Benjamin Franklin – 3 of His Popular Inventions
- Bifocals: Franklin was both nearsighted and farsighted, and had to alternate between two pairs of glasses depending on what he was trying to see. As a solution to his frustrating problem, Franklin had the lenses from his two pairs of glasses cut in half and reassembled in one frame with the lenses for distance on top and the lenses for reading on the bottom. Franklin's idea for bifocals is still the basic model used today.
- Franklin stove: Most homes in colonial America were heated by fires in open fireplaces. Fireplaces were inefficient heat sources because of the large amount of wood needed and were dangerous because sparks could easily ignite a fire elsewhere in the house. Franklin invented an iron furnace stove that used less wood, radiated more warmth through the heated iron, and was safer because the fire was better contained. Franklin stoves are still in use in some homes today.
- Odometer: While serving as postmaster for the northern colonies, Franklin had to establish mail routes. In order to measure distances, he invented an odometer, which could be attached to the axle of his carriage wheels to count the rotations. Odometers are standard instruments in modern vehicles.