- Academic Lineage
-
The American Physical Society (APS) recently sponsored a project
encouraging people to trace their "academic lineage."
That is, to find your thesis advisor's thesis advisor, and so
on, as far back as you can trace. In some sense, an academic lineage
represents the passing down of theoretical interests, methodological
training, personal traits, and other features that shape a researcher.
Of course, one should not make too much of this, as most of us
have been influenced by other mentors beyond our immediate thesis
supervisor. Furthermore, because there are far more scientists
and engineers alive today than there were a hundred years ago,
it should not be surprising to come across some familiar names.
Beyond personal curiosity, my professional interest in this exercise has to
do with the roots of the discipline of Aerospace Structures. A broader interest
has to do with the relationship of engineering (technology) to science. Before
1800 or so, science and technology were very separate activities: natural philosphy
somehow nobler than the practical concerns of engineers. Engineers gradually
adopted the methods and trappings of scientists, starting in about the mid-1800s,
completing the process by the mid-1900s. The first doctoral degrees in engineering
were awarded around 1900, and were still rare for some time following that.
In what follows, if a Ph.D. advisor was not evident (perhaps because of the lack of an earned doctoral degree!), known significant mentors were identified.
"Technical knowledge, after a long path through royal societies, royal
academies and military engineering schools, all of which circumvented the
universities, finally reached the technical colleges, the prototypes of which
at the time of the French Revolution were not accidentally called schools
for powder and saltpeter. This odor of sulphur frightened the old universities
so much that they wanted to refuse the technical colleges the right of promotion
to doctoral degrees. And it was first the life's work of the great mathematician
Felix Klein, who compensated for his extinguished genius with organizational
talent, which in the German Reich prevented science and technology, universities
and schools of engineering, from taking fully separate ways. In the garden
of the Mathematical Institute at Gottingen, as the first physics laboratory
in the history of German universities, a couple of cheap sheds appeared, out
of which emerged all of quantum mechanics and the atomic bombs. David Hilbert,
Klein's successor to the professorship, was thus doubly refuted. His theory
that no hostility exists between mathemeticians and engineers simply because
there is no relationship between them at all was overshadowed by world developments,
and his hypothesis that all mathematical problems can be decided was pushed
aside by Alan Turing's computer prototype. Since then, all knowledge, even
the mathemetician's most abstract, is technically implemented. "If the
19th century," to use Nietzsche's wicked phrasing, "was a victory
of the scientific method over science," then our century will be the
one that saw the victory of scientific technology over science.
- Friedrich Kittler
I've enjoyed the process of tracing this out, for a couple
of reasons. While I was generally familiar with the results
of their efforts, knowing more about the people who were
active participants in the transition period of technical education
gives one a better appreciation of engineering as a human enterprise,
and provided me with a greater sense of continuity with the past.
The efforts of these people had a lasting impact on the world
as we know it, and the range of questions they dared to address,
as well as their success in applying the knowledge gained, do
give one something to aspire to.
- George A. Lesieutre
- D. Lewis Mingori
- Thomas R. Kane
- Raymond D. Mindlin (1906-1987)
- H. Malcolm Westergaard (189x-1950)
- Felix Klein (1849-1925)
- August O. Föppl (1854-1924)
- C. Otto Mohr (1835-1918)
- Franz Grashof (1826-1893)
- Arthur Newell Talbot (1857-1942)
- Ira Osborn Baker (1853-1925)
- Stillman W. Robinson (1838-1910)
- De Volson Wood (1823-1897)
*****
- George André Lesieutre
-
- Professor, Aerospace Engineering
- The Pennsylvania State University
-
- A WORK IN PROGRESS
-
- Dissertation: "Finite Element Modeling of Frequency-Dependent
Material Damping using Augmenting Thermodynamic Fields"
- University of California, Los Angeles, 1989
- Advisor: D.L. Mingori
-
- to top
*****
- Diamond
Lewis "Tino" Mingori
-
- Professor and Head, Mechanical and Aerospace Engineering
- University of California at Los Angeles
-
- Education
-
- Dissertation: "Attitude Stabilization of Satellites
by Means of Gyroscopic Devices"
- Stanford University, 1966
- Advisor: Thomas R. Kane
-
- Research Interests
- Dynamics and control, including spacecraft attitude control,
spinning and dual spin spacecraft dynamics, spinning rocket stability,
fault detection, modeling and model reduction, and identification
and vibration control of flexible structures. In the areas of
spacecraft dynamics and control, work addresses such topics as
recovery from flat spin, passive spin balancing using internal
moving masses, passive vibration isolation using flexible couplings,
effects of asymmetry on the stability of spinning spacecraft,
and the dynamics of spin-up through resonance. Additional research
contributions in the areas of model reduction, robust control,
dynamics, and system identification.
to top
*****
Thomas
Reif Kane
- Emeritus Professor of Mechanical Engineering
- Stanford University
- Education
- B.S. Columbia University - Mathematics (1949)
B.S. Columbia University - Civil Engineering (1950)
M.S. Columbia University - Civil Engineering (1952)
PH.D. Columbia University - Applied Mechanics (1953)
- Dissertation: "Reflection of Flexural Waves at the Edge
of a Plate"
- Columbia University, 1953
- Advisor: Raymond D. Mindlin
-
- Research Interests
- Multibody Dynamics; Stability of Motion; Dynamics of Human
Motion;
Spacecraft Dynamics; Computerized Symbol Manipulation.
-
- Awards/Honors
- University of Pennsylvania Alumni Teaching Award, 1956
American Astronautical Society Dirk Brouwer Award, 1983
Alaxander von Humboldt-Stiftung Humboldt-Preis, 1988
Doctor of Technical Sciences, T.U. Wien, Austria, 1989
to top
*****
Raymond
D. Mindlin
- (1906-1987)

- Professor of Civil Engineering
- Columbia University
-
- Education
- B.A., 1928, Columbia University (also, sprinter on the varsity track team)
- B.S., 1931, Columbia University
- C.E., 1932, Columbia University (the Illig medal for "proficiency in
scholarship")
- Ph.D., 1936, Columbia University
-
- He also attended summer courses at the University of Michigan, Department
of Engineering Mechanics, organized by Stephen Timoshenko, in 1933, 1934,
and 1935. Instructors there included L. Prandtl, R. V. Southwell, and H. M.
