Category The Physical Tourist A Science Guide for the Traveler

A Parisian Walk along the Landmarks of the Discovery of Radioactivity

Ginette Gablot[17]

To see the landmarks associated with the discovery of radioactivity by Henri Becquer – el a century ago and the transfer of this new field of research from the most prestigious scientific institutions of the day to new scientific sites is worth a walk that will take most of a morning or afternoon to complete.[18]

The tour begins at the Museum National d’Histoire Naturelle (le Museum) at the Jardin des Plantes, 36 rue Geoffroy Saint-Hilaire, where Henri Becquerel, a specialist in phosphorescence, worked. As was his father and grandfather before him, Henri Bec­querel was professeur de physique appliquee aux sciences naturelles. On January 20, 1896, Henri Poincare presented Wilhelm Conrad Rontgen’s discovery of X rays to the Academie des Sciences. Henri Becquerel, who assisted, wondered whether phospho­rescent minerals emitted the same rays, and to test this point he selected crystalline uranium and potassium sulfate from the Museum’s prestigious collections in the Galerie de Mineralogie. Some of these very impressive crystals, as well as apparatus such as the electrometer designed by Pierre Curie for Alfred Lacroix, professor of min­eralogy, are displayed both in the main exhibition hall and in the Tresor. But for a more comprehensive visit, including an opportunity to see the ore collection used by Marie Curie and Becquerel’s electroscope, please contact the Curator a week or more before you come (tel. 33-(0)1-40 79 34 45, www. mnhn. fr).

Walking across the garden toward rue Cuvier, a plaque on Georges Cuvier’s house (figure 1) notes that Henri Becquerel discovered radioactivity there three months after Rontgen’s discovery. The ‘‘uranic rays’’ emitted by the element uranium produce an image on a photographic plate. Becquerel also demonstrated that this radiation ionizes air, making it a conductor of electricity.1

The streets around the Museum carry the names of the famous naturalists Etienne Geoffroy Saint-Hilaire, Cuvier, the Comte de Lacepede. The rue Cuvier is a great example of the sort of conviviality of the time. On one side is the Museum where Henri Becquerel spent his childhood years; on the other side are buildings that include the house at number 16 where Pierre Curie was born in 1859; his father worked as a labo-

Fig. 1. Georges Cuvier’s house. Credit: Bibliotheque centrale MNHN Paris 2008.

ratory assistant to Georges Duvernoy and Pierre Gratiolet at the Museum for a few years.

Let us stop in front of number 12 rue Cuvier. Constructed in 1900, this building was the first annex of the Sorbonne. Today it is part of Pierre et Marie Curie University. Pierre Curie, who discovered piezoelectricity with his brother Jacques in 1880 (fig­ure 2), had been famous since his and Marie’s discovery of radium in 1898, and in 1900 he was appointed lecturer in the Faculte des Sciences and taught physics in this build-

Fig. 2. Pierre and Jacques Curie’s piezoelectric quartz crystal. Credit: Musee Curie: CNRS/Institut Curie. Photo realisee par B. Vincent.

ing. He continued his studies on radioactive substances in the little laboratory located behind the lecture hall. In the courtyard behind this building was the pavilion built for Pierre Curie when he was appointed to the chair of physics in the Faculte des Sciences in 1904. Marie Curie became head of Pierre’s laboratory and isolated radium and determined its atomic weight.

After Pierre Curie’s accidental death in 1906, those who worked with Marie Curie included Andre Debierne, Jacques Danne, Albert Laborde, Harriet Brooks, Ellen Gleditsch, and Jan Danysz. Just before the outbreak of the Great War in August 1914, there were fifteen people in Marie Curie’s team. In 1911, Pierre Curie’s name was given to the international radium standard, and Marie Curie’s laboratory’s service de mesures subsequently acted as a bureau of standard in radioactivity.

