britishmuseum:

The British Museum opened its doors to visitors for the first time on 15 January 1759. The Trustees decided that the Museum should be freely open to the general public as well as to academic visitors. However, they were afraid that the collections would be damaged if large crowds of people were allowed into the building. They therefore ordered that visitors should not be admitted unless they held tickets, and that only a small number of tickets should be issued for each day.

Like this ticket, issued for 1 p.m., all tickets were issued for a particular time. Visitors were taken around the Museum in groups of five, each group guided by one of the Under-Librarians. They were taken up the Great Staircase, through the upper rooms and down again to the ground floor. During their tour they were shown the collections of manuscripts, medals, antiquities and natural history.