This is an old revision of the document!
This sleight was uncredited when it appeared in Jean Hugard and Fred Braue's Expert Card Technique, 1940, p. 303. However, in The Fred Braue Notebooks, Volume 3, 1985, p. 3, Braue credits the move to John Scarne.
The two-handed Mercury technique was predated by a one-handed folding method. William H. McCaffrey described one in his “Cash and Change-Purse” from The Sphinx, Vol. 37 No. 5, July 1938, p. 113.