Maker, unknown, France, c. 1815. Inverted Y-frame great wheel skeleton clock with large second beating balance wheel driven by a pinwheel escapement and sweep second hand.

An extremely thick, just over 3/8", inverted-y shaped framework with heavy pillars. The outstanding finely-cut and finished wheelwork has double screwed collets and spokes terminating in hoops. The balance, 3" in diameter has its rim chamfered between the feet of the crossings, to give the appearance of alternately bright and matte, producing an attractive effect when the clock is in motion. The pin-wheel escapement drives the second beating balance wheel, incorporates Lepaute’s pallet arrangement, is set for beat by a threaded weight, has a pivoted fast/slow arm that engages the balance spring and has steel end-caps on the two top wheels. The train wheels are further embellished by finely executed turned lines close to the roots of the teeth. The whole stands on an ormolu mounted duble-stepped white marble base on four baluster feet. The second wheel, which is in parallel to the balance wheel, is also 3" in diameter. The center wheel of 4" in diameter, lies behind the chapter ring. Through the center of this ring may be seen the motion work, the pallets, and the escape wheel. The great wheel is 7" in diameter.

The escape wheel is concentric with the center wheel and lies behind it. It is separated from the center wheel by a cock in which runs the inner pivots of both the center and escape pinions. The brass escape wheel has staggered, round section pins at right angles on both sides, being a form of pinwheel lever.

There is no draw and the pallets are very carefully counterpoised and separately cocked, two cocks with banking pins being employed. The pallet arbor is planted on the line of centers above the pin wheel. The effective length of the flat steel balance spring is adjusted by a slider which carries curb pins.

There are two other known examples including one from the Major Heathcote collection pictured in several reference books including: Continental and American Skeleton Clocks by Derek Roberts, Fig. 62, pg. 76., Skeleton Clocks, F.B. Royer-Collard, Fig. 5-12, pg. 77.