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Gas Lighting
David Melville invented it. The design was a way for people to save energy and have a more efficient method for lighting. -
Stethoscope
René Théophile Hyacinthe invented it.This invitation gave rise to one of the most important and ubiquitous medical instruments. It's good for the public health. -
Refrigerator
An American engineer Jacob Perkins invented it. It can help people to stockpile foods for longer time. -
Stapler
Samuel Slocum invented it. It can make people's life easier.
