electric spark fended from the rain. This machine was the that passes through a considerable interval of first that was favored with a visit of the etherial air.
fire. M. D'Alibard himself was not at home; but, (2.) Lightning most frequently strikes such ob- in his absence, he had entrusted the care of his jects as are high and prominent, in preference apparatus to one Coissier, a joiner, who had to others, as the summits of hills, the masts of served fourteen years in the army, and on whose ships, high trees, towers, spires, &c. The electric courage and understanding he could depend. fuid, when striking from one body to another, This artisan had all the necessary instructions always passes through the most prominent parts. given him; and was desired to call some of his,
neighbours, particularly the curate of the parish, powers was made by M. de Romas. He conwhenever there should be any appearance of a structed a kite of seven feet in height, and three thunder storm. At length the long expected feet wide; this kite he raised to the height of event arrived. On Wednesday, 10th May, 1752, 550 feet by a string, in which was interwoven a between two and three P. M. Coissier heard a fine metallic wire to render it a good conductor. pretty loud clap of thunder. Immediately he On the 7th of June, 1753, when this kite was ran to the machine, taking with him a phial elevated, M. de Romas informs us that he drew furnished with a brass wire; and presenting the from the conductor to which the string was atwire to the end of the rod, a small spark issued tached sparks three inches long, and a quarter from it with a snap like that which attends a of an inch thick. On one or two occasions he spark from an electrified conductor. Stronger met with increasing success, and was enabled to sparks were afterwards drawn in the presence of draw sparks, or rather streams, of the electric the curate and a number of other people. The matter from his apparatus, of a foot in length, curate's account of them was, that they were of and an inch in thickness. But on the 16th of a blue color, an inch and a half in length, and August, 1757, M. de Romas, with an additional smelled strongly of sulphur. In making them, length of string to his kite, was still more suche received a stroke on his arm a little below cessful. The storm at the time was not great, the elbow; but he could not tell whether it came neither was there much thunder, and but little from the brass wire inserted into the phial, or rain had fallen; yet streams of lightning, nine from the bar. He did not attend to it at the or ten feet long, and an inch in thickness, darted time; but the pain continuing, he uncovered his from his conductor to the ground, accompanied arm when he went home in the presence of with a noise equal to that attending the disCoissier. A mark was perceived round it, such charge of a pistol. as might have been made by a blow with the 23. It was not to be expected that, in the wire on his naked skin.
infancy of the science, experiments on such a 21. Dr. Franklin himself had an opportunity, scale should be always conducted with safety: about a month after this, of verifying his own accidents will happen in the management of the hypothesis. He was waiting for the erection of best constructed apparatus, and the first opea spire in Philadelphia, not imagining that a rators on atmospherical electricity received many pointed rod of a moderate height could answer severe and unexpected shocks: Numerous, howthe purpose. At last it occurred to him, that by ever, and dangerous as these accidents have means of a common kite he could have a readier been, there is only one instance known of their access to the higher regions of the atmosphere having proved fåtal ; to that we have already than any other way whatever. Preparing, there- alluded, and shall here state some of the leading fore, a large silk handkerchief and two cross particulars attending the melancholy catastrophe. sticks of a proper length on which to extend it, Professor Richman, of St. Petersburgh, had conhe took the opportunity of the first approaching structed an apparatus for making experiments thunder-storm to take a walk into a field where on atmospherical electricity, for a work on that there was a shed convenient for his purpose. But, subject in which he was engaged. On the morndreading the ridicule which too commonly at- ing of the day that terminated his mortal career tends unsuccessful attempts in science, he com- he was attending a meeting of the Academy of municated his intention to nobody but his son, Sciences, and, hearing the sound of distant thunwho assisted him in raising the kite. A consi- der, he hastened home to observe his apparatus, derable time elapsed before there was any ap- and took with him Mr. Solokow, his engraver, pearance of success. One very promising cloud that he might make any sketch required during had passed over the kite without any effect; the action of the apparatus. On inspecting his when, just as he was beginning to despair, he electrometer, he found it indicated 4° on the observed some loose threads of the hempen quadrant; and, while pointing out to his friend string to stand erect and avoid one another, just the danger to be apprehended should it rise to as if they had been suspended by the conductor 45°, a loud peal of thunder burst over the city. of a common electrical machine. On this he At this moment the professor inclined his head presented his knuckle to a key which was fas- towards the apparatus to observe the height to tened to the string, and thus obtained a very which the electrometer had risen, and while in evident electric spark. Others succeeded even this posture, with his hand about a foot from before the string was wet; but, when the rain the conducting rod, a ball of fire, of a bluishhad begun to descend, he