Series II. Correspondence consists of outgoing correspondence and incoming correspondence. Two letter books contain outgoing correspondence (B2 F1-2). Each volume contains an alphabetical index. Most of the outgoing correspondence consists of invitations to lectures and issues pertaining to dates and fees. The incoming correspondence (B2 and B3) ranges from 1855 to 1877. In addition to lecturers, the Union invited musicians, dramatists, and singers to perform. The letters contains responses, acceptances, and refusals to the Corresponding Secretary from many distinguished men and women lecturers. Some mention dates and the titles of the lectures, concerts, or plays to be presented. An index of correspondents can be found in Appendix I.