Surveyor’s Prismatic Compass - Retailed by Winsor & Newton, London - Likely Manufactured by Stanley – c1900

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Surveyor’s Prismatic Compass – Retailed by Winsor & Newton, London – Likely Manufactured by Stanley – c1900

Short Description

A large working surveyor’s prismatic compass.

Blackened brass design 11.0 cm in diameter, weighs 500gm. Engraved on the case lid “Winsor & Newton Ltd, London”. This is the famous supplier or art materials and likely relates to a foray by them into materials for surveying / cartography etc. We cannot find another example of a Winsor labelled instrument, so the initiative was likely short lived. We put the manufacturer as Stanley as there are examples of similar instruments by them in the suggested period.

It really is a super instrument with the added element of fixtures allowing solar measurement or very high vertical objects – see more below.

The sighting arm still contains its “horsehair” and lifts and extends stays in the vertical position. It has the added feature of the variable angled mirror on a rail that runs up and down the sighting arm for high items or solar observations. There is a “fixing” button at the bottom of the sighting ram to lock the compass for solid reading.

The hinged prism housing can be moved to its operating position over the base plate. With the compass held steady and flat a notch on the refractor body is aligned with the horsehair on the arm. A compass reading can be taken through the magnified refractor lens. Attached to the arm are two moveable coloured glass filters in red and amber for solar work and contrast

The silvered compass dial rotates freely, and the glass is free of scratches.

Below the compass is a short, threaded arm for fitting to a surveyor’s pole or equivalent.

Bar a short scratch and a little wear to the blackened cover everything is in fine condition.

Large early prismatic compass with solar reading additions

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