194 issimply divicU-cl in degrees, marked quadrantly from north, go0 o= go!! o° 9o°.
Four cardinal points are named. From north to south runs a semicircular wire
meridian carrying a movable pointer.
The accounts show that on 24 November, 1792, the instrument marker Van Laun
was paid ƒ 32, which may have been for the construction of this stand. The Inventory
records a 6-inch diameter terrestrial globe (75/5) separately from the stand by Van
Laun (75/3). The construction of the stand was probably inspired by the Adams
armillary sphere, which also has an adjustable horizon ring; see Gat. 94.
Inv. 75I3, 75I5
9a TERRESTRIAL GLOBE 1789 & 1791 (726) Fig. 100, 101, 102
By Gedrge Adams, London, and Dudley Adams, London
Signed on the calendar plate: G. Adams, Mathematical Instrument-Maker TO
HIS Majesty. Fleet Street, LONDON.
Signed on the globe: Made by D. ADAMS, Globe-Manufacturer & Mathemati.
Instrument Maker, Charing Cross, London. 1789
Diameter of globe 455) height of stand to calendar plate 900, overall height 1,300;
diameter of calendar plate 460, diameter of hour dials 174.
The globe, presumably of pasteboard covered with plaster of Paris, has a map of
twelve gores printed from engraved plates and coloured; there are no separate pole
disks. The globe is set on a polar mounting above the calendar plate, which represents
the ecliptic circle and is inscribed with circles of months and days, the degrees and
signs of the zodiac, and the sun’s declination. Above this plate are two dial plates
with gear wheels that cause a pointer to move across the dial when the globe is
rotated. The dials are divided into twice twelve hours, and each hour into five
minutes, the six o’clock line making two sections inscribed Day and Night. The dials
are also divided into degrees of longitude, marked from 0° to 1800 between the
twelve-o’clock positions. The dial on the polar axis has a movable index so that the
time and difference of longitude can be read for any two places on the globe. Below
the calendar plate is a movable arm, which, when set to the day, points out the sun’s
place in the ecliptic. At one end of the arm is a pillar with a brass ball representing
the sun with a wire pointer to represent a ray of light. At the other end
of the arm a second pillar, opposite the sun, supports a vertical circle that shows the
limit of the illuminated part of the globe, and behind this, 180 distant, is a parallel
circle that represents the limit of twilight. Attached to the arm is a horizontal ring
divided into the days of the moon’s age. Around the globe is a loose-fitting horizon
circle with a meridian circle set at right angles, both circles being divided in degrees.
The globe is supported on a fluted, mahogany tripod stand which is enclosed in a
glazed hexagonal-shaped case that was designed by Leendaert Viervant, the architect
of the Oval Room.
The letters from Adams to Van Marum reveal some of the difficulties that had
to be faced by manufacturers at this time. In his estimate of 8 December, 1789,
Adams quoted a price of £ 37 for a 18-inch globe on a new mounting with a
wooden foot, or £ 43 to £ 44 with a brass foot. The quotation for a celestial globe
x99