Then mark how two electric streams conspire To form the resinous and vitreous fire. Darwin. If a metallic point be fixed on the prime conductor, and the flame of a candle be presented to it, on electrising the conductor either with vitreous or resin ous ether, the flame of the candle is blown from the point, which must be owing to the electric fluid in its passage from the point carrying along with it a stream of atmospheric air. Id. But now a bride and mother-and now there! How many ties did that stern moment tear! From thy Sire's to his humblest subject's breast Is linked the electrick chain of that despair, Whose shock was as an earthquake's, and opprest Thy land which loved thee so that none could love Byron. thee best. And the wild sparkle of his eye seemed caught From high, and lightened with electric thought. Id. 1. The particular branch of science denominated electricity appears to have derived its name from that of the first substance in which any of its properties were discovered. This was amber, the Greek name of which is nλEKTρov, evidently derived from 'HλEKTwp, a name by which Homer designates the Sun. It has been said by some that the ancients, observing amber to possess the property of attracting light substances when rubbed, termed it electrum, and that hence arose the word electricity. Those who entertain this opinion, would derive the name from the Greek verb eλw to draw; but this appears to us to be a very forced derivation, since amber was doubtless called by the name of electron, long before it was known to possess the magnetic property of attraction. Perhaps it was so called from its bright and shining appearance. But, whatever may be the etymology of the term, it is now employed to designate that science which investigates the attractions and repulsions, the emissions of light, and explosions, which are produced, not only by the friction of vitreous, resinous, and metallic surfaces, but by the heating, cooling, evaporation, and mutual contact of a vast number of sub stances. 2. It is rather remarkable that, although the attractive energy of electricity has all the appearance of being a very recent discovery, it has been said to be the first physical fact recorded in the history of science.' The electrical properties of amber were known and pointed out upwards of 2000 years ago; but the subject did not engage the attention of the learned till the beginning of the seventeenth century. This was perhaps a fortunate circumstance, since it at all events prevented the science from being clouded or perverted by the ignorance of early times. 3. Dr. William Gilbert, of Colchester, appears to have been the first person who essentially contributed to the establishment of electricity as a science. In the year 1600 he published his work entitled De Magnete, which contains a number of experiments made with various substances, possessing the properties of amber, now termed electrics. Of Dr. Gilbert, Cavallo says that he ought to be considered as the father of electricity. 4. No further discoveries were made in this science of any importance till the year 1670, when the celebrated Mr. Boyle much enlarged the list of electrics, and by experiment discovered that their effects were much increased by warming and wiping them before the application of friction, and that during the friction they emitted faint flashes of light; this appearance he considered as an additional characteristic of the electrical power. 5. Otto Guericke of Magdeburg, the inventor of the air-pump, and a contemporary with Mr. Boyle, confirmed the experiments of the latter, and much enlarged the state of electrical knowledge. He constructed an apparatus in which the electric, a globe of sulphur, was made to revolve on an axis; the hand was applied to it as a rubber; and by this contrivance, which was in principle the same as the most modern construction of the electrical machine, he was enabled to obtain an accumulation of electricity far beyond any thing that had been effected by his predecessors. This philosopher discovered also the principle of electrical repulsion. 6. In the year 1709 appeared the first treatise on electricity; it was the production of Mr. Hawksbee, who far exceeded his predecessors in the discoveries which he made. He was the first who observed the electric power of rubbed glass; the flashing light of an excited electric had been observed by Boyle; but, as Mr. Hawksbee by his glass globe could collect the electric matter in much greater quantities than had been done before, he had the pleasure of beholding the intensity of its light, and of observing the snapping noise by which its discharges are attended. Some of the experiments made by Mr. Hawksbee were very curious, and deserve more notice than has hitherto been taken of them. Among others the following may be mentioned. He lined more than one-half of a glass globe with sealing-wax, and, having exhausted it of its air, he put it in motion in an appropriate frame. On applying his hand to it, for the purpose of excitation, he was surprised to observe an exact