Just as his son William had helped him with his famed kite-flying experiment, now William’s son, Temple, a lanky and fun-loving 15-year-old, lent a hand as he lowered a homemade thermometer into the ocean. Three or four times a day, they would take the water’s temperature and record it on a chart. Benjamin Franklin had learned from his Nantucket cousin, a whaling captain named Timothy Folger, about the course of the warm Gulf Stream. Now, during the latter half of his six-week voyage home from London, Franklin, after writing a detailed account of his futile negotiations, turned his attention to studying the current. The maps he published and the temperature measurements he made are now included on NASA’s Web site, which notes how remarkably similar they are to ones based on infrared data gathered by modern satellites.

The voyage was notably calm, but in America the longbrewing storm had begun. On the night of April 18, 1775, while Franklin was in mid-ocean, a contingent of British redcoats headed north from Boston to arrest the tea party planners Samuel Adams and John Hancock and capture the munitions stockpiled by their supporters. Paul Revere spread the alarm, as did others less famously. When the redcoats reached Lexington, 70 American minutemen were there to meet them. “Disperse, ye rebels,” a British major ordered. At first they did. Then a shot was fired. In the ensuing skirmish, eight Americans were killed. The victorious redcoats marched on to Concord, where, as Ralph Waldo Emerson would put it, “the embattled farmers stood, and fired the shot heard round the world.” On the redcoats’ daylong retreat back to Boston, more than 250 of them were killed or wounded by American militiamen.

When Franklin landed in Philadelphia with his grandson on May 5, delegates of the Second Continental Congress were beginning to gather there. Among them was Franklin’s old military comrade George Washington, who had become a plantation squire in Virginia after the French and Indian War. Yet there was still no consensus, except among the radical patriots in the Massachusetts delegation, about whether the war that had just erupted should be waged for independence or merely for the assertion of American rights within a British Empire. For that question to be resolved would take another year.

Franklin was selected as a member of the Congress the day after his arrival. Nearing 70, he was by far the oldest. Most of the 62 others who convened in the Pennsylvania statehouse— such as Thomas Jefferson and Patrick Henry from Virginia and John Adams and John Hancock from Massachusetts—had not even been born when Franklin first went to work there more than 40 years earlier. Franklin moved into the house on Market Street that he had designed but never known and where his late wife, Deborah, had lived for ten years without him.His 31-year-old daughter, Sally, took care of his housekeeping needs, her husband, Richard Bache, remained dutiful, and their two children, Ben, 6, and Will, 2, provided amusement. “Will has got a little gun, marches with it, and whistles at the same time by way of fife,” Franklin wrote.

For the time being, Franklin kept quiet about whether or not he favored independence, and he avoided the taverns where the other delegates spent the evenings debating the topic. He attended sessions and committee meetings, said little, and dined at home with his family. Beginning what would become a long and conflicted association with Franklin, the loquacious and ambitious John Adams complained that the older man was treated with reverence even as he was “sitting in silence, a great part of the time fast asleep in his chair.”

Many of the younger, hotter-tempered delegates had never witnessed Franklin’s artifice of silence, his trick of seeming sage by saying nothing. They knew him by reputation as the man who had successfully argued in Parliament against the Stamp Act, not realizing that oratory did not come naturally to him. So rumors began to circulate. What was his game? Was he a secret loyalist?

As the Pennsylvania delegate William Bradford confided to the young James Madison, some of the other delegates had begun to “entertain a great suspicion that Dr. Franklin came rather as a spy than as a friend, and that he means to discover our weak side and make his peace with the ministers.”

In fact, Franklin was biding his time through much of May because there were two people, both close to him, whom he first wanted to convert to the American rebel cause. One was Joseph Galloway, who had acted as his lieutenant and surrogate for ten years in the Pennsylvania Assembly but had left public life. The other was even closer to him—his 44-year-old son, William, who was the governor of New Jersey and loyal to the British ministry. William, having read of his father’s return to Philadelphia in the newspapers, was eager to meet with him and to reclaim his son.

Benjamin and William chose a neutral venue for their summit: Trevose, Galloway’s grand fieldstone manor house north of Philadelphia. The evening started awkwardly, with embraces and then small talk. At one point, William pulled Galloway aside to say that he had avoided, until now, seriously talking politics with his father. But after a while, “the glass having gone around freely” and much Madeira consumed, they confronted their political disagreements.

