James Cook and astronomer William Wales tested the clock on Cook's second South Seas journey aboard , 1772–75 and were full of praise after initial scepticism. "Kendall's watch has exceeded the expectations of its most zealous advocate," Cook reported in 1775 to the admiralty. Cook also described it in his log as "our trusty friend the Watch" and "our never-failing guide the Watch". It was thus K1 which proved to a doubting scientific establishment that H4's success was no fluke. Three other clocks, constructed by John Arnold, had not withstood the loads of the same journey. Although constructed like a watch, the chronometer had a diameter of and weighed .