image of his hand on the concave surface of the wax, as distinctly defined as if there had been nothing but transparent glass between his eye and his hand, although the wax was in some places an eighth of an inch in thickness. When pitch was used instead of wax the effect was the same. 7. After this period the science of electricity appears to have been for some time stationary, from the discoveries of Sir Isaac Newton absorbing the attention of the public; but, soon after the death of that distinguished individual, it obtained renewed attention, and some very important discoveries were made in it by Mr Stephen Grey, a pensioner of the Charter-house. his observing, that a piece of leaf-gold, repelled With the date of this gentleman's experiments by an excited glass tube, and which he endeacommenced the modern triumph of electricity. voured to drive about the room with a piece of Directing his attention to the nature of electrical excited gum copal, instead of being repelled by phenomena, he endeavoured to excite them in it, as it was by the glass tube, was eagerly atall known bodies; and, though in many cases he tracted. The same was the case with sealing was unsuccessful, he thus added considerably to wax, sulphur, resin, and many other substances. the catalogue of electrics. Many substances, in He discovered, also, that it was impossible to exwhich no attractive power was excited by rub- cite a tube in which the air was condensed. He bing while in their natural state, became strongly also observed, that such substances as were least attractive if excited after being moderately susceptible of electric excitement by friction were warmed, but lost this property as they became the best conductors of electricity; though all the cold. This fact, says the late ingenious Mr. bodies he tried became electric by communicaSinger, clearly pointed out a relation between tion when placed on a non-conducting support. the state of bodies and their power of evincing In this way he electrified himself, being supelectric appearances; and the nature of this re- ported by silk lines, and touched by an excited lation was explained by Mr. Grey's subsequent glass tube; and on this occasion the abbe experiments. Every attempt to render metals Nollet, who accompanied him in these experielectric by friction or otherwise proved inef- ments, drew the first electrical spark from the fectual in the hands of Mr. Grey, as well as in human body. those of his predecessors, when it occurred to him that, as electric light appeared to pass between excited bodies and such as were incapable of excitation, the attractive power might be also capable of communication from one to the other. 8. For this purpose Mr. Grey inserted a wire and ball, by means of a piece of cork, in the extremity of a glass tube, and, on rubbing the tube, found its attractive power was communicated to the wire and ball. He proceeded with this experiment until the length of the wires which he used became inconvenient. He then suspended the ball by means of pack-thread, from the tube, and found the electricity was still communicated. The same result was obtained when the ball was suspended by the pack-thread, from a balcony twenty-six feet high: on exciting the tube small light substances were attracted by the ball from the pavement of the court below. 9. In connexion with Mr. Wheeler, Mr. Grey afterwards extended his experiments, and succeeded in transmitting the electric power from his excited tube through nearly 800 feet of packthread, without any apparent diminution of its force. In arranging the apparatus for these experiments these gentlemen found that a silken cord was incapable of transmitting the attractive power of the tube; an effect which they at first attributed to its comparative smallness, but they afterwards observed that a wire of much smaller diameter carried off the electrical effect completely, and thus discovered that there are in nature various bodies differently qualified for the transmission of the electric matter, some conveying it most readily, and to a great distance, and others incapable of transmitting it to any perceptible distance. The former class of bodies are now termed conductors of electricity, and the second class non-conductors, or electrics; these terms are said to have been first applied to them by Desaguliers. 10. Soon after Mr. Grey's discovery of the difference between conductors and non-conductors, M. Du Fay discovered the difference between positive and negative, or, as they were for some time, and are still by some called, the vitreous and resinous electricities. This discovery was accidentally made in consequence of 11. M. Du Fay, says Mr. Singer, has also the merit of having given the first clear account of that apparent repulsion which obtains in most electric experiments, and which was first observed by Otto Guericke, who had noticed that the fibres of an electrified feather receded from each other, and from the tube or globe by which they had been electrified. Du Fay viewed this as the indication of a general principle in electricity, which may be thus expressed. Electrified bodies attract all those that are not so, but repel them as soon as they are electrified by their contact. 