Counting the Cogs – The Mystery Machine

Today I attended a meeting of the Sea Level and Ocean Climate group at the National Oceanography Centre, Liverpool, where Professor Philip Woodworth gave a short talk about tide prediction machines.

Prof Woodworth started with a brief history of tide predicting machines. The concept was demonstrated by Sir William Thomson (later Lord Kelvin) but Prof Woodworth argued that Edward Roberts should also be considered for the title of ‘Father of tide predicting machines’. Roberts was a mechanical engineer who built many of the machines put into use. Only around 25 machines were ever built and 20 of them were made in Britain. The very first machine is now in the Science Museum in London.

One of the very interesting aspects of the talk was a bit of detective work that Prof Woodworth and his colleagues had been involved in. I blogged recently about a film of a tide predicting machine that we’d had digitised; this machine was initially thought to be the Roberts-type machine currently in storage in Liverpool. However, upon closer inspection (including carefully counting the gears) it transpired to be a mystery machine. The Roberts machine in Liverpool could analyse 42 tidal constituents but the machine in the video only had 30 wheels. After a lot of questions and emails Prof Woodworth discovered that the machine in the video was actually a Roberts-type machine that had been built for the Soviet Union, which ended up in Moscow.

Other tidal prediction machines are preserved in museums around the world. These include the biggest machine ever built, in the Deutsches Museum in Munich.

Prof Woodworth is now investigating where the other missing machines are and if they are still in working order. He has started to contact the various agencies around the world who were known to operate them. We hope to get the Roberts or Doodson-Légé machine back out on display in the future.

Model tide predicting machine

The photo is of a functioning model of a tide predicting machine built by engineers at NOCL to illustrate the principles of a machine. The model was running at the talk.

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