Planétaire de François Ducommun, coll. MIH
Pendule à oiseau chantant, Pierre Jaquet-Droz, coll. MHL
Pendule astronomique d'Albert Billeter, coll. MAHN

Scientific aspects


The Planetary Clock by François Ducommun
Musée international d’horlogerie, La Chaux-de-Fonds


Planet clock signed by François Ducommun (1767-1837), La Chaux-de-Fonds, 1816. The mechanism includes the planetary system and a perpetual calendar, both activated by a handle. The central movement represents the solar system as it was understood at the start of the 19th century: the sun is surrounded by seven planets and their satellites. It shows the periods of revolution, rotation and the apsides.

The mechanical section is protected by two hemispheres formed of sheets of paper glued then decorated with the signs of the zodiac and the constellations. These oil-painted designs have been attributed to Charles-Samuel Girardet (1780-1863). The upper hemisphere can be raised to uncover the mechanism. The assembly sits on a wooden support mounted on castors.

  • Overall dimensions: Ø120 cm / height: ~145 cm closed
  • The work has been part of the MIH collection since 1917 and is listed under number V-12.


Songbird pendulum clock by Pierre Jaquet-Droz 
Musée d’horlogerie du Locle, château des Monts


A large-scale imposing and majestic pendulum clock in the Empire Egyptian Revival style. The mahogany cabinet is adorned with perfectly carved decorative elements from the Napoleonic Empire, in gold-plated bronze. Displaying a very high level of workmanship, the elements represent sphinxes, winged victories, busts with Egyptian hairstyles, swans and lotus leaves. There are two hands, both in the oriental style. The movement, powered by a double fusée and chains, sounds the hours and quarter hours on two bells.

The escapement has a crown-wheel. The brass plate bears the signature "Pierre Jaquet-Droz à La Chaux-de-Fonds".

The birdsong is produced by a serinette with a pin barrel, housed in the upper section of the clock. This instrument can play six different airs on ten flutes. During the melody, the bird pivots on the spot, opening its beak, shaking its tail feathers and puffing up its chest. The motor mechanism for the serinette is located underneath the clock movement.

These two mechanisms are connected by a small belt. The serinette can be made to start playing manually, as desired, by pulling the small cord located on the left of the clock or activated automatically to sound every hour. A small lever, placed on the right hand side of the cabinet, is used to select one of the six available airs. A second lever, underneath the first, is used to activate the serinette or to silence it, for example during the night.  

  • Dimensions: height 92.5 cm, width 43.3 cm, depth 27 cm
  • Materials: wood, bronze, brass, feathers and enamel


The astronomical clock by Albert Billeter
Musée d’art et d’histoire, Neuchâtel


Longcase clock with time and astronomical complications signed Albert Billeter 1840. Probably produced in La Chaux-de-Fonds, the time mechanism includes a pin pallet escapement and a balance, keeping time to the nearest second with mercury temperature-compensation. The cabinet is made from wood and glass.

The astronomical indications are displayed via a base plate made from brass which supports small dials with enamel cartouches. The displays are as follows:

  • Mean time
  • Legal time
  • Equation of time
  • Complete date (date, day, month and year)
  • Signs of the zodiac
  • Central seconds, marked by enamelled discs around the circumference
  • Lunar cycle

An enamelled cartouche at 6 o'clock gives the name of the clock's manufacturer "Verfertigt von Albert Billeter" .

The winding system was modified at a later date to run on electricity and the chime and the perpetual calendar's return system are missing.

  • Overall dimensions: height 219 cm, width 69 cm, depth 43 cm.

This object is part of the collection at the Musée d'art et d'histoire in Neuchâtel and is listed under number AA 5004.