William argued that it was best for them all to remain neutral, but his father was not moved. Benjamin “opened himself and declared in favor of measures for attaining to independence” and “exclaimed against the corruption and dissipation of the kingdom.” William responded with anger, but also with a touch of concern for his father’s safety. If he intended “to set the colonies in flame,” William said, he should “take care to run away by the light of it.”

So William, with Temple at his side, rode back to New Jersey, defeated and dejected, to resume his duties as royal governor. The boy would spend the summer in New Jersey, then return to Philadelphia to be enrolled in the college his grandfather had founded there, the University of Pennsylvania. William had hoped to send him to King’s College (now Columbia) in New York City, but Benjamin scuttled that plan because he believed the school had become a hotbed of English loyalism.

It is hard to pinpoint when America decided that complete independence from Britain was necessary and desirable. Franklin, who for ten years had alternately hoped and despaired that a breach could be avoided, made his own private declaration to his family at Trevose. By early July 1775, a year before his fellow American patriots made their own stance official, he was ready to go public with his decision.

But it is important to note the causes of Franklin’s evolution and, by extension, that of a people he had come to exemplify. Englishmen such as his father who had immigrated to a new land gave rise to a new type of people. As Franklin repeatedly stressed in letters to his son, America’s strength would be its proud middling people, a class of frugal and industrious shopkeepers and tradesmen who were assertive of their rights and proud of their status. Like many of these new Americans, Franklin chafed at authority. He was not awed by established elites. He was cheeky in his writings and rebellious in his manner. And he had imbibed the philosophy of the new Enlightenment thinkers, who believed that liberty and tolerance were the foundation for a civil society.

For a long time he had cherished a vision in which Britain and America flourished in one great expanding empire. But he felt that it would work only if Britain stopped subjugating Americans through mercantile trading rules and taxes imposed from afar. Once it was clear that Britain remained intent on subordinating the colonies, the only course left was independence.

The bloody Battle of Bunker Hill and the burning of Charleston, both in June 1775, further inflamed the hostility that Franklin and his fellow patriots felt toward the British. Nevertheless, most members of the Continental Congress were not quite as far down the road to revolution. Many colonial legislatures, including Pennsylvania’s, had instructed their delegates to resist any calls for independence.

On July 5, the same day that Franklin signed the Olive Branch Petition, which blamed Britain’s “irksome” and “delusive” ministers for the troubles and “beseeched” the king to come to America’s rescue, he made his rebellious sentiments public. In a letter to his longtime London friend (and fellow printer) William Strahan, he wrote in cold and calculated fury: “You are a Member of Parliament, and one of that Majority which has doomed my country to destruction. You have begun to burn our towns, and murder our people. Look upon your hands! They are stained with the blood of your relations! You and I were long friends: You are now my enemy, and I am Yours. B. Franklin.”

Curiously, Franklin allowed the letter to be circulated— but he never sent it. Instead, it was merely a vehicle for publicizing his view. In fact, Franklin sent Strahan a much mellower letter two days later, saying, “Words and arguments are now of no use. All tends to a separation.”

By early July, Franklin had become one of the most ardent opponents of Britain in the Continental Congress. No longer was there any doubt where Franklin stood. “The suspicions against Dr. Franklin have died away,” Bradford now wrote to Madison. “Whatever was his design at coming over here, I believe he has now chosen his side and favors our cause.” Likewise, John Adams reported to his wife, Abigail: “He does not hesitate at our boldest measures, but rather seems to think us too irresolute, and I suppose [British] scribblers will attribute the temper and proceedings of this Congress to him.”

For the colonies to cross the threshold of rebellion, they needed to begin conceiving of themselves as a new nation. The draft of the Articles of Confederation and Perpetual Union that Franklin presented to the Congress on July 21 contained the seeds of the great conceptual breakthrough that would eventually define America’s federal system: a division of power between a central government and the states.

