1851 Great Exhibition: Official Catalogue: Class X.: John Crichton
452. CRICHTON, JOHN, 112 Leadenhall Street — Manufacturer.
Solid arch sextant, with improved reflector to vernier; double limb sextant; 4-inch sextant; box sextant; coast surveying sextant, as made for the Trinity yachts; ebony sextant.
Quadrants, plain, and with tangent screw to index, and with tangent screws to index and horizon.
Quadrants with spring vertical adj ustment, and with two and three back shades to horizon.
Quadrant, with handle, telescopes, and mahogany cause, divided to 30 seconds.
Azimuth compass, prismatic, large and small sizes.
Sympiesometer; marine barometer; artificial horizon, with iron bottle and improved iron trough.
Gravatt's levels, bronzed and bright; 5-inch theodolite.
Naval telescopes, 3 feet and 2 feet, with signals.
Achromatic night-glass; day or night telescope; gunner's quadrant with level; gunner's callipers, large and small; and shell callipers, for side and bottom, as made for the Honourable East India Company.