Split-Seconds with Diablotine” L

“Split-Seconds with Diablotine” L. C. Grandjean, Locle, No. 3165. Made circa 1870. Very fine, rare, early and unusual 18K gold, hunting-cased, two-train keyless pocket watch with split seconds independent 1/4 seconds chronograph and "diablotine". Four-body, "bassine et filets", engine-turned and polished with reeded band, the interior of the front cover with engraved dedication. Hinged gold cuvette with engine-turned border, glazed gold-rimmed cover to view the movement. White enamel, three-piece, radial Roman numerals, outer minute track and fifths of a second ring with Arabic numerals 20-240, subsidiary 1/4 seconds "foudroyante". Blued steel Breguet hands. 20’’’, nickel plated, double train special caliber with tandem winding, 30 jewels, "fausses-côtes" decoration, counterpoised straight line lever escapement, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator. Split independent seconds chronograph with push pieces in the band. Diam. 57 mm. Notes Unlike watches with usual independent seconds mechanism, this watch can be considered a true chronograph with independent train, because the chronograph hands can be reset to zero. It can therefore be considered one of the first applications of the Adolphe Nicole patent front 1862 and one of the first developments of the split seconds mechanism for chronographs.