|May 15, 1926
This line-drawn map (Dutch, schetskaart) had been published in 1915 as a fold-out map, between pages 860 and 861 of the article by “J.J.S.” entitled “De exploratie van Nieuw-Guinea” (In: Tijdschrift van het koninklijk Nederlandsch Aardrijkskundig Genootschap vol. 32 [new series], pp. 542-543 and 857-861.) A loose copy of this map, carried on the expedition, can also be found in the National Anthropological Archives. This copy was carried on the plane and was incidentally also used to pass handwritten notes between the pilot and passenger when they were flying, as the noise of the engine must have made oral communication difficult.