![Bonhams : William Harrison - a silver pair cased pocket watch, hallmarked 1827 and a keyless fob watch in engraved case. (2) Bonhams : William Harrison - a silver pair cased pocket watch, hallmarked 1827 and a keyless fob watch in engraved case. (2)](https://img1.bonhams.com/image?src=Images/live/2010-02/18/94432538-18-2.jpg&height=430&quality=90)
Bonhams : William Harrison - a silver pair cased pocket watch, hallmarked 1827 and a keyless fob watch in engraved case. (2)
![John Harrison Liverpool - Wrist and Pocket Watches 2018/11/30 - Realized price: EUR 1,875 - Dorotheum John Harrison Liverpool - Wrist and Pocket Watches 2018/11/30 - Realized price: EUR 1,875 - Dorotheum](https://www.dorotheum.com/fileadmin/lot-images/45U181130/normal/john-harrison-liverpool-5791996.jpg)
John Harrison Liverpool - Wrist and Pocket Watches 2018/11/30 - Realized price: EUR 1,875 - Dorotheum
![Derek Pratt's Reconstruction Of John Harrison's H4, The World's First Precision Marine Chronometer (Part 1 of 3) - Quill & Pad Derek Pratt's Reconstruction Of John Harrison's H4, The World's First Precision Marine Chronometer (Part 1 of 3) - Quill & Pad](https://quillandpad.com/wp-content/uploads/2016/12/1-1_Derek-Pratt-H4-BHJ-Feb2015.jpg)
Derek Pratt's Reconstruction Of John Harrison's H4, The World's First Precision Marine Chronometer (Part 1 of 3) - Quill & Pad
The John Harrison Foundation for the Study of Timekeeping Practices - H4: The Ultimate Achievement By 1755 John Harrison had been attacking the Longitude Problem for twenty-seven years. H3 had been abandoned
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