Why do old authors censor certain years/names?

by maggotmagnet

I am currently reading Harriet Beecher Stowe's The Minister's Wooing after having finished Uncle Tom's Cabin.

Why is it that she sometimes puts an em-dash to censor certain years and names? (Example: "Mr. B—", "the year 17— AD"). I've seen other older authors do this as well. I find it incredibly inconsistent and quite distracting. Any insight?

AncientHistory

While there is always more to be said about the subject, you might like to check out my answer for Why do some older authors put a line through all but the first letter of some of the names in their works?.