1. See, for example, ’Espinasse (1962), pp. 61–63. Glasgow (1885), in Watch and Clock Making says that “About the year 1665. Dr. Hooke invented what is known as the recoil, or anchor, escapement. This was afterwards adopted in a clock made by Clement, a London clockmaker of the time. It should be admitted here that Hooke’s recollection of what occurred forty years earlier might not be any more reliable than Newton’s, which we will later discount, but the difference lies in the evidence from the documents of the Society.”
2. Apparently feeling that a patent would reveal his invention, thus making it possible for others to improve upon it. This question is discussed in various places, including ’Espinasse (1956), pp. 61–69. Waller, in his “Life of Dr. Robert Hooke,” says that he saw the draft of an agreement between Brouncker, Boyle, Moray, and Hooke, to promote this invention, with Hooke receiving most of the proceeds. See Gunther, VI, p. 11. In his biographical sketch, Hooke describes this as having occurred “Immediately after his Majesty’s Restoration.”
3. The innovation was using a spring to regulate the watch, as opposed to powering it. See Wright (1989) and references therein for details of Hooke’s efforts with the balance-spring watch.
4. Apparently (Jardine, 2000, pp. 268–9) making trips back and forth between London and Oxford for some time. Hooke’s work with Boyle led eventually to one of the few extant monuments to his having lived. Thus, on a plaque marking the location of Boyle’s laboratory in Oxford, we find a reference to Hooke’s discovery of the cell.
5. Boyle, New Experiments (1660). “Mr G”, Ralph Greatorex, was a leading engineer who had been involved in pumping the fens of Southeast England.