The Berkeley, California Public Library used to have an "after-hours reference librarian" on duty in the late 1970s or so. You could call up in the evening and

The Berkeley, California Public Library used to have an "after-hours reference librarian" on duty in the late 1970s or so. You could call up in the evening and ask them a question. I remember once calling and asking how much Vitamin C was in an orange, waiting on hold for a minute or two, and then getting the answer.