Ben Franklin constantly looked for practical ways in which people’s lives could be helped or improved through scientific discoveries, observations of the natural world, and inventions. Although this was a lifelong interest, Ben was able to devote more time to his other interests after retiring from printing in 1748 at the age of 42.
During the many years that Ben published “Poor Richard’s Almanack” he had included detailed information about weather patterns, and it was Ben’s interest in ocean currents that led him to write about what we now know as the Gulf Stream. He wondered why ships that delivered mail from North America to England took less time than those traveling from England to North America. Although explorers and whalers knew of it, it was Ben that published its existence in his Maritime Observations.
In 1744, Franklin published “An Account of the New Invented Pennsylvanian Fire-Places,” where he recorded observations on a metal stove that would function like a free-standing fireplace. Although the stoves that he described had some technical issues and were later improved, he is credited with inventing what is now known as the Franklin stove.
Ben Franklin had a natural curiosity for understanding the laws of nature, such as the properties of electricity. He was fascinated by the power of lightning, but was also aware of the damage caused as it hit the tops of buildings and ship masts. Through much experimentation, he observed that attaching a pointed metal object on any tall object and connecting it to a wire that led down to the ground, or was grounded, could direct the electricity away from buildings and reduce the chance of fire from lightning strikes. Invented in 1749, his lightning rods were also known as "Franklin rods" and were installed on Independence Hall in Philadelphia and later on many other buildings. Lightning rods have been much developed and improved since Franklin’s time; the concept is just as important today, as buildings are taller than ever before.
As he grew older, Ben’s eyesight grew weaker. In 1785 he wrote about how he used two pairs of eyeglasses: one for reading, and the other for seeing distant objects. He described how he took the two eyeglasses, cut the lenses in half, and combined the two lenses in one pair. He called them his "double spectacles," and we now know these as bifocals.
Although Franklin is credited with many inventions, he never patented any of them for profit. He felt that it was more important to serve a greater good in society and to share the discoveries and practical inventions that came from his observations.