Very fine brass astronomical equinoctial ring with two brass circles with engraved foliage decoration, signed "Jean-Baptiste-Nicolas Delure A Paris", on the hanger ring. The meridian ring is engraved with a latitude scale 90-0-90 degrees, reverse with a scale for determining solar altitude and zennith distance, an equinoctial ring with obverse engraved with hour scale in Roman numerals, the central bridge with pin-hole sliding over calendar and zodiac scales, 100 mm diam.Jean-Baptiste-Nicolas De...

Maritime hourglass with blown glass bulbs, orange sand, junction ring covered with cord, the circular ebony frame with six turned baluster columns. The invention of the hourglass is attributed to an 8th-century monk in Chartres, France, with the marine sandglass appearing as early as the 14th century. In earlier examples, the bulbs were connected with a material such as putty or hardened wax, bound in leather, linen or string. From about 1720, the two bulbs were welded together over a brass bead...

Maritime hourglass with blown glass bulbs, orange sand, junction ring covered with cord, the circular ebony frame with six turned baluster columns.The invention of the hourglass is attributed to an 8th-century monk in Chartres, France, with the marine sandglass appearing as early as the 14th century. In earlier examples, the bulbs were connected with a material such as putty or hardened wax, bound in leather, linen or string. From about 1720, the two bulbs were welded together over a brass bead ...

Very fine marine parallel rulers in brass. The parallel ruler is the oldest and most traditional way to measure and trace routes and bearings. The principle is simple: the ruler is placed on the road to be measured and then, like a pantograph, the other part of the ruler is placed on one of the declination roses on the map to determine the angle. They are, essentially, two straight-edges hinged so that they maintain the same angle. By alternating the moving edge, and securely holding down the no...

A sloop compass in the original wooden box with lit. The compass with floating rose (Cardan system). Slung in gimbals, the east point is decorated and graduated in half points and decorated N & E points.The cardan suspension system, also called a gimbal, is a pivotal support that allows the rotation of an object about a single axis. If simultaneously assembled three rings, one on another by orthogonal rotation axes, an object placed inside the third ring always remains horizontal, regardless of...