{{Short description|Steel survey tower}} {{Use mdy dates|date=February 2024}} [[File:Theb2520_-_Flickr_-_NOAA_Photo_Library.jpg|thumb|Bilby tower under construction in 1927]] [[File:Theb2546_-_Flickr_-_NOAA_Photo_Library.jpg|thumb|Completed Bilby tower showing inner tower for instrument isolated from outer tower for surveyor access]] A '''Bilby tower''' is a type of [[Surveying|survey]] tower made from [[steel]] and used by the [[United States Coast and Geodetic Survey]] (USC&GS) from 1927 to 1984.<ref>{{Cite web |title=Survey Towers: Bilby Tower |url=https://celebrating200years.noaa.gov/survey_towers/bilby.html |url-status=dead |archive-url=https://web.archive.org/web/20170204230427/http://celebrating200years.noaa.gov/survey_towers/bilby.html |archive-date=February 4, 2017 |access-date=February 3, 2024 |publisher=[[NOAA]] |language=EN-US}}</ref> It is named after [[Jasper S. Bilby]] who designed it in 1926.<ref>{{Cite web |title=Bilby Towers |url=https://celebrating200years.noaa.gov/magazine/bilby/welcome.html |url-status=dead |archive-url=https://web.archive.org/web/20231110163751/http://celebrating200years.noaa.gov/magazine/bilby/welcome.html |archive-date=November 10, 2023 |access-date=February 3, 2024 |publisher=[[NOAA]] |language=EN-US}}</ref> In 1927, [[Herbert Hoover]], then the [[Secretary of Commerce]], commended Bilby's tower "for its cost and time efficiency" and cited the surveyor's service as "essential to the United States government".<ref>{{Cite web |title=Bilby Steel Tower |url=https://www.in.gov/history/state-historical-markers/find-a-marker/find-historical-markers-by-county/indiana-historical-markers-by-county/bilby-steel-tower/ |access-date=February 4, 2024 |publisher=[[Indiana Historical Bureau]] |language=en}}</ref>
== History == [[Jasper S. Bilby]] (1864–1949) was a [[surveyor]] employed by the USC&GS from 1884 to 1937. He served as Chief Signalman of the USC&GS from 1930 to 1937. Born in [[Rush County, Indiana]], he later moved to a homestead near [[Osgood, Indiana|Osgood]].<ref name="Clark-20162">{{Cite web |last=Clark |first=Justin |date=March 10, 2016 |title=Jasper Sherman Bilby: To Map the Earth, Part I |url=https://blog.history.in.gov/jasper-sherman-bilby-to-map-the-earth-part-one/ |access-date=February 3, 2024 |website=The Indiana History Blog |publisher=[[Indiana Historical Bureau]]}}</ref>
=== Design of the 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.<ref>{{Cite book |last=Wilford |first=John Noble |url=https://archive.org/details/mapmakers00wilf_0/ |title=The Mapmakers |date=2000 |publisher=[[Alfred A. Knopf]] |isbn=978-0-375-40929-5 |edition=Revised |location=New York |pages=357–359 |author-link=John Noble Wilford |url-access=registration}}</ref> The tower was tested with positive results and Bilby received a commendation from [[United States Secretary of Commerce|Secretary of Commerce]] [[Herbert Hoover]] for the invention.<ref name="Clark162">{{Cite web |last=Clark |first=Justin |date=March 14, 2016 |title=Jasper Sherman Bilby: To Map the Earth, Part II |url=https://blog.history.in.gov/jasper-sherman-bilby-to-map-the-earth-part-ii/ |access-date=February 4, 2024 |website=The Indiana History Blog |publisher=[[Indiana Historical Bureau]] |language=en-US}}</ref>
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.<ref>{{Cite journal |last=Ervin |first=Adrienne |date=1927 |title=Bilby Tower for Government Surveys |journal=[[The Military Engineer]] |volume=19 |issue=107 |pages=400–401 |jstor=44605260 |jstor-access=free}}</ref> 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 ({{Inflation|index=US|value=3000000|start_year=1927|fmt=eq}}).<ref name="Clark162" /><ref>{{Cite book |url=https://docs.lib.noaa.gov/rescue/cgs/005_pdf/CSC-0132.PDF |title=Annual Report of the Director, United States Coast and Geodetic Survey to the Secretary of Commerce for the Fiscal Year Ended June 30, 1928 |publisher=[[Government Printing Office]] |year=1928 |location=Washington, D.C. |pages=24 |archive-url=https://web.archive.org/web/20170302074645/https://docs.lib.noaa.gov/rescue/cgs/005_pdf/CSC-0132.PDF |archive-date=March 2, 2017 |url-status=dead}}</ref> Its use also spread outside the United States, reaching as far as [[Australia]] and [[Denmark]].<ref name="Clark162" /> The towers were credited by ''[[The New York Times]]'' as being "one of the greatest aids to geodetic work."<ref>{{Cite news |last=Durham |first=John |date=September 21, 1930 |title=Nation's Vast Geodetic Survey to Give New Accuracy in Maps |url=https://www.nytimes.com/1930/09/21/archives/nations-vast-geodetic-survey-to-give-new-accuracy-in-maps-work-now.html |work=[[The New York Times]] |pages=X14 |id={{ProQuest|98916316}}}}</ref>
