The Derby Silver Company was founded in 1872 and began operations on Canal Street in Shelton, CT one year later. The company soon outgrew its quarters and in 1877 constructed a larger building, which still stands on Bridge Street, Shelton, near the Housatonic River, overlooking Derby. A number of additions were completed in subsequent years. The original Canal Street building was razed when the railroad was built through Shelton in 1888. In 1898, the plant merged with the International Silver Company, a consortium of Connecticut silver companies. At that time the Derby Silver Company works was known as Factory B. Thus, as a rule of thumb, items with the Derby Silver Company logo most likely date from the 19th century, while items with the International Silver Company logo, either Derby or Factory B, are from the 20th. When 9 numbers (or a long sequence of digits) are engraved on the bottom of Derby Silver Co. plated candle holders, they almost always refer to internal manufacturer inventory, pattern, or catalog numbersrather than a date, price, or silver purity grade.  Derby Silver Company, which operated between roughly 1873 and 1933 in Shelton, Connecticut, used these numbers to identify specific designs within their factories, especially during their time as "Factory B" of the International Silver Company.