C. de Jager & A. Jappel 
Transactions of the International Astronomical Union [PDF ebook] 
Proceedings of the Fourteenth General Assembly Brighton 1970

The changing character of the IAU General Assemblies becomes most clear from a comparison of the agenda of the Brighton meeting with that of one of the earlier meetings. The fourth General Assembly (Cambridge Mass. , 1932) had about 240 participants, registered guests included, the Brighton meeting had about 2300 people attending. The Cambridge meeting lasted 5, working days, of which, however, three half days were exclusively devoted to excursions, leaving four real meeting days. At that time the nearly 30 commissions had each only one meeting, during part of a morning or afternoon; some commissions did not meet at all. There was one public lecture, by Sir Arthur Eddington, on ’The Expanding Universe’. Most of the small European countries were represented by two or three delegates only, but the delegations of France and Great Britain were composed of 20 and 18 scientists respectively; at that time there were only two delegates from Germany. After the Brighton General Assembly, with about 200 commission meetings – one commission met eleven times! – six Joint Discussions, four Invited Discourses, a Special Meeting and hardly time for excursions, there were a few complaints about too many overlapping meetings.