Focusing on the academic and the social life of the British scientist John Milne (1850-1913), this paper sketches how his research network was formed and transformed, crossing British and Japanese boundaries. Trained as a field scientist, Milne had explored the geological and geographical frontiers by the time that the Meiji government invited him to be a professor of geology and mining at the Imperial College of Engineering. Subsequently, in the Asiatic field, the scientist from the British Empire found interests in earthquakes and volcanoes as well as archaeological and anthropological topics. Mobilizing European knowledge and Japanese resources, Milne built a seismological research network in Japan and eventually expanded it to Britain. However, his research network was not immortal; even though he married a Japanese woman and attained honors from the Japanese emperor, during the age of Japan’s nationalist turn in the last decade of the nineteenth century, he left Japan. In the United Kingdom, he found that the research network available to him was insufficient. Simultaneously, the research system embedded in Japan had been appropriated by a younger generation of Japanese scientists, and its foreign origin has gradually been forgotten.