fpirit of difpute appears to have prevailed amongst its inhabitants. During the life-time of William Penn, the conftitution had been three times altered. After this period, the hiftory of Pennfylvania is little elfe than a recital of the quarrels between the proprietaries, or their governors, and the affembly. The proprietaries contended for the right of exempting their land from taxes; to which the affembly would by no means confent. This fubject of difpute interfered in almost every question, and prevented the most falutary laws from being enacted. This at times fubjected the people to great inconveniences. In the year 1744, during a war between France and Great Britain, fome French and Indians had made inroads upon the frontier inhabitants of the province, who were unprovided for fuch an attack. It became neceffary that the citizens, fhould arm for their defence. Governor Thomas recommended to the affembly, who were then fitting to pafs a militia law. To this they would agree only upon condition that he should give his affent to certain laws, which appeared to them calculated to promote the intereft of the people. As he thought thefe laws would be injurious to the proprietaries, he refused his affent to them; and the affembly. broke up without paffing a militia law. The fituation of the province was at this time truly alarming: expofed to the continual inroads of an enemy, and deftitute of every means of defence. At this crifis Franklin ftepped forth, and proposed to a meeting of the citizens of Philadelphia, a plan of a voluntary affociation for the defence of the province. This was approved of, and igned by twelve hundred perfons, immediate

ly. Copies of it were circulated throughout the province; and in a fhort time the number of figners amounted to ten thousand. Franklin was chofen colonel of the Philadelphia regiment; but he did not think proper to accept of the ho

nour.

Pursuits of a different nature now occupied the greatest part of his attention for fome years. He engaged in a courfe of electrical experiments, with all the ardor and thirst for discovery which characterized the philofophers of that day. Of all the branches of experimental philofophy, electricity had been leaft explored. The elective power of amber is mentioned by 7heophraftus and Pliny, and, from them by later naturalifts. In the year 1600, Gilbert, an English phyfician, enlarged con fiderably the catalogue of fubftances which have, the property of attracting light bodies. Boyle, Otto Guericke, a burgomaiter of Magdeburgh, celebrated as the inventor of the air pump, Dr. Wall, and Sir Ifaac Newton added fome facts. Guericke firft obferved the repuifive power of electricity, and the lightand noise produced by it, In 1709, Hawkefbec communicated fome important obfervations and experiments to the world. For feveral years electricity was entirely neglect ed, until Mr Gray applied himself to it, in 1728, with great affiduity. He and his friend Mr. Wheeler, made a great variety of experiments; in which they demonftrated, that electricity may be communicated from one body to another, even without being in contact, and in this way may be conducted to a great distance. Mr. Gray afterwards found, that by fufpending rods of iron by filk or hair lines, and bringing an excited tube under them, fparks might be drawn, and a light

M. Du

perceived at the extremities in the dark. Faye, intendant of the French king's gardens, made a number of experiments, which added not a little to the fcience. He made the difcovery of two kinds of electricity, which he called vitreous and refinous; the former produced by rubbing glafs, the latter from excited fulphur, fealing-wax, &c. But this idea he afterwards gave up as erroneous. Between the years 1739 and 1742, Defaguliers made a number of experiments, but added little of importance. He firft ufed the terms conductors and electrics, per fe. In 1742, feveral ingenious Germans engaged in this fubject. Of these the principal were, profeffor Boze of Whittemberg, profeffor Winkler of Leipfic, Gordon, a Scotch Benedictine monk, profeffor of philofophy at Erfurt, and Dr. Ludolf of Berlin, The refult of their trefearches aftonished the philofophers of Europe. Their apparatus was large, and by means of it they were enabled to collect large quantities of electricity, and thus to produce phenomena which had been hitherto unobferved, They killed fmall: birds, and fet fpirits on fire. Their experiments excited the curiofity of other philofophers. Collinfon about the year 1745, fent to the library company of Philadelphia an account of thefe experiments, together with a tube, and directions how to use it. Franklin, with fome of his friends, immediately engaged in a course of experiments; the refult of which is well known. He was enabled to make a number of important difcoveries, and to propofe theories to account for various phenomena; which have been univerfally adopted, and which bid fair to endure for ages. His obfervations he commu-nicated, in a series of letters, to his friend Collin

on; the firft of which is dated March 28, 1747 In thefe he makes known the power of points in drawing and throwing off the electrical matter, which had hitherto escaped the notice of electricians. He alfo made the grand difcovery of a plus and minus, or of a pofitive and negative ftate of electricity. We give him the honour of this, without hefitation; although the English have claimed it for their countryman Dr Watfon. Watson's paper is dated January 21, 1748; Franklin's July 11, 1747; feveral months prior. Shortly after, Franklin, from his principles of plus and minus ftate, explained, in a fatisfactory manner, the phenomena of the Leyden phial, firft obferved by Mr. Cuneus, or by profeffor Mufchenbroeck of Leyden, which had much perplexed philofophers. He fhewed clearly that the bottle, when charged, contained no more electricity than before, but that as much was taken from the one fide as was thrown on the other; and that, to difcharge it, nothing was neceffary but to make a communication be tween the two fides, by which the equilibrium might be reftored, and that then no figns of electricity would remain. He afterwards demonftrated, by experiments, that the electricity did not refide in the coating, as had been fuppofed, but in the pores of the glafs itfelf. After a phial was charged, he removed the coating, and found that upon applying a new coating the flock might ftill be received. In the year 1749, he firft fuggefted his idea of explaining the phenomena of thunder-gufts, and of the aurora borealis, upon electrical principles. He points out many particulars in which lightning and electricity agree; and he adduces many facts, and reafoning from facts, in fupport of his pofitions. In the fame year he conceived the afonifhingly

bold and grand idea of afcertaining the truth of his doctrine, by actually drawing down the forked lightning, by means of fharp-pointed iron rods raifed into the region of the clouds. Even in this uncertain ftate, his paffion to be ufeful to mankind difplays itfelf in a powerful manner. Admitting the identity of electricity and lightning, and knowing the power of points in repelling bodies charged with electricity, and in conducting their fire filent-. ly and imperceptibly, he fuggefts the idea of fecuring houfes, fhips, &c. from being damaged by lightning, by erecting pointed iron rods, which fhould rife fome feet above the most elevated part, and defcend fome feet into the ground or the water, The effect of thefe, he concluded, would be either to prevent a ftroke by repelling the cloud beyond the striking distance, or by drawing off the electrical fire which it contained; or, if they could. not effect this, they would at least conduct the ftroke to the earth, without any injury to the: building..

It was not until the fummer of 1752, that he was enabled to complete his grand and unparalleled difcovery by experiment The plan which he had originally propofed, was to er & on fome high tower, or other elevated place, a centry-box, from which fhould rife a pointed iron rod, infulated by being fixed in a cake of refin. Electrified clouds paffing over this, would he conceived, impart to it a portion of their electricit, which would be rendered evident to the tenfes by fparks being emitted, when a key, a knuckle, or other conductor, was prefented to it. Philadelphia at this time afforded no opportunity of trying an experiment of this kind.