A duplex pocket watch movement, George Allen, London, early 19th century The gilt full-plate fusee movement with column pillars and duplex escapement incorporating jewelled pivots for the escape wheel arbor and three arm gilt balance with screw timing weights and faceted diamond endstone, the backplate with removable mainspring bridge, balance cock incorporating regulation sector and signed George Allen, Red Lion Pafsage, HOLBORN and numbered No. 2166, the circular white enamel Roman numeral dial with subsidiary seconds dial and spade hands, the dial plate 4cm diameter. George Allen is recorded in Baillie G.H. Watchmakers & Clockmakers of the World as working from Red Lion Passage, London 1805-24. The single-wheel duplex watch escapement employed in the current lot is to a design developed in its final form by Thomas Tyrer, who patented it in 1782. The duplex escapement is a form of frictional rest escapement which when properly set-up can achieve a very good rate, however it can be temperamental due to its tight tolerances and susceptibility to shock. The duplex escapement was subsequently generally superseded by the more reliable lever escapement which was further developed and refined during the first decades of the 19th century.