Many readers of the Journal will have learned of the death, at the Hague on the 19 July 1968, of Jacobus Theodor Verstelle. He was aged 68. An authority of international standing on geodesy and hydrography, he was awarded the De Ruyter Medal in 1957 for ‘outstanding services in the fields of navigation and survey’ and became in 1965 an Officer of the Order of Oranje Nassau. He was elected to Fellowship of this Institute in 1955.