Around 1772, Arnold modified this escapement so that it now was pivoted vertically and acted on by a spring. This was a much more successful arrangement, and it is known that in 1772 at least two pocket timekeepers with this escapement were supplied to Joseph Banks at a cost of £100 (Arnold No.5), and also Banks' fellow Etonian Captain Constantine John Phipps, 2nd Baron Mulgrave. In a long and detailed article on this matter published in "Australiana" November 2014 Vol 36 No. 4, John Hawkins details the association between these two men and the probability that this instrument is one and the same, the world's first pocket chronometer originally destined for Cook's second voyage, purchased by Banks and lent to Phipps.