Under Franklin’s proposal, the Congress would have only a single chamber, in which there would be proportional representation from each state based on population. The body would have the power to levy taxes, make war, manage the military, enter into foreign alliances, settle disputes between colonies, form new colonies, issue a unified currency, establish a postal system, regulate commerce and enact laws. Franklin also proposed that, instead of a president, the Congress appoint a 12-person “executive council” whose members would serve for staggered three-year terms. Franklin included an escape provision: in the event that Britain accepted all of America’s demands and made financial reparation for all of the damage it had done, the union could be dissolved. Otherwise, “this confederation is to be perpetual.” Franklin’s proposed central government was more powerful than the one eventually created by Congress.

As Franklin fully realized, this pretty much amounted to a declaration of independence from Britain and a declaration of dependence by the colonies on each other. Neither idea had widespread support yet. So he read his proposal into the record but did not force a vote on it.

By late August, when it was time for Temple to return from New Jersey to Philadelphia, William tentatively suggested that he might accompany the boy there. Franklin, uncomfortable at the prospect of his loyalist son arriving in town while the rebellious Congress was in session, decided to fetch Temple himself.

William tried hard to keep up the pretense of family harmony and in all his letters to Temple included kind words about his grandfather. William also tried to keep up with Temple’s frequent requests for money; in the tug-of-war for his affections, the lad got fewer lectures about frugality than other members of his family had.

Given his age and physical infirmities, Franklin, now serving as America’s first postmaster general, might have been expected to contribute his expertise to Congress from the comfort of Philadelphia. But always revitalized by travel, he embarked on a Congressional mission in October 1775.

The trip came in response to an appeal from General Washington, who had taken command of the motley Massachusetts militias and was struggling to make them, along with various backwoodsmen who had arrived from other colonies, into the nucleus of a continental army. With little equipment and declining morale, it was questionable whether he could hold his troops together through the winter. Franklin and his two fellow committee members met with General Washington in Cambridge for a week. As they were preparing to leave, Washington asked the committee to stress to the Congress “the necessity of having money constantly and regularly sent.” That was the colonies’ greatest challenge, and Franklin provided a typical take on how raising £1.2 million a year could be accomplished merely through more frugality. “If 500,000 families will each spend a shilling a week less,” he explained to his son-in-law, Richard Bache, “they may pay the whole sum without otherwise feeling it. Forbearing to drink tea saves three-fourths of the money, and 500,000 women doing each threepence worth of spinning or knitting in a week will pay the rest.” For his own part, Franklin forked over his postmaster’s salary.

At a dinner in Cambridge, he met John Adams’ wife, Abigail, who was charmed, as she noted in a letter to her husband: “I found him social but not talkative, and when he spoke something useful dropped from his tongue. He was grave, yet pleasant and affable. . . . I thought I could read into his countenance the virtues of his heart; among which patriotism shone in its full luster.”

On his way back to Philadelphia, Franklin stopped in Rhode Island to meet his sister, Jane Mecom, and take her home with him. The carriage ride through Connecticut and New Jersey was a delight for both Jane and Franklin. The good feelings were so strong that they were able to overcome any political tensions when they made a brief stop at the governor’s mansion in Perth Amboy to call on William. It would turn out to be the last time Franklin would see his son other than a final, tense encounter in England ten years later. They kept the meeting short. Until 1776, most colonial leaders believed—or politely pretended to believe—that America’s dispute was with the king’s misguided ministers, not the king himself. To declare independence, they had to convince their countrymen, and themselves, to take the daunting leap of abandoning this distinction. One thing that helped them do so was the publication, in January of that year, of an anonymous 47-page pamphlet entitled Common Sense. In prose that drew its power, as Franklin’s often did, from being unadorned, the author argued that there was no “natural or religious reason [for] the distinction of men into kings and subjects.” Hereditary rule was a historic abomination. “Of more worth is one honest man to society and in the sight of God, than all the crowned ruffians that ever lived.” Thus, there was only one path for Americans: “Every thing that is right or natural pleads for separation.”

