Dr. Sven Hedin, a famous Swedish geologist, came to China and organized the Northwest Scientific Expedition with the cooperation of professors Hsu Pin-chang (徐炳昶) and Liu Pan-nung (劉半農) for the exploration of ruins in Mongolia, Sinkiang, and Kansu. As they were short of funds, the Postal Administration issued, with the approval of the Ministry of Communications, a set of commemorative stamps. With the exception of a small portion sold to the public in the usual manner by the Post Offices at Nanking, Shanghai, Peiping, Canton and Hankow these were all purchased by the expedition at the original face value for resale at higher prices to philatelists to help finance the expedition. The central design of the stamps is a copy of〝Nomads in the Desert,〞a famous painting of the Yuan Dynasty in the collection of the Palace Museum, Peiping. Below the central design are a white panel bearing the Chinese inscription〝西北科學考察團紀念〞(to commemorate the Northwest Scientific Expedition) and a black panel with the same inscription in Latin and the years 〝1927-1933.〞