Description
ITEM 6506
‘Troughton & Simms’ 5” Wye Theodolite
A classic example of a ‘Wye’ theodolite by Messrs Troughton & Simms, whose signature in the old style of hand engraving appears on the horizontal plate, followed by the word ‘LONDON’. The style of writing and the details of its construction suggest a date of mid-to-late 19th century. This example has an attractive round compass on its horizontal plate. (Later in the 19th century a long trough compass was more common, which was carried as an accessory in the case, and fitted to the instrument as required.) The presence of a round compass is a reminder of the derivation of the theodolite from its 18th century predecessors, when magnetic bearings were more relied upon. It comes with a long ‘erecting’ eyepiece shown in place in our photo. Without this, the image appears inverted. However, for daily use the shorter inverting eyepiece was preferred as it had a brighter image. The 5-inch diameter circles are engraved on silver to 30-minute intervals and read by vernier to 1-minute, as was standard. It has an attractive polished finish protected by lacquer and which is in good condition. It originally had one magnifier for the horizontal circle only, which was attached to the underside of the plate, but this has been removed. It comes in a restored mahogany case with the large brass numerals ‘65’ inlaid on the top of the lid.
Approximate Dimensions
Instrument: 250 mm overall height
360 mm over telescope as shown
Case: 278 x 218 x 152 mm high
Approximate Weight
Instrument and Case: 6 kg
Price
SOLD
(No tripod with this instrument)
Freight is extra.
© Akrona Instruments