collected electric fire white color, flashed from the rod to his head, pretty copiously. He had afterwards an insu- with a report equal to that of a pistol. Richman lated iron rod to draw the lightning into his fell backwards on a chest behind him, and exhouse; and performed almost every experiment pired in a moment. Solokow was much stunned with real lightning, that had before been done by the discharge; and described the ball of elecwith the artificial representations of it by elec- tric fire as being about the size of his closed trical machines. With this apparatus he con- hand. The wires of the apparatus were melted nected two small bells and a pendulum between and scattered about the room; the door was torn them, which were so arranged as to ring when from its hinges and thrown upon the floor; the electrified, and thus to give notice of the ap- house was filled with sulphureous vapor, the proach of a thunder-cloud.
ashes were thrown from the fire-place, and the 22. Experiments with the electrical kite were door-posts rent asunder. repeated in all directions, and with various suc 24. A vein was opened in the professor's body cess; in France a most brilliant display of its twice, but no hiood" followed; after which, they
codrascured to recover life by violent friction, stance in which the experiments were repeated, but in vain. There appeared a red spot on the though this was done in the presence of those forehead, from which spirted some drops of who pretended to have been so successful; and, blood through the pores, without wounding the in some cases, with the very apparatus they skin. The shoe belonging to the left foot was themselves had used. The theory was, conseburst open, and uncovering the foot at that part, quently, no longer credited. they found a blue mark; whence it was con 27. To enumerate, in chronological order, cluded, that the electric matter having entered all the discoveries that have been made in the at the head, made its way out again at that foot. science of electricity, from the invention of the Upon the body, particularly on the left side, Leyden phial to the present period, would swell were several red and blue spots resembling lea- this introductory sketch far beyond its proper ther shrunk by being burnt. Many more also limits; and yet, as having so eminently contribecame visible over the whole body, and par- buted towards raising the science to its present ticularly over the back. That upon the forehead elegant, improved, and highly prosperous state, changed to a brownish red, but the hair of the there are several whose names it would be inhead was not singed. In the place where the justice to pass by in silence. As the chief of shoe was burst, the stocking was entire; as these we may notice the following : Mr. Canton, was the coat every where, the waistcoat only an eminent English electrician, who distinbeing singed on the fore Aap: but there ap- guished himself by a very successful repetition peared on the back of Mr. Solokow's coat long of Dr. Franklin's experiments on atmospherical marrow streaks, which probably arose from frag- electricity; a method of electrifying the air of a ments of the red hot wires falling on it and burn- room, either positively or negatively; and paring off the nap. Next day, when the body was ticularly by disproving the correctness of the opened, the cranium was very entire, having theory of vitreous and resinous electricity, and Teither fissure nor coutra-fissure : the brain was showing that every electric is capable of giving sound; but the transparent pellicles of the wind- it both in a positive and negative form, according pipe were excessively tender, and easily rent. to the nature of the surface of the body, and the There was some extravasated blood in it, as also kind of rubber with which it is excited. in the cavities below the lungs. Those of the This ingenious electrician made several rebreast were quite sound; but those towards the markably fine experiments on electrical atmosback of a brownish black color, and filled with pheres, which led to the establishment of the more of the blood above-mentioned. The throat, fact, that bodies immersed in them became posthe glands, and the small intestines, were all in- sessed of the electricity the opposite of that flamed. The singed leather-colored spots pene- of the body into the atmosphere of which they trated the skin only. In forty-eight hours the are placed. body was so much corrupted that they could 28. In connexion with the name of Canton with difficulty place it in the coffin. It is said must be mentioned that of Beccaria, author of a that, at the time of his death, professor Richman work entitled Dell Elettricismo Artificiale e tad in his pocket seventy rubles of silver, which Naturale, and which was translated into English were not in the least affected by the lightning. in the year 1776. The discoveries of Signor
25. There was no longer any doubt re Beccaria were nearly the same as those of his maining as to the identity of lightning, and the contemporary, Mr. Canton, although they had electricity produced by the electrical machine; had no communication with each other on the and the great practical use made of this disco- subject. Beccaria also made some very imporcorery was to secure buildings, ships, &c., from tant experiments on the conducting power of being damaged by lightning, by erecting on water; in these be ascertained, that water is a the pointed metallic rods, rising a little above very imperfect conductor of electricity; that it the highest part of the building, and passing conducts it according to its quantity, and that, along it so as to communicate with the ground when used in very small quantities, its resistance or the nearest water, a full account of which
was greatest. See BECCARIA. will be given in the course of this essay.
