Horizontal Sundial by Choizi of Paris, in Case


This oval dial made of silver has a bird-shaped gnomon that folds up. Holes in the dial and in the bird's eye may be for a string gnomon. The dial is calibrated from IIII to XII to VIII (with each hour divided into four parts) for a latitude of 50 degrees, from 5 to 12 to 8 (with each hour divided into two parts) for a latitude of 45 degrees, and from 5 to 12 to 7 (with each hour divided into two parts) for a latitutde of 40 degrees. Approximate latitudes for sixteen Eurpoean cities are engraved on the underside. The peg legs on the underside may have been aded later. The compass opposite the gnomon has its silver housing screwed to the back of the dial. The compass needle is metal; the cover glass. Only the four cardinal compass points are marked. There is a fleur de lis on the dial at Nourth.

The design of the overall dial is called the "Butterfield" style after Micael Butterfield (1635-1724), an English instrument maker who worked in Paris. The Choizi (or Choizy) firm made mathematical instruments at least as early as 1667 and existed into the 1700s.

The red leather case has a velvet lining and brass fasteners.


The Whipple Museum of the History of Science, Catalog 6: Sundials and Related Instruments, 1998, Part I, Section 6.

Date Made: ca 1740

Maker: Choizi

Location: Currently not on view

Place Made: France: Île-de-France, Département de Ville-de-Paris

Subject: MathematicsTimekeeping


See more items in: Medicine and Science: Mathematics, Science & Mathematics


Exhibition Location:

Data Source: National Museum of American History

Id Number: 1987.0707.02Catalog Number: 1987.0707.02Accession Number: 1987.0707Catalog Number: 330837

Object Name: Sundial, Horizontal

Physical Description: metal (sundial material)leather, cloth, metal (case material)Measurements: overall, closed: 1.5 cm x 5.6 cm x 7 cm; 19/32 in x 2 7/32 in x 2 3/4 in

Guid: http://n2t.net/ark:/65665/ng49ca746b4-af7a-704b-e053-15f76fa0b4fa

Record Id: nmah_1121542

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