16. Circular Saw
Shakers community in Massachusetts claimed that Tabitha Babbitt was the inventor of the first circular saw for use in the sawmill in 1813.
A marine biologist Jeanne Villepreux-Power created the first aquarium in 1832. She was referred to as the “Mother of Aquariophily” by an English biologist Richard Owen.
18. Medical Syringe
Letitia Mumford Geer invented the one-handed medical syringe in 1899. It consisted of a cylinder with a nozzle and piston for injecting drugs. It can be operated by holding in between the fingers. The modern-day syringes are developed from Geer’s idea. Earlier syringes have required both hands to use the injection.