Mechanical equinoctial and declinatory brass... - Lot 239 - Chayette & Cheval

  2. Result
  3. Mechanical equinoctial and declinatory brass... - Lot 239 - Chayette & Cheval
  4. Lot n° 239 
Lot n° 239
Go to lot
Estimation :
8000 - 9000 EUR
Result : NC
Mechanical equinoctial and declinatory brass... - Lot 239 - Chayette & Cheval
Mechanical equinoctial and declinatory brass dial, unsigned, Germany, mid-18th century. A rectangular plate with cut sides, supported on four wedge-shaped screws (one replaced), is fitted with a support for an A-shaped plumb bob (the plumb bob is missing). Inscriptions engraved on two sides of the plate: 'latus in muro meridionalis applicandum' (side to be applied to the south wall) and 'latus in muro septontrionalis applicandum' (side to be applied to the north wall). Between these two inscriptions, a circular plate engraved with a compass rose (with 32 named directions) rotates within a 360 degree scale (divided at one degree into four quadrants). The scale is engraved on the plate with Latin indications for their declinations. In the upper part, a circular serrated hour dial is mounted between two supports. The minute dial turns around the central dial (the needle is missing) to aim at the sun by means of the summit alidade. The circular plate engraved with the locations, the plate with a zodiac calendar and the alidade may be later. H. 33cm ; W. 23.3cm D. 16.1Ò cm. Provenance: Roussel Collection, Drouot Sale Paris, March 13-14-15, 1911, lot 198. Gertrude Hamilton Collection, n°135, reproduced under figures 135 fig. I and II. In spite of some suffering, this dial remains of the highest interest as it is the only example currently known where the functions of an equinoctial minute dial are combined with those of a declinator. Mechanical equinoctial dials were developed at the end of the 17th century. They became popular in southern Germany and in Central Europe because of their very accurate time reading (to one minute or less). Several examples of various shapes can be found in the National Museum of Technology in Prague, in the Huelsmann Collection in Bielefeld and in the collections of the Time Museum, Rockford, Illinois. The declinatories designed at the same time were used to measure the declination, East or West, of a vertical surface on which one wanted to draw a dial. One side of the instrument is placed on the wall, adjusted for the latitude and altitude of the sun. At noon, the orientation of the instrument indicates on the compass rose the declination sought (see the description in Nicolas Bion, Traité de la construction et des principaux usages des instruments de mathématiques, 1709, 304-5, plate 25, figure 3).
My orders
Sale information
Sales conditions
Return to catalogue