ELECTRICITY, HISTORY OF. It does not appear that the ancients had any thing more than an imperfect and partial knowledge of the electric fluid. Thales, the Milesian, who lived about six hundred years before Christ, was aware of the electrical property of amber, that when rubbed it would attract light bodies to itself; and Theophrastus observed that lyncurium or tourmalin possessed the same property ; but beyond this there is no mention of the subject, either by this or any other writer, until the seventeenth century, when Dr. William Gilbert, a native of Col chester, published his treatise, ' De Magnete,' in which we find manyimportant and interest ing particulars. These received farther illus tration from the experiments of Boyle, Otto Guericke, Dr. Wall, and some others, but more especially from Mr. Hawksbee, who, in his work on electricity, first noticed the elec trical power in glass, and the light proceeding from it. He also first heard the snapping noise that accompanies excitation, and noticed the different phenomena relating to electrical at traction and repulsion : besides, by introducing the glass globe into the electrical apparatus, he much facilitated his own experiments and those of others. After an interval of about twenty years, Mr. Stephen added very material ly to the science of electricity by numerous im portant experiments. He first showed how the power of native electrics might be commu nicated to other bodies in which it cannot be excited, by supporting them on silken lines hair lines, cakes of resin, or glass. Ile els:, more accurately distinguished between elec tries and non-electriu., and displayed the effect of electricity on water more clearly that Gil bert had done.
The experiments of Mr. Grey were eluci dated and enlarged by M. du Fay, member of the Academy of Sciences at Paris. He ob served that electrical operations were obstruct., ed by great heat, as well as by a moist air; that all bodies, both solid and Rukl, would re ceive electricity, when placed on warm or dry glass or sealing wax ; that those bodies which are naturally the least electric have the great est degree of electricity communicated to them by the approach of the excited tube. He first observed the electric spark from a living body suspended on silken lines, and established a principle first suggffited by Otto Guericke, that all electric bodies attract others that are not so, and epel them as soon as they are be come electric by the vicinity or contact of the electric body. He likewise distinguished
electricity into two kinds, which he called vi treous, as belonging to_glass, rock crystal, tic. and resinous, as applied to that of amber, gum lac, &c.. ; the former of these has since been called positive electricity, and the latter nega tive.
Mr. Grey resumed his experiments in 1734, the result of which was the discovery of conductors. He also concluded from several experiments that the electrical power was of the same nature as that of thunder and light ning. Desaguliers and other experimental ists in France, England, and Germany, fol lowed op the experiments of Mr. Grey with further researches, which displayed the power of electricity in new forms, particularly by the discovery that if electricity be accumula ted in a phial, it may be discharged again so as to occasion the electric shock. Mr. Van Kleist, of Leyden, first observed the property of the phial, and Cunmus followed it by ex hibiting the experiment. Mr. lffuschenbroeck, who also tried the experiment with a very thin bowl, assured M. Reaumur in a letter, that he felt himself struck in his arms, shoulder, and breast, so that be lost his breath, and was two days before he recovered from the effects of the and the terror which this unex pected result produced. He added, that he would not receive a second shock for the whole kingdom of Ftance. 11L Allcmand made the experiment with a common beer eass,.. from which he found himself power fully affected in his breath, and felt so severe a pain all along his right arm, that he ap prehended serious consequences from It. These inconveniences, however, passed off after a few days, and others being induced to repeat the experiment, the practice of electri city became soon after common, and was, after a time, also applied to medical purposes. Ma chines of different forms were now invented, and the electrical apparatus was continually enlarged, by some new device, to increase the force or direct the operations of the electricity ; among ether things, when it was ascertained that lightning was no other than electrical matter, conducting rods began to be employed on the tops of buildings and on the masts of vessels, for the purpose of saving them from the effects of storms. Many important trea. uses on the science of electricity have been written within the last century, by Adams, Cavallo, Cavendish, Ferguson, Morgan, Van Marum, Van Swinden, &c.