and showing, on reverse, a superb strike of the circular "CARRIED BY FIRST AERIAL MAIL/CAIRO-DELHI/DECR. 1918" in violet, signed by Borton on face; small fault at foot, otherwise fine. Photo" /> Air Mail cover 1918 (Dec.) Borton and Maclaren flight in Handley Page converted 0/400, unstamped envelope to Saugor and redirected, marked<I> "On Field Service"</I> and showing, on reverse, a superb strike of the circular "CARRIED BY FIRST AERIAL MAIL/CAIRO-DELHI/DECR. 1918" in violet, signed by Borton on face; small fault at foot, otherwise fine. Photo | Christie's