WALTON, Mary, American. This resident of New York City was very critical of noise and air-pollution. In 1879 Mary devised a system to reduce factory smoke emissions into the atmosphere. Prior to release the smoke was forced through water tanks which dissolved much of the gaseous matter. The water effluent was then run off into the sewage systems. This invention also had usage in railway engine burners. Then in 1881, she developed a mechanism for reducing the noise of passing trains (on the overhead railways). This involved surrounding the metal rails with wooden frames, which were filled with cotton. The cotton was fixed into position using tar and the frame then filled with sand. This was a soundproofing mechanism that worked well enough to reduce noise levels. Mary’s inventions were taken up commercially, the NY Metropolitan Railway being the first one to adopt them on their overhead city lines.