From 1790 to 1880, the U.S. Patent Office required that patent applications for a new inventions must have a model accompanying them. When the requirement was aboli...  ...ent was abolished, there were around 200,000 such models . Some went...

A model of an electromagnetic engine. Rothschild Patent Model Collection, Scherzi Photography...  ...Inventors today have got it easy. If they want to patent something, all they have to do is file...  ...Before 1880, however, if you want...