Lot 382

De la Combe, 183 mm, circa 1816
An instrument to calculate the equation of time
Case: wood, brass. Dial: glass.
The equation of time, i.e., the discrepancy between solar time and mean solar time known from astronomical pendulum clocks can be calculated here for the whole year, using the adjustable date hand. The scale "Soleil retarde / Soleil avance" displays the discrepancy during the year, with time being slow up to circa 15 minutes in February or in advance up to circa 15 minutes in November. The construction is fitted with the same kidney-shaped disc that is generally used in timepieces.

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