THE French Riviera, which Mr. Holt Marvell described in last Tuesday's talk, is well known as a holiday resort, and so is Brittany, with which Miss Maxse will deal next week. Today Mr. Branch Johnson will talk about a part of France less known than it deserves to be -the border-land where France and Germany meet, where the historic towns of Strasbourg and Colmar look down on the broad waters of the Rhine. He himself knows Alsace well, and he is an expert on the folk-lore of the French countryside.