One of the most important models in the Jaeger-LeCoultre heritage, the Geophysic chronometer has an interesting history. The Chronometre Geophysic was created in 1958 during the official International Geophysical Year, an international scientific project that lasted from July 1, 1957, to December 31, 1958 where 67 nations participated in scientific exploration of our planet.
On August 1st 1958, the first ever atomic submersible vessel, named USS Nautilus in tribute to the fantastic submarine imagined by Jules Verne, set off in absolute secrecy with the unprecedented aim of making a submerged transit from one ocean to the other via the most direct route – meaning beneath the ice sheet covering the Arctic. After three days in submersion, the Nautilus made the transit without anyone apart from the crew being aware of this achievement.
Jaeger-LeCoultre was of course particularly proud of this feat and the part they played in this event in history. The original Geophysic featured a movement that had originated from military watches (Mark XI) and incorporated a hacking-seconds mechanism. The calibre 478BWSbr movement also utilised a glucydur balance for stability through changes in temperature and was fitted with a shock absorber; a “swan neck” index for micrometric adjustment; and the essential soft-iron inner case that protected the mechanism from the effects of magnetism up to 600 gauss. These attributes made it possible for the timepiece to be utilised during the expedition beneath the North Pole.
The Geo Reference featured a chronometer-grade, manual caliber P478/BWSBr movement, with 17 jewels, fitted with a spirale Breguet, including a stop-lever design that enables the wearer to hack-set the watch. In keeping with the spirit of the watch as a tool for scientists and explorers, the movement is not decorated, but it exudes an emphasis on accurate timekeeping rather than fine cosmetics. The movement of the Geo was directly descended from the Mark 11’s military grade JLC 488 SBr with some refinements, such as added shock absorption.
The Geophysic was designed with a double case and screw-back for water resistance. The inner case is made of “soft iron” to achieve magnetic resistance of 600 Gauss. The dial is pressure-fit with retaining screws at 4 and 11 o’clock.
In 2015 Jaeger paid tribute to this legendary timepiece and introduced three new models, one in stainless steel another one in pink-gold, and an exclusive boutique only model in platinum. Inspired by the original, all three draw on the design of the 1958 timepiece and further enhance this classic look, with a more contemporary appearance. The Geophysic 1958 features a larger case of 38.5mm than its historic predecessor, not only bringing it into realms of perfect in the modern era of watchmaking. The minimalistic case design is a thing of beauty and features polished lugs and bezel, with a brushed centre case. Turning the timepiece over you’ll see the beautifully embellished screw-down case back that plays with the J and L initials of Jaeger-LeCoultre superimposed on a globe crisscrossed by latitude and longitude lines. In true style of the original, the case back doesn’t afford any glimpse of the in-house JLC movement, though denotes the number of limited pieces and the inscription Geophysic, and Jaeger-LeCoultre. The Geophysic’s 1958 tribute is water-resistant to 100 metres.
Parthian Watch Company is a big fan of both the original and tribute Geophysic models. Visit our Jaeger leCoultre page and choose from the four outstanding examples we have to offer.