Comparative thermometer

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Bryson's 'Comparative Thermometer' gives the temperature in degrees Celcius (left), Fahrenheit (centre) and Reaumur (right). Down each side of the instrument is a list of important towns all over the world, with corresponding average midday shade temperatures for winter (W), summer (S), or yearly average (Y). It was designed by the Geographer-in-Ordinary to the Queen, Alexander Keith Johnston (1804-71), Hon. Secretary and founder member of the Scottish Meteorological Society, who was in partnership with his brother as W. & A.K. Johnston, famous for their maps and globes.

This spirit-in-glass thermometer mounted on a ceramic scale is marked at the top: 'BRYSON'S / NEW / Comparative / Thermometer / Arranged by / A.K. Johnston. F.R.S.E.'. The scale in degrees centigrade and Reaumur is marked from -17 to 37 degrees C, and -13 to 29 degrees R. The scale shows winter and summer extremes, and temperature means, for different parts of the globe.

James Mackay Bryson (1824-94), from an Edinburgh dynasty of instrument makers and scientists, appears to have been interested in the applications of thermometers for special purposes; but this particular example was probably a one-off special commission, and is more a curiosity than a 'scientific instrument'.

Record details

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• Online ID: 000-180-001-000-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland Part 2
  Project description   View all records in project
• Ref: National Museums Scotland  T.1856.38
• Date: Around 1850
  c. 1850
  
• Material: Porcelain scale
  Thermometer, comparative, bryson's
  
• Dimensions:
• What: Thermometer, comparative, bryson's
  
• Subject:
• Who: Bryson (Eponym)
  J.M. Bryson, Edinburgh (Maker)
  
• Where: Scotland, Midlothian, Edinburgh
  
• Event:
• Description: Bryson's comparative thermometer with quadruple gradations on a porcelain scale, Edinburgh, c. 1850
  
• References:
  • Clarke, T.N, A.D. Morrison-Low and A.D.C. Simpson. Brass & Glass: Scientific Instrument making Workshops in Scotland. Edinburgh, 1989, pp 112-117. 
• Translations:
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