We now take a quiet 15-minute stroll to the birthplace of radium, the Ecole Munic – ipale de Physique et de Chimie Industrielles. Go back up rue Cuvier and continue on rue Lacepede in front of you to rue Monge. Go left on rue Monge to rue l’Epee de bois. Go right on rue de l’Epee de bois to rue Mouffetard. Cross the covered passage­way, which will take you to rue Jean Calvin. A few steps away is number 10 rue Vauquelin (named after Louis Nicolas Vauquelin, chemist and discoverer of chromi­um). Enter the Ecole Superieure de Physique et Chimie Industrielles de la Ville de Paris (open only from Monday to Friday). Tell the guard that you have come to see the plaque in honor of the Curies, placed where the shed they used as a laboratory once stood. It is located in the courtyard, straight ahead. France lost its principal school of chemical engineering, in Mulhouse, during the Franco-Prussian war in 1870. The municipal council of Paris subsequently agreed to finance a school of chemistry and physics oriented toward industry. The Ecole Municipale de Physique et de Chimie Industrielles opened in 1882 with chemist Paul Schutzenberger from Mulhouse as director and Pierre Curie as a laboratory assistant in physics. Curie carried out research, especially on crystal symmetry and magnetism,2 and became professor in 1894. His most famous student was Paul Langevin, who later worked there on ultra­sound.

In 1895 Pierre Curie married Marya Sklodowska, who chose the study of Becquer – el rays as the subject of her doctoral thesis. Pierre joined his wife in isolating the unknown element they believed to be present in minimal quantities in pitchblende (uranium mineral). The chemical analysis they employed was based upon comparison of the intensity of radiation emitted by different successively treated separation prod­ucts. When an ionization chamber is used with a radioactive substance, a current is established in it with an undetermined intensity. A technician then sends a known counter-current produced by a piezoelectric quartz crystal to the ionization chamber. A Curie electrometer indicates when the two currents are in equilibrium.

In 1898 the Curies discovered polonium, named after Marie Curie’s homeland, and radium, in collaboration with the chemist Gustave Bemont. The Nobel Prize in Physics was awarded to Henri Becquerel and Pierre and Marie Curie in 1903. Soon, to manu­facture radium, the Curies contacted the Societe Centrale de Produits Chimiques to carry out the first stage in the chemical treatment. The final stages of chemical separa­tion by fractional crystallization were carried out by Marie Curie in the shed whose location is now marked by the plaque mentioned above. The partnership between the Curie laboratory and industry thus began.3 The few extant instruments that were used by the Curies are displayed in a small museum, the Espace des sciences Pierre-Gilles de Gennes. If you want a guide, please contact the head; www. espci. fr/esp.

We leave the Ecole Municipale de Physique et de Chimie Industrielles going toward Place Lucien Herr and continuing to rue Brossolette. Looking upward on the brick building, which dates to 1932, notice a plaque about the Curies’ shed, medallions with the names of Ampere, Lavoisier, and Pierre Curie, and mosaics with scientific themes (figure 3). This decoration pays tribute to the Alsatian founders of the original school of chemical engineering in Mulhouse. On the corner, which is also called Place Kastler, still stood until a few years ago Charles Beaudouin’s factory where the Curies’ and Fer­nand Holweck’s instruments were produced.

Fig. 3. One of the mosaics with a scientific theme. Photo realisee par G. Gablot.

Continue further on rue Erasme. Turn left on rue d’Ulm, following on your left the side wall of the Ecole Normale Superieure where Paul Villard discovered gamma rays in 1900. Now reverse direction on rue d’Ulm, going toward the Pantheon. Take a left at the rue Pierre et Marie Curie and go to the middle of that street to the entrance of the campus interuniversitaire Pierre et Marie Curie is in front of you. In 1906, the Univer – site de Paris acquired this site. Benefitting from State support and the support of French and foreign foundations, new premises were constructed for a group of scien­tists led by Marie Curie and Jean Perrin. This small area eventually became the seed bed for generations of researchers whose names, along with the Joliot-Curies, are asso­ciated with the history of modern French physics. These include Pierre Auger, Edmond Bauer, Louis de Broglie, Yvette Cauchois, Alfred Kastler, and Francis Perrin.

