Golden Gem adding machine

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 1899 in Germany (No DE121108) Henry and Heinrich Goldmann. During the next 10 years are issued 3 patents in USA and 4 in different countries—Canada, Switzerland, Austrian and England, granted to different people (see the lowe drawing from US patent No 847759, from 19.03.1907, granted to Gancher und Zabriskie). The Golden Gem was introduced by the Automatic Adding Machine Co., New York, in 1904. The company's advertising in 1917 claims over 100000 had been sold by that year. At that point they cost $10 each.

The patent drawing of Golden Gem from 1907

The size of the device is 12 x 8 cm, and it was heavy, some 750 g. To operate the Golden Gem (see the lower photo), 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!).

The Golden Gem adder

Subtraction 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.