12. The consideration of this general principle led the same assiduous philosopher to a discovery of the first importance, viz. the existence of two distinct attractive powers, produced by the friction of different substances, the one excited by rubbing glass, rock crystal, gems, wool, hair, and many other substances, he called vitreous electricity. The other, resulting from the friction of amber, copal, gum-lac, resins, sealing-wax, &c., he named resinous electricity. The characteristics of these attractive powers are, that they strongly attract each other, and produce a mutual counteraction of effect, whilst they separately act in an apparently similar manner on all unelectrified bodies: but the effect of either of them is destroyed or weakened by the approach of the other. If gold leaf be electrified by rubbed glass it immediately recedes from it, and will not again approach whilst it remains in its electric state. But in this state it is strongly attracted by any excited body of the resinous class, and will fly to sealing-wax or amber more rapidly than to an unelectrified body. Hence it was concluded, by Du Fay, that there are two distinct electricities, each repulsive of its own particles, but having a strong attraction for those of the other. So that all bodies electrified with the vitreous electricity repel those that are similarly electrified, and attract such as are unelectrified or endowed with the resinous electricity. And the converse of this is the case with such as are possessed of the resinous electricity. 12. The terms resinous and vitreous electricity, continues the same author, were sufficiently appropriate at the time they were proposed; but it has been since found that either kind of elec neighbours, particularly the curate of the parish, whenever there should be any appearance of a thunder storm. At length the long expected event arrived. On Wednesday, 10th May, 1752, between two and three P. M. Coissier heard a pretty loud clap of thunder. Immediately he ran to the machine, taking with him a phial furnished with a brass wire; and presenting the wire to the end of the rod, a small spark issued from it with a snap like that which attends a spark from an electrified conductor. Stronger sparks were afterwards drawn in the presence of the curate and a number of other people. The curate's account of them was, that they were of a blue color, an inch and a half in length, and smelled strongly of sulphur. In making them, he received a stroke on his arm a little below the elbow; but he could not tell whether it came from the brass wire inserted into the phial, or from the bar. He did not attend to it at the time; but the pain continuing, he uncovered his arm when he went home in the presence of Coissier. A mark was perceived round it, such as might have been made by a blow with the wire on his naked skin. 21. Dr. Franklin himself had an opportunity, about a month after this, of verifying his own hypothesis. He was waiting for the erection of a spire in Philadelphia, not imagining that a pointed rod of a moderate height could answer the purpose. At last it occurred to him, that by means of a common kite he could have a readier access to the higher regions of the atmosphere than any other way whatever. Preparing, therefore, a large silk handkerchief and two cross sticks of a proper length on which to extend it, he took the opportunity of the first approaching thunder-storm to take a walk into a field where there was a shed convenient for his purpose. But, dreading the ridicule which too commonly attends unsuccessful attempts in science, he communicated his intention to nobody but his son, who assisted him in raising the kite. A considerable time elapsed before there was any appearance of success. One very promising cloud had passed over the kite without any effect; when, just as he was beginning to despair, he observed some loose threads of the hempen string to stand erect and avoid one another, just as if they had been suspended by the conductor of a common electrical machine. On this he presented his knuckle to a key which was fastened to the string, and thus obtained a very evident electric spark. Others succeeded even before the string was wet; but, when the rain had begun to descend, he collected electric fire pretty copiously. He had afterwards an insulated iron rod to draw the lightning into his house; and performed almost every experiment with real lightning, that had before been done with the artificial representations of it by electrical machines. With this apparatus he connected two small bells and a pendulum between them, which were so arranged as to ring when electrified, and thus to give notice of the approach of a thunder-cloud. 