Then Franklin moved that the Constitution be signed by the delegates as “done in Convention by the unanimous consent of the states present.”

While the last delegates were affixing their signature, Franklin’s eyes were on the president’s chair, on the back of which a sunset—or sunrise—was painted. To those near him he said, “I have often and often in the course of the session ... looked at that sun behind the president without being able to tell whether it was rising or setting. But now at length I have the happiness to know that it is a rising and not a setting sun.”

In the year of the Convention, the Massachusetts delegate, Elbridge Gerry, called on Franklin, bringing a friend named Manasseh Cutler. Later Cutler wrote down his recollections of this first meeting with the philosopher-statesman.

He was sitting hatless under a mulberry tree in his garden, “a short, fat, trunched old man in a plain Quaker dress, bald pate, and short white locks.” Present were several men and women, one of whom was Sarah Bache. When Cutler was introduced, Franklin rose, took him by the hand, expressed his joy at seeing him, and begged him to be seated by his side. He spoke in a low voice and his “countenance was open, frank, and pleasing.”

Sarah Bache served tea under the tree. She had three of her younger children with her, who “seemed to be excessively fond of their grandpapa.” They talked until dark when Franklin took his guests into his study, “a very large chamber and high-studded.” The walls were lined with bookshelves and there were more books in four alcoves extending two-thirds of the length of the room. Cutler guessed rightly that this was “the largest and by far the best private library in America.”

Their host showed them a sort of artificial arm—a long pole with prongs at the end that could be opened or shut with a rope, which he had devised to take down and put up books on the upper shelves. (Previously he had used a chair which could be unfolded into a ladder, but now he was not sufficiently agile.) He had other curiosities in the room, such as a glass machine for “exhibiting the circulation of the blood in the arteries and veins of the human body” and his rocking armchair, with a fan placed over it which he could operate by a small motion of his foot.

Because Cutler was a botanist, Franklin showed him a precious folio containing Systema Vegetabilium, by Linnaeus, the founder of systematic botany. Heavy as the folio was, Franklin insisted on lifting it himself, and to Cutler he expressed regret that he had not in his youth given more attention to the science of botany.

They discussed many other matters and Cutler was astonished at Franklin’s extensive knowledge, “the brightness of his memory, and clearness and vivacity of all his mental faculties, notwithstanding his age,” and at the “incessant vein of humour ... which seems as natural and involuntary as his breathing.”

But his age was catching up with Benjamin Franklin, as no one realized better than he. In February 1788, he fell on the stone steps that led into his garden, bruising himself badly and spraining his wrist, so that temporarily he could not even write to his friends. The accident was followed by a severe attack of his kidney stone ailment. He was still confined to bed when Pennsylvania celebrated gloriously its twelfth Fourth of July. The Pennsylvania Council held meetings at his house during his illness, and in October, Thomas Mifflin, a veteran of the Revolutionary War, was elected to succeed him.

To quiet the anxiety of his sister in Boston, Jane Mecom, he wrote, “There are in life real evils enough, and it is a folly to afflict ourselves with imaginary ones.... As to the pain I suffer, about which you make yourself so unhappy, it is, when compared with the long life I have enjoyed of health and ease, but a trifle.”