29. Some interesting discoveries were made 26. A short time previous to the event of in the year 1759, on the electrical qualities of professor Richman's death, a most remarkable silk, by Mr. Symner. An account of these he atempt was made by a gentleman in Italy, to published in the Philosophical Transactions. gain on the credulity of his countrymen and His attention seems to have been directed to the others, by pretending that if odoriferous sub- subject by accidentally observing, that, on pula stances were enclosed in glass tubes, and the ling off his silk stockings in the evening, a tubes excited, the medicinal virtues of those crackling noise proceeded from them, and that substances would transpire through the glass, in the dark they emitted sparks of fire. He impregnate the atmosphere of the conductor, found that these electrical appearances were and thus be readily communicated to the pa- always the strongest when a silk and worsted tient without being taken into the stomach. The stocking were both on one leg, and that it was most astonishing cures were said to have been of no consequence which of them was next the performed by these medicated tubes; and the skin, but that they must be of different colors, it. Vetitor, J. Francisco Pivati, published an ac one white and the other black. Two stockings count of them to the world. Both the British of this description, worn on the leg for the short and French philosophers united in investi- space of ten minutes, on being pulled off, stood gating the merits of Pivati's experiments, and inflated as if the leg had been within them, and, the result was a complete failure, in every in- on being drawn asunder, attracted each other at Vol. VIII.
the distance of eighteen inches. These effects 34. The theories of Alpinus and Cavendish are always most powerful when the stockings are were much improved on by the ingenuity of M. new, or when newly washed. Those who choose Coulomb. By those philosophers the action of to try this very simple experiment will find it the electric matter, in producing attraction or resucceed equally well if the stockings are placed pulsion, was considered merely as diminishing one within the other, drawn a few times through with the distance; but by the experiments of the hand, and then quickly pulled asunder. Coulomb it was proved that the electrical force,
30. Mr. Kinnersly, an intimate friend of Dr. like that of gravity, is in the inverse ratio of the Franklin, made several experiments that contri- squares of the distance. The instrument with buted to the advancement of electricity. These which Coulomb made his experiments was of related chiefly to the discovery of the two elec- his own construction: he gave it the name of the tricities, the conducting power of water at dif- 'torsion balance,' from the manner of its action; ferent temperatures, and the power of strong a description of it will be given in the course of charges of electricity when passed through brass this essay. Coulomb also made numerous exwires. In the first of these experiments he had periments for the purpose of ascertaining the been anticipated by M. Du Fay; but he soon laws by which the dissipation of the electrical perceived that Du Fay did not consider the two matter in the air is regulated; and also to ascerelectricities in the same light as that in which tain the distribution of it in an overcharged they were viewed by Franklin, viz. positive and body. In prosecuting these enquiries he was negative.
certainly as successful as could possibly be ex31. In 1757 a work appeared on electricity, pected, considering the extreme delicacy of his entitled Disputatio Physica Experimentalis de apparatus, and the effects which the variableness Electricitatibus, by Mr. Wilke, of Rostock, in of the atmosphere produces on the strongest Lower Saxony, in which the author gives some electrical experiments. very interesting details of his researches respect 35. To M. De Saussure we are also indebted ing the electricity developed during the melting for some remarkably fine experiments, which and cooling of electrical substances, and also seem to have been made with great care, on the that produced by the friction of different bodies. electricity developed during the conversion of This gentleman found that, when sulphur is fluids into vapor.
