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Golden Gem Chain Adder Back
Golden Gem Adding Machine Model 16 with Stylus circa 1920 Automatic Adding Machine Co. New York NY U.S.A. The Golden Gem adding machine enjoyed a long sales success through the first half of the 20th century. The first patent for this popular chain adder was established in 1904. To operate the Golden Gem, the stylus is inserted into a link corresponding to the desired number and pulled down. As the continuous chain revolves, it advances a number wheel whose value is seen in the window at top (see photo with cover removed below). When a wheel revolves from 9 to 0, a tens carry mechanism automatically advances the next wheel by one. (This works well, but advancing the tens carry on multiple digits at once (e.g. from 999 to 1000) requires some extra hand strength!). Substraction is possible (via the 9s complement method) using the red numbers shown to the right of each chain. Clearing of the result register is achieved by turning the knob at bottom right until all digits show zero. 
The neat wooden box shown above was hand-made by the original owner. It has a little compartment for storing the stylus. The original owner was Chinese and decided that he preferred the abacus (because it was faster!) and left this wonderful piece on a shelf for many years.
Model 16 (top) and Original 'Classic' Model The Model 16 (top) is quite a bit bigger than the 'classic' Golden Gem Adder, which is shown with its cover off and chains exposed. Golden Gem Model 16 Other Chain Adders
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Pico Chain Adder Precision Instrument Co. New Jersey (source ebay) The Pico Chain Adder (shown above) appears a near duplicate to the Golden Gem, but with a gray crinkle finish and exposed brass plate and trim hardware.
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Dux Chain Adder circa 1910
Forum Schmidt, Copenhagen, Denmark (source: ebay)
The Dainish Dux Chain Adder appears roughly similar in shape and function to the Golden Gem, but is more handsome and much less commonly encountered.
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