Westergaard. His initial publication dates from the middle of this period,
a solo, full-length paper describing a new type of polariscope for photoelastic
analysis. In April of 1935 he published a paper on the torsion of structural
beams, with Westergaard.
For his doctoral research, Mindlin set himself a fundamental problem in theoretical
elasticity: determining the stresses in an elastic half-space subjected to
a sub-surface point load. Working without any guidance at Columbia,
he succeeded in finding the solution by employing the method of nuclei of
strain. The results, nowadays referred to as "Mindlin's problem,"
represent a generalization of the two classical 19th century solutions respectively
associated with the names of Kelvin and Boussinesq, and have become the basis
for analytical formulations widely employed in geotechnical engineering.
-
- Dissertation: "Force at a Point in the Interior of a Semi-Infinite
Solid"
- Columbia University, 1936
- (Informal) Advisor: H. Malcolm Westergaard
- (Prof. Daniel Drucker (Brown, Illinois, Florida), Mindlin's first Ph.D.
student, confirmed that Mindlin considered Westergaard to be an informal thesis
advisor.)
-
- Positions
- 1936-1938, Research Assistant
- 1938-1940, Instructor in Civil Engineering
- 1940-1942, Assistant Professor of Civil Engineeering
1942-1945 Applied Physics Laboratory, Silver Spring, Maryland, engaged in
naval ordnance work. He played a significant role in the development of the
proximity fuse, one of the major achievements in the scientific war effort.
For his part in its success he was presented, shortly after the end of the
war, with the Presidential Medal for Merit, the highest decoration awarded
to civilians.
1945-1947, Associate Professor
- 1947- Professor
-
- Awards
- National Medal of Science (1979)
Presidential Medal for Merit (1946) (the highest civilian decoration of the
second World War)
-
- National Academy of Engineering (1966)
- National Academy of Sciences (1973)
-
- Fellow, American Academy of Arts and Sciences (1958)
- Fellow, ASME (1962), Honorary Member of the ASME (1969)
- Fellow, of the Accoustical Society of America (1963)
- Honorary D.Sc. degree from Northwestern University (1975)
-
- ASCE: the Research Prize (1958) and the von Karman Medal (1961)
- ASME: the Timoshenko Medal (1964) and the ASME Medal (1976)
- ASA: the Trent-Crede Award (1971)
- Naval Ordnance Development Award (1945)
- Army Electronics Command C. B. Sawyer Award (1967)
-
- Columbia University: the Great Teacher Award (1960) and the Egleston Medal
(1971)
-
- * The source of much of this information is: The Collected Papers of
Raymond D. Mindlin, edited by H. Deresiewicz, M.P. Bieniek, F.L. DiMaggio,
Springer-Verlag, 1989.
to top
*****
Harald
Malcolm Westergaard
- (189x-1950)
- Dean, Graduate School of Engineering
- Harvard University
-
- Education
- B.S., Royal Technical College, Copenhagen
- Ph.D., Civil Engineering, Technische Hochschule München, 1914
- Ph.D., Civil Engineering, University of Illinois, 1916
-
- Westergaard studied with Prof. Felix Klein at
the University of Göttingen for a year, until Klein's retirement in 1913.
-
- Dissertation: "Anwendung der Statik auf die Ausgleichsberechnung"
- Technische Hochschule München, Civil Engineering, 1914 (awarded 1921,
after WWI)
- Advisor: August Föppl
- Dissertation: "Tests and analysis relating to the strength and elasticity
of concrete and reinforced concrete under bi-axial stress"
- University of Illinois, Civil Engineering,1916
- Advisor: Arthur Newell Talbot
- Positions
- 1916-1936 Professor, Theoretical and Applied Mechanics, University of Illinois
- 1936-1950 Dean, Graduate School of Engineering, Harvard University
- 194x-194x+2, Captain, U.S. Navy (WWII))
-
- Because Westergaard had limited options within the Danish university system,
which had single professors, Professor Ostenfeld of the Royal Technical College
guided Westergaard first to Gottingen, to Munich, and then to Illinois. Westergaard
initially reached the United States with the financial assistance of the American-Scandinavian
Foundation. He became well known for his early analysis, in the 1930s, of
the earthquake-resistance of Hoover Dam. He also was consulted on other major
projects, including the Panama Canal and the San Diego airport. He published
a fundamental paper in the field of fracture mechanics, and published a textbook
on elasticity and plasticity.
-
- Before World War II he was active in bringing to the United States Jewish
intellectuals, who were mostly in German universities and having a hard time
because of the policies of the Nazis. Some of these people included physicist
Reinhold Rudenberg, who helped develop the electron lens, Richard von Mises,
Karl Terzaghi, and Arthur Casagrande. They were not only valued colleagues,
but family friends.
-
- Westergaard married Rachel Harriet Talbot, daughter of his doctoral advisor,
Arthur Newell Talbot. One of his daughters, Mary
Talbot Westergaard Barnes, lives in State College, PA!
-
- * Information from Prof. James Phillips, Theoretical and Applied Mechanics,
University of Illinois, and Mary Barnes.
to top
*****
August Otto Föppl
- (1854-1924)
-
- Professor of Engineering Mechanics
- Technische Hochschule München
-
- Education
- 1874, Structural Engineer, Stuttgart Polytechnicum
-
- August Föppl was born in the small town of Gross-Umstadt (in the Duchy
of Hesse) to the family of a doctor. He attended public elementary school
and the Darmstadt Gymnasium. Impressed by local railroad construction, he
entered the Polytechnical Institute of Darmstadt for preparatory training
in structural enegineering in 1869. He moved on to the Stuttgart Polytechnicum
in 1871. The masterful lectures of Otto Mohr confirmed
his interest in structural engineering. Mohr left Stuttgart in 1873 for Dresden,
and Föppl entered the Polytechnical Institute at Karlsruhe to finish
his engineering education. In his autobiography, Föppl was critical of
the teaching of Franz Grashof, the professor of engineering mechanics
at Karlsruhe.
-
- When he graduated, the German economy was slow. He took some temporary work
in bridge design at Karlsruhe, completed a year of compulsory military training,
then taught at a trade school in 1876 (Holzminden). From 1877 to 1892 he taught
at the Technische Hochschule Leipzig. Föppl was not satisfied in these
positions, but it was difficult to get a professorship since the number of
vacancies was small and the competition very great. It was necessary to publish
some important work and to become well known in science in order to have a
chance of capturing a professorship at a polytechnical institute. Such positions
commanded great respect in Germany, and the best engineers of the country
would compete for any vacancy. Föppl published several important papers
on space structures and designed a market building in Leipzig that had a cast-iron
structure to support the roof. Later, he published a collection of papers
in book form that became very popular. He became interested in electricity
when its industrial applications blossomed in the early 1880s. His work led
to a book, "Introduction to the Maxwellian Theory of Electricity,"
a publication that is known to have had an impact on Einstein.
