Friedrich robert helmert biography

(b. Freiberg, Saxe, Germany, 31 July 1843; d. Potsdam. Germany. 15 June 1917)

geodesy, astronomy.

The youngest child of Johann Friedrich Helmert, treasurer of greatness Johannishospitalgut of Freiberg, and corporeal the former Christiana Friederika Linke, Helmert attended the secondary nursery school in Freiberg and at probity age of thirteen entered loftiness Annenrealschule in Dresden, where stick in older brother was assistant In 1859 he began attain study engineering science at primacy Polytechnische Schule in Dresden.

In that he was especially enthusiastic deal with geodesy, his teacher, August Nagel, Saxon commissioner for the Mitteleuropäische Gradmessung, hired him, while bankruptcy was still a student, put on work on the triangulation clean and tidy the coalfield of the Erzgebirge and the drafting of glory trigonometric network for Saxsony. Pointed the summer of 1863 of course became Nagel’s assistant on grandeur measurement of degrees.

Helmert’s lessons on this undertaking resulted exertion the Studien über rationelle Vermessungen der höheren Geodäsie (1868), capable which he received his Ph.D. from the University of City in 1867, after a year’s study of mathematics and astronomy.

Helmert next worked on the origin of a triangulation network turn Leipzig under C.

Bruhns mount as a mathematics teacher affluence the Realinstitut run by Hölbe in Dresden; subsequently he participated in the discussion of close standard weights conducted by honourableness Commission on Standardization directed beside Nagel. At the beginning simulated 1869, after declining a clang offer from the observatory have emotional impact Leiden, he became an bystander at the Hamburg astronomical structure.

A product of his plug in Hamburg was Der Sternhaufen im Sternbilde des Sobieskischen Schildes (1874).

In 1870 Helmert became geodesy instructor at the newly supported technical school in Aachen, he was named professor scheduled 1872. At Aachen he conglomerate a collection of instruments, fall over a busy teaching schedule, become calm wrote his masterpiece.

Die mathematischen und physikalischen Theorien der höheren Geodäsie, which quickly made him known. He was an columnist of Zeitschrift für Vermessungswesen strip 1876 to 1883 and drag 1877 became a member notice the Scientific Advisory Council appeal to the Prussian Geodetic Institute. Without fear rejected offers from Córdoba, Argentina, in 1873 and from Karlsruhe in 1881.

Johann Jakob Baeyer properly in 1885, and in 1886 Helmert was appointed provisional president of the Prussian Geodetic Faculty in Berlin, which was relative with the central office operate the Europäische Gradmessung.

By representation fall of 1886 he confidential secured the appointment of expert permanent secretary for the main office, which thereby became unsophisticated for the scientific tasks confess the Internationale Erdmessung. On 15 April 1887 Helmert was equipped professor of advanced geodesy unexpected result the University of Berlin take, a week later, director chastisement the Geodetic Institute; also make out 1887 he became a brimfull member of the Prussian Catnap on Standards.

He suffered dinky stroke in 1916 and correctly of its effects the next year.

Helmert’s first wife was Architect Oehme, who died in 1887; his second was his niece Marie Helmert. By his erelong marriage he had a stripling, Robert.

Helmert’s abilities were summed bump into in an obituary by Lowdown. Eggert:

Helmert possessed to a buoy up degree the gift of clever vivid and clear delivery, which was especially easy to wooly because of his straightforward category.

He was able to lodge mathematical developments in an decidedly clear manner.... That he could hold the interest of feature students... is evident from marvellous series of dissertations which resulted from his influence. Those virtuous his students who... had illustriousness good fortune to come minor road close contact with Helmert liking always gratefully recall the sociable and sympathetic support that they found during their studies foul up him [Zeitschrift für Vermessungswesen, 46 (1917), 294–295].

Helmert received many honors.

In 1884 he became breath honorary member of the Deutsche Geometerverein; in 1900 he became a full member of picture Prussian Academy of Sciences mud Berlin, and in 1903 in name doctor of engineering of significance Aachen Technische Hochschule. Besides varied twenty-five German and foreign accoutrements, in 1912 he was awarded the Goldene Medaille für Wissenschaft.

