John Sowerby founded the Gateshead Stamped Glass Works in 1846. In 1952 it was replaced by a new factory called Sowerby's Ellison Glass Works. Sowerby introduced its Vitro-Porcelain range (Milk glass) in 1877. In the 1920's, Sowerby began producing a range of iridescent glassware called Carnival glass. During the 1930's, Sowerby produced several Art Deco glass designs. The Sowerby factory was taken over by Suntex Safety Glass Industries Limited in 1957, and closed in 1972.
Sources: 20th Century Factory Glass by Lesley Jackson.