Accession No

0662

Brief Description

horizontal inclining dial, by Johann Engelbrecht, Czech, 1785

Origin

Czech Republic; Beraun

Maker

Engelbrecht, Johann

Class

dials; horology

Earliest Date

1785

Latest Date

1785

Inscription Date

1785

Material

metal (brass)

Dimensions

breadth 128mm; height 108mm

Special Collection

Robert Whipple collection

Provenance

Purchased by Robert Stewart Whipple from Antique Art Galleries, Grafton Street, London, England, on 12/02/1931.

Inscription

‘Fecit Iohannes Engelbrecht, 1785’ (signed at southern end)

Description Notes

horizontal inclining dial, by Johann Engelbrecht, Czech, 1785

Brass; 3 levelling screw feet; dial plate calibrated IIII-XII-VIII by 1 to 15 and marked with 4 cardinal points ‘ME:OC:SE:OR’; hyperbolic shadow length lines calibrated by zodiacal sign, subdivided to 10 days and marked with relevant day of the month; (1st Aries March 21); folding gnomon of 50o angle with plumb-bob turning over latitude scale of 40-60 by 10 to 1o; gnomon incised on face and marked ‘a’.

Condition: good.

[NOTE: On 15/04/2015 XRF analysis was conducted on this instrument. Results and analysis are given in the ‘Notes’ field.]

References

Events

Description
The horizontal dial is the most common form of sundial. The portable version proved very popular with the upper classes during the 19th Century. During this period it could best be described as the wristwatch of its day.

The hour lines are engraved onto a horizontal surface, with a gnomon (pointer) in the centre. Seasonal variations (caused by the earth’s orbit being elliptical, not circular) have to be compensated for, as they can affect the raw reading by up to 18 minutes.
18/10/2002
Created by: Saffron Clackson and Boris Jardine on 18/10/2002

FM:39841