Also through the Junto, he called public attention to Philadelphia’s fire hazards and means of avoiding them. From this effort came the Union Fire Company, the first organized firemen in the colonies. Subsequently, he was responsible for the first fire insurance company in the colonies.
Since 1739, England had been at war with Spain, and in 1744, war with France erupted. The struggle involved the colonies when, in July 1747, French and Spanish privateers plundered two plantations on the Delaware River, a little below New Castle. There were rumors of a French plan to sack Philadelphia. The city had no defenses. The Quaker-dominated Assembly had refused to vote money for war purposes.
Seeing danger threaten, Franklin published “Plain Truth,” a pamphlet which succeeded in convincing even the Quakers of the need for preparedness. Under his leadership, Pennsylvania’s first volunteer militia, with some 10,000 members, was formed. He was offered the post of colonel in the Philadelphia branch. He declined, preferring to serve as a common soldier. William, now sixteen, was also in service, not in the militia but in a company raised by the British for a campaign against French Canada.
In 1748, France, Spain and England settled their difficulties temporarily in the peace treaty of Aix-la-Chapelle. For the time being, the colonies were free from danger of invasion or attack. At last the Franklin family could return to normal life.
He was forty-two and by the standards of the time a rich man. Since his income was sufficient for his needs, he made up his mind to retire. A fellow printer named David Hall took over the management of his printing shop. Franklin moved to a quiet part of town, at Race and Second streets, and bought a 300-acre farm in Burlington, New Jersey, where he could practice the art of a gentleman farmer.
It was time, he believed, to devote the remaining years of his life to his friends, to his writing, to the pursuit of learning. Particularly a branch of learning that had occupied his attention on and off for the past several years—the study of electricity.
5
THE THUNDER GIANT
A few years before his retirement, Franklin, on a visit to Boston, attended a display of electrical tricks given by a Dr. Adam Spencer of Scotland. There is no record of the nature of these “electrical tricks.” Franklin commented later that Dr. Spencer was no expert and that they were imperfectly performed. Since he had never seen anything of the sort before, he was “surpris’d and pleased.”
That sparks could be produced by friction had been known since ancient times. Little more was known about electricity until, in the first part of the eighteenth century, a young Frenchman, Charles François du Fay, identified two different types of electricity: vitreous, produced by rubbing glass with silk; resinous, produced by rubbing resin with wool or fur. Such frictional electricity was brief-lived. Sparks flashed and were gone, and that was the end of it.
Was there any way in which electric charges could be preserved from the rapid decay which they underwent in the air? Around 1747 two scientists were working independently on this problem—E. C. von Kleist of Pomerania and Pieter van Musschenbroek of the University of Leyden. Within a few months of each other, they had found a method of storing electricity in a container. The Leyden jar, this container was named. It was the first electrical condenser.