Mechanical Devices and EngineeringArtifacts illustrating early mechanical devices like a perpetual motion fountain, an onager, and various engineering tools from the 18th and 19th centuries. Alexander Graham Bell's photophone, which uses light to transmit sound. Date: 1880 210 assets in this story1746-300013241889-489999236145-487521486145-589197241848-194710556145-452523026145-589174441746-299999841899-187918736177-V60460990 PREVIOUS of 3 NEXT