-
- He was elected to the professorial chair for Engineering Mechanics at the
Technische Hochschule Munchen (Munich Polytechnic, now the Technische Universität
München) in 1894, succeeding Johann Bauschinger as the head of the Mechanical
Engineering Laboratory. He remained in this position until 1921. His work
emphasized practical engineering problems, including experimental verification.
Problems addressed had to do with, among other things, the strength of cement,
material behavior under hydrostatic compression, and fatigue. Föppl was
the first to give a satisfactory theory of whirling of a flexible shaft rotating
at high speed. He was an outstanding lecturer and, working methodically from
the simple and special to the complex and general, held student interest even
in very large classes. His teaching work is mirrored in the initially four-volume
publication "Lectures in Engineering Mechanics." (Introduction to
Mechanics; Graphical Statics; Strength of Materials; Dynamics; and later,
Theory of Elasticity). The book on strength of materials became the most popular
textbook in German-speaking countries, and was translated into Russian and
French.
-
- He was Ludwig Prandtl's doctoral thesis advisor (lateral buckling of beams)
and father-in-law. (When Prandtl was thirty-four, he decided it was time to
marry, so he went to his old professor to ask for his daughter's hand in marriage.
But Prandtl didn't say which daughter. Föppl and his wife had a hurried
caucus and prudently decided it should be the older one. That was fine. The
marriage was a long and happy one.)
-
- On Föppl's recommendation, Felix Klein hired
Prandtl as the founding director of the Institute of Applied Mechanics at
the University of Göttingen. At Gottingen, Prandtl served as Theodore
von Karman's doctoral thesis advisor (buckling of columns in the plastic region).
(In 1906, von Karman received a fellowship from the Hungarian Academy of Sciences
and chose to study at the University of Gottingen in Germany, where his professors
included Klein in applied mechanics, Prandtl in fluid mechanics, and mathematician
David Hilbert. His approach to engineering problems was through mathematical
calculations, which were then tested in a laboratory, often by his students,
for he was not mechanically adept.)
-
- In 1922 , Föppl was succeeded at Munich by his son Carl Ludvig Föppl.
-
- * Much, but not all, of this information was obtained from History of
Strength of Materials, by Stephen P. Timoshenko, Dover, 1983 (originally
McGraw-Hill, 1953).
-
- to top
-
- *****
Arthur
Newell Talbot
- (1857-1942)
-
- Professor of Municipal and Sanitary Engineering
- University of Illinois
-
- Education
- B.S., Civil Engineering, University of Illinois, 1881
- Civil Engineer, University of Illinois, 1885
-
- Positions
- 1881-1885, Railroad Location, Construction, and Maintenance, the U.S. West
- 1885-1890, Assistant Professor of Engineering and Mathematics, University
of Illinois
- 1890-1926, Professor of Municipal and Sanitary Engineering, in charge of
Theoretical and Applied Mechanics, University of Illinois
-
- Arthur Newell Talbot was born October 21, 1857, at Cortland, Illinois, a
village about 55 miles west of Chicago. His early life was lived under pioneer
conditions among the sturdy people who were developing new homes in a prairie
land. His early education was in the school in Cortland, and in the high school
at Sycamore. After completing his high school course he taught at a country
district school for two years.
-
- In 1877 he entered the University of Illinois, then known as the Illinois
Industrial University, to study civil engineering. Here he came in contact
with Ira Osborn Baker who had begun his long career
as a teacher of civil engineering three years earlier and was already beginning
to attract attention. Talbot was a brilliant student; indeed his scholastic
average remained the record for many years. However, he did not devote all
of his time and energy to study but was active in extracurricular activities.
He was secretary, vice president, and president of Philomathean Literary Society,
associate editor of the Illini delegate to the Interstate Oratorical Association,
class essayist, a leading officer in the student government, the ranking officer
in the Cadet Corps.
-
- In September 1885, he returned to the University of Illinois as assistant
professor of engineering and mathematics and taught a wide range of subjects,
which at different times included mathematics, surveying, engineering drawing,
contracts and specifications, roads and pavements, railroad engineering, mechanics
and materials, hydraulics, tunneling and explosives, water supply and sewerage.
In 1890, his title was made Professor of Municipal and Sanitary Engineering,
in charge of Theoretical and Applied Mechanics. After the era of expansion
in engineering schools began, mechanics and engineering materials absorbed
his attention even more than sanitary engineering, and without a change in
title the emphasis of his work continued to be placed on mechanics and materials.
-
- Before the turn of the century, Talbot made many contributions to the engineering
profession in a number of fields. A small treatise on a very flexible method
for laying out easement curves at the ends of circular curves (first described
by him in 1891) was published in 1899 as "The Railway Transition Spiral"
and has gone through several editions and has been used by many railroads.
His pioneer work in sewage treatment by means of septic tanks later made it
possible for municipalities to contest certain patent claims on methods and
principles of sewage disposal. During this period his investigations provided
methods for the standardization of testing paving brick for strength and abrasion.
-
- Professor Talbot was active and influential in the formation of the Engineering
Experiment Station, and under his leadership it was an immediate success.
A comprehensive and thorough investigation on reinforced concrete, conducted
and directed by him, started in 1903 and continued for many years on reinforced
concrete beams, slabs, columns, footings, pipes, frames, and buildings. This
experimental work became a principal source of the early knowledge on which
the properties and requirements for the design of reinforced concrete structures
were based by engineers and engineering organizations and on which principles
and methods of practice were formulated. The conception of relations existing
between the strength of a concrete mixture and items involving the absolute
volume of the cement, the fine and coarse aggregate, and the voids in the
mixture, as well as the so-called relative water content of the mixture, put
forth in a paper in 1921, and in a later bulletin, has proved useful to concrete
engineers. Tests of stone, brick and concrete, the investigation of steel
columns and timber stringers, and a variety of other experimental and analytical
work have also added to engineering knowledge.
