mechanical equatorial sundial
Datecirca 1840
Inventory Number7487
ClassificationSundial
Subject
Maker
Al. Zimmerman
Cultural Region
Place of Origin
Dimensionsopen - 45 degree, as photographed: 13.7 × 7.1 × 13.2 cm (5 3/8 × 2 13/16 × 5 3/16 in.)
closed: 2.9 × 7.1 × 13.2 cm (1 1/8 × 2 13/16 × 5 3/16 in.)
case: 4.4 × 15.2 × 9.9 cm (1 3/4 × 6 × 3 7/8 in.)
closed: 2.9 × 7.1 × 13.2 cm (1 1/8 × 2 13/16 × 5 3/16 in.)
case: 4.4 × 15.2 × 9.9 cm (1 3/4 × 6 × 3 7/8 in.)
Material
AccessoriesOriginal wood and brown leather case.
DescriptionEquinoctial dial with a continuous circular chapter ring marked I-XII, I-XII with a complex geared linkage to a smaller dial with 60 subdivisions. The linkage also engages an aperture that can be aligned with the sun. The vertical angle of the chapter ring is adustable from approximately 0° to 90° in 1° increments via a geared knob. The compass rose is divided into 4 points marked "N", "O", "S" and "W". There is an additional scale spanning 360° with 1° subdivisions.,Complex geared mechanical readout
mechanical equinoctial sundial
mechanical equinoctial sundial
SignedSigned "Al. Zimmerman" engraved on top side of dial support.
Inscribed"Erfunden durch" / "Joseph Ferchel" / "Konigl. bayr Geometer" / "Verfertigt. Al. Zimmerman" engraved om the bracket holding the chapter ring.
Curatorial RemarksAppraisal by Brieux, 9/24/84: $3000
MHS Oxford has similar but not so nice.
FunctionTime-finding by orienting the chapter ring to be parallel to the equinoctial with the aid of a magnetic compass and an angular adjustment for latitiude. The minute dial is then rotated about the chapter ring until the sun shines thru the peep hole and is centered on the line.
ProvenanceJoseph Drecker, Aachen, Germany, before 1928 (no. 106); Frederik Casparus Wieder, Noordwijk, The Netherlands, 1928; D. P. Wheatland, Topsfield, MA, 1959; gift to CHSI, ca. 1987.
Historical AttributesDial was invented by Joseph Ferchel.
English
Date: circa 1770
Accessories: Fitted red leather case with red cloth interior.
Object number: 7119
Claude Dunod
Date: circa 1725
Accessories: None. Unit is housed in a protective box
Object number: 7120
Jacobus Lusberg
Date: date 1688
Accessories: Oval green sharkskin fitted case and seperate plummet.
Object number: 7068
Swedish
Date: 1800
Accessories: ivory case with engine-turned engraving on top of cover
Object number: HO81Z-6
G. Winckler
Date: 1790
Accessories: Leather covered rectangular case and 4 leveling screws. Paper with calculations in pencil and printed "KUNSTAUKTIONSHAUS Math. Lempertz ...Koln " loose in case.
Object number: 7106
Thér Barrelet
Date: date 1793
Accessories: None. Plumb bob is missing.
Object number: 7114