The volume contains two lists showing the distribution of three circulars issued by the Humber Conservancy Board:

1. Warning Notice issued 15 January 1920 regarding unauthorised works: Lists of riparian owners, owners of works, public offices, and companies, agents and others to whom copies have been sent.

2. Circular letter to master mariners and others on the subject of the Humber Rules and Byelaws (1910): Lists of master mariners, skippers of trawlers, tugmasters and masters of river craft to whom the letter was addressed.

3. Second circular letter to skippers of Hull and Grimsby Trawlers—distribution commenced 10 February 1923.

Copies of the original circulars can be found within the file.