-
- A notable piece of research which Dr. Talbot directed since 1914 is the
investigation of railroad track, commonly called "Stresses in Railroad
Track." This investigation has been conducted with a view of obtaining
definite and authoritative information on the properties, mode of action,
and resistances developed in the various parts of the track structure (rail,
ties, ballast, and roadbed) under the application of locomotives and cars
moving at various speeds. At the time the work was begun, comparatively little
of a scientific nature was known of the stresses in rail and other parts of
the track or of the effect on the track of the many variations in action of
the rolling stock in its operation. This research project produced reliable
knowledge on the interrelation between track and rolling stock and contributed
to a more rational basis for the design and construction of the track structure.
It has been characterized as one of the most significant contributions to
the scientific knowledge of railroads ever made.
-
- Doctor Talbot exercised a far-reaching influence on engineering developments
through committee activity in engineering societies. Taking a leading part
in the work of the first joint committee on Concrete and Reinforced Concrete
(1904-1916) as a representative of the American Society of Civil Engineers,
he was influential in formulating principles and methods of design based on
the tests he had made and upon other data and analyses. A chairman of the
sub-committee on design, he formulated and advocated many of the views that
were adopted by the committee. The report of this committee exercised a marked
influence, among engineers and architects, on the ideas and practices in engineering
design and on building regulations, in the pioneer period of reinforced concrete
construction. Most of the fundamentals of design then put forth are still
accepted. The tests of reinforced concrete made at the Illinois laboratory
were widely used by engineering schools and thus the information spread even
more rapidly to engineering offices.
-
- Doctor Talbot attained high rank among engineering teachers and was influential
in the Society for the Promotion of Engineering Education (now the American
Society for Engineering Education) since its formation in 1893, holding various
offices including that of president. He was prominent in the work of the American
Society of Civil Engineering, serving on its research committee and on other
committees and on its Board of Direction; he was president of that society
in 1918. He was president of the American Society for Testing and Materials
in 1913-1914.
-
- A portrait of Professor Talbot, presented to the University of Illinois
in 1925, now hangs in the Engineering Library. The principal speaker at the
presentation, a V.P. of McGraw-Hill, concluded as follows: "This is his
great achievement. This is the work that makes him brother of those giants
who since the days of Watt have been bearers of gifts to humanity. Into that
grand galaxy of engineers' names fits worthily his name, the name of our teacher,
our inspiring leader in science and in engineering, our lovable friend, Professor
Arthur Newell Talbot."
-
- Honorary Degrees
Doctor of Science, Univ. of Pennsylvania (1915)
Doctor of Engineering, Univ. of Michigan (1916)
Doctor of Laws, Univ. of Illinois (1931)
-
- Awards
- The Washington Award of the Western Society of Engineers "For pre-eminent
services in promoting the public welfare, for his life work as student and
teacher, investigator and writer and for his enduring contribution to the
science of engineering" (1924)
-
- The George Henderson Medal by the Franklin Institute -- "No. 5 for
invention in railway engineering" (1924)
-
- A Tablet at Urbana and Champaign Sanitary District Building, among other
things, states: "On this date, 1897, the Champaign Septic Tank was built.
Designed by Prof. A. N. Talbot. It was among the first of its kind in this
country." (1924)
-
- Bronze Plaque by American Railway Engineering Association -- "An appreciation
to Arthur Newell Talbot, worker in research and scientific advancement,"
accompanied by resolutions reciting "... its high appreciation of you
as a scientist, and teacher, and investigator and organizer, and, last but
not least, as a man" (1925)
-
- The Henry C. Turner Medal by the American Concrete Institute "For outstanding
contributions to the knowledge of reinforced concrete design and construction"
(1928)
-
- The Benjamin Garver Lamme Medal by the Society for the Promotion of Engineering
Education Achievement in engineering education" (1932)
-
- A Bronze Tablet by Students -- "Honors the achievements of Arthur Newell
Talbot and his contributions to engineering and the prestige of the College
of Engineering, University of Illinois" (1937)
-
- The John Fritz Medal by the United Engineering Societies "Moulder of
men, eminent consultant on engineering projects, leader of research and outstanding
educator in civil engineering" (1937)
-
-
- * Information from Prof. James Phillips, Theoretical and Applied Mechanics,
University of Illinois.
-
- to top
-
- *****
Christian Otto Mohr
- (1835-1918)
-
- Professor of Engineering Mechanics
- Stuttgart Polytechnikum
-
- Education
- B.S., Hannover Polytechnical, 1855?
-
- Positions
- Railroad structural engineer
- 1868-1873, Professor of Engineering Mechanics, Stuttgart Polytechnikum
- 1873-1900, Professor of Engineering Mechanics, Dresden Polytechnikum
-
- Born of Holstein landowners on the coast of the North Sea (Wesselburen),
Otto Mohr became one of Europe's most decorated engineers of the 19th century.
He entered Hannover Polytechnical Institute at the age of 16. Early in his
career, while working as a structural engineer on the railroads in Hannover
and Oldenburg, he designed some of the first steel trusses as well as some
of the most renowned bridges in Germany. During those years, Mohr also began
his theoretical work in mechanics and strength of materials.
-
- In 1868, at the age of 32, Mohr was invited to become the professor of engineering
mechanics at the Stuttgart Polytechnikum. Despite an unpolished delivery,
his lectures were well received by students (including August
Föppl) because of their simplicity, clarity, and conciseness. Being
both a theoretician and practicing civil engineer, Mohr knew his subject thoroughly
and was always able to bring something fresh and interesting to his students'
attention. In 1873, Mohr moved to the Dresden Polytechnikum, and taught there
until the age of 65 (1900). Following retirement, he remained in the Dresden
area where he continued his scientific work until his death.
-
- In addition to a lone textbook, Mohr published many research papers on the
theory of structures and strength of materials. Graphical solutions to specific
problems were a common theme in many of them. Borrowing upon earlier work,
he expanded the graphical representation of stress about a point to three
dimensions. Later, using the "circles of stress" with which his
name is now commonly associated, Mohr developed the first theory of strength
based on shearing stresses. Mohr made numerous contributions to the theory
of structures, including the Williot-Mohr diagram for truss displacements,
the moment-area method for beam deflections, and the Maxwell-Mohr method for
analyzing statically indeterminate structures.
-
- (Joseph Victor Williot, 1843-1907, was a French engineer, and James Clerk
Maxwell, 1831-1879, was a famous British scientist.)