Within weeks of its appearance in Philadelphia, the pamphlet had sold an astonishing 120,000 copies. Many thought Franklin was the author, but his hand was more indirect: the real author was a young Quaker from London named Thomas Paine, who had failed as a corset maker and tax clerk before gaining an introduction to Franklin, who took a liking to him. When Paine decided he wanted to immigrate to America and become a writer, Franklin procured his passage in 1774 and wrote to Richard Bache to help get Paine a job. Soon he was working for a Philadelphia printer and honing his skills as an essayist. Paine’s pamphlet galvanized the forces favoring outright revolution. On June 7, Virginia’s Richard Henry Lee declared to Congress: “These United Colonies are, and of right ought to be, free and independent states.” Although the Congress put off a vote on the motion for a few weeks, it ordered the removal of all royal governments in the colonies. Patriotic new provincial congresses asserted themselves, including one in New Jersey that on June 15, 1776, declared that Gov. William Franklin was “an enemy of the liberties of this country.” For his part, the elder Franklin was not acting particularly paternal. A letter he wrote to Washington the day that his son was being tried didn’t mention that painful fact. Nor did he say or do anything to help his son when the Continental Congress, three days later, voted to have him imprisoned.

On the eve of his confinement, William wrote to his son, now firmly ensconced in his grandfather’s custody, words that seem touchingly generous: “God bless you, my dear boy; be dutiful and attentive to your grandfather, to whom you owe great obligation.” He concluded with a bit of forced optimism: “If we survive the present storm, we may all meet and enjoy the sweets of peace with the greater relish.” They would, in fact, survive the storm, and indeed all meet again, but never to relish the peace. The wounds of 1776 would prove too deep.

As the congress prepared to vote on the question of independence, it appointed a committee for what would turn out to be a momentous task that at the time did not seem so important: drafting a declaration that explained the decision. The committee included Franklin, of course, and Thomas Jefferson and John Adams, as well as Connecticut merchant Roger Sherman and New York lawyer Robert Livingston.

The honor of drafting the document fell to Jefferson, then 33, who was the committee’s chairman, because he had gotten the most votes from its members and he was from Virginia, the colony that had proposed the resolution. For his part, Adams mistakenly thought he had already secured his place in history by writing the preamble to an earlier resolution that called for the dismantling of royal authority in the colonies, which he wrongly proclaimed would be regarded by historians as “the most important resolution that ever was taken in America.” As for Franklin, he was laid up in bed with boils and gout when the committee first met. Besides, he later told Jefferson, “I have made it a rule, whenever in my power, to avoid becoming the draughtsman of papers to be reviewed by a public body.”

And thus it was that Jefferson had the glory of composing, on a little lap desk he had designed, some of the most famous phrases in American history while sitting alone in a second- floor room on Market Street a block from Franklin’s home: “When in the course of human events . . . ”

The document contained a bill of particulars against the British, and it recounted, as Franklin had often done, America’s attempts to be conciliatory despite England’s repeated intransigence. Jefferson’s writing style, however, was different from Franklin’s. It was graced with rolling cadences and mellifluous phrases, soaring in their poetry and powerful despite their polish. In addition, Jefferson drew on a depth of philosophy not found in Franklin. He echoed both the language and grand theories of English and Scottish Enlightenment thinkers, most notably the concept of natural rights propounded by John Locke, whose Second Treatise on Government he had read at least three times. And he built his case, in a manner more sophisticated than Franklin would have, on a contract between government and the governed that was based on the consent of the people.

When he had finished a draft and incorporated some changes from Adams, Jefferson sent it to Franklin on the morning of Friday, June 21. “Will Doctor Franklin be so good as to peruse it,” he wrote in his cover note, “and suggest such alterations as his more enlarged view of the subject will dictate?”

Franklin made only a few changes, the most resounding of which was small. He crossed out, using the heavy backslashes that he often employed, the last three words of Jefferson’s phrase “We hold these truths to be sacred and undeniable” and changed them to the words now enshrined in history: “We hold these truths to be self-evident.”

The idea of “self-evident” truths drew less on John Locke, Jefferson’s favorite philosopher, than on the scientific determinism espoused by Isaac Newton and the analytic empiricism of Franklin’s close friend David Hume. By using the word “sacred,” Jefferson had asserted, intentionally or not, that the principle in question—the equality of men and their endowment by their creator with inalienable rights—was one of religion. Franklin’s edit turned it instead into an assertion of rationality.

On July 2, the Continental Congress finally took the consequential step of voting for independence. As soon as the vote was completed (there were 12 yeas and one nay), the Congress formed itself into a committee of the whole to consider Jefferson’s draft declaration. They were not so light in their editing as Franklin had been. Large sections were eviscerated. Jefferson was distraught. “I was sitting by Dr. Franklin,” he recalled, “who perceived that I was not insensible to these mutilations.” At the official signing of the parchment copy on August 2, John Hancock, the president of the Congress, penned his name with flourish. “There must be no pulling different ways,” he declared. “We must all hang together.” According to the historian Jared Sparks, Franklin replied: “Yes, we must, indeed, all hang together, or most assuredly we shall all hang separately.”

