Dip circle (detail)

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A dip circle is an instrument for finding the vertical component of the earth's magnetic field. This is a detail of a brass dip circle made around 1810, probably by John Miller and Alexander Adie, scientific instrument makers based in Edinburgh.

The detail shows part of the scale on the back of the circle. It is inscribed 'Miller & Adie Edinburgh'.

The dip circle was devised around 1576 by Robert Norman of London. He noticed that a carefully balanced compass needle did not stay horizontal; its inclination or 'dip' shows that the direction of the Earth's magnetic field is not parallel to its surface.

Record details

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• Online ID: 000-190-001-015-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1902.29.2
• Date: Around 1810
  c. 1810
  
• Material: Dip circle
  
• Dimensions:
• What: Dip circle
  
• Subject: 5. CARTOGRAPHY, Surveying (Departmental Classification)
  22. PHYSICS, Magnetism and Electricity (Departmental Classification)
  
• Who: Miller and Adie, Edinburgh (Maker)
  
• Where: Scotland, Midlothian, Edinburgh
  
• Event:
• Description: Dip circle, probably by John Miller and Alexander Adie, Edinburgh, c. 1810
  
• References:
  • For Miller & Adie, see Clarke, T.N., Morrison-Low, A.D. & Simpson, A.D.C., Brass & glass scientific instrument making workshops in Scotland as illustrated by instruments from the Arthur Frank Collection at the Royal Museum of Scotland. Edinburgh: NMS, 198 
  • McConnell, Anita, Geomagnetic Instruments before 1900: An illustrated account of their construction and use. London: 1980 
• Translations:
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