-
- * Some of this material taken from History of Strength of Materials,
by S.P. Timoshenko, McGraw-Hill, 1953.
to top
- *****
Franz Grashof
- (1826-1893)
-
- Professor of Applied Mechanics and Mechanical Engineering
- Karlsruhe Polytechnical Institute
-
- Education
- B.S., Berlin Royal Technical Institute (Gewerbeinstitut), 1849
-
- Positions
- Mechanic
- 1854-1863, Lecturer, Berlin Royal Technical Institute
- 1863-1893, Professor of Applied Mechanics and Mechanical Engineering, Karlsruhe
Polytechnical Institute
A German engineer, born July 11, 1826, in Dusseldorf, Germany, Franz Grashof left school at the age of 15 to work as a mechanic while attending trade school. From 1844 until 1847, Grashof studied mathematics, physics and machine design at the Berlin Royal Technical Institute (Gewerbeinstitut). After his graduation in 1949, he spent 2-1/2 years as a seaman on a sailing ship which visited India, Australia, the Dutch Indies, and Africa. Upon returning home in 1851 he started to prepare himself for the teaching profession and began lecturing in applied mathematics in 1854 at the Gewerbeinstitut.
In 1856, he helped to launch the Society of German Engineers (Verein Deutscher Ingenieure, VDI), and assumed an enormous load as author, editor, corrector and dispatcher of its journal. In this journal he published a number of articles dealing with various problems of applied mechanics. This activity brought him a measure of fame and led to his election by the Karlsruhe Polytechnical Institute to replace Redtenbacher as the chair of Applied Mechanics and Mechanical Engineering, in 1863. Grashof’s teaching activities extended from machine mechanics over the whole field of rational mechanics, including "Strength of Materials," "Hydraulics," "Theory of Heat," and "General Engineering," and his work on deformable solid mechanics set the pattern for all subsequent textbooks in the field, including Föppl's book. p>
He was very interested in strength of materials and, in 1866, published his “Theorie der Elasticität und Festigkeit.” In this book he did not confine himself to elementary strength of materials, but introduced the fundamental equations of the theory of elasticity. These he applied to the theory of bending and torsion of prismatical bars and to the theory of plates. In treating bending of bars, he found solutions for some shapes of cross section which were not considered by Saint-Venant, and he determined the longitudinal tensile force which would be produced during bending if hinged ends were immovable. Treating cylindrical shells subjected to internal pressure, Grashof did not merely apply Lamé’s formula but addressed the local bending stresses which are produced when the edges of the shell are rigidly connected with the end plates. He found complete solutions for several cases of symmetrically loaded circular plates, and also considered uniformly-loaded rectangular plates, developing approximate solutions for several cases.
A close examination of Grashof’s work and of his numerous reviews of the work of other scientists proves him to be particularly outstanding in the matter of scientific principles. He was known to have corrected many erroneous notions of other prominent contemporary scientists, including Rudolf Clausius (1822-1888). Grashof represents, perhaps, one of the best paragons of contemporary engineering science that Europe had produced at that time. Moreover, since 1867, Grashof was generally recognized as the leading promoter of the academically orientated technological universities in Germany.
As an individual, Grashof was very generous even when he disagreed with other scientists and enjoyed great respect among the professionals of his time. He was a master of the entire field of applied mathematics; he had taught mathematics for many years at the Trade Institute in Berlin, before he assumed the Chair of Engineering Mechanics at Karlsruhe. Grashof, like his modern counterpart, the engineering scientist, strove for the most profound insight and clarity in all of his works in engineering science. He found this kind of clarity in scientific expositions which embraced all possible “special cases” in a manner that explicitly expressed the conditions of the foundations of the theory. Through this rational mechanistic approach, Grashof was able to reveal the adequacy or inadequacy of the theory and the experimental data for the solution of any problem. His investigations indicated where experimental data were lacking, thus giving impetus to a host of experimental research problems.
In presenting his work, Grashof preferred the use of analytical methods and rarely used figures for illustration. He usually began with the discussion of a problem in its most general form and only later, after a general solution was found, did he introduce the simplifications afforded in specific cases. This manner of presentation makes reading difficult; therefore the book was not popular with practical engineers and was too difficult for the majority of engineering students (including Föppl). However, the more persevering students could gain a very thorough knowledge of the theory of strength of materials from it. To this day, Grashof's book has not lost its interest, as it was the first attempt to introduce the theory of elasticity into a presentation of strength of materials for engineers.
The accusation raised by engineers, who were strongly oriented to the empirical approach, against Grashof’s general and comprehensive mathematical formulation of engineering physics was fully rebuffed by Grashof in the third volume of his Theoretische Machinenlehre (Theory of Machines). Grashof, Emil Winkler (1835-1888), and Gustav Anton Zeuner (1828-1907) were the harbingers of the modern era of engineering science and the technological university. Grashof’s lectures at Karlsruhe were predicated upon the needs of, and developed for, the mechanical engineer in the Department of Mechanical Engineering; it was upon this foundation that the great reputation of Karlsruhe's engineering school rested. The demands imposed upon the students in the Structural Engineering Department did not reach much beyond the modest level of Navier's beam theory. The lectures on structural mechanics offered by Professors Baumeister and Sternberg were considerably more elementary and less demanding than those of Grashof. In this aspect, these lectures were similar to those of Mohr, and herein resided the "clarity" that Föppl found wanting in the lectures of Grashof.
Grashof was a methodical and nontemperamental teacher, much like the famous physicist, Gustav Robert Kirchhoff (1824-1887). His lectures were meticulously composed and rather impersonally delivered; his competence regarding the subject was beyond question. Grashof lectured discursively without notes, and was not known to commit errors or to fall into conceptual pitfalls at the blackboard. He was, in fact, a reputedly precise, confident, and clear lecturer yet tending to be somewhat monotonous in his delivery. However, he was a mathematically-motivated engineer and inclined to place considerable demands upon the initiative of his students. In this, he did not seem to realize the difficulties encountered by mathematically ill-prepared and less capable students, such as Föppl, who were not educated at Karlsruhe.
After Grashof's death on October 26, 1893 at Karlsruhe, the Society of German Engineers honored his memory by instituting the Grashof Commemorative Medal as the highest distinction that the society could bestow for merit in the engineering skills.
- Sources:
- * From: Grigull, Sandner, Straud, Winkler. Origins of Dimensionless Groups of Heat and Mass Transfer. Lehrstuhl a Fuer Thermodynamik Technische Universitaet Muenchen. IHTC, Muenchen 1982.
