Compass, Surveyors, Hearn & Potter

Hearn and Potter Circumferentor
Hearn and Potter Circumferentor

Description:

  • Object ID: ALSA 2006.06.01
  • Made by: Hearn & Potter, Toronto, C.W.
  • Model: Unknown
  • Serial Number: Unknown
  • Date Made: Dating from around 1850.
  • Approximate size: Unknown.
  • Accessories: Wooden Box, Brass Cover, Two Brass Sights.
  • Condition: fair

Commentary:

The instrument sems to be designed to be set on a pole. Two bubble tubes are set at right angles on the brass plate of the compass. A removable brass plate cover protects the glass cover of the compass.

There is a brass plaque prepared by the ALSA with the compass that states:
VERNIER COMPASS
The Vernier Compass is one which allows a surveyor to adjust for magnetic variation and obtain correct bearings directly from the compass. This is made possible by the inclusion on the compass of a sliding scale which measures the parts of the divisions indicated on another stationary scale.
Dating from around 1850, this vernier compass was manufactured in Toronto by Hearn & Potter.

Source of Object: Unknown.

Notes: The Society has only one in their collection.

References: Visit article Circumferentors – Made in Canada before Confederation for additional information.

Description by: Updated by Ed Titanich, October 2, 2024.