Tide Analysers: The Machines That Ran Backwards
Predictors foretell; analysers dissect. How the rarer reverse machines extracted harmonic constants from gauge records — and why few were built.
Machines
Portraits of individual predictors: Kelvin’s ten-crank prototype, America’s 37-component No. 2, the rigorous Bidston instruments, Hamburg’s forgotten Gezeitenrechenmaschinen, and the rare analysers that ran the problem backwards. Each profile names what to look at when you visit the survivor in person.
German Gezeitenrechenmaschinen: The Forgotten Competitors
Hamburg's elegant answer to Kelvin and America: the German tide-calculating machines, their refined wire runs, and the engineers history overlooked.
The Bidston Observatory Machines and Arthur Doodson
Liverpool's Bidston Observatory rebuilt tidal science: Doodson's least-squares rigour, 60+ constituents, and the quiet machines that predicted for hundreds of ports.
Inside the US Coast Survey Machine No. 2: 37 Components Explained
America's 37-constituent brass giant (1912): how Harris and Fischer scaled Kelvin's idea to world-record size, and what each bank of cranks did.
How Lord Kelvin's First Tide Predictor Actually Worked
Inside the 1872 Légé-built prototype: ten cranks, one wire, and the first proof that brass could add the moon and sun into tomorrow's tide.
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