One of the lesser known chapters in the history of English marine chronometers, at least to the general horological public, is that a copy was made of H4 by the English watchmaker, Larcum Kendall. Kendall had worked with both Mudge and Graham, and he was tasked with duplicating H4 owing to the (legitimate) concern on the part of the Admiralty, that the cost of H4 was so high as to make it impractical for widespread use (in fact, H4 was worth a significant fraction of the price of a ship-of-the-line).