750 GBP ($900 USD) postage included

A museum worthy box sextant by Charles Schmalcalder for Charles Nugent K.C. c.1834


7 x 3 cm.





Country of manufacture

UK and Ireland

Categories: Navigational instruments, Calculating, Engineering antiques, Office Antiques


A historically important all brass box sextant by Charles Schmalcalder for Charles Nugent, Knight Commander (K.C.) c.1834.

Measuring 2 3/4 inches (7.0cm.) in diameter, it is of the typical form of the day with improvements (nuances) only Schmalcalder could imagine. The green/red light filters lock into position when the telescope (with solar filter) is inserted due to an angle cut on their edge. Primary and secondary mirrors are adjusted from top and side using the square key provided. Magnifier for the vernier actually locks into position when latitude is to be read and swings freely while sighting (someone in the past thought it was loose, not understanding the engineeering and tried to tighten it-crudely).

The silver scale runs out to 140 degrees, the vernier reading from 0-30 arc minutes (down to 1 arc second). All bright brass construction (80% original lacquer on face), peep and telescope sighting options, nice patination of brass top and bottom. Screw on lid.  Roping (knurling of brass) is extremely fine and without issues. Mirrors intact with good silvering.

History: This instrument can be dated to 1834.  Charles Edmund Nugent was Rear Admiral in 1797, Vice Admiral in 1801, Fleet Captain after the death of Nelson under Cornwallis, Full Admiral in 1808, Admiral of the Fleet in 1833 (honorary) and knighted (Knight Grand Cross) in 1834.

(Karl August Schmalkalder) Charles Augustus Schmalcalder (1781-1843) by this time had one registered patent for a delineator (1806) and another for the prismatic compass in 1812. He died in a horse drawn carriage accident while crossing the street at his last shop address ( 32 Strand), aged 62 years.

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CA ScientificaOpticae

Scientifica Opticae

Mark Hacking (Scientifica Opticae Inc.) has been an avid collector/dealer for over 30 years. A former Science teacher, he has an innate love for anything natural or mechanical. Specializing in optical (microscopes, telescopes), surveying, medical, weighing and drawing instruments, he is an active participant of the Scientific Instrument Fair in London. Living in Stratford, Ontario, Canada, with his wife and two children; Mark looks forward to meeting as many fellow collectors as possible, and has a worldwide following on eBay (Sciopti).

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