An historically interesting late 16th/early 17th-Century Italian brass Horary Quadrant,

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TIME-MEASURTING INSTRUMENTS

Details

An historically interesting late 16th/early 17th-Century Italian brass Horary Quadrant,
unsigned and undated, for use at the latitude of around 45° -- 6.8cm. (2¾in.) radius; 0.1cm. (0.04in.) thick

See Illustrations

Side A: This is a conventional Italian horary quadrant of the type produced in the 16th and 17th centuries. The outer curved edge is divided in 5° intervals, numbered in fives, 0-90°. Subdivision to 1° has been attempted but inaccurately. The time is read in Italian hours, counting from 9 at sunrise to 24 at sunset. Half the lines are continuous and the other half are dotted according to the time of day, dotted lines being for the afternoon. Across the middle is the equinoctial line. The set of hour lines is flanked by calendar and zodiac scales. The names of the month are in Latin, some abbreviated. Sigils are used for the Zodiac scale. There is a cartouche, outlined in strapwork, with the following wording: QVADRANS OMNIV. HORARVM AD ELEVAT. POLI. GR. 45. Below is the inscription: Cõ Scala Altimeta et Planimetra. At the apex is a plain rectangle with the interior edges marked in units from 1 to 12, alternately shaded. On a ribbon is the inscription: VMBRA RECTA VMBRA VERSA. Inside this shadow square is a faintly scratched figure of an armillary sphere.
There are two simply-made sights. The upper edge of the plate has been cut to leave a pair of protruding lugs, one at each corner. Each lug has fitted over it a sight vane in three sections which are soldered above the sighting hole and pinned to the lugs each with a single rivet. The front vane has a pierced knob at the top with a suspension ring through it. From the apex of the hour diagram hangs a string plumb-line with a heart-shaped brass weight at the end. On the string runs a small brass bead. In use, the sight vanes align with the object, the plumb-line gives the angle of altitude, and the bead is moved to the time of year given by the zodiac or calendar. With the string hanging free, the bead cuts the hour line at the required time.
Side B: This is a curiosity. The 90° arc, the hour diagram, and the names of the month are labelled in mirror image, as are the numbers on the degree scale, the hour scale, and the shadow square. Inside the shadow square is a fully engraved outline of an armillary sphere, similar to that scratched on side A, but in reverse. The reversed letters and numbers are engraved, but perhaps not in the same hand as side A.

Literature

For some similar aspects of Italian horary quadrants, see:
TURNER, G. L'E., 'The Florentine Workshop of Giovan Battista Giusti, 1556-c. 1575', Nuncius: Annali di Storia della Scienza, 10, fasc. 1 (1995), pp 131-172

Special notice

No VAT will be charged on the hammer price, but VAT at 17.5% will be added to the buyer's premium which is invoiced on a VAT inclusive basis

Lot Essay

It is not uncommon on Italian-hour quadrants for the reverse side to be left blank, or to have calendrical information. What is unusual here is to have the same information as on the front, but in mirror image. Again, the shadow square can often be left blank, but here the image of an armillary sphere has been lightly sketched within the square on side A, while on the reverse, the armillary has been engraved deeply, but in mirror image. It is pointless to speculate on the reason behind this curiosity.

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