Franklin had scarcely got his fort supplied and the frontier farms protected when the Governor recalled him to the Assembly. On his way, he rested at Bethlehem, though he could hardly sleep in a comfortable bed any more. While there, he asked about Moravian customs and was told of their communal life, their practices of working for mutual profits, sleeping in dormitories, and eating at common tables. He found that their church music was good, but their sermons seldom delivered to mixed audiences. Their marriages, arranged by the church elders, seemed to work out happily as often as those resulting from voluntary courtships.
Back in Philadelphia, Franklin found that most non-Quakers bad joined a military company, He was chosen colonel of his regiment, and this time accepted the commission. At the first military review, the men accompanied him home and fired several volleys in salute, which broke his electrical equipment. And later, when Franklin was leaving town, his officers escorted him to the ferry, riding with drawn swords. Pennsylvania's Proprietor was particularly offended about this honorary escort, since such courtesies had been withheld from him. He reported that Franklin was trying to seize the Province by force and even tried depriving Franklin of his postmaster's office. Franklin, on the other hand, was embarrassed by such ostentation. But soon all colonial commissions were repealed in England.
Meanwhile Franklin's scientific reputation was growing. In 1746, while in Boston, he bad been introduced to electrical experiments by a Dr. Spence from Scotland. Soon thereafter, a London scientist named Colinson bad sent a glass tube for such experiments to the Philadelphia Library Company, and Franklin had eagerly begun to duplicate the experiments he had seen, as well as to devise new ones. He then wrote Colinson to tell of the Philadelphia experiments, and Colinson read the accounts at the Royal Society of London. At first these papers were ignored in London, and one — on the similarity between lightning and electricity — was openly laughed at. One reader, however, Dr. Fothergill, pressed for their publication and wrote a preface when they appeared in pamphlet form. The pamphlet, with later papers added, ran through five editions.
Translated into French, these papers strongly offended Abb6 Nollet, the royal authority on natural sciences, whose theory on electricity Franklin contradicted. At first the Abb6 believed this pamphlet a clever attack by his Paris enemies. When finally convinced that a Benjamin Franklin actually lived in Philadelphia, he published a defense of his theory and an attack on Franklin. But Franklin declined to answer, feeling that he had clearly described experiments that could be duplicated and verified if his work were valid. Soon French supporters successfully defended him, and his book was translated into Italian, German, and Latin.
The Franklin papers grew famous because an experiment that he had suggested — drawing lightning from the clouds was executed successfully in France and excited the public. After hearing of the continental stir over Franklin's experiments, the Royal Society of London began to consider the papers seriously. They made amends for their former neglect by making Franklin an honorary member, excused from yearly dues. They also presented him the gold medal of Sir Godfrey Copley for 1753, which was delivered at a public dinner by Pennsylvania's new Governor, Denny.
During the customary after-dinner drinking, Denny called Franklin aside and suggested that they could make many mutually advantageous arrangements if Franklin would help persuade the Assembly to pass bills exempting Proprietary estates from taxes. Franklin replied that, fortunately, he was prosperous enough to need no special favors, and as an Assembly member could not possibly accept any; but he promised to champion the Proprietor's measures whenever they were for the good of the people. Denny thereafter made the same demands as his predecessors, with the same results — Franklin became his chief political opponent in the Assembly. But they remained personal friends; in fact, Denny was able to give Franklin his first news about James Ralph, the youthful friend who had accompanied him on his first trip to England and had now become a prosperous prose writer.
In 1746 the Leyden jar, first known condenser of electricity, had been developed, and soon afterwards a London scientist had concluded that all bodies contained electricity. Little more was known when Franklin began his systematic experiments around 1749. He first devised with a Junto silversmith an improved method of obtaining electricity through the glass tube or Leyden jar, and contributed much to knowledge about this device. He even devised the first electric battery. But he made more fundamental contributions by viewing electricity as a single fluid and by coining the terms "positive" and "negative" to describe its properties. And while others before Franklin had suspected that lightning was electricity, it was Franklin who designed the experiments that proved it. Ironically, the proof was actually performed successfully in France a month before Franklin performed a similar test in America. This historical accident occurred because Franklin felt a spire taller than any in Philadelphia, and to which a pointed iron rod could be attached, was necessary to draw the lightning from the clouds. But before he heard of the French successes, he had thought of using a kite. And soon thereafter Franklin suggested the first practical use to which the knowledge about electricity could be put: the lightning rod, which protected buildings and ships from being struck and burned.