Heinrich Friedrich Weber

• 1. Introduction

  ›

  Heinrich Friedrich Weber was born on the 7th of November 1843 in Magdala, a small town near Weimar, and died on the 24th of May 1912. He became a German physicist whose name now surfaces mostly in connection with a famous student. Yet Weber left his own mark in the laboratory. Measurements he made in Berlin in the early 1870s baffled physicists for nearly thirty years. Who shaped him into an experimenter? What exactly did his instruments reveal? And why did the most celebrated student he ever taught turn away from him in anger? The answers begin in a university lecture hall in Jena.

  1

• 2. The Jena Apprenticeship

  ›

  Around 1861, Weber entered the University of Jena, where Ernst Abbe became the first of two physicists who decisively shaped his career. Weber quickly found that his gift for mathematics fell short of what the work demanded, and he gave mathematics up entirely. Physics took him back. Abbe saw a young, energetic scientist and steered him toward rethinking the theory of optics.

  Abbe taught more than content. He stressed laboratory work and precise instruments, argued that science should connect to practical life, and showed by example how much one person could achieve. Pierre Weiss, who wrote Weber's obituary and later succeeded him at the Zurich institution known after 1911 as the Eidgenössische Technische Hochschule, singled out that last lesson. He called it "the mainspring of his Weber's life, the source of his most beautiful successes."

  In 1865, Weber earned his doctorate under Abbe with a dissertation on the theory of how light diffracts. After that, the road led away from Jena and into a quiet stretch of tutoring.

  1

• 3. Finding Helmholtz

  ›

  In Pforzheim, during the second half of the 1860s, Weber worked as a private tutor and published just one article. The town's location proved useful. It sat close to the University of Heidelberg, where he met Gustav Kirchhoff, one of the leading theoretical physicists of his day. It also lay near the Polytechnische Schule in Karlsruhe, where in 1870 he became assistant to Gustav Heinrich Wiedemann.

  At Heidelberg he also met Hermann von Helmholtz, then a professor of physiology. The introduction may have come through Kirchhoff or Wiedemann, since both were close friends of Helmholtz. When Helmholtz left Heidelberg in 1871 to become professor of physics at the University of Berlin, he brought Weber with him as his first assistant.

  Helmholtz became the second great influence on Weber, and the stronger of the two. For three years, from 1871 to 1874, Weber helped equip the new Berlin laboratory and ran its student laboratories. That same laboratory would produce the work for which Weber is best remembered.

  1

• 4. The Specific Heat Puzzle

  ›

  Two papers in the Annalen der Physik, one in 1872 and one in 1874, carried Weber's most noteworthy findings. In them he measured the specific heats of carbon, boron, and silicon across a range of temperatures. Specific heat describes how much energy a material absorbs as it warms.

  The Dulong-Petit law told physicists what to expect. Weber's elements disagreed. At low temperatures their specific heats came out noticeably smaller than the law predicted. As the temperature climbed, those values rose with extraordinary speed.

  Only above 1,000 degrees Celsius did the three elements finally behave as Dulong and Petit had said. For nearly thirty years the result stood as an anomaly that no one could explain. Then one of Weber's own students offered a new explanation, which gave the old measurements their meaning.

  2

• 5. A Household of Scholars

  ›

  In 1875, Weber married Anna Hochstetter. They raised three daughters and five sons, and every one of their children went on to an academic career.

  The sons' paths ran through the sciences and medicine. Oskar became a chemist and Friedrich a geologist. Ernst combined civil engineering with astronomy. Helmut and Richard both became physicians.

  A household where all eight children entered scholarly work suggests a father who lived out Abbe's lesson that one person can accomplish a great deal. Weber's most famous pupil, however, was not one of his own children.

  2

• 6. The Einstein Problem

  ›

  Albert Einstein regarded Weber as one of his doctoral advisors, and the relationship ended badly. After a bitter disagreement, Einstein moved to Alfred Kleiner as his supervisor instead.

  Weber had also served as thesis advisor to Mileva Marić. He gave Einstein's paper a grade of 4.5 and hers a 4.0, on a scale of 1 to 6. Those were the two lowest essay grades in the class.

  Einstein left behind a sharp verdict on the teaching itself. He remarked that Weber's lectures were fifty years out of date and never reached Maxwell's equations. That complaint, from a student who gave Weber a bitter disagreement, is the line that most often follows his name beyond the laboratory, set against the measurements that had once puzzled physics.

  345