22. Experiments with the electrical kite were repeated in all directions, and with various success; in France a most brilliant display of its powers was made by M. de Romas. He constructed a kite of seven feet in height, and three feet wide; this kite he raised to the height of 550 feet by a string, in which was interwoven a fine metallic wire to render it a good conductor. On the 7th of June, 1753, when this kite was elevated, M. de Romas informs us that he drew from the conductor to which the string was attached sparks three inches long, and a quarter of an inch thick. On one or two occasions he met with increasing success, and was enabled to draw sparks, or rather streams, of the electric matter from his apparatus, of a foot in length, and an inch in thickness. But on the 16th of August, 1757, M. de Romas, with an additional length of string to his kite, was still more successful. The storm at the time was not great, neither was there much thunder, and but little rain had fallen; yet streams of lightning, nine or ten feet long, and an inch in thickness, darted from his conductor to the ground, accompanied with a noise equal to that attending the discharge of a pistol. 23. It was not to be expected that, in the infancy of the science, experiments on such a scale should be always conducted with safety: accidents will happen in the management of the best constructed apparatus, and the first operators on atmospherical electricity received many severe and unexpected shocks. Numerous, however, and dangerous as these accidents have been, there is only one instance known of their having proved fatal; to that we have already alluded, and shall here state some of the leading particulars attending the melancholy catastrophe. Professor Richman, of St. Petersburgh, had constructed an apparatus for making experiments on atmospherical electricity, for a work on that subject in which he was engaged. On the morning of the day that terminated his mortal career he was attending a meeting of the Academy of Sciences, and, hearing the sound of distant thunder, he hastened home to observe his apparatus, and took with him Mr. Solokow, his engraver, that he might make any sketch required during the action of the apparatus. On inspecting his electrometer, he found it indicated 4° on the quadrant; and, while pointing out to his friend the danger to be apprehended should it rise to 45°, a loud peal of thunder burst over the city. At this moment the professor inclined his head towards the apparatus to observe the height to which the electrometer had risen, and while in this posture, with his hand about a foot from the conducting rod, a ball of fire, of a bluishwhite color, flashed from the rod to his head, with a report equal to that of a pistol. Richman fell backwards on a chest behind him, and expired in a moment. Solokow was much stunned by the discharge; and described the ball of electric fire as being about the size of his closed hand. The wires of the apparatus were melted and scattered about the room; the door was torn from its hinges and thrown upon the floor; the house was filled with sulphureous vapor, the ashes were thrown from the fire-place, and the door-posts rent asunder. 24. A vein was opened in the professor's body twice, but no biood followed; after which, they but they did not think of any method by which their suppositions could be brought to the test of experiment. The remarks of the abbé Nollet on this subject, considering the time at which they were made, are so striking, that we consider them well deserving of a place in the memory of every lover of the electrical science, and shall here record them. 18. If,' says he, any one should take upon him to prove from a well connected comparison of phenomena, that thunder is in the hands of nature what electricity is in ours; that the wonders which we now exhibit at our pleasure, are little imitations of those great effects that frighten us, and that the whole depends upon the same mechanism: if it can be demonstrated that a cloud prepared by the action of the winds, by heat, by a mixture of exhalations, &c., is opposite to a terrestrial object; that this is the electrified body, and at a certain proximity to that which is not; I avow that this idea, if it were well supported, would give me a great deal of pleasure; and, in support of it, how many specious reasons present themselves to a man who is well acquainted with electricity! The universality of the electric matter, the readiness of its action, its inflammability, and its activity in giving fire to other bodies, its property of striking externally and internally even to their smallest parts, the remarkable example we have of this effect in the Leyden experiment, the idea which we might truly adopt in supposing a greater degree of electric power, &c.; all these points of analogy, which I have been some time meditating, begin to make me believe, that, by taking electricity for the model, one might form to one's self, in respect to thunder and lightning, more perfect and more probable ideas than have hitherto been offered.' 