Games from the Kent and Sussex Congress, continued

We have received a further pair of games from this joint event, covered in two earlier entries.  In the first contest, Mr. Yates, winner of Open Tournament A, registers a powerful victory against the French Defense of Mr. Brown:

And here Mr. du Mont at his 19th move hopes to win the isolated Queen's pawn of Mr. Beamish, only to be out-calculated by his wily opponent.  We invite our readers, before playing through the game, to consider the position just before the capture of the pawn by 19.Nxd4, as diagrammed below, and to attempt to work out for themselves its refutation.