Air Mail cover 1910 (13 Nov.) Heliopolis Aviation Meeting, a series of four picture postcards by L.L. (No. 1, 2, 19 and 193) all bearing "Sphinx" values (1, 2 or 3m.) and affixed to front (3) and reverse of cards and all cancelled by "HELIOPOLIS/AERODRÔME" c.d.s. (13.11). Fine and rare. Photo