19. It is generally admitted that the French philosophers were the first to verify these conjectures; they preceded the justly celebrated Dr. Franklin in drawing the electric matter from the clouds by means of an iron conducting rod; but, within a month after they had done so, the American philosopher effected the same thing in a manner that never seems to have entered into their minds. Speaking of the observations of the abbé Nollet, above quoted, Mr. Singer justly remarks, that thy bear no comparison with the acute conception, sound philosophical argument, and satisfactory experiments, by which Dr. Franklin has demonstrated the identity of the electric fluid, and the cause of thunder. Dr. Franklin, says he, had observed with equal attention the peculiarities of the natural phenomenon, and the power to which he ascribed its production; he enumerated the following as their leading features of resemblance: (1.) The zigzag form of lightning corresponds exactly in appearance with an electric spark that passes through a considerable interval of air. (2.) Lightning most frequently strikes such objects as are high and prominent, in preference to others, as the summits of hills, the masts of ships, high trees, towers, spires, &c. The electric fluid, when striking from one body to another, always passes through the most prominent parts (3.) Lightning is observed to strike most frequently into those substances that are good conductors of electricity, such as metals, water, and moist substances; and to avoid those that are non-conductors. (4.) Lightnings inflame combustible bodies. The same is effected by electricity. (5.) Metals are melted by a powerful charge of electricity. This phenomenon is one of the most common effects of a stroke of lightning. (6.) The same may be observed of the fracture of brittle bodies, and of other expansive effects common to both causes. (7.) Lightning has often been known to strike people blind. Dr. Franklin found, that the same effect is produced on animals when they are subject to a strong electric charge. Dr. (8.) Lightning destroys animal life. Franklin killed turkies of about ten pounds weight, by a powerful electric shock. (9.) The magnetic needle is affected in the same manner by lightning and by electricity, and iron may be rendered magnetic by both causes. The phenomena are therefore strictly analogous, and differ only in degree; but if an electrified gun-barrel will give a spark, and produce a loud report at two inches distance, what effect may not be expected from perhaps 10,000 acres of electrified cloud? And is not the dif ferent extent of these conductors, equal to the different limit of their effects? But to ascertain the accuracy of these ideas, let us have recourse to experiment. Pointed bodies receive and transmit electricity with facility; let, therefore, a pointed metal rod be elevated in the atmosphere, and insulated; if lightning is caused by the electricity of the clouds, such an insulated rod will be electrified whenever a cloud passes over it, and this electricity may then be compared with that obtained in our experiments. Such were the suggestions of this admirable philosopher: they soon excited the attention of the electricians of Europe, and having attracted the notice of the king of France, the approbation he expressed excited in several members of the French Academy a desire to perform the experiment proposed by Franklin, and several insulated and pointed metallic rods were erected for that purpose. 20. In this pursuit the most active persons were two French gentlemen, Messrs. D'Alibard and Delar. The former prepared his apparatus at Marly la Ville, five or six leagues from Paris; the latter at his own house, on some of the highest ground in that capital. M. D'Alibard's machine consisted of an iron rod forty feet long, the lower extremity of which was brought into a sentry-box, where the rain could not come; while on the outside it was fastened to three wooden posts by long silken strings defended from the rain. This machine was the first that was favored with a visit of the etherial fire. M. D'Alibard himself was not at home; but, in his absence, he had entrusted the care of his apparatus to one Coissier, a joiner, who had served fourteen years in the army, and on whose courage and understanding he could depend. This artisan had all the necessary instructions given him; and was desired to call some of his ATE COURT are puined one who the sten, cost a few ones thoug ve tard, and he can a Duned PaĽ TYDET, 3. Mr. E me 1, en mtimate friend of Dr. Franking made several experiments that entre buted to the advancement of vertrety. Tee good copy to the cxcovery of the two extrictare, the nonducting pores of water at of Serena peretes, and the power of string argu Actresty whe In the first of those experiments he had been adopted by M. Du Fay; but be woon proved that Du Fay did not consider the two electricities in the same lost as that in which they were viewed by Frankini, viz. positive and 31. In 1757 a work appeared on electricity, entitled Disputatio Pryda Experimentalis de Electricitat bus, by Mr. Wilke, of Rostock, in Lower Saxony, m which the author gives some very interesting details of his researches respecting the electricity developed during the melting and coomg of electrical substances, and also that produced by the friction of different bodies. This gentleman found that, when sulphur is melted in an earthen vessel placed upón conductors of electricity, it is strongiy electrified when taken out after it is cold; but that it shows no signs of electricity if cooled upon electrics. Melted sealing-wax, he found, acquired negative electricity when poured into glass vessels, but positive electricity when poured into sulphur. Mr. Wilke also confirmed the experiments of Dr. Franklin and Mr. Canton on electrical atmospheres, and illustrated the phenomena of electrical light. 