"Henry Percy Douglas" . "1939" . . . . "1939" . . . . "1876" . "Percy Douglas" . . . . . . . . . . . . . . "Sir Percy Douglas" . . . . "H.P. Douglas" . . . . . "Percy Douglas" . "Hydrographer of the Navy(1924\u20131932)" . . . . . . . . . . . . . . . . . . . . . . . . . . . "1939" .