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84
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Apparatus for demonstrating the earth-moon relationship, uns…
See original version (French)
84
-
Apparatus for demonstrating the earth-moon relationship, uns…
See original version (French)
Estimate €2,000 - €3,000
Voluntary lot
Description
Apparatus for demonstrating the earth-moon relationship, unsigned
Ottoman Empire, early 20th century
Brass and printed paper.
W. 32.5cm (12.8 in.); H. 39cm (15.4 in.)
A rectangular base with four curved legs holds a candle, representing the sun, in front of a reflector. Opposite the sun is a horizontal disc on which is glued a calendar of the European months printed on paper. In the centre of this disc, a second disc with a calendar of the months of the Hegira lunar calendar is mounted with its mechanism at an angle of 23.5° (the obliquity of the ecliptic). It carries a globe around which a small sphere representing the moon rotates and should thus represent the earth. However, the globe currently in place is an Indo-Persian celestial globe from the late 19th century, which calls into question the operation of the instrument. In principle, when a ray of light is projected onto the globe [of the earth] and the gear system set in motion by means of a small crank placed at the foot of the candle post, the movement of the moon around the earth, and phenomena related to it, such as eclipses, are indicated in both calendars.
The names of the months on the horizontal printed paper are direct transcriptions of the European (French or English) names of the Christian calendar. The names on the inclined plate bearing the globe are the Turkish names of the Hegira calendar.
This demonstration instrument seems to have been made to illustrate lessons in an Ottoman secondary school. The mechanism needs to be revised, as currently only the celestial sphere turns with the crank.
Provenance
Private collection since 2000, acquired from an antique dealer in the South of France.
We would like to thank Mr Anthony TURNER, expert for the description of this lot.
A Sun-Earth-Moon demonstration apparatus, unsigned, brass and printed Ottoman paper, early 20th century
A rectangular base on four curved feet supports a candle representing the sun, set in front of a reflector. Opposite the sun, a horizontal disc is overlaid with a printed paper calendar of the European months. At its centre, a second disc inscribed with the months of the lunar Hijri calendar is mounted with its gearwork at an angle of 23.5° (the obliquity of the ecliptic). The inclined disc carries a globe - intended to represent the earth - around which a small sphere figuring the moon revolves. The globe currently in place is, however, a late 19th-century Indo-Persian celestial globe, which compromises the original function of the instrument. In principle, when a beam of light from the candle is cast onto the [earth] globe and the gearwork is set in motion by means of a small crank fitted at the foot of the candle support, the revolution of the moon around the earth and the related phenomena - including eclipses - are indicated on the two calendars.
The month names on the horizontal printed paper are direct transcriptions of the European (French or English) names of the Christian calendar. Those on the inclined plate bearing the globe are the Turkish names of the Hijri calendar. This teaching apparatus appears to have been made to illustrate astronomy classes in an Ottoman college or lycée.
See original version (French)
Auto-translation. Refer to original language for legal validity.
Pictures credits: Contact the Auction House
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