- * Timoshenko; History of Strength of Materials.
- * Gunhard Æ. Orovas, Introduction (in English) to Drang Und Zwang (August Föppl and Ludwig Föppl), 1969, reprint of the 3rd edition, 1941.
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*****
- Ira Osborn Baker
- (1853-1925)

Education
- Certificate in Civil Engineering, Illinois Industrial University (later,
the University of Illinois), 1874
- Bachelor of Civil Engineering, Illinois Industrial University, 1878
- Civil Engineer, Illinois Industrial University, 1878
- Doctor of Engineering (Honorary), Illinois Industrial University, 1903
-
- Positions
- 1874-1922, Professor of Civil Engineering, University of Illinois
-
Ira Osborn Baker was a young faculty member in Civil Engineering during
Talbot's undergraduate days, and was named Professor of Civil Engineering
in 1880, just before Talbot's graduation. It was during these years that Arthur
Newell Talbot was beginning his own illustrious career in closely related
areas, so it is quite likely that Baker was one of Talbot's mentors.
Born on September 23, 1853 in Litton, Indiana, Baker attended high school
in Illinois, then returned to Indiana to teach in a country school for six
months. In March 1871, he enrolled at the Illinois Industrial University (later
renamed the University of Illinois) in civil engineering. He was one of five
civil engineers among the university's 19 graduates in June 1874.
He then assumed a position teaching civil engineering and physics, beginning
a 48-year faculty career at the University of Illinois. For 39 of those years,
he was head of the civil engineering department. When the university was authorized
to offer degrees, rather than certificates, he was among the first to be awarded
the degrees of bachelor of civil engineering and of civil engineer in 1878
and an honorary doctor of engineering degree in 1903.
As no satisfactory textbooks existed for the subjects he was teaching, Baker
developed his own by writing the text on tracing paper and blueprinting the
necessary copies. Several of these evolved into standard textbooks. His "Treatise
on Masonry Construction," first published in 1889, was the first comprehensive
textbook published in English dealing with foundation methods and principles
involved in the use of cement. The book was reprinted in several editions
and was used widely in schools in the United States, as well as in Japan,
China, Mexico, and other countries. His book "A Treatise on Roads and
Pavements" was published in 1903 and also went through several editions.
Baker pioneered in laboratory development at the university, creating a cement-testing
laboratory in 1889 and later a road-materials laboratory. These were used
for teaching and research. Baker himself conducted investigations of brick,
stone, cement, and concrete, making many valuable contributions to the knowledge
of these materials.
Baker is proclaimed as the person primarily responsible for the founding
of the Society for the Promotion of Engineering Education (now the American
Society of Engineering Education, ASEE). In addition to his efforts in founding
the Society for the Promotion of Engineering Education, which he served as
president from 1899 to 1900, he organized the Illinois Society of Engineers
in 1886 and was active in the American Society of Civil Engineers and the
Western Society of Engineers. Baker often served as an advisor to public officials
in the State of Illinois on matters dealing with drainage, highway bridges,
and building codes. After his retirement from the University of Illinois in
1922, he retained the title Professor Emeritus of Civil Engineering until
his death on November 8, 1925.
Founding of ASEE (The American Society of Engineering Education)
With a great diversity of opinions concerning the direction of engineering
education in the late 1800s, it was evident that that a forum for exchange of
ideas was needed. In 1890, Stillman W. Robinson, a professor of mechanical engineering at The
Ohio State University, organized a "Mechanical Engineering Teachers Association."
The group held its first meeting the following year at Columbus, Ohio and met
again in Buffalo in 1892, at which time its members voted to change its name
to "Engineering Teachers Association," presumably to broaden its appeal to engineering
educators other than just teachers of mechanical engineering. Although this
society did not last more than another year or two, it did indicate that the
time was right for creating a society to focus on engineering education.
The World's Columbian Exposition, held in Chicago in 1893, was a
natural opportunity to bring together a larger group of engineering faculty
members to discuss the problems facing engineering education and suggest possible
actions. A number of congresses on important branches of knowledge and industry
were being established in connection with the exposition. Ira Osborn Baker,
a 39-year-old professor of civil engineering at the University of Illinois,
convinced the organizers that the International Congress of Engineering should
consider engineering education as a topic separate from the disciplinary discussions.
His suggestion was accepted and resulted in Division E, Engineering Education,
whose sessions were organized and chaired by Baker. This was the first major
meeting on engineering in which engineering education was recognized as an important
subject and indeed was given equal status with the branches of engineering.
When Baker opened the meetings of Division E on July 13, 1893, 70 individuals
were present, an attendance considered to be very large. While most of the attendees
were young (in their 20s or 30s) a significant number were highly experienced
educators. The group represented a large cross section of schools from every
region of the country. In the formal sessions, the participants listened to
papers on various aspects of engineering education and discussed their implications.
Quickly, there was a general feeling that a permanent organization devoted to
the advancement of engineering education was necessary.
Stillman W. Robinson,
president of the Mechanical Engineering Teachers Association, was at the session.
Robinson, then 55 years of age, began his teaching career in 1866, when he accepted
a position as assistant in civil engineering at the University of Michigan under
Professor De Volson Wood. Wood, 61, was perhaps the most senior engineering
teacher in the country, having taught continuously since 1849, first in a local
public school, then while he was a student at the Rensselaer School in its preparatory
division, and then from 1857 in engineering. The two men worked closely together
and in 1867, jointly developed a steam rock drill. Although Robinson moved to
the Illinois Industrial University, which became the University of Illinois,
in 1870, and although Wood moved to the newly founded Stevens Institute of Technology
in 1872, the two men remained close. When Wood was writing his book, A Treatise
on the Resistance of Materials, Robinson working from a prepublication copy,
solved many of the tutorial problems.
A year after Robinson moved to the Illinois
Industrial University, Ira O. Baker enrolled there as a student. For two years,
Baker took classes from Robinson and for four years served as an assistant to
him in physics laboratory practice. Although 20 years later, Society records
would state that the organizers of the congress were apparently unaware of the
existence of Robinson's organization until just a few days before the meetings
began, there clearly was a long-standing relationship between Robinson and Wood
and between Robinson and Baker at the time of the Columbian Exposition.
