Mechanical Calculating Device (Boing Boing Flickr Pool)


"Mechanical Calculating Device," a photo contributed to the Boing Boing Flickr Pool by BB reader sicsnewton, in Flagstaff Arizona.


  1. That’s a Millionaire Calculator, which was designed by Hans Egli company. It was designed by Otto Steiger in the late 19th century. The Computer History Museum has several of them, there were at least two slightly different designs.

    As I understand it, the name came about much the same way that Tombstone, Arizona got it name. Someone supposedly said “You’ll never become a Millionaire selling numbers” and that’s where the name came from.

    They’re great machines, it’s possible to do division which was the machine’s claim to fame.

    1. Not sure if serious?

      It runs on nothing, and is mechanical. I imagine those slides and knobs are used to enter the equation, and the crank on the right then is used to get the answer.

      I really REALLY want a Curta. It is such and elegant, very well crafted thing. They aren’t super duper expensive, but I don’t have the extra funds right now. Hey – my birthday is coming up and I have a paypal account.

  2. Hand-cranked. See crank on right side. I’ve gotten to see some of these early calculating engines in action at the Computer History Museum in Mountain View, CA and it’s amazing what you can do with gears and a hand crank :).

    1. I bet somewhere, there’s a Curta in a junk bin for $1 because someone thought it was a weird fishing reel.

  3. These would come in super handy during that apocalypse I keep hearing so much about! It’s comforting to know that come zombie, nuclear winter, 2012… I could still do my taxes.

  4. I did a double take when I saw this photo. I saw this exact device while at the Observatory last Friday. The room it was in was chock full of antique SCIENCE, all dark wood and brass.

    Totally worth a visit if you’re in the area.

  5. This is the Millionaire Calculator, make around 1899 to 1910 by Otto Steigler in Zurich, Switzerland.

    I’ve restored one, and a good friend of mine, Chris Hamann, is now rebuilding two of them. Chris discovered that the calculators do not have fully interchangeable parts – craftsmen had custom made individual parts for each calculator!

    The Millionaire calculator is amazing because it does single digit multiply and divide with a single turn of the crank. The multiply table (2×3=6) is built into the machine through a collection of brass rods, each rod’s length and position corresponds to a position in the multiply table.

    One turn of the crank does a single multiply and advances the carriage. It’s exciting to use, since you feel the gear and carriage motion as you turn the crank. Unlike the precision Curta, turning the crank on the Millionaire takes a bit of effort (though not as much as cranking Babbage’s analytic engine which requires serious arm motion!

    It’s perhaps the exact opposite of the miniature Curta calculator, yet quite complimentary. The Millionaire weighs about 70 pounds; the Curta weighs about 8 ounces. For all its elegance, the Curta doesn’t do single-crank multiply/divide (multiplication on the Curta is a series of additions – with very sweet shortcuts).

    A comparison between the Millionaire and the Curta shows the amazing progress in miniaturization that happened from 1900 to 1950.

    Here’s a view of the two disassembled Millionaire calculators. Check out the bottom photo to see the solid brass multiply matrix.

    Warm cheers to all!
    -Cliff (and Chris Hamann)

  6. Ah, yes… from the bygone days when accountants sported green eyeshades, grease-stained dungarees, blue collars, rough calluses, massive biceps, and membership in both the Teamsters and the Steamfitter’s Union. The machinists of today are CAD-poking clammy-palmed pantywaists by comparison.

    1. No massive biceps on the operators of this machine, though. During this era, the word “computer” referred to the woman who did the calculations and recorded the results. They still make today’s workers look like CAD-poking clammy-palmed pantywaists, though.

  7. Oh hey. I won two Klein bottles off of Cliff Stoll just by using one of these last January. Really great fun; though you need external book keeping to compute, say, √2 on it. Newton-Raphson FTW.

  8. The wear marks on this are really interesting. It’s difficult for me to imagine how this thing was used.
    The Science Museum in South Kensington has a myriad of devices like this, not to mention the Babbage engine. They also have Turing’s computer and the most draw dropping old Cray.

  9. I would dearly love to own a Curta, but they are in very short supply putting them beyond my means

    I have made a a fully functional hand-cranked Babbage Difference Engine and an Antikythera Eclipse predictor, both using LEGO:

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