The enamel miniature on the back of the present watch represents Jacques Charles and the Robert brothers' flight in the hydrogen balloon "La Caroline" from Saint-Cloud to Meudon in France on 15 July 1784 together with M. Collin-Hullin and Louis Philippe II, Duke of Chartres. The project of "La Caroline" was to build an elongated, steerable craft that followed Jean Baptiste Meusnier's proposals for a dirigible balloon. The design incorporated Meusnier's internal ballonnet (air cells), a rudder and a method of propulsion.
Jacques Alexandre César Charles (1746 -1823) was a French inventor, scientist, mathematician, and balloonist. Charles and the Robert brothers launched the world's first (unmanned) hydrogen-filled balloon in August 1783, then in December 1783, Charles and his co-pilot Nicolas-Louis Robert ascended to a height of about 1,800 feet (550 m) in a manned balloon. Their pioneering of the use of hydrogen for lift led to this type of balloon being named a Charlière (as opposed to a Montgolfière which used hot air).
Innocently called "conversation piece", watches featuring a libertine scene have been highly popular since the late 16th century. Available with a variety of representations, either painted or automated, hidden or rather blunt as the present, such watches were amusement for the wealthy not only in Europe but also in the Orient, particularly in China.