Having declared the collective colonies a new nation, the Second Continental Congress now needed to create a new system of government. So it began work on what would become the Articles of Confederation. The document was not completed until late 1777, and it would take another four years before all 13 colonies ratified it, but the basic principles were decided during the weeks following the acceptance of the Declaration of Independence.

By July 1776, Adm. Richard Howe was commander of all British forces in America, with his brother, Gen. William Howe, in charge of the ground troops. He had gotten his wish of being commissioned to negotiate a reconciliation. He carried a detailed proposal that offered a truce, pardons for the rebel leaders (with John Adams secretly exempted) and rewards for any American who helped restore peace.

Because the British did not recognize the Continental Congress as a legitimate body, Lord Howe was unsure where to direct his proposals. So when he reached Sandy Hook, New Jersey, he sent a letter to Franklin, whom he addressed as “my worthy friend.” He had “hopes of being serviceable,” Howe declared, “in promoting the establishment of lasting peace and union with the colonies.”

Congress granted Franklin permission to reply, which he did on July 30. It was an adroit response, one that made clear America’s determination to remain independent, yet set in motion a fascinating final attempt to avert revolution. “I received safe the letters your Lordship so kindly forwarded to me, and beg you to accept my thanks,” Franklin began. But his letter quickly turned heated, even resurrecting a phrase— “deluge us in blood”—that he had edited out of Jefferson’s draft of the declaration:

“It is impossible we should think of submission to a government that has with the most wanton barbarity and cruelty burnt our defenseless towns in the midst of winter, excited the savages to massacre our peaceful farmers, and our slaves to murder their masters, and is even now bringing foreign mercenaries to deluge our settlements with blood.”

Skillfully, however, Franklin included more than fury. “Long did I endeavor,” he went on, “with unfeigned and unwearied zeal, to preserve from breaking that fine and noble china vase, the British empire; for I knew that, being once broken, the separate parts could not retain even their share of the strength or value that existed in the whole.”

Perhaps, Franklin intimated, peace talks could be useful. If Britain wanted to make peace with an independent America, Franklin offered, “I think a treaty for that purpose is not yet quite impracticable.”

Howe was understandably taken aback by Franklin’s response. He waited two weeks, as the British outmaneuvered General Washington’s forces on Long Island, before answering his “worthy friend.” The admiral admitted that he did not have the authority “to negotiate a reunion with America under any other description than as subject to the crown of Great Britain.” Nevertheless, he said, a peace was possible under terms that the Congress had laid out in its Olive Branch Petition to the king a year earlier, which included all of the colonial demands for autonomy yet still preserved some form of union under the Crown.

Franklin had envisioned just such an arrangement for years. Yet it was, after July 4, likely too late. Franklin felt so, and John Adams and others in his radical faction felt that way even more fervently. Congress debated whether Franklin should even keep the correspondence alive. Howe forced the issue by paroling a captured American general and sending him to Philadelphia with an invitation for the Congress to send an unofficial delegation for talks before “a decisive blow was struck.”

Three members—Franklin, Adams and Edward Rutledge of South Carolina—were appointed to meet with Howe on Staten Island. The inclusion of Adams was a safeguard that Franklin would not revert to his old peace-seeking habits.

Howe sent a barge to Perth Amboy to ferry the American delegation to Staten Island. Although the admiral marched his guests past a double line of menacing Hessian mercenaries, the three-hour meeting on September 11 was cordial, and the Americans were treated to a feast of good claret, ham, tongue and mutton.

Howe pledged that the colonies could have control over their own legislation and taxes. The British, he said, were still kindly disposed toward the Americans: “When an American falls, England feels it.” If America fell, he said, “I should feel and lament it like the loss of a brother.”

Adams recorded Franklin’s retort: “My Lord, we will do our utmost endeavors to save your Lordship that mortification.”

Why then, Howe asked, was it not possible “to put a stop to these ruinous extremities?”