Enter the campus and ask the guard about the busts of the Curies. This small gar­den is part of the Institut du Radium, which is dedicated to research in radioactivity and its biological and medical applications. You are at the rear of the Curie Labora­tory (figure 4) where Marie Curie worked from 1914 to 1934. Here also in January 1932 her daughter Irene, together with her husband Frederic Joliot, one of Langevin’s students at the Ecole Municipale de Physique et de Chimie Industrielles, studied a radiation observed two years earlier in Berlin by Walther Bothe and Herbert Becker and found that this radiation was capable of projecting energetic protons from hydrogenous substances. A few weeks later in Cambridge, James Chadwick demon­strated that this radiation is comprised of neutrons. Two years later, at the Institut du

Fig. 4. The Laboratoire Curie. Credit: Musee Curie: CNRS/Institut Curie.

Radium, with the aid of a Geiger-Muller counter presented to them by Wolfgang Gen – tner, they discovered artificial radioactivity, for which they received the Nobel Prize in Chemistry in 1935.

Today this building and the Pavilion Pasteur, on both sides of the garden, are part of the Institut Curie, a foundation dedicated to research and to the treatment of cancer.4 The Curie Museum comprises Marie Curie’s office and chemistry laboratory and a small exhibition room (www. curie. fr/musee), open from 10:00-18:00 Tuesday to Friday, except public holidays. Admission is free, and tours in English are available (tel. 33- (0)1-56 24 55 33).

Nothing of course remains of the radioactive sources that were so useful in explor­ing the structure of nuclei, especially polonium, which was a particularly effective source of alpha particles. The usual technique involved the combination of an electri­cal measurement, as described above, with an examination of the tracks of emitted par­ticles as observed with a Wilson cloud chamber. In the first exhibition room, the device for the electrical measurement and the cloud chamber, as improved by Frederic Joliot (figure 5), are displayed along with other artifacts that have been selected for the cen­tennial celebration of Joliot’s birthday in 2000. To see other instruments, for instance, different types of ionization chambers, electrometers, electroscopes, magnetic pendu­lums, and molecular pumps by Holweck, please contact the Head of the Musee et Archives de I’Institut du Radium, Renaud Huynh: renaud. huynh@curie. fr.

Fig. 5. The variable-pressure cloud chamber designed by Joliot. Credit: Musee Curie: CNRS/Institut Curie. Photo realisee par B. Vincent.

Letters, papers, and photographs remain from the scientists who worked in the Insti – tut du Radium, such as Mitsuo Yamada, Ramaiah Nai’du, Dimitri Skobeltzyn, Vladimir Vernadsky, Sonia Slobodkine-Cotelle, and Catherine Chamie. To consult these archival sources, which include those of the Curie Laboratory and the Joliot-Curies, please con­tact Nathalie Huchette: documentation. musee@curie. fr. (The Departement des Manu – scrits de la Bibliotheque nationale de France owns the P. and M. Curie papers.)

From rue d’Ulm, turn left on rue Pierre et Marie Curie, continue to rue Saint Jacques, and take a right. Continue down rue Saint Jacques to the intersection with rue Soufflot and look to the right, where you will see the domed Pantheon, which is dedi­cated to the Grands hommes and is open daily. As a kind of secular beatification, the remains of Pierre and Marie Curie were transferred to the Pantheon in 1995.

