The first work obtained was in the preliminary surveys of the Bear Mountain Railroad. Soon, however, Professor Bache, recognizing his abilities, procured young Hilgard a position in the Coast Survey, in which service he continued, with short interruptions, until his death. In the field work, in computations and investigations in the office, in the publication of the records and results of the Survey, in his influence on political leaders, Mr. Hilgard rendered highly intelligent and valuable aid to the service. Throughout the American Civil War he served the Union army and navy by the construction of maps and charts and by surveys as well as by tidal and other information. During the failing health of Professor Bache, Hilgard, who was at that time in charge of the Coast Survey office, was obliged to perform the duties of Superintendent, which he did without extra compensation until the appointment of Benjamin Peirce to the position. Though it seems fitting that Hilgard should have become Superintendent upon the death of Bache, he did not receive the appointment until 1881. At that time his health was so impaired that, as he said, " it came too late." He was soon forced to resign. While Assistant Superintendent, his work in the Office of Weights and Measures gained him most favorable notice in Europe and he was invited to the directorship of an International Bureau of Weights and Measures about to be established in Paris. Declining this, but continuing his connection with the International Committee, a beautiful Sèvres vase was presented to him by President Theirs on behalf of the French Government in recognition of his services. He also had great satisfaction in being instrumental in bringing to a successful ending the operations for the telegraphic determination of transatlantic longitudes.