The Art of Money Getting or, Golden Rules for Making Money was originally published in 1880 by P. T. Barnum.
Part 20 Don’t Blab
Some men have a foolish habit of telling their business secrets. If they make money they like to tell their neighbors how it was done. Nothing is gained by this, and ofttimes much is lost. Say nothing about your profits, your hopes, your expectations, your intentions. And this should apply to letters as well as to conversation. Goethe makes Mephistophiles say: “Never write a letter nor destroy one.” Business men must write letters, but they should be careful what they put in them. If you are losing money, be specially cautious and not tell of it, or you will lose your reputation.