In May of 1870, Thomas Child was hired by the Imperial Maritime Customs Service to be a gas engineer in Peking (Beijing). The 29-year-old Englishman left behind his wife and three children to become one of roughly 100 foreigners living in the late Qing dynasty’s capital, taking his camera along with him. Over the course of the next 20 years, he took some 200 photographs, capturing the earliest comprehensive catalog of the customs, architecture, and people during China’s last dynasty. On Thursday, an exhibition of his images will open at the Sidney Mishkin Gallery in New York, curated by Stacey Lambrow. In addition, descendants of the subjects of one of his most famous images, Bride and Bridegroom (1870s), will be in attendance.