As a result of the old question “Did Harrison win the Longitude Prize?”, and recent discussions on Twitter, started by Marcus du Sautoy here (he had been filming with the Royal Observatory’s Senior Specialist in Horology, Jonathan Betts, that day) and Tim Hartford (e.g. here), I have attempted to explain the various rewards offered and paid out by the Commissions of Longitude over on the Longitude Project Blog.
[Incidentally, Marcus du Sautoy’s tweet linked above reads:
But it was Harrison’s H4 that won him the Longitude Prize. Much more compact. Couldn’t fit the H1 in your waistcoat yfrog.com/ny3adlnj
— Marcus du Sautoy (@MarcusduSautoy) March 2, 2012
As well as raising the issue of winning the ‘Longitude Prize’, this also suggests that the sea watch H4 was an improvement on the first of Harrison’s sea clocks, H1, because it was compact and could fit in your pocket. I’m sure, though, that du Sautoy knows very well – and that the TV programme will reflect – the fact that H4 was a radically different approach to the problem rather than just a smaller version of the previous attempts. In addition, it would have performed very poorly if it had been kept in a pocket. In fact, Harrison complained bitterly when Maskelyne tested the going of H4 while it was held at steeper angles then he considered feasible for an object left on a table on board a rolling ship. Later, of course, pocket chronometers were developed.]