Frictionless ship's log, probably made by T. Walker & Son Ltd

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This 'frictionless' ship's log was the first effective model to be commercially produced, and was originally patented by Edward Massey in 1802. This example is a development known as the 'A1 Harpoon Log' patented in 1861, and was made around 1880, probably by T. Walker & Son Ltd., a scientific instrument maker based in London, but with a factory in Birmingham.

The mechanical log has a five blade propeller, each blade marked with an anchor and 'T.W'. The white enamelled dial plate has three dials and is marked: 'T. WALKER'S/PATENT/HARPOON/SHIP LOG/-A.1.-/London'. As the brass outer case rotates, it moves the hands around the dials, thus ascertaining the speed of a ship as it passes through water.

Thomas Walker (1805-1871) was Edward Massey's nephew. Although he set up in business in Birmingham separately, he became interested in his uncle's invention. He improved it, began making them for Edward Massey's successors, and finally the business was acquired by Thomas Walker & Son.

Record details

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• Online ID: 000-180-000-984-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.1970.12
• Date: After 1863
  Around 1880
  
• Material: Brass case / white enamelled dial plate. Inscription: [anchor] / T.W; T.WALKER'S / PATENT / HARPOON / SHIP LOG / -A.1.- / London; 14234
  Mechanical log / case
  
• Dimensions: 0.54 mm
  
• What: Mechanical log / case
  
• Subject: 9. NAVIGATION (Departmental Classification)
  19. MATHEMATICS (Departmental Classification)
  
• Who: T. Walker, London (Maker)
  
• Where: England, London
  
• Event:
• Description: Mechanical ship's log in a brass case made after 1863 and signed by T. Walker of London
  
• References:
  • For Edward Massey, see Alan Treherne. The Massey Family: Clock, Watch, Chronometer and Nautical Instrument Makers. Newcastle-under-Lyme, 1977. 
  • For Walker and his business, including the A1 log, see J.E. Willmott. A Short History of the Firm of Thomas Walker Limited Birmingham, Nautical Instrument Makers. Birmingham, 1951. 
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