Rare French platinum and gold cylinder pocket watch Circa 1824

Platinum and gold hunting cased pocket watch
–
A very fine and extremely rare French, platinum and gold hunting cased and English-type ruby cylinder escapement, circa 1824. Sold to Monsieur P. Condurat on April 27, 1824, for 1,600 Francs. Yellow gold engine-turned covers, platinum body with an engine-turned band. Gold cuvette with the aperture for the winding and regulator. Silver dial by Tavernier, engine-turned, brushed chapter ring with radial Roman numerals, outer minute chapter with dot indexes. Gold Breguet hands. A frosted gilt movement, standing barrel, English-type steel cylinder with ruby insert escapement, plain three-arm balance with blued steel flat balance spring, index regulator via the cuvette. Dial and cuvette signed.
–
Diameter: 41 mm
–
Signed: Breguet  Paris
–
Breguet used the cylinder escapement throughout his life. Like the virgule, it is a frictional rest escapement but of a far superior kind. In reality, the cylinder escapement as made by the English makers was not much better than the verge. This was because the diameter of the cylinder was too great in relation to the diameter of the balance, causing a loss of energy through friction. To reduce the friction, the English makers, who were very skilled in the art of jeweling, made the cylinder half-section ruby. The ruby was fitted into a steel frame it was this form of cylinder escapement first used by Breguet.
–
The present watch is only the second known survivor of a Breguet watch fitted with this escapement. By about 1795 Breguet had developed the ruby cylinder to the very familiar overhanging ruby cylinder; it is therefore rare to find this escapement at such a late date and perhaps this indicates that the movement was constructed in fact many years before it was cased and sold; the lack of pare-chute and compensation curb would also suggest this. These escapements performed so well and with such increased consistency of rate that temperature errors previously swamped by general bad performance now needed correction. For this reason, except in his smallest watches, Breguet’s ruby cylinder escapements use a compensation curb.