Hydrometer & thermometer

Add to album

This hydrometer, pictured here in its fitted case with a thermometer, is of a type designed by the chemist J.Y. Buchanan (1844-1925), for use on the 'Challenger' Expedition of 1873.

The thermometer's scale reads from -10 to 50 degrees centigrade. The hydrometer is used in conjunction with the thermometer for measuring the specific gravity of sea water, in particular the salinity of samples after they had been brought up in water bottles from particular depths.

At the time that this was devised, little was known about the ocean depths, deep-sea currents or temperatures, and this was one of many instruments developed to try to measure various aspects of samples recovered on voyages of scientific exploration in the late 19th century.

Record details

To search on related items, click any underlined text below.

• Online ID: 000-180-000-979-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland Part 2
  Project description   View all records in project
• Ref: National Museums Scotland  
• Date: 1875
  
• Material:
• Dimensions:
• What:
• Subject:
• Who:
• Where:
• Event:
• Description:
• References:
  • A.D. Morrison-Low. Marine Sampling and Collecting Equipment in the Collections of the national Museums of Scotland. The Scottish Naturalist (forthcoming). 
  • For more about instrumentation aboard HMS 'Challenger', see Anita McConnell. No Sea Too Deep: the history of Oceanographic Instruments. Bristol, 1982, pp 106-116. 
  • J.Y. Buchanan. On the determination, at sea, of the specific gravity of sea-water. Proceedings of the Royal Society 23 (1875), pp 301-308. 
• Translations:
• Related Records: