British Physicist & Mathematician Hertha Marks Ayrton was born #OTD in 1854.
She became a recognized expert on the electric arc, a type of electrical discharge that was little understood at the time. Her research clarified the causes of hissing & flickering in arc lamps and contributed to improving the design and consistency of the lamps. She developed the "Ayrton fan" or "flapper," a device intended to clear poisonous gases from the trenches in World War I.