Almost ten years ago (14 March 1938), in this same lecture hall, the Astronomer Royal, our newly elected President, opened a discussion on the recently published Air Almanac. That meeting, held under the auspices of the Royal Geographical Society, can justly be said to mark an epoch in the application of astronomical methods to air navigation in this country; but it was remarkable in other ways too. First, it provided that opportunity for criticism, by users and by others interested, of the provision to be made for astronomical navigation in the air, which it is hoped the Institute will provide for all aids to navigation. Secondly, the preparation of the Astronomical Navigation Tables was first announced; this may not appear very remarkable in itself, but it was the first time, since the days of Nevil Maskelyne, fifth Astronomer Royal, that the Nautical Almanac Office had prepared any major tables for the reduction of navigational observations!