Curio collection
Lawrence & Mayo Transit Theodolite No. 513
United Kingdom, 1913
About the object
A classic British vernier transit theodolite by Lawrence & Mayo of London, engineered for precision surveying and civil engineering. Finished in black enamel with exposed lacquered brass scales and verniers, the instrument features a full vertical circle, sensitive spirit levels, and a three-screw leveling tribrach base.
About this object
Precision British brass and cast iron surveying instrument by Lawrence & Mayo, London
Condition
The theodolite displays authentic historical wear with edge chipping, rubbing, and paint loss across the black-enameled A-frames and base casting. The brass scales, knurled adjustment screws, and vernier readouts show natural patina and minor surface oxidation. Glass spirit levels and telescope lenses appear intact with expected dust and superficial handling marks.
Provenance
Provenance documentation was not supplied for this specific Lawrence & Mayo Transit Theodolite No. 513; this listing is based on the supplied photographs only.
Maker Mark
LAWRENCE & MAYO LONDON Nº 513
Instrument Type
Vernier Transit Theodolite
Leveling Base
Three-screw leveling tribrach with knurled thumbscrews
Vials
Dual tubular spirit levels mounted on plate and vertical standards
Optics
Terrestrial surveying telescope with rack-and-pinion focusing and objective cover
Engraved Maker Inscription
Clear period hallmark reads 'LAWRENCE & MAYO LONDON Nº 513' stamped directly into the horizontal limb edge.
Full Vertical Circle
Equipped with a finely divided brass vertical circle and dual vernier reading magnifiers for zenith angle measurement.
Stout A-Frame Standards
Rigid black-lacquered dual-standard frame supporting the central transit telescope axis without flexure.
Precision Spirit Levels
Features multiple adjustable tubular spirit levels mounted on the horizontal plate and upper standards for exact leveling.
Three-Screw Tribrach Base
Classic geodetic tribrach design featuring large knurled brass leveling screws and a threaded tripod mount socket.
Surveyor's Telescope
Equipped with brass objective end cap, knurled focusing controls, and an eyepiece with diopter adjustment.
Mapping the Modern World
Surveying instruments like this transit theodolite formed the backbone of British railway construction, municipal surveying, and geographical triangulation, providing the rigid mechanics necessary for uncompromised accuracy across demanding colonial terrains.
The Signature of Lawrence & Mayo
Each instrument produced by Lawrence & Mayo underwent exhaustive hand-finishing, with its serial number and London provenance permanently engraved into the brass dial, attesting to rigorous optical and mechanical calibration before leaving the workshop.
1868 · Founding of Lawrence & Mayo
Lawrence & Mayo is established in London, quickly expanding into optical, navigational, and surveying instruments across the British Empire.
1877 · Expansion into India
The firm establishes offices and workshops in Bombay and Calcutta to supply precision instruments to railways and government surveys.
1913 · Production of Transit No. 513
Transit theodolite serial number 513 is manufactured in London for high-accuracy field triangulation and civil engineering works.
1930s · Transition to Optical Micrometers
Traditional open-vernier transit theodolites gradually give way to enclosed glass-circle tachymeters and modern optical designs.
Enamel Finish
Visible chipping, paint flaking, and edge wear down to the underlying brass on the standards and barrel.
Brass Components
Even aged patina and surface oxidation on adjustment wheels, scale rings, and thumbscrews.
Scales & Markings
The maker engraving 'LAWRENCE & MAYO LONDON Nº 513' remains crisp and clearly legible on the lower plate rim.
Bubble Levels
Tubular glass spirit levels remain mounted in brass housings with intact fluid reservoirs.
- Materials
- Enameled brass/bronze, silvered scales, optical glass
- Place & period
- United Kingdom, 1913
- Source collection
- Curio Gallery · Curio collection