34. The theories of Alpénus and Cavendish. were much improved on by the menuity of M Coulomb by tuose phosenhers the action a the fentit tamen, in prodorer attraction or repoison, was cocadered merely as dusting with the distance; but by the experiments of Colomb it was proved that the eternmical force, Lie that of zuty, as in the intense ratio of the squares of the distance. The instrument with which Coclomb made his experments was of Lis own onstruction: be care in the name of the torios balance," from the manner of its action; a description of it will be ren in the course of This essay. Coulomb also made numerous experiments for the purpose of ascertaining the laws by which the dissipation of the electrical matter in the air is regulated; and also to ascertain the distribution of it in an overcharged body. In prosecuting these enquiries he was certainly as successful as comid possibly be expected, considering the extreme delicacy of his apparatus, and the effects which the variableness of the atmosphere produces on the strongest electrical experiments. 35. To M. De Saussure we are also indebted for some remarkably fine experiments, which seem to have been made with great care, on the electricity developed during the conversion of fluids into vapor. The fluids on which he operated were distilled water, spirit of wine, and ether. The same philosopher likewise made some highly interesting experiments on atmospherical electricity, for the verification of which he made a journey to the Alps. 36. Most of those who have devoted the attention to the study of electricity, as a science, have distinguished themselves by the invention of some new instrument, the use of which has generally led to some important discovery. constructed instrument for collecting and retaining the electric matter; and another called a condenser, the use of which is to accumulate, and render visible, the smallest portions of electricity, natural or artificial. The celebrity of Volta, however, rests chiefly on the important improvements which he made in that branch of electricity designated GALVANISM, under which they will be fully considered. This was peculiarly the case with Sig. Volta, 32. M. Alpinus, a member of the Imperial professor of natural philosophy at Como in Italy. Academy at St. Petersburgh, seems to have been. He invented the electrophorus, an ingeniously the first who gave to the world a mathematical demonstration of the theory of electricity. An exposition of his treatise was published by the abbé Hauy; and an excellent paper, on the same subject, was drawn up for the Royal Society by Mr. Cavendish, before he knew any thing of the theory of M. Alpinus. The merits of M. Alpinus are certainly great, but we consider Cavendish as having much higher claims as an electrician; his experiments on the conducting power of water and wire; his very ingenious construction of the artificial torpedo; and above all, his success in employing electricity as a chemical agent, justify this opinion. 33. The labors of Dr. Priestley, as an electrician, are deservedly held in the highest esteem; the doctor brought no common share of ingenuity and perseverance to bear upon the science; and to him we are indebted for a considerable number of important improvements and interesting experiments in electricity, as connected with chemistry; for a most excellent treatise on the History of Electricity; an Introduction to Electricity; several valuable papers on the same subject, inserted in the Philosophical Transactions; and for numerous improvements in the construction of electrical apparatus. 37. We have already noticed the scientific experiments of Coulomb, and must here observe that Dr. Robison, late professor of natural philosophy in the university of Edinburgh, is justly entitled to a share of the honor bestowed on Coulomb, since he had, so early as the year 1769, made numerous and remarkably successful attempts, with an admirable electrometer of his own invention, to determine the laws of electric action. But the professor did not publish an account of his experiments at the time they were made, which certainly gives them the appearance of posteriority. The conclusion to which Dr. Robison's experiments led him was, that the force of electrical attraction and repulsion is nearly in the inverse ratio of the square of the distance. The specific result,' says Dr. Brewster, which he obtained was, that the mutual repulsion of |