Continue on rue Saint Jacques, walk along the Sorbonne on your left, and stop at the College de France on your right, at Place Marcelin Berthelot. Frederic Joliot became professor at the Colle’ge de France in 1937; the mineral chemistry chair was first trans­formed into a nuclear chemistry chair and later into a nuclear physics and chemistry chair. He settled into the new building, where a second basement was dug, and where he built a cyclotron that produced a beam in March 1939. Also in early 1939, in his Lab – oratoire de Synthese Atomique in Ivry, he demonstrated the physical proof of the fis­sion of uranium by neutron bombardment. He then carried out with Hans Halban and Lew Kowarski the first experiments that indicated the feasibility of a chain reaction. Between May 1939 and May 1940, with Francis Perrin they took out five patents on the construction and utilization of nuclear energy.5

In October 1945, the Commissariat a l’Energie Atomique – with Joliot as its head and Irene Joliot-Curie, Pierre Auger, Bertrand Goldschmidt, Lew Kowarski, and Fran­cis Perrin as its scientific council – was established for the rapid development of civil­ian nuclear energy at Fort de Chatillon. Please contact Mme. Magonthier for a guided tour, Monday to Friday, of the first French reactor Zoe (fax 33-(0)1-46 54 96 10). Dur­ing the 1950s, these enormous machines required vast spaces, and the “atom splitters” left the Latin Quarter to take up residence at the Institut de Physique Nucleaire in Orsay.

The Physical Tourist. A Science Guide for the Traveler edited by John S. Rigden and Roger H. Stuewer © 2009 Birkhauser Verlag Basel, Switzerland

District XVI

Csomori dt 20, Albert Szent-Gyorgyi Primary School. In the garden of this school is a bronze bust of Szent-Gyorgyi (1893-1986).

Csomori dt 142, Albert Szent-Gyorgyi Primary School. This is the other building of this school. There is a commemorative marble plaque on it that reads:

It is not Destruction, but Creation that makes Human Life Lasting, Health, Happi­ness, Beauty and Knowledge can make it Enjoyable. Albert Szent-Gyorgyi

XVI District

Szechenyi u. 9-11, Georg von Bekesy Secondary School for Postal Communications. There is a bronze copy of the statue of Bekesy (1899-1972) by his brother Miklos at the Research Institute for Telecommunications at Zombori u. 2 in the IX District (see above) at this school.

Bernese Metrology

Just one block away from the Einsteins’ Kramgasse apartment is Bern’s historic clock – tower. The Zytgloggenturm (figure 4) was built around 1218 and marks the first bound­ary of the original old town. After it was seriously damaged in the big fire of 1405, it was no longer used as a prison. The astronomical clock on its eastern face was built by Caspar Brunner from Nurnberg in 1527-1530. The allegorical figures on the tower’s eastern face represent the four stages of life, those on the western face the four seasons. During the second half of the 19th century, the clocktower had the important task of indicating the local Bernese time. The clockworks, including puppets that revolve on the hour, were renovated in 1904.As early as 1874, the Society of Natural Scientists had recommended that the city modernize its timekeeping system and change over to a dozen public electrically driven clocks. The new telegraph and railway networks had made the introduction of a standard time indispensable. Clocks in Zurich, for example, diverged from Bernese clocks by as much as four and a half minutes.

You can still see a collection of local standard lengths dating from 1877 attached to the wall in one of the archways of the clocktower.[28] These were for the convenience of local merchants and their customers and go back to the middle of the 17th century. Standardization of the myriad local Swiss measures first began in earnest during the short-lived Helvetic Republic when a law was passed in 1801 requiring the introduc­tion of the French metric system. Three decades had to elapse, however, before twelve cantons voluntarily signed a concordat in 1835 to institute a uniform Swiss system, which then gradually began to gain general acceptance.

The Swiss Federal Constitution of 1848 laid down the jurisdiction for the establish­ment of the Federal Verification Office (Eidgenossische Eichstatte), which eventually came into existence in 1864 in the old treasury building formerly situated a block west­ward from today’s Casinoplatz. If we take Amthausgasse to the Federal Houses of Par­liament, we will have gone past two subsequent locations of the renamed Federal Office of Weights and Measures. Between 1897 and 1907 it was at Amthausgasse 17, then until

Fig. 4. Bernese clocktower, originally the watchtower at the western edge of the old town. Source: Arnold H. Schwengler, Liebes altes Bern. Stadtbilder 1850-1925 (Bern: Buchverlag Verbandsdruckerei, 1975), p. 39.

