With a regular simulation, whether analogue or digital, you create a mathematical model, and evaluate that model in some way to get a result, which hopefully matches the actual phenomena in whatever it is you were trying to simulate.
Here, it's more like instead of measuring the phenomena, they instead measured something that is physically related to that phenomena. There seems to be no modelling involved.
An analogue is a physical entity with the same physics as some other thing.
A straightforward engineering example would be scale model of an airplane in a wind-tunnel.
> The MONIAC (Monetary National Income Analogue Computer), also known as the Phillips Hydraulic Computer and the Financephalograph, was created in 1949 by the New Zealand economist Bill Phillips to model the national economic processes of the United Kingdom, while Phillips was a student at the London School of Economics (LSE). The MONIAC was an analogue computer which used fluidic logic to model the workings of an economy. The MONIAC name may have been suggested by an association of money and ENIAC, an early electronic digital computer.