Because, Franklin replied, it was too late for any peace that required a return to allegiance to the king. “Forces have been sent out and towns have been burnt,” he said. “We cannot now expect happiness under the domination of Great Britain. All former attachments have been obliterated.” Adams, likewise, “mentioned warmly his own determination not to depart from the idea of independency.”

The Americans suggested that Howe send home for authority to negotiate with them as an independent nation. That was a “vain” hope, replied Howe.

“Well, my Lord,” said Franklin, “as America is to expect nothing but upon unconditional submission . . . ”

Howe interrupted. He was not demanding submission. But, he acknowledged, no accommodation was possible, and he apologized that “the gentlemen had the trouble of coming so far to so little purpose.”

Within two weeks of his return from meeting Lord Howe, Franklin was chosen, by a Congressional committee acting in great secrecy, to embark on the most dangerous and complex of all his public missions. He was to cross the Atlantic yet again to become an envoy in Paris, with the goal of cajoling from France, now enjoying a rare peace with Britain, the aid and alliance without which America was unlikely to prevail.

Franklin was elderly and ailing, but there was a certain logic to the choice. Though he had visited there only twice, he was the most famous and most respected American in France. In addition, Franklin had held confidential talks in Philadelphia over the past year with a variety of French intermediaries and believed that France would be willing to support the American rebellion. Franklin professed to accept the assignment reluctantly. “I am old and good for nothing,” he said to his friend Benjamin Rush, who was sitting next to him in the Congress. “But as the storekeepers say of their remnants of cloth, I am but a fag end, and you may have me for what you are pleased to give.” But he was secretly pleased.

He knew he would love Paris, and it would be safer than America with the outcome of war so unclear. (Howe was edging closer to Philadelphia at the time.) Indeed, a few of Franklin’s enemies, including the British ambassador to Paris, thought he was finding a pretense to flee the danger.

Such suspicions were probably too harsh. If personal safety were his prime concern, a wartime crossing of an ocean controlled by the enemy’s navy at his advanced age while plagued with gout and kidney stones was hardly the best course. Surely the opportunity to serve his country, and the chance to live and be feted in Paris, were reasons enough. Before departing, he withdrew more than £3,000 from his bank account and lent it to the Congress for prosecuting the war.

His grandsonTemple had been spending the summer taking care of his forlorn stepmother in New Jersey. The arrest of her husband had left Elizabeth Franklin, who was fragile in the best of times, completely distraught. Benjamin sent some money to Elizabeth, but she begged for something more. Couldn’t he “parole” William so he could return to his family? Franklin refused, and dismissed her complaints about her plight by noting that others were suffering far worse at the hands of the British.

Temple was more sympathetic. In early September, he made plans to travel to Connecticut to visit his captive father and bring him a letter from Elizabeth. But Franklin forbade him to go. Less than a week later he cryptically wrote Temple: “I hope you will return hither immediately and your mother will make no objections to it. Something offering here that will be much to your advantage.”

In deciding to take Temple to France, Franklin never consulted with Elizabeth, who would die a year later without seeing either her husband or stepson again. Nor did he inform William, who did not learn until later of the departure of his only son, a lad he had gotten to know for only a year.

Franklin also decided to take along his other grandson, his daughter’s son, Benny Bache. So it was an odd trio that set sail on October 27, 1776, aboard a cramped but speedy American warship aptly named Reprisal: a restless old man about to turn 71, plagued by poor health but still ambitious and adventurous, heading for a land from whence he was convinced he would never return, accompanied by a high-spirited, frivolous lad of about 17 and a brooding, eager-to-please child of 7. Two years later, writing of Temple but using words that applied to both boys, Franklin explained one reason he had wanted them along: “If I die, I have a child to close my eyes.”

In France, Franklin engaged in secret negotiations and brought France into the war on the side of the colonies. France provided money and, by war’s end, some 44,000 troops to the revolutionaries. Franklin stayed on as minister plenipotentiary, and in 1783 signed the Treaty of Paris that ended the war. He returned to the United States two years later. Then, as an 81- year-old delegate to the federal Constitutional Convention in Philadelphia in 1787, Franklin played perhaps his most important political role: urging compromise between the large and small states in order to have a Senate that represented each state equally and a House proportional by population. He knew that compromisers may not make great heroes, but they do make great democracies. He died in 1790 at age 84.