The fluids on which he opemelted in an earthen vessel placed upon con- rated were distilled water, spirit of wine, and ductors of electricity, it is strongly electrified when ether. The same philosopher likewise made taken out after it is cold; but that it shows no some highly interesting experiments on atmosigns of electricity if cooled upon electrics. spherical electricity, for the verification of which Melted sealing-wax, he found, acquired negative he inade a journey to the Alps. electricity when poured into glass vessels, but 36. Most of those who have devoted the i positive electricity when poured into sulphur. attention to the study of electricity, as a science, Mr. Wilke also confirmed the experiments of Dr. have distinguished themselves by the invention Franklin and Mr. Canton on electrical atmos- of some new instrument, the use of which has pheres, and illustrated the phenomena of elec- generally led to some important discovery. trical light.
This was peculiarly the case with Sig. Volta, 32. M. Alpinus, a member of the Imperial professor of natural philosophy at Como in Italy. cademy at St. Petersburgh, seems to have been He invented the electrophorus, an ingeniously the first who gave to the world a mathematical constructed instrument for collecting and retaindemonstration of the theory of electricity. An ing the electric matter; and another called a exposition of his treatise was published by the condenser, the use of which is to accumulate, abbé Hauy; and an excellent paper, on the and render visible, the smallest portions of elecsame subject, was drawn up for the Royal So tricity, natural or artificial. The celebrity of ciety by Mr. Cavendish, before he knew any Volta, however, rests chiefly on the important thing of the theory of M. Alpinus. The merits improvements which he made in that branch of of M. Alpinus are certainly great, but we con- electricity designated GALVANISM, under which sider Cavendish as having much higher claims they will be fully considered. as an electrician; his experiments on the con 37. We have already noticed the scientific exducting power of water and wire; his very periments of Coulomb, and must here observe ingenious construction of the artificial torpedo ; that Dr. Robison, late professor of natural phiand above all, his success in employing elec- losophy in the university of Edinburgh, is justly tricity as a chemical agent, justify this opinion. entitled to a share of the honor bestowed on
3.3. The labors of Dr. Priestley, as an elec- Coulomb, since he had, so early as the year 1769, trician, are deservedly held in the highest es- made numerous and remarkably successful atteem; the doctor brought no common share of tempts, with an admirable electrometer of his ingenuity and perseverance to bear upon the own invention, to determine the laws of electric science; and to him we are indebted for a con action. But the professor did not publish an siderable number of important improvements and account of his experiments at the time they were interesting experiments in electricity, as con- made, which certainly gives them the appearance nected with chemistry; for a most excellent of posteriority. The conclusion to which Dr. treatise on the History of Electricity; an Intro- Robison's experiments led him was, that the force duction to Electricity; several valuable papers of electrical attraction and repulsion is nearly in on the same subject, inserted in the Philosophical the inverse ratio of the square of the distance. Transactions; and for numerous improvements “The specific result,' says Dr. Brewster, 'which in the construction of electrical apparatus. he obtained was, that the mutual repulsion of
two spheres, electrified in the same manner, var If two silk ribands, the one black and the 1
other white, about two or three feet in length, and d representing the distance of f.06
perfectly dry, be applied to each other by their their centres.'
surfaces, and then drawn smartly a few times be38. As electricity now began to be more gen: velvet or woollen cloth, they will be found to
tween the finger and thumb, or over dry silk erally cultivated, it was to be expected that great adhere to each other with considerable force; improvements in the construction of apparatus would take place. This was the case; and the and when separated at one end will rush together
Each riband, when sepabrilliant success of Van Marum of Haarlem, in again with rapidity. experiments which had failed in the hands of rated, will attract any light substances to which others, was obviously owing to the prodigious it is presented; and, if the experiment be made power of the large apparatus constructed by Mr.
