He developed the fireplace insert. An open fireplace always has been a great way to heat cold air and send it up a chimney. Franklin made the fireplace more efficient by designing a wood-burning stove that enclosed the firebox. The device he called the “Pennsylvania fireplace,” and which quickly became known as the “Franklin stove,” needed less wood to make more heat and cut down on smoke and drafts. Thomas Jefferson bought one. Pennsylvania Deputy Governor George Thomas liked the device so much he said its inventor should patent it. Franklin declined: “As we enjoy great advantages from the invention of others, we should be glad of an opportunity to serve others by any invention of ours, and this we should do freely and generously.” (The Granger Collection, New York)