Friedrich Robert Helmert

{{Infobox scientist

|name = Friedrich Robert Helmert

| image = F-R Helmert 1.jpg

|caption = Professor Friedrich Robert Helmert. Photographer unknown.

|birth_date = {{Birth date|df=yes| 1843|07|31}}

|birth_place = Freiberg, Kingdom of Saxony

|death_date = {{Death date and age|df=yes| 1917|06|15|1843|07|31}}

|death_place = Potsdam, Germany

|residence =

|nationality =German

|alma_mater = Polytechnische Schule, now Technische Universität, in Dresden, University of Leipzig

|known_for = contribution into geodesy and theory of errors.

|footnotes =

|spouse =

|children =

|field = Mathematics, geodesy

|work_institutions = Technical University in Aachen, University of Berlin.

|advisor =

|prizes = recipient of some 25 German and foreign decorations

|religion =

}}

Friedrich Robert Helmert (31 July 1843 – 15 June 1917) was a German geodesist and statistician with important contributions to the theory of errors.

Career

Helmert was born in Freiberg, Kingdom of Saxony. After schooling in Freiberg and Dresden, he entered the Polytechnische Schule, now Technische Universität, in Dresden to study engineering science in 1859. Finding him especially enthusiastic about geodesy, one of his teachers, {{ill|Christian August Nagel|de}}, hired him while still a student to work on the {{ill|Royal Saxon Triangulation|de|Königlich-Sächsische Triangulirung}} of the Ore Mountains and the drafting of the trigonometric network for Saxony. In 1863 Helmert became Nagel's assistant on the {{ill|Central European Arc Measurement|de|Gradmessungskommission}}. After a year's study of mathematics and astronomy Helmert obtained his doctor's degree from the University of Leipzig in 1867 for a thesis based on his work for Nagel.

In 1870 Helmert became instructor and in 1872 professor at RWTH Aachen, the new Technical University in Aachen. At Aachen he wrote Die mathematischen und physikalischen Theorieen der höheren Geodäsie (Part I was published in 1880 and Part II in 1884). This work laid the foundations of modern geodesy. See history of geodesy. Part I is devoted to the mathematical aspects of geodesy and contains a comprehensive summary of techniques for solving for geodesics on an ellipsoid.

The method of least squares had been introduced into geodesy by Gauss and Helmert wrote a fine book on least squares (1872, with a second edition in 1907) in this tradition, which became a standard text.{{sfn|Hald|1998|p=633|ps=: "[It] is a pedagogical masterpiece; it became a standard text until it was superseded by expositions using matrix algebra."}} In 1876 he discovered the chi-squared distribution as the distribution of the sample variance for a normal distribution.{{sfn|Hald|1998|pp=633–692|loc=27. Sampling Distributions under Normality}}F. R. Helmert, "[http://gdz.sub.uni-goettingen.de/dms/load/img/?PPN=PPN599415665_0021&DMDID=DMDLOG_0018 Ueber die Wahrscheinlichkeit der Potenzsummen der Beobachtungsfehler und über einige damit im Zusam- menhange stehende Fragen]", Zeitschrift für Mathematik und Physik [http://gdz.sub.uni-goettingen.de/dms/load/toc/?PPN=PPN599415665_0021 21], 1876, pp. 192–219 This discovery and other of his work was described in German textbooks, including his own, but was unknown in English, and hence later rediscovered by English statisticians – the chi-squared distribution by Karl Pearson (1900), and the application to the sample variance by 'Student' and Fisher.

From 1887 Helmert was professor of advanced geodesy at the University of Berlin and director of the Geodetic Institute. In 1916 he had a stroke and died of its effects the following year in Potsdam.

File:Stein.Helmert.jpg

Honours

Helmert received many honours. He was president of the global geodetic association of "Internationale Erdmessung", member of the Prussian Academy of Sciences in Berlin, was elected a member of the Royal Swedish Academy of Sciences in 1905, and recipient of some 25 German and foreign decorations.

The lunar crater Helmert was named in his honor, approved by the IAU in 1973.[http://planetarynames.wr.usgs.gov/Feature/2437 Helmert], Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)

References

=Works cited=

{{cite book |title=A history of mathematical statistics from 1750 to 1930 |last=Hald |first=Anders |author-link=Anders Hald |year=1998 |publisher=Wiley |location=New York |isbn=978-0-471-17912-2 }}

=General references=

Walther Fischer "Helmert, Friedrich Robert" Dictionary of Scientific Biography volume 7, pp. 239–241, New York: Scribners 1973.
O. B. Sheynin (1995). "Helmert's work in the theory of errors". Archive for History of Exact Sciences, 49, 73–104.
Die Genauigkeit der Formel von Peters zur Berechnung des wahrscheinlichen Fehlers director Beobachtungen gleicher Genauigkeit, [http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1876AN.....88..113H&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf Astron. Nach., 88, (1876), 192–218] An extract from the paper is translated and annotated in H. A. David & A. W. F. Edwards (eds.) Annotated Readings in the History of Statistics, New York: Springer 2001.
{{cite journal | last1=Ihde | first1=Johannes | last2=Reinhold | first2=Andreas | title=Friedrich Robert Helmert, founder of modern geodesy, on the occasion of the centenary of his death | journal=History of Geo- and Space Sciences | publisher=Copernicus GmbH | volume=8 | issue=2 | date=2017-08-08 | issn=2190-5029 | doi=10.5194/hgss-8-79-2017 | pages=79–95| bibcode=2017HGSS....8...79I | doi-access=free }}
{{cite journal | last=Witte | first=Bertold | title=Friedrich Robert Helmert in memory of his 100th year of death | journal=GEM - International Journal on Geomathematics | publisher=Springer Science and Business Media LLC | volume=8 | issue=2 | date=2017-10-25 | issn=1869-2672 | doi=10.1007/s13137-017-0098-3 | pages=153–168| bibcode=2017IJGm....8..153W | s2cid=126314185 }}

External links

[http://www.royalsoc.ac.uk/DServe/dserve.exe?dsqIni=Dserve.ini&dsqApp=Archive&dsqCmd=Show.tcl&dsqDb=Catalog&dsqSearch=(PersonCode=='NA377') Royal Society citation 1908 (very succinct)]

There is an obituary at

[http://adsabs.harvard.edu//full/seri/MNRAS/0078//0000256.000.html MNRAS 78 (1918) 256]

There is a photograph of Helmert at

[http://www.york.ac.uk/depts/maths/histstat/people/helmert.gif Helmert] on the [http://www.york.ac.uk/depts/maths/histstat/people/welcome.htm Portraits of Statisticians] page

and three more at

[http://www.klima-luft.de/steinicke/ngcic/persons/helmert.htm Helmert]