Margaret Knight, famous inventorMargaret Knight is considered the most famous 19th century inventor. In 1868, she invented a machine that folded and glued paper, which made the flat-bottomed paper bags still in use today. She built a wooden model, but needed an iron one to apply for a patent. Charles Annan, who worked in the shop with her, stole the design and filed for a patent. She sued, was awarded the patent in 1871, and founded the Eastern Paper Bag Co. She also invented several devices for rotary engines and a numbering machine.