Beschreibung:

A particularly fine and unusual horary quadrant to the design of Edmund Gunter (1581-1626)
A particularly fine and unusual horary quadrant to the design of Edmund Gunter (1581-1626), signed and dated: Tho: Poole Nottingham 1689 . Brass; overall radius 133mm (5.2in), radius of scale 121mm (4.7in), thickness 1-2mm. Engraved at the centre with Latitudo 53 d 0' ; the modern value for Nottingham is 52° 57'. Edmund Gunter received his MA from Christ Church, Oxford, in 1606, and was Gresham Professor of Astronomy from 1619 to 1626. In 1624 he published Use of the Sector, Crosse-staffe, and other Instruments , which included an Appendix where he described his design for a horary quadrant. The use of such an instrument is given in M. Cowham, A Dial In Your Poke (Cambridge, 2004, pp 33-37). Front At the apex of the present instrument is a cartouche with the signature and date, and a perpetual calendar in a rectangular frame. Spaces are filled by ornamental bands. Next is a curved scale of the months of the year in four bands, from 23 September to 10 March. The scale is in days alternately shaded. On the straight left side is a non-linear scale of Hours , divided in twentieths. On the straight right is a non-linear scale of degrees of Lat (Latitude), divided in half-degrees. This edge carries the pair of pin-hole sighting vanes, used in conjunction with a silk thread hanging from a very small hole at the apex of the diagram (thread, plummet and sliding bead are missing). Adjacent to this hole is a larger one for a cord. At the bottom is a curved degree scale used with the plumb line. It is divided in single degrees alternately shaded. Across the face are various sets of curves. Originating from the top left corner are two arcs representing two sides of the Ecliptic Circle, the positions of the Signs of the Zodiac picked out by their sigils. At the middle of the face is a curve labelled Suns Declin divided in twenty minutes from zero to 24 degrees. Below this arc are two more sets of lines reading hours from 12 to zero. The curves by changing direction reach another scale at the bottom; a similarly spread-out set of curves read from 10 to 90 degrees. Back The nocturnal is of the pictorial type,with a volvelle (diameter 89mm 3½in), moved by the fingers using two small studs across a diameter. On the edge are two circular scales, the outer divided in months and subdivided in days, alternately shaded. Each month is named in italic letters in full or abbreviated according to the space available. The inner scale is divided into 360° alternately shaded. The 360° position cuts the outer scale at the tenth day of March, the Vernal Equinox. The volvelle rotates within a circular scale of the hours of the day that is engraved on the base plate, the hours are numbered twice XII in roman numerals. Each hour is divided in halves, quarters and sixths, the latter alternately shaded. On the face of the volvelle are representation of sixteen or more constellations, each skilfully engraved and with the star positions shown by asterisms sized for magnitude. The constellations include: Ursa major, Cor Caroli, Leo, Gemini, Auriga, Perseus, Triangulum, Taurus, Pegasus, Draco, Cancer, Virgo, Deneb, Hercules, Casssiopeia, Corona borealis. The prominent figure of the crowned heart of King Charles II is unusual. That name is not used for the constellation, but for the {alpha} star in the constellation Canes Venatici. It was proposed by Sir Charles Scarborough (1616-1694), physician to Charles II on his return from exile to London on 29 May 1660, claiming the star shone with special brilliancy on the day (R.H. Allen, Dover edn, 1963, p.115). At the top of the plate and on the sides are human figures, astronomical instruments, and a calendrical table in two parts. The vignettes are a globe on a stand showing meridians with two men viewing the horizon, and a man on a high-backed chair holding a compass over a table; a large cube-dial with a man pointing to the gnomon; a large terrestrial globe with a man holding a long pointer. Other spaces are filled