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*****
- Stillman Williams Robinson
- (1838-1910)

Education
- (Mechanical) Engineering, University of Michigan, 1863
-
- Positions
- 1866-1867, Assistant in Civil Engineering, University of Michigan
- 1867-1870, Assistant Professor of Mining Engineering and Geodesy, University
of Michigan
- 1870-1878, Professor of Mechanical Engineering and Physics, Illinois Industrial
University
- 1878-1895, Professor of Mechanical Engineering and Physics, Ohio State University
Stillman Robinson was a practicing engineer, inventor, author, consultant,
and dedicated teacher. He organized the Association of Teachers of Mechanical
Engineering in 1890 and served as its president and, in 1893, was an active
participant in the formation of the Society for the Promotion of Engineering
Education and a member of its first governing council.
Born on a farm near South Reading, Vermont on March 6, 1838, Robinson became
an apprentice in a machine shop at the age of 17, where he served for four years.
In 1860, he decided to study engineering, and journeyed from Vermont to Michigan,
making the 625 mile trip mainly on foot and working at odd jobs along the way.
He entered the University of Michigan in January 1861 and graduated from the
three-year course in June 1863. He then accepted a position with the United
States Survey of the Northern and Northwestern Lakes as an assistant engineer,
where he remained for three years.
In 1866, he returned to the University of Michigan as an assistant in civil
engineering and the following year was appointed assistant professor of mining
engineering and geodesy. He was awarded 39 patents for a wide range of inventions,
including a thermometer graduating machine, timepieces, a steam rock drill,
photograph cutter, telephone, air compressors, automatic car brakes, shoemaking
machinery, substructures for elevated railways, hypodermic syringes, and a lens
grinding machine. He also published 70 articles in professional journals.
In 1870, Robinson accepted a position as professor of mechanical engineering
and physics at the Illinois Industrial University, which at the time offered
little engineering instruction. Anxious to carry out some of his ideas regarding
the use of shop practice and experimental work in teaching, he appeared before
the Board of Trustees ten days after arriving at the university, presented a
case for uniting theoretical and practical instruction, and was granted $2,000
to purchase tools and partly finished apparatus. With the help of his students,
he proceeded to construct a steam engine, adapting it with special features
for experimental purposes. His was the first distinctly educational shop in
America. It was run on a commercial basis, taking contracts to make articles
for dealers and to repair machinery. In recitation classes, Robinson often worked
with students to design machines that were then built in the shop.
In 1878, Robinson moved to Ohio State University as professor of mechanical
engineering and physics. Again, he began by creating a mechanical laboratory
, constructing much of the equipment himself. While at the university, he was
appointed by the Railroad Commission of Ohio to inspect the track, bridges,
and equipment of all the railroads in the state, which led him to develop new
methods based on mathematical analysis for constructing easement curves to produce
smooth transitions from straight to curved tracks. Robinson participated in
the organizational meeting of the American Society of Mechanical Engineers in
April 1880, and was active in the society's first meeting in November of that
year. Robinson resigned from the university in 1895, but maintained his outside
activities until his death on October 31, 1910.
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*****
- De Volson Wood
- (1823-1897)

Education
- Albany State Normal School, 1853
- Civil Engineer, Rensselaer Polytechnic Institute, 1857
- A.M. (Honorary), Hamilton College, 186?
- M.Sc. (Honorary), University of Michigan, 186?
-
- Positions
- 1854-1855, Assistant Professor of Mathematics, Albany State Normal School
- 1855-1857, Instructor, Mathematics, Rensselaer Polytechnic Institute
- 1857-1872, Professor of Civil Engineering, University of Michigan
- 1872-1897, Professor of Mathematics and Mechanics, Stevens Institute of
Technology
-
De Volson Wood was the first president of the Society for the Promotion of
Engineering Education. A dedicated, exemplary teacher, he spent 48 years in
the classroom, 40 of which were in engineering. He was reported to have rarely
missed a day of class in his many years of teaching. At the time of his election
to the SPEE presidency, Society records referred to him as "the senior teacher
of engineering in the country, if not in the world."
Wood was born in 1832 near Smyrna, New York. At the age of 17, after completing
his secondary education, he began teaching in his native town, an occupation
in which he engaged continuously for the rest of his life. A year later he enrolled
in the Albany State Normal School, while continuing to teach, and graduated
in 1853. After a year spent as principal in a public school, he returned to
the Albany normal school as assistant professor of mathematics. The following
year he enrolled as a junior at the Rensselaer Polytechnic Institute. A Preparatory
Division was just being organized, and he was asked to take charge of the mathematical
studies of the preparatory students, which paid for his Rensselaer education.
Upon graduating as a civil engineer in 1857, he decided to move to Chicago.
On the way he visited the University of Michigan's campus, where he was asked
by President Tappan to fill in for a few days for a recently appointed professor
of civil engineering who had not appeared. Wood remained on the faculty for
fifteen years, organizing its department of civil engineering. While there,
he received honorary degrees of A.M. from Hamilton College and M.Sc. from the
University of Michigan. In 1872, he accepted an offer from President Morton
and the Trustees of the newly established Stevens Institute of Technology to
become professor of mathematics and mechanics. He remained at Stevens until
his death in 1897.
His influence as a teacher was renowned. The American Mathematical
Monthly wrote, "The civil, mechanical, and electrical engineers, architects,
railroad managers and presidents, college professors and presidents, etc., who
formerly were Prof. Wood's students, and who now are scattered over the whole
world, would, if simultaneously rounded up, form the most intelligent army that
ever moved on the face of this mundane sphere." The inventor with Stillman W.
Robinson of a steam rock drill in 1866, Wood published textbooks on trussed
bridges and roofs, elementary mechanics, resistance of materials, analytical
mechanics, coordinate geometry, mechanics of fluids, trigonometry, thermodynamics,
and turbines. He also authored some 69 papers and chapters for several encyclopedias.
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*****
Felix
Klein
- (1849-1925)
-
- Professor of Mathematics
- University of Göttingen
-
- Dissertation: "Line Geometry and its Applications to Mechanics"
University of Bonn, 1868
- Advisor: Julien Plücker
-
- Klein was born in Dusseldorf and attended the Gymnasium there. After graduating,
he entered the University of Bonn and studied mathematics and physics during
1865-1866. While still studying at University of Bonn, he was appointed to
the post of laboratory assistant to Plucker in 1866. Plucker held a chair
of mathematics and experimental physics at Bonn but, by the time Klein became
his assistant, Plucker's interests had become very firmly rooted in geometry.
