Mr. William H. Mapes, long connected with the hydrographic division, and of great usefulness as inspecting engineer, died suddenly on the 15th of April, 1879, in his forty-fourth year. He entered the service in 1857, and was employed ten years as engineer on sea-going steamers engaged in hydrography. At intervals he supervised the repairs of engines and vessels, and the construction of all vessels assigned for the work of the survey, in the course of the last ten years. For these duties Mr. Mapes was especially qualified by intelligence, good judgment, native industry and unvarying kindness towards all. This record is due to his memory; his devotion to the interests of the service was entire, and his business intercourse was marked by scrupulous integrity.

In: Report of the Superintendent of the Coast and Geodetic Survey 1879. P. 12.