A Blotter

1. A piece of blotting paper in a pad as a piece of desk furniture. Synonym: desk pad https://en.wikipedia.org/wiki/Blotting_paper
2. (law enforcement) A daily register of arrests and other events in a police station: a police blotter.
3. A register of the related events made in the form of the list of times and brief descriptions.
4. (slang) A portion of blotter acid.