Mary Walton, an independent inventor, was not one to stand idly by choking on the smog that the factories produced during the Industrial Revolution. In 1879, Mary patented a device that minimized the smoke that was pouring into the air. It was designed to deflect the emissions into water tanks where they were later flushed into the cities' sewage system.
While living in Manhattan, Mary was particularly concerned with the pollution. After cleaning up the air, she moved onto the noise pollution that seemed to fill the air as well as the heads of New Yorkers. Working in her basement, Walton built a model train set and began working to cut down on the clanging of the trolleys. She built a wooden box, painted it with tar, lined it with cotton, and filled it with sand. The vibration from the rails was absorbed.
On February 8, 1891, after putting her invention under the struts that supported the city trains, she received a patent for her work. She gave the city some peace of mind by selling the rights of her patent to the New York City Metropolitan railroad.