Prior to the introduction of Bilby towers, surveyors would try to build towers only to the minimum functional height to minimize the resourced expended to erect a tower. Bilby towers, with their low costs and ease of setting up, made this less of an issue. The last Bilby tower erected by the [[National Geodetic Survey]] was in 1984, and it was placed near [[Hartford, Connecticut]].<ref>{{Cite web |last=Dracup |first=Joseph F. |title=Geodetic Surveying 1940–1990 |url=https://www.ngs.noaa.gov/PUBS_LIB/geodetic_surveying_1940.html |publisher=[[National Geodetic Survey]]}}</ref>
=== Bilby's legacy === In 1930, Bilby was promoted to the newly created position of "Chief Signalman" of the USC&GS.<ref name="Clark162" /><ref>{{Cite news |last=Smith |first=Gretchen S. |date=May 16, 1930 |title=J. S. Bilby Is Urged To Continue Work |url=https://www.newspapers.com/article/evening-star-js-bilby-is-urged-to-cont/124860448/ |access-date=May 31, 2023 |work=[[The Evening Star (Washington, D.C.)|The Evening Star]] |page=B8 |via=[[Newspapers.com]]}}</ref> In 1932 the federal retirement age was waived to allow him to continue serving. He retired in 1937.<ref name="Clark162" /> Over the course of his 53-year career, Bilby traveled over 500,000 miles across the United States.<ref name="Clark-20162" /> Bilby died on July 18, 1949, in [[Batesville, Indiana]].<ref name="Clark162" /> The last remaining tower, at [[St. Charles Parish, Louisiana|St. Charles Parish]] in [[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.<ref>{{Cite news |date=August 21, 2014 |title=Bilby Tower Dedication Honoring Jasper Sherman Bilby - xyHt |url=http://www.xyht.com/surveying/bilby-tower-dedication-honoring-jasper-sherman-bilby/ |access-date=June 28, 2017 |work=xyHt |language=en-US}}</ref>
==Features== The Bilby tower was designed to be used for [[Triangulation (surveying)|triangulation]].<ref>{{Cite book |last=Gossett |first=F. R. |url=https://catalog.hathitrust.org/Record/102182069 |title=Manual of Geodetic Triangulation |date=1959 |publisher=[[U.S. Government Printing Office]] for the [[Coast and Geodetic Survey]]}}</ref> The towers have two unconnected parts—an internal tower for mounting surveying instruments and an external tower for [[Surveyor|surveyors]]. This separation allowed for isolating the instruments from the vibrations induced by people, which increased the precision of measurements. It was portable, reusable and quick to assemble and dismantle.<ref>{{Cite web |title=Historic Traveling Bilby Tower 'Comes Home' to Osgood, Indiana |url=http://oceanservice.noaa.gov/news/features/nov13/last-bilby-tower.html |url-status=dead |archive-url=https://web.archive.org/web/20170711025752/http://oceanservice.noaa.gov/news/features/nov13/last-bilby-tower.html |archive-date=July 11, 2017 |access-date=February 3, 2024 |publisher=[[National Ocean Service]] |language=EN-US}}</ref> Its quick erection made it possible to conduct surveying rapidly—a team of five men could assemble a steel Bilby tower in only five hours.<ref>{{Cite journal |last=Bowie |first=William |author-link=William Bowie (engineer) |date=1931 |title=Triangulation |url=https://www.jstor.org/stable/24975698 |journal=[[Scientific American]] |volume=144 |issue=6 |pages=369–373 |jstor=24975698}}</ref>
==See also==
* [[Triangulation (surveying)]] * [[Triangulation station]]
== References == <references group="" responsive="1"></references> [[Category:Towers]] [[Category:Surveying instruments]] [[Category:Surveying of the United States]] [[Category:Aermotor Windmill Company]] [[Category:Towers completed in 1927]]