The Adix calculator by Pallweber and Bordt

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Blue Velvet

I’d waited years for this one. I first saw an Adix -- and a perfect exemplar it was -- years ago, in Portobello Road in London. It was like a sight from a steampunk fairy tale: an intricate cogwheel mechanism in aluminum and brass, fitted into a small wooden box padded in blue velvet and satin fabrics. And an impossible price tag… which is why it took me years to find one at a price I could bring myself to spend.
The little Adix calculator is a Column Adder, which is to say, it can only add numbers of one digit -- as when summing up the long columns of numbers in accounting work: you add the units first, note the result and the carry, add the tens and the carry next, and so on. Rather

The Adix calculator by Pallweber and Bordt

Click photo to enlarge

limited, but faster perhaps than using your head for long sums -- especially when you note that this device has a true keyboard, instead of the cranks, slides and dials of other small adders of its era. Depress any key, and the result readout instantly increments by the appropriate number.

Click a photo to enlarge

The mechanism is fairly simple: The depressed key pushes to the right the serrated plate under it (tinted red in the photo below). The cutout under each key has a different slope, so the plate gets

pushed a distance proportional to the number keyed in. The plate in turn pushes the wire rod (tinted green) which rotates the crank arm (blue) through an angle proportional to the key’s number. The crank is loosely coupled to the large brass cogwheel, but this stays put because of the ratchet action of the spring (yellow). Then, when the key is released and the rod and crank move back, the cogwheel does turn with the crank, and in doing so increments the units gear of the result readout. Carry from units to tens and so on happens through the gearing you’d expect.

Click photo to enlarge

This charming device was actually quite modern for its time. Made in Mannheim from 1903 by Pallweber and Bordt, it is the first application of that new material, Aluminum, to computing machinery. It was made in a number of models, and this is the first one to include a Reset mechanism, the lever at top right. Strangely, and by design, this lever only zeroes two digits of the result readout; one must first add the ten’s complement to bring the units digit to zero, then pull the lever to clear the higher two digits. This is still better than the earlier models, which required you to twiddle the large brass gears while depressing the “1” key in order to zero the readout; this required access to the gears, which is why the mechanism was not enclosed. Later models have a Bakelite cover over their innards -- efficient, but much less pretty...

		Exhibit provenance: eBay, from a seller in the Adix's country of origin, Germany. More info: A scan of the (German) instructions for this little marvel is available here.

Blue Velvet