I am much indebted to Commander W. E. May for calling my attention to the numerous references to George Margetts (see this Journal, 6, 403) in The Marine Chronometer by R. T. Gould (J. D. Potter, 1923). The following extracts from this book will provide some of the biographical information which I was unable to give previously. ‘George Margetts (1748–1804), already referred to as the inventor of a form of lever escapement, produced several machines of this kind.’ (Namely chronometers showing sidereal and mean time.)

There has recently been some discussion in the Journal1 as to the meaning of the word ‘dyoll’ when it appears in English ship inventories of the years 1410–12, which have been partially published, by Nicolas2 and Sir Alan Moore.3 Nicolas quotes from the Accounts and Inventories of John Starlyng, Clerk of the King's Ships to Henry IV, but he mistakenly dates these documents 1338, which date has been corrected by Moore to 1410–12.

In Table II of Captain Wylie's paper (Vol. VII, p. 64) column v should indicate that the Marconi Mk. IV radar has a differentiator.