SJX Watches
Chronicles of Precision: The Quest for Equation of Time Part II
Continuing from part I of the history of the equation of time. In the late 17th century, London’s clockmaking landscape experienced a remarkable surge of innovation and collaboration, fuelled by interactions among prominent horologists and the broader scientific community. Among this period’s leading figures were Christian Huygens and Robert Hooke, who made substantial strides in crafting clocks that could precisely display solar time without the need for cumbersome equation tables. This era marked the advent of the equation cam, a revolutionary mechanism designed to reconcile the disparities between solar time and mean time. Inspired by the analemma-a figure-eight pattern illustrating the Sun’s varying positions in the sky throughout the seasons-these mechanisms featured a distinctive mathematically calculated kidney-shaped cam, symbolising a pivotal step forward in horological precision and accuracy. At the heart of this innovation lies the cam and lever mechanism, an integral component of the invention. It comprises a shaft propelled by the clock’s mechanism, completing a full rotation annually. Affixed to this shaft is a meticulously crafted kidney-shaped cam, tailored precisely to match the annual fluctuations outlined by the equation. This cam engages with a follower and a connected lever, facilitating the seamless translation of its rotational motion into practical adjustments within the timepiece. Drawing of an equation pendulum by Ferdinand Berthoud (1...