She must have clapped her hands in delight at the stove he set up in their common room in 1740. Houses then were mostly heated by fireplaces. Large or small, they had in common that one was scorched on approaching the fire too closely and chilled at the far side of the room. It was impossible for a woman to sit by the window to sew on a winter day. Her fingers would be too stiff with cold to hold a needle. It was taken for granted that everyone had colds during the winter months, especially the women, who of necessity were indoors more than the men. There was the problem of smoke too. With the usual fireplace, most of the smoke came into the room instead of going up the chimney, blackening curtains and spreading soot everywhere. Franklin’s Pennsylvania Fireplace, later called the Franklin Stove, was made of cast iron, could be taken apart and moved easily from room to room. It spread no smoke and, most amazingly, heated the entire room an almost equal temperature. Debby’s sole complaint about her husband had to do with the way he spoiled his son William. Ever since the death of little Franky, he humored the boy to excess. William had a string of private schoolmasters—one of them decamped with Franklin’s wardrobe when William was nine. He had his own pony, like the sons of the rich. Whatever the boy wanted, he managed to wangle from his indulgent father. “The greatest villain on earth,” Debby once called this clever lad. The two of them never did get along. Even William had to take second place after their first and only daughter, Sarah, was born in 1743. Sarah would bring to her father joy and comfort to modify the pain caused by his son. He was busy that year with a new project. In May he issued a circular letter headed “Proposal for Promoting Useful Knowledge Among the British Plantations in North America,” which be mailed to men of learning throughout the colonies. Now that the first drudgery of settling was over, he wrote, the time had come “to cultivate the finer arts and improve the common stock.” For this purpose, he proposed formation of an organization whose members, through meetings or by correspondence, would exchange information on all new scientific discoveries or inventions, and he offered his own services as secretary “till they shall be provided with one more capable.” From this letter grew the American Philosophical Society, which came into being the following year. (The words “philosophical” and “scientific” were then used as synonyms.) Its activities were parallel to those of the famous Royal Society in London. One of Franklin’s first contributions to the new society was a paper on his “Pennsylvania Fireplace,” which he and Debby had been enjoying several years, including diagrams and instructions on how to install it. He refused to patent his invention: “As we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours.”