imperceptibly; but these in a moment render abortive the labours of ages. On this account there should be, in all cities, ample provisions to prevent fires from spreading. Franklin early saw the necessity of these; and, about the year 1738, formed the first fire company in this city. This example was soon followed by others; and there are now numerous fire companies in the city and liberties. To these may be attributed in a great degree the activity in extinguishing fires, for which the citizens of Philadelphia are distin guished, and the inconsiderable damage which this city has sustained from this cause. Some time after, Franklin suggested the plan of an association for insuring houses from losses by fire, which was adopted; and the association continues to this day. The advantages experienced from it have been great.

From the first establishment of Pennsylvania, a spirit of dispute appears to have prevailed amongst its inhabitants. During the life-time of William Penn, the constitution had been three times altered. After this period, the history of Pennsylvania is little else than a recital of the quarrels between the proprie taries, or their governors, and the Assembly. The proprietaries contended for the right of exempting their lands from taxes; to which the Assembly would by no means consent. This subject of dispute interfered in almost every question, and prevented the most salutary laws from being enacted. This at times subjected the people to great inconveniences." In the year 1744, during a war between France and Great Britain, some French and Indians had made inroads upon the frontier inhabitants of the province, who were unprovided for such an attack. It became necessary that the citizens should arm for their defence. Governor Thomas recommended to the Assembly, who were then sitting, to pass a militia law. To this they would agree only upon condition that he should give his assent to certains laws, which appeared to them calculated to promote the interests of the people. As he thought these laws would be injurious to the

proprietaries, he refused his assent to them; and the Assembly broke up without passing a militia law. The situation of the province was at this time truly alarming; exposed to the continual inroad of an enemy, destitute of every means of defence. At this crisis Franklin stepped forth, and proposed to a meeting of the citizens of Philadelphia, a plan of a voluntary association for the defence of the province. This was approved of, and signed by twelve hundred persons immediately. Copies were instantly circulated throughout the province and in a short time the number of signers amounted to ten thousand. Franklin was chosen colonel of the Philadelphia regiment; but he did not think proper to accept of the honour.

Pursuits of a different nature now occupied the greatest part of his attention for some years. He engaged in a course of electrical experiments, with all the ardour and thirst for discovery which characterized the philosophers of that day. Of all the branches of experimental philosophy, electricity had been least explored. The attractive power of amber is mentioned by Theophratus and Pliny, and from them by later naturalists. In the year 1600, Gilbert, an Eng lish physician, enlarged considerably the catalogue of substances which have the property of attracting light bodies. Boyle, Otto Guericke, a burgomaster of Magdeburg, celebrated as the inventor of the airpump, Dr. Wall, and Sir Isaac Newton, added some facts. Guericke first observed the repulsive power of electricity, and the light and noise produced by it. In 1709, Hawkesbec communicated some important observations and experiments to the world. For several years electricity was entirely neglected, until Mr. Grey applied himself to it, in 1728, with great assiduity. He and his friend Mr. Wheeler, made a great variety of experiments; in which they demonstrated, 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. Grey afterwards found, that, by suspending rods

of iron by silk or hair lines, and bringing an excite tube under them, sparks might be drawn, and a light perceived at the extremities in the dark. M. du Faye, intendant of the French king's gardens, made a number of experiments, which added not a little to the science. He made the discovery of two kinds of electricity, which he called vitreous and resinous; the former produced by rubbing glass, the latter from excited sulphur, sealing wax, &c. But this idea he afterwards gave up as erroneous. Between the years 1739 and 1742, Desauguliers made a number of experiments, but added little of importance. He first used the terms conductors and electrics per se. In 1742, several ingenious Germans engaged in this subject; of these the principal were, professor Boze, of Wittemberg, professor Winkler, of Leipsic, Gordon, a Scotch Benedictine monk, professor of philosophy at Erfurt, and Dr. Ludolf, of Berlin. The result of their researches astonished the philosophers of Europe. Their apparatus was large, and by means of it they were enabled to collect large quantities of the electric fluid, and thus to produce phenomena which had been hitherto unobserved. They killed small birds, and set spirits on fire. Their experiments excited the curiosity of other philosophers. Collinson, about the year 1745, sent to the Library Company of Philadelphia an account of these experiments, together with a tube, and directions how to use it. Franklin, with some of his friends immediately engaged in a course of experiments; the result of which is well known He was enabled to make a number of important discoveries, and to propose theories to account for various phenomena; which have been universally adopted, and which bid fair to endure for ages. His observations he communicated in a series of letters, to his friend Collinson; the first of which is dated March 28, 1747. In these he shews the power of points in drawing and throwing off the electrical matter, which had hitherto escaped the notice of electricians. He also made the grand discovery of a plus and minus, or of a positive and

negative state of electricity. We gave lim the honcur of this, without hesitation; although the English have claimed it for their countryman, Dr. Watson. Watson's paper is dated January 21, 1748; Franklin's July 11, 1747; several months prior. Shortly after, Franklin, from his principles of the plus and minus state, explained, in a satisfactory manner, the phenomena of the Leyden phial, first observed by Mr. Cuneus, or by professor Muschenbroeck, of Leyden, which had much perplexea philosophers. He shewed clearly, that the bottle, when charged, contained no more electricity than before, but that as much was taken from one side as was thrown on the other; and that, to discharge it, nothing was necessary but to produce a communication between the two sides by which the equilibrium might be restored, and that then no signs of electricity would remain. He afterwards demonstrated, by experiments, that the electricity did not reside in the coating, as had been supposed but in the pores of the glass itself. After a phial was charged, he removed the coating, and found that upon applying a new coating the shock might still be received. In the year 1749, he first suggested his idea of explaining the phenomena of thunder gusts, 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 reasonings from facts, in support of his positions. In the same year he conceived the astonishingly bold and grand idea of ascertaining the truth of his doctrine, by actually drawing down the lightning, by means of sharp pointed iron rods raised into the region of the clouds. Even in this uncertain state, his passion to be useful to mankind displays itself 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 silently and imperceptibly, he suggested the idea of securing houses, ships, &c. from being damaged by lightning, by erecting pointed rods, that

should rise some feet above the most elevated part, and descend some feet into the ground or the water. The effect of these, he concluded, would be either to prevent a stroke 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 electric matter to the earth, without any injury to the building.

It was not until the summer of 1752, that he was enabled to complete his grand and unparalleled discovery by experiment. The plan which he had originally proposed, was, to erect on some high tower, or other elevated place, a sentry-box, from which should rise a pointed iron rod, insulated by being fixed in a cake of resin. Electrified clouds passing over this, would, he conceived, impart to it a portion of their electricity, which would be rendered evident to the. senses by sparks being emitted, when a key, the knuckle, or other conductor was presented to it. Philadelphia at this time afforded no opportunity of trying an experiment of this kind. While Franklin was waiting for the erection of a spire, it occurred to him that he might have more ready access to the region of clouds by means of a common kite. He prepared one by fastening two cross sticks to a silk handkerchief, which would not suffer so much from the rain as paper. To the upright stick was affixed an iron point. The string was, as usual, of hemp, except the lower end, which was silk. Where the hempen string terminated, a key was fasteneu. With this apparatus, on the appearance of a thunder gust approaching, he went out into the commons, accompanied by his son, to whom alone he communicated his intentions, well knowing the ridicule which, too generally for the interest of science, awaits unsuccessful experiments in philosophy. He placed himself under a shade, to avoid the rain-his kite was raised-a thunder cloud passed over it-no sign of electricity appeared. He almost despaired of success, when, suddenly, he observed the loose fibres of his string to move towards