Printed copies of formal addresses of greeting and congratulation sent by the Cambridge Philosophical Society to other learned societies in recognition of their anniversaries:
Yorkshire Philosophical Society centenary 1922;
Royal Society tercentenary, 1960 [Adam Sedgwick, one of the founders of the Cambridge Philosophical Society, was also prominent among the founders of the Royal Society];
Société Royale de Botanique de Belgique centenary, 1962;
Fondation Curie, 50th anniversary 1971 [Marie Curie was elected an honorary member of the Cambridge Philosophical Society in 1914].