The Gem Adding Machine

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Black Gem

Here is a Gem. That’s its name: the Gem Adding Machine. Most of them were produced in a chrome finish that made them reminiscent of surgical or dental instruments; but since, as you may have already gathered, I always look for the combination of aesthetics and function in old computing machinery, I made sure to find one of the less common Gem adders that have a black wrinkle paint finish, a color scheme much more pleasing to the eye. It has a seven-digit width, though I've seen ones with 5 and 9 as well.

Click photo to enlarge

The Gem adder, or Golden Gem as it was sometimes labeled, is small, portable, and very nice to use. It can only add, but it does this extremely well: you insert a stylus in the chain at the right digit and slide it all the way down, and the result register at the top increments to add your digit; carry is handled automatically thanks to the internal gearing. This may seem trivial, but at the time there were countless small adders in use -- slide adders and the Locke Adder, for example -- that required you to handle the carry manually. It also has a clearing mechanism, which some of the others lack, and a nice folding support to prop it at the right angle. On top of which, it is simply well constructed:

you can sense the hefty feel of solid metal, and the mechanism just feels right as you slide the chains or rotate the reset knob.
The Golden Gem was introduced by the Automatic Adding Machine Co., New York, in 1904. It was designed by Abraham Gancher, and the company's advertising in 1917 claims over 100,000 had been sold by that year. At that point they cost $10 each.

Click a photo to enlarge

Good job, Mr. Gancher! Today we have better calculating solutions, but had I been living in 1904, I would have bought your creation without hesitation!

		Exhibit provenance: eBay, of course... More info: A photo of the Gem’s inner works is available at the Vintage Calculators Web Museum: http://www.vintagecalculators.com/html/golden_gem.html

Black Gem