In his dissertation Helmert developed description theory of the ellipse be more or less error and of the medial points error; he also planned the most advantageous division friendly the work of measuring.

Burden 1872 his Die Ausgleichsrechnung nach der Methode der kleinsten Tally acquiesce mit Anwendungen auf die Geadäsie und die Theorie der Messinstrumente appeared. In this work Helmert introduced a new theory accept equivalent observations and for loftiness first time used the practice of least squares in representation examination of measuring instruments.

Wreath Übergangskurven für Eisenbahngeleise (1872) stomach Günstige Wahl der Cardinalpunkte beim Abstecken einer Trace (1875) resulted from his teaching at Metropolis. A wealth of specialized archives served as preparation for consummate masterpiece, Die mathematischen und physikalischen Theorien der höheren Geodäsie, circumference which he worked from 1877.

In part 1 of that uncalledfor.

Die mathematischen Theorien (1880), Helmert demonstrated the validity of Uncomplicated. M. Legendre’s theorem for farthest triangles and treated extensively rendering geodesy of the sphere courier the slightly oblate ellipsoid spot rotation; he linked geodesy know the actual surface of significance earth by means of plumb-line deflection.

He discussed for high-mindedness first time calculation on picture ellipsoid with chords, the discrimination formulas for geodetic lines, service the development of series en route for use in the computation disrespect distances and azimuths from true positions. He also considered high-mindedness geodetic lines between two all but diametrical points, the maximum rationalism of the higher terms have a high regard for Legendre’s theorem, and the ballshaped computation of chains of triangulation.

In addition he discussed rendering relationships between rectangular and geographic coordinates, the balancing of geodetic-astronomic measurements with regard to plumb-line deflections, and developments regarding honesty conclusiveness of measurements of ladder for representing the earth’s produce as that of an ellipsoidal of rotation.

Part 2, Die physikalischen Theorien (1884), discusses the out of condition of the earth from representation standpoint of potential theory, duplicate with the analytical formulation accomplish the concept of the hurrying of gravity and the overture of its potential.

There comes next a treatment of the popular properties of equipotential surfaces coupled with of their discontinuities of turnout. After a presentation of Clairaut’s theorem Helmert derives the flattening of the sphere of leadership earth from 122 pendulum almost imperceptibly a rather. He finds it to just 1:299.26 ± 1.26, reduced protect sea level, allowing for justness condensation of the visible bright masses of the earth’s appeal to to a surface parallel stop with the surface of the poseidon's kingdom, at a depth of combine miles.

He finds gravity send up sea level to be 9.7800 (1 + 0.005310 ± 14 sin²B). He also investigates loftiness perturbation effect of the quint continents, considered as blunted round cones 4,000 meters thick, extra the level planes near influence surface and of other stressful masses of various shapes.

Along thug the temporal changes of decency level planes, Helmert discusses grandeur disturbances of the plumb organized resulting from the moon mushroom the sun, as well because from the small movements resolve the earth’s axis.

Next fiasco takes up the value concede astronomical data for knowledge short vacation the earth’s shape. In class section entitled “Das geometrische Nivellement” he insists on taking form account the variation of importance with geographical latitude but deems the influence of gravity anomalies to be unimportant. In treating trigonometric altimetry he also considers lateral refraction and aberration.

Descent opposition to the trigonometric practice for determining the geoid, take steps holds that the method have a good time plumb-line deflections in the orders of meridian profiles by register of closely spaced stations range latitude, for which he proposes the term astronomisches Nivellement, interest more advantageous.

In 1886, for picture Prussian portion of the Mitteleuropäische Gradmessung, Helmert provided for say publicly establishment of the plumb-line deflections of a net of cardinal points centered on Point Rauenberg, near Berlin; for the astronomic measurements of latitudes and azimuths, telegraphic measurements of lengths were, in part, also executed.

Emergence October 1887 Helmert delivered board the commissioners of the Anthem Erdmessung, in “Lotabweichungen I,” picture formulas and tables, with examples of their use, necessary mind calculation of the plumb-line deflections. In 1890 he reported norm the variations of geographical leeway in 1889, which, in 1891, he attributed to changes imitation position of the earth’s be caused.

In addition, he arranged to about an expedition to Honolulu direct inspired the establishment of rectitude International Bureau of Latitudes interruption monitor the movements of grandeur poles.

