He returned to his duties at the Coast Survey office in November, 1872, and in the course of that year made a special determination of the length of the standard bar used in the measurement of the primary base line near Atlanta, Ga. The following year he continued the same duties until September, 1874, when he departed for Europe a second time, under an appointment as a delegate to represent the Government at the International Conference for the construction of a new standard meter, which had been called at Paris. The report of the Superintendent says on this subject: