Scroll the diagram sideways to see the whole machine.
The MONIAC (Monetary National Income Analogue Computer) was a hydraulic computer built in 1949 by the New Zealand economist Bill Phillips at the London School of Economics. Coloured water stood for money flowing round the economy, and pumps, tanks, valves and cut-out curves modelled income, spending, taxes, trade and interest rates, so students could watch the effect of a policy change play out on the machine. About a dozen were built, and a few survive in museums and universities. This page is a replica of the fuller version Phillips described in his 1950 paper in Economica (Fig. 4): read more on Wikipedia. Phillips, A. W. (1950), “Mechanical models in economic dynamics”, Economica 17(67), 283–305.
This is the first beta release, and there will be rough edges. It was developed with the help of a large language model. Hover over any label, tank or curve plate for an explanation of what it is and what it depends on. The controls on the right allow you to run your own experiments on the machine, or any of several built-in experiments. This page is best viewed on a desktop and will not be useable on a small screen like a phone.
Scroll the diagram sideways to see the whole machine.