Marine timekeeper known as 'H5' by John Harrison and Son 1770

Made:
1770 in London
maker:
Harrison and Son
Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770 Marine timekeeper known as 'H5' by John Harrison and Son 1770

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Marine timekeeper known as 'H5' by John Harrison and Son 1770
The Clockmakers' Museum/Clarissa Bruce
© The Clockmakers’ Charity

Silver pair-cased verge escapement marine timekeeper, known as H5, by John Harrison & Son, London.

White enamel dial with gold central star to adjust hands. Verge escapement with Harrison’s special diamond pallets. Steel balance and spring. Fusee. Maintaining power. 7 1/2 seconds remontoir on 4th wheel. All wheels from the 3rd, jewelled. Long bimetallic strip on adjustable frame. Original key and starting pin. Signed ‘John Harrison & Son London 1770 No. 2’. Case hallmarked for 1768 – 9 and stamped ‘HT’ (probably Henry Taylor who became a free Clockmaker in 1746). With original mahogany carrying case and three silk cushions.

Mechanically, this timekeeper is very similar to that of John Harrison's prize-winning longitude watch, H4 (in the collections of the Royal Museums Greenwich). It is now generally known as H5, being the fifth and last timekeeper that he produced as part of the 'Longitude Reward', and completed when he was 77. Personally tested by King George III at his observatory in Richmond, this timekeeper helped secure Harrison the last part of his Longitude prize-money.

Clockmakers Museum No. 598

Details

Category:
Clockmakers
Object Number:
L2015-3480
Materials:
brass (copper, zinc alloy), diamond, enamel, gold (metal), ivory, mahogany (wood), silk, silver (alloy) and steel (metal)
type:
chronometer
taxonomy:
  • furnishing and equipment
  • measuring device - instrument
  • timepiece
credit:
Lent by the Worshipful Company of Clockmakers