This portrait, which depicts Franklin as a learned scientist and inventor, was one of his favorites. Pictured on the left is the signal-bell apparatus Franklin devised to detect the presence of electrically-charged clouds. The bolt of lightning , seen through the open window, became an attribute closely identified with Franklin. At Franklin's death French philosopher/scientist Jacques Turgot wrote: "He seized the lightning from the sky and the scepter from the hand of tyrants."
The Franklin Stove
Franklin wrote this description of the stove he had invented to promote sales of a model being manufactured by his friend Robert Grace. A series of partitioned iron plates permits a continuous supply of fresh warm air, separated from the smoke, to be distributed equally throughout the room. By controlling the airflow, less heat is lost, and much less wood is needed. Franklin's stove became so popular in England and Europe that this essay was frequently reprinted and translated into several foreign languages.
Franklin's Design for Bifocals
Benjamin Franklin is credited with the invention of bifocal glasses, which he sketched here for his friend George Whatley, a London merchant and pamphleteer. Franklin told Whately he found them particularly useful at dinner in France, where he could see the food he was eating and watch the facial expressions of those seated at the table with him, which helped interpret the words being said. He wrote: "I understand French better by the help of my Spectacles."
Experiments in Electricity
In 1751, Peter Collinson, President of the Royal Society, arranged for the publication of a series of letters from Benjamin Franklin, 1747 to 1750, describing his experiments on electricity. Franklin demonstrated his new theory of positive and negative charges, suggested the electrical nature of lightning, and proposed a tall, grounded rod as a protection against lightning. These experiments established Franklin's reputation...