THE development, in 1929, of a large volume of dredgeable gold‐bearing gravel in the Mandated Territory of New Guinea brought the Directors of Placer Development, Ltd., the exploration company which had proved the area and wished to equip it, face to face with an unusually difficult transport problem. The solution of this was so satisfactorily overcome by the use of aeroplanes, that the writer fel...... hiện toàn bộ