A Humber Conservancy Board Journal comprising a log of weather observations taken at Chalderness. Two entries are made for each date: one entry is made when the lights are taken down and the other when the lights are put up. Each entry records the time lights were taken down/put up, the direction and force of the wind, and any remarks on the general condition of the weather during the day/night.

A key outlining the symbols used can be found on the inside front cover.