In 1968, the year Klein received his doctorate, however, Plucker died, leaving
his major work on the foundations of line geometry incomplete. Klein was the
obvious person to complete it, leading him to become acquainted with Clebsch.
Clebsch moved to Gottingen in 1868 ,and Klein was appointed as a lecturer
there in early 1871.
-
- In 1872, at the remarkably early age of 23, Klein was appointed professor
at Erlangen, in Bavaria in southern Germany. He was strongly supported by
Clebsch, who regarded him as likely to become the leading mathematician of
his day. However there were only a few students at Erlangen, so Klein was
pleased to be offered a chair at the Technische Hochschule at Munich in 1875.
There he taught advanced courses to large numbers of excellent students and
his great talent at teaching was evident. Also in 1875, Klein married Anne
Hegel, the granddaughter of the philosopher Georg Wilhelm Friedrich Hegel.
-
- After five years at the Technische Hochschule at Munich, Klein was appointed
to a chair of geometry at Leipzig. Leipzig seemed to be a superb outpost for
building the kind of school he now had in mind: one that would draw heavily
on the abundant riches offered by Riemann's geometric approach to function
theory. But unforeseen events and his always delicate health conspired against
this plan. The stress involved in playing two large roles, that of the tranquil
scholar [GL ??] and that of the active organizer, led to a nervous breakdown
in 1882, and he was plagued by depression throughout 1883-1884.
-
- His career as a research mathematician essentially over, Klein accepted
a chair at the University of Gottingen in 1886, and sought to re-establish
Gottingen as the foremost mathematics research centre in the world. He taught
a wide variety of courses, mainly on the interface between mathematics and
physics, such as mechanics and potential theory. Klein established a research
centre there that was to serve as a model for the best mathematical research
centres throughout the world. He introduced weekly discussion meetings, a
mathematical reading room, coordinated lectures, and a library holding copies
of all lecture notes. Furthermore, Klein attracted international students,
and worked to enable the official enrollment of women by 1908.
-
- Klein is generally acknowledged as a pioneer with regard to the close connection
between mathematics and applications that lead to solutions of practical problems.
In the 1890s engineers and technicians, who lamented a mathematical education
which was remote from practicality, set in motion an anti-mathematics movement.
Klein was aware that abstract, pure mathematics was in danger of becoming
isolated. In order to change the public image of mathematics and create greater
awareness of the utility of modern mathematical methods, Klein not only turned
his own research to applied mathematics, but encouraged engineers to improve
their training in mathematics and science. His valuable results on the application
of mathematics were aptly described by Richard von Mises (1883-1953), founder
of the journal "Zeitschrift fuer angewandte Mathematik und Mechanik",
thus:
It is within various areas of mechanics, however, that Klein
has ventured deepest into applied areas. He succeeded in promoting
the kinematics of rigid bodies by developing English research
which was virtually unknown in Germany at the time, and he searched
for related areas in "engineering mechanics", i.e.
direct solutions to real-world problems. The outstanding
teaching material originating from the lectures in Gottingen
by Klein and Sommerfeld on the theory of rigid bodies reaches
into technical problems dealing with gyroscopes and gyro-compasses,
yawing of vessels, etc. Klein also published a theory
of stresses in plane-truss assemblies based on an imaginative
combination of Maxwellian reciprocal figures and Airy stress
functions, a theory which has proved its fruitfulness up until
present times for dealing with problems occurring in the statics
of structures. (Richard von Mises, Felix Klein. ZAMM 4 (1924)
87- 88)
- However, it was not sufficient for Klein alone to yield up
research results. Around the turn of the century, Klein succeeded,
together with many allies, in bringing about much improved conditions
for the development of applied mathematics. The advent of specialised
teaching in this discipline made the establishment of corresponding
subject areas necessary and eventually led to the creation of
the first professorships in Germany in applied mathematics. Not
only was Klein successful in convincing government ministeries,
he also gained support for his plans from heads of industry.
Within the framework of the "Gottinger Vereinigung zur Foerderung
der angewandten Physik und Mathematik" affluent circles
supported Klein's endeavours with over 2 million Goldmarks between
1898 and 1920. His efforts brought about not only the 'Institute
of Applied Mathematics and Mechanics' at Gottingen, but the 'Institute
of Theoretical Physics', the 'Institute of Geophysics', the 'Institute
of Applied Electricity', the 'Research Institute for Aerodynamics
and Hydrodynamics' and the 'Seminar for Acturial Mathematics.'
Furthermore, to change the public image of mathematics, it was
not sufficient to limit activities to universities. Klein strived,
in an international context, for reform of the teaching of mathematics
"from primary school to university." In 1908 at the
IV International Congress of Mathematicians in Rome, he was elected
chairman of the International Commission of Mathematical Instruction.
-
- Klein's success in his efforts to open up modern mathematical
methods and theories to wider circles was made possible by his
international reputation as a renowned mathematician. When the
Berlin mathematicians, who over a long period had remained sceptical
of Klein's application-oriented endeavours, elected him as corresponding
member to the Berlin Academy of Science in 1913, their election
recommendation stated: "Klein [is] one of the few mathematicians
who is still capable of an overall view of mathematics."
- Klein retired from Gottingen due to ill health in 1913. However
he continued to teach mathematics at his home during the years
of World War I.
- "The greatest mathematicians, as Archimedes, Newton,
and Gauss, always united theory and applications in equal measure."
-
- "Thus, in a sense, mathematics has been most advanced
by those who distinguished themselves by intuition rather than
by rigorous proofs."
- - Felix Klein
-
- * Some of this information from the History
of Mathematics Archive
-
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-
- *****
Julien Plücker
- (1801-1868)
-
Dissertation:
- Elberfeld, Germany (1829?)
-
- Research interests (exerpted from the History of Mathematics
Archive webpage):
-
- Plucker was educated at Heidelberg, Berlin and Paris. He
was appointed to Bonn in 1829, and became professor of mathematics
at Halle in 1834, then at Bonn in 1836. He made important contributions
to analytic geometry and physics. He initiated the investigation
of geometrical configurations associated with line complexes.
-
- In 1847, he turned to physics, accepting the chair of physics
at Bonn ,working on magnetism, electronics and atomic physics.
He anticipated Kirchhoff and Bunsen in indicating that spectral
lines were characteristic for each chemical substance.
-
- In 1865 ,he returned to mathematics, and Felix
Klein served as his assistant during1866-1868.
-
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-
- *****