1914 it was in the basement of Parliament at Bundesplatz 3. At the turn of the twenti­eth century, it was still preoccupied with making the transition from local scales to the Parisian metric system in accordance with an international convention signed by Switzerland in 1875.Emil Konig (1871-1948), Director of the Federal Office of Weights and Measures from 1909 to 1932, moved it away from routine verification and enforce­ment, which duties were transferred to private testing stations. The incorporation of electro-technology into its program necessitated another move, in 1914, into a new building in Kirchenfeld at Wildstrasse 3, a street named after its first director, the Pro­fessor of Physics Heinrich Wild (1833-1902).6This building currently houses Einstein’s former employer, the Swiss Federal Institute of Intellectual Property (Eidgenossisches Institut fur geistiges Eigentum). A modern extension of the building, completed in 1958, is now the main entrance at Einsteinstrasse 2.

Emil Konig’s son Hans (b. 1904), who was appointed as Extraordinary Professor of Technical Physics in 1939 and founded the university’s Institute of Applied Physics in

1961, succeeded his father as Director of the Federal Office of Weights and Measures from 1951 to 1969. During his directorship its focus turned to fundamental research on units of measurement and natural constants, which had hitherto been left in the hands of the Physikalisch-Technische Reichsanstalt in Berlin-Charlottenburg, the National Physical Laboratory in Teddington, England, and the National Bureau of Standards in Washington, D. C. In introducing the measurement of light wavelengths, Hans Konig laid the foundation for later developments in Swiss high-precision metrology. Between 1910 and 1955, the Office’s personnel increased from 3 to 19, and in the following 40 years to over 100. In the mid-1960s the Office was moved to a better-equipped and iso­lated new building complex in Wabern, south of Kirchenfeld. Renamed as the Federal Office of Metrology in 1977, it expanded its functions in subsequent decades to com­ply with European organizations for calibration and accreditation and, since 2001, has been called the Federal Office of Metrology and Accreditation (Metrologie und Akkreditierung Schweiz, metas). Einstein knew both of the Konigs, especially the father Emil, who had given a number of talks of particular interest to engineers at the Society of Natural Scientists. That will be our next stop.

Cooper Union

In a city filled with unique institutions, one still stands out. Its full name is Cooper Union for the Advancement of Science and Art; it was created in 1859 and subse­quently nurtured by one person, Peter Cooper (1791-1883). Cooper Union (website <www. cooper. edu>) is located at Cooper Square, close to the Lexington Avenue sta­tion of the No. 6 subway train. What makes it unique is that it was, and remains, a com­pletely tuition-free college. It includes a physics department in one of its three schools, the Albert Nerkin School of Engineering. As noted above, one of its students, from 1966-1970, was Russell A. Hulse (b. 1950), who became a graduate student of Joseph H. Taylor, Jr. (b. 1941) at the University of Massachusetts at Amherst, where they began their joint research that led to their discovery of gravitational radiation from binary pulsars for which they shared the Nobel Prize in 1993.

Peter Cooper was a self-made, uneducated workingman’s son who became a famous inventor and industrialist. The main building of Cooper Union is a noble brownstone

Board of Transportation

The City of new York



July U, Ж7

Dr. V. T. Имя,

Physics Doparteent,

Fordhan University Pordhaa Road,

New York 56, N. T.

Dear Sirr

Referring to your latter addressed to the Beard of Transportation under date of July 3, 1947, relative to the eTperinent which you propose to aake in the 190tb Street Sub­way Station of the Independent Syeten, thie ie to court r» information given you orally by Sr* Civil Engineer A. K. Clark that the house for your teatlng nachins has bean erected at the northerly end of the southbound platfora of the 190th Street Station, and that Mr. Clark will aeet you at 3:30 on the af­ternoon of July 15th, eo that we nay be assured that all neces­sary step* have been taken preparatory to the beginning of your oxperlmntal work on the following day.

Very truly yours,


Fig. 7. Victor F. Hess’s letter of May 20,1947, to the New York City