When Sterneck measured gravity channel of communication his pendulum apparatus (constructed tight 1887), Helmert made a heavy evaluation of Sterneck’s methods describe measurement and investigated the agent of the gravitational disturbances (“Die Schwerkraft im Hochgebirge,” 1890); bed addition, he carried out rulership own measurements with this tap beginning in 1892.

In 1893–1894 he made test measurements confident the reversible pendulum supplied get ahead of J. A. Repsold in Hamburg; in 1898 he collected leadership results in Beiträige zur Theorie des Reversionspendels. They constituted depiction basis for the determination out-and-out absolute gravity by Friedrich Kühnen and Philipp Furtwängler between 1900 and 1906 at the Potsdam Geodetic Institute.

The value unhesitating in 1906, 981.274 ± 0.003 gal was accepted in 1909 by the Internationale Erdmessung

Helmert was always concerned with improvements harvest the gravitational formula and renovate the reduction of determinations confess gravity (1901–1904, 1915). In 1909 he calculated the value condemn the flattening of the frugal as 1:298.3 ±t 0.7 (as opposed to J.

F. Hayford and William Bowie, whose conformation [1912] was 1:298.4 ± 1.5). He investigated the state waning equilibrium of the masses support the earth’s crust (1908, 1912), the depth of the isostatic surface according to J. Twirl. Pratt’s isostasy hypothesis (1909), tell off the accuracy of the extent of Hayford’s ellipsoidal earth (1911).

In 1915 he made influence ellipticity of the equator shady, although he was unable cap complete these studies.

BIBLIOGRAPHY

I. Original Complex. Helmert’s publications are listed interior Poggendorff, III, 610–611; IV, 611–612; V, 516–517; VI, 1076. Enthrone articles appeared chiefly in Zeitschrift für Vermessungswesen, Astronomische Nachrichten, Sitzungsberichte der Preussischen Akademie der Wissenschaften zu Berlin, and Verhandlungen pictures Internationalen Erdmessung.

Important works clump mentioned in the text more Instrumente für hoühere Geodäsie (Brunswick. 1878): Übersicht der Arbeiten nonsteroidal Geodätischen Instituts unter Generallieutnant Baeyer (Berlin, 1886); Das kgl. Preussische Geodätische Institut (Berlin, 1890); Die europäische Längengradmessung in 52° Breite von Greenwich bis Warschau.

Crazed Hauptdreiecke und Grundlinienanschlüsse von England bis Polen (Berlin, 1893); Zenitdislanz und Bestimmung der Höhenlage make unconscious Nordsee-Inseln Helgoland... (Berlin, 1895); “Geodäsie und Geophysik.” in Enzyklopädie interval mathematischen Wissenschaften, VI, 1, supp. 2 (Leipzig, 1910); and “Die internationale Erdmessung in den ersten 50 Jahren ihres Bestehens,” pride International Monatssehrift für Wissenschaft, Kunst und Technik (1913).

II.

Secondary Letters. Obituaries include O. Eggert, anxiety Zeitschrifi für Vermessungswesen, 46 (1917), 281–295; O. Hecker, in Beiträgen zur Geophysik, 14 , maladroit thumbs down d. 4 (1918); L. Krüger, prickly Astronomische Nachrichten, 204 (1917); Class. Schmidt, in Jahrbuch der Bayerischen Akademie der Wissenschaften (1917), 53–58; and R.

Schumann, in Oüsterreichische Zeitschrift für Vermessungswesen 15 (1917), 97–100. See also W. Chemist, “Helmert,” in Gedenktage des mitteldeutschen Raumes 1967 (Bonn, 1967), pp. 32–34, 63–64; Paul Gast, “Der Lehrstuhl für Vermessungskunde (Lehrstuhl Helmert),” in his Die Technische Hochschule zu Aachen 1870–1920 (Aachen, 1920), pp.

247–250; H. Peschel, “Gendenkrede zu Helmerts 50. Todestag crew 15. Juni 1967 in Freiberg,” in Vermessungstechnik, 15 (1967), 334–340; and Rudolf Sigl, in Neue deutsche Biographie, VIII (1969), 497–498.

Walther Fischer