HOUDINI, Harry (Erik Weisz, 1874 – 1926). Houdini Day’s Agency Advertising Label. Affixed to a mailing cover postmarked London, W.C. on September 7, 1910, and bears the typed address of Ben Ali Bey, the “inventor” of Black Art, in Berlin. Affixed to the flap of the cover is die-cut label printed in red and blue with scalloped edges advertising Houdini’s “permanent address for 1909” at Day’s Agency, Effingham House, The Strand. Diameter approximately 1 ½”. The first example we have seen; RARE.