a dark room, a flash of light will occasionally Cuthbertson of London, and placed in Tyler's attend the separation of the ribands. museum at Haarlem. Some notice of these ex
42. Sticks of sealing-wax, resin, or sulphur, periments will be taken in the course of this when rubbed with dry woollen cloth, or fur; and article; at present it may be sufficient to state, tubes or rods of glass, when rubbed with silk, that, whatever other philosophical instrument exhibit similar powers; and, if of sufficient size, makers may have conceived, 'Mr. Cuthbertson produce, when applied within a short distance of has brought forth the most useful, because the the face or hand, a distinct and singular sensa
tion. most powerful, electrical apparatus with which
These effects having been first produced we are yet acquainted.
by the friction of amber (electron) are called 39. Mr. Cavallo is justly entitled to respect
electrical phenomena; and the processes emful notice in every historical sketch of the rise ployed for their production, the excitation of and progress of the electrical science, to which
electricity. he made many important additions.
43. Aitraction is the phenomenon most conlosopher made numerous experiments on atmo- stantly attendant on excitation; it is therefore spherical electricity; and also added to our stock considered as an indication of the presence and of electrical apparatus, by his invention of the action of electricity, and is the basis of all its most ingeniously constructed instruments for
Electricians formerly, says Mr. Singer, measuring, doubling, condensing, and multiply- employed for such trials a light wooden or metal ing electricity.
needle, supported by its centre on a point, or a 40. There are other philosophers who have li- the excited body was presented, and, if they were
thread or feather delicately suspended. To these berally contributed to the progressive improvement of this branch of natural philosophy, attracted by it, the attraction was attributed to elecon whose merits we cannot here dwell; but tricity, and the excited body was called an electric. this we the less regret as their improvements contrivance for the same purpose, they called an
44. This suspended needle, and every other and discoveries must be still fresh in the memory electroscope, when employed to indicate the exof those who feel an interest in the science. istence of electricity; and an electrometer when Among these we would simply enumerate the ingenious and laborious Nicholson, the venerable considered as a measure of its force; but the M. Hauy, Mr. Brooks, Mr. Bennet, Mr. Henley, latter term appears fully sufficient, since every Mr. Morgan, La Place, and the truly ingenious contrivance hitherto employed to ascertain the appalist M. Poisson.
presence of electrical phenomena is also calcu40.* Many other names of deserved celebrity electrometers, for common purposes, are con;
lated to measure their power. The most useful might be here mentioned, as having successfully structed by suspending two narrow slips of gola labored in raising electricity to its present emiDent station among the sciences; but we must
leaf from the cap of a glass cylinder. When bring this part of our article to a conclusion by these are unelectrified they will hang parallel and acknowledging our obligations to them, and inti contiguous; the presence of the smallest quanmating that we shall occasionally avail ourselves tity of electricity will cause them to diverge toof their labors. This remark is meant to apply wards the sides of the
. particularly to the excellent treatise on electricity
Small balls turned from the pith of elder, and by the late Mr. George John Singer, a popular suspended by fine threads or silver wires, are lecturer on this science. Mr. Singer's name
sometimes substituted for the gold strips. They stands high in the scientific world ; and com
are less easily affected, but they are more durapetent judges have pronounced his Elements of ble. The pith balls, suspended by thread or Electricity and Electro-Chemistry one of the wire, are also occasionally used without a glass best and most original works on the subiect in cylinder. But these and other electrometers will the English language
be explained hereafter.
45. Electrical phenomena are thus characPART I.
terised by the attraction and recession of light
substances; the consequent production of motion ON THE PHENOMENA OF EXCITED ELEC in them, and of sensation in living bodies, and TRICITY.
by the evolution or production of light. There -41. The more simple methods of exciting are various methods by which these effects may electries, enable us to perform several pleasing be produced, but the following are the most oband instructive experiments, without the aid of vious sources of their production. (1.) Friction. costly and complex apparatus ; the principal of (2.). Change of form. (3.) Change of temperathese we now proceed to describe.
ture. (4.) Contact of dissimilar bodies.