He had poor vision and needed glasses to read. Tired of constantly taking them off and putting them back on, he figured out a way to make his glasses let him see both near and far. He cut two spectacles in half and put half of each lens in a single frame. We call them bifocals.
Some of his other inventions and discoveries include:
- A flexible urinary catheter that appears to have been the first one produced in America
- The lightning rod to protect buildings and ships from lightning damage
- An iron furnace stove that is called a Franklin stove. He also established the first fire company and the first fire insurance company to help people live more safely.
- The simple odometer to keep track of distance
- The long arm; a long wooden pole with a grasping claw at the end to help reach books (or other items) on high shelves.