Retrotechtacular: MONIAC

There is an argument to be made that whichever hue of political buffoons ends up in Number 10 Downing Street, the White House, the Élysée Palace, or wherever the President, Prime Minister or despot lives in your country, eventually they will send the economy down the drain.

Fortunately, there is a machine for that. MONIAC is an analogue computer with water as its medium, designed to simulate a national economy for students. Invented in 1949 by the New Zealand economist [WIlliam Phillips], it is a large wooden board with a series of tanks interconnected by pipes and valves. Different sections of the economy are represented by the water tanks, and the pipes and valves model the flow of money between them. Spending is downhill gravitational water flow, while taxation is represented by a pump which returns money to the treasury at the top. It was designed to represent the British economy in the late 1940s as [Philips] was a student at the London School of Economics when he created it. Using the machine allowed students and economists for the first time to simulate the effects of real economic decisions in government, in real time.

So if you have a MONIAC, you can learn all about spectacularly mismanaging the economy, and then in a real sense flush the economy down the drain afterwards. The video below shows Cambridge University’s restored MONIAC in operation, and should explain the device’s workings in detail.

We’ve featured more than one analogue computer here at Hackaday over the years, but this is the first water-powered one. There was a 1959 commercial offering for example, or tide prediction computers, Enrico Fermi’s beautiful-in-simplicity Monte Carlo simulation calculator, and an analogue computer tutorial from our colleague Bil Herd.

Thanks [Josh] for the reminder.

Header image: Marcin Wichary [CC BY 2.0], via Wikimedia Commons.

26 thoughts on “Retrotechtacular: MONIAC

    1. I have a bathtub too .. I should now call it, my “Water Integrator”,

      It can also integrate three times to display my Volume, but the reading is difficult when you need to stay submerged to get the total body volume ..


        1. thanks for the read.

          pardon me for being funny ;)

          As a mechanical engineer I do really like the “ancient” ways of solving a problem elgantly and not go brute force on it (brute force = FEM, CFD, Coupled Solvers)

          I can only recomend that every mechanical engineer should posses a 1930s edition of Stephen Timoshenko’s
          “Vibration problems in engineering” (or in german “Schwingungsprobleme der Technik”).

          Which is also about describing systems with differential equations and solve those,

      1. I like to think that eventually Hex was linked to the Glooper, thus creating the Inter-tubes*.

        *The tubes, of course, are how the ants and water traveled from one system to the other. One of the biggest engineering challenges was how to interface between the two, with the final solution being powered by thirsty ants.

    1. That is no accident. Terry Pratchett was a clever, wonderful author who always tried to slip in something educational into everything he wrote. History, Math, Science and Art were all fair game.

      It’s like finding the hidden Mickey Mouse in every Disney movie, but better! You always learn something, surreptitiously.

        1. Was Pulp Fiction a Disney one? I remember something absurd like that due to them or one of their subsidiaries acquiring a studio, may have been a different “very un-disney” movie though.

  1. In my opinion, this analog computer is a great teaching tool. Direct showing of changes is much better than just entering the numbers into a formula and getting the result.

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