A fine George II lacquered brass, shagreen, and lignum vitae Culpeper double-reflecting compound microscope
Edmund Culpeper, London, circa 1730
With sliding brass shutter to eyepiece threaded into ogee shaped moulded lignum vitae top section above gilt-tooled green vellum covered draw-tube with inked focus staging lines sliding into a brass and lignum collared green rayskin outer tube and fitted with long tapered brass tube objective lens to lower section, the whole raised on three fine baluster turned supports with circular stage fitted with a slider clamp to central oculus and pivoted light condenser lens, the lower section with three further taller brass canted baluster supports over circular ogee moulded base fitted with pivoted concave mirror to the concentric ring decorated top surface, in original oak pyramidal box with an apron drawer containing frog plate, two additional objectives, five bone sliders and canister for glasses and brass wire retainers, a circular glass fish plate engraved with three concentric lines and signed Culpeper Fecit within brass outer rim and other items, the interior back panel applied with crossed daggers and instrument trade label inscribed E. Culpeper Sculp. London to lower left, (eyepiece holder incomplete, box lacking most of its mouldings and door lock) the instrument 36cm (14.25ins) high closed; the box 44.5cm (17.5ins) high excluding later ring handle.
Edmund Culpeper is recorded in Clifton, Gloria Directory of British Scientific Instrument Makers 1550-1851 as working 1700-37. He adopted the Crossed Daggers motif of his former master Walter Hayes to whom he was apprenticed in 1684. In 1706 Culpeper took over Hayes' shop located at The Crossed Daggers in Moorfields London, later moving to the Black & White House in Middle Moorfields in 1731 and finally Under the Piazza at the Royal Exchange, London, where he is believed to have remained until his death in around 1740. The Culpeper trade card shows instruments made by his firm, these included surveying devices, quadrants, sundials, globes, and optical instruments such as the screw-barrel microscope and spectacles.
Culpeper invented the tripod compound microscope sometime between 1725 and 1730, and made at least five major modifications in the years before his death. All models consisted essentially of two platforms, each supported by three turned brass pillars, with one set of pillars alternating in position with the other. The first model had platforms of wood. All later models, including the current lot, had brass platforms. Attached to the upper platform is a tube covered in stained shagreen. The microscope body draw tube, made from vellum covered cardboard, fits within the outer support tube. Focussing is accomplished by pushing the body tube up or down, with the position being maintained by friction between the vellum covering of the draw-tube and the inner surface of the support tube. There are also inked lines drawn on the body tube corresponding to the parfocal position of different objectives.
The current instrument has survived in fine original unrestored condition having been in the same family ownership for as long as anyone can remember. It also retains almost all of its accessories which include a glass fishplate scratch-engraved with Culpepers signature.
The tube is in good original condition with no noticeable splits to the turned section and moderate wear to the green-stained vellum section. The wooden plate at the objective end also appears free from damage as does the brass nosepiece. The objective lens currently fitted appears undamaged. Of the two additional objective lenses one is badly chipped and the other appears to have a flat glass insert. The eyepiece end is lacking its lens and the turned housing/carrier is incomplete (approx. 45% in two pieces is present), the brass shutter for the eyepiece is present. The internal large diameter field lens appears intact but is dirty/dusty. The distance between the eyepiece lens and the objective is 8.75 inches (22.2 cm approx.).
The outer tube is in good condition with no noticeable cracking or distortion. The brass elements retain original old surface albeit now worn and discoloured. The stage is complete with slider clamp and threaded ocular aperture insert into which the ivory cone ocular accessory can be screwed. The stage has a pivoted magnifier which appears undamaged as well as a friction forceps mount (no forceps present). The turned base also appears undamaged with no shrinkage cracks, warpage or unsightly chips to the edge. The plano-concave mirror has some discolouration to the silvering otherwise appears undamaged.
The box is structurally sound however is lacking the top edge mouldings to three sides and base moulding to all four sides. The door is also lacking its lock. Internally the box retains its original drawer although one small division is missing and the other longer one is loose. The label is in good condition. Externally the original dry patinated/oxidised oak finish has some water staining and marks from the door being held shut with tape.
Generally a fine instrument in good original unrestored condition with significant faults mainly limited to the eyepiece assembly.
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