The Etiquette of Visiting Cards

            In the practice of turning card corners, the upper left hand corner denotes "visits," and is used for an ordinary call; the upper right hand corner turned down means "felicitation," and is for a visit of congratulation; the lower left hand corner, "conge," represents a farewell call; and the lower right corner "condolence," expresses a desire to sympathize with bereavement. The rule most generally understood is the turning of one end of the card, which denotes a wish to see the ladies of the family.

 

Found at http://scloho1.blogspot.com/2008_09_07_archive.html

[Taken from the Centennial (Warrenton, NC) 19 May 1876]