Benjamin Franklin's idea of ​​the Franklin stove became popular because he attached a long pipe to a large black pot, reaching up to the roof of his house. This not only helps warm a home, but also allows smoke to escape outside of the home to protect people's lungs. The stove also reduced wood consumption. The Franklin stove he created was much more durable than the old style: a small stove with a pot on top. Franklin did not patent any of his inventions, but rather allowed other people to rethink and sell his basic inventions so that they could make a living. Benjamin Franklin's greatest invention was bifocal glasses. This idea came to him with age because he constantly alternated between two types of glasses. He had difficulty seeing up close or far away. Franklin had his optician take the lenses from his two pairs of glasses, cut them in half horizontally, then put them back into eyeglass frames, with the near lens on the bottom and the distance lens up.