The book History of the American Watch Case, Warren H. Niebling, Whitmore Publishing, Philadelphia, PA, 1971 (available on loan by mail to members from the NAWCC Library & Res
…earch Center), has a small amount to say about the Essex Watch Case Co. It began in 1884, making a grade of gold-filled cases named "Columbia." After several years, Thomas B. Hagstoz, who at one time was in a partnership that held the J. Boss patent for gold-filled case manufacture, was named president of Essex. Under his leadership, Essex expanded its line to include 14K and 18K solid gold cases as well as silver cases. "By 1894 they were turning out 300 cases a day." The Essex Watch Case Co. appears to have been taken over by the Courvoisier-Wilcox Mfg Co. some time between 1892, when the Columbia grade was still being sold by the Essex Watch Case Co., and 1895, at which time surviving ads show the change. Perhaps this occurred during the Panic of 1893. This firm continued the Essex line of solid gold cases; gold-filled cases, such as the Superior (and probably others); and silver cases as well. As pictures (posted by richiec) show, the Superior case was marked 14K - Guraanteed 25 Years while the case paper clearly shows that it is a gold-filled case. Columbia was a mid to high grade gold filled case guaranteed to last 15 to 20 years before wearing down to its copper center (MORE) 