Bilby tower

Bilby began designing the first version of the Bilby tower in 1926 and worked with the Aermotor Windmill Company to develop the first prototypes. The tower was designed to elevate surveyors high enough to look over obstructions and to account for the curvature of the Earth in their calculations.[6][7] The tower was tested with positive results and Bilby received a commendation from Secretary of Commerce Herbert Hoover for the invention.[6]

The Bilby Tower was a massive success, saving money compared to previous options and increasing the efficiency of the USC&GS surveyors. They could be constructed and deconstructed in less than a third of the time of previous towers, were lighter, and were easier to move.[8] In 1928 alone, use of the Bilby Tower cut costs by up to 35%, and over its first ten years of use it saved the government an estimated $3,000,000 (equivalent to $50,540,230 in 2022).[6][9] Its use also spread outside the United States, reaching as far as Australia and Denmark.[6] The towers were credited by The New York Times as being "one of the greatest aids to geodetic work."[10]

In 1930, Bilby was promoted to the newly created position of "Chief Signalman" of the USC&GS.[6][11] In 1932 the federal retirement age was waived to allow him to continue serving. He retired in 1937.[6] Over the course of his 53-year career, Bilby traveled over 500,000 miles across the United States.[4] Bilby died on July 18, 1949, in Batesville, Indiana.[6] The last remaining tower, at St. Charles Parish, Louisiana, was dismantled by the Surveyors Historical Society in 2012 and re-erected in 2013 at the Osgood Trails Park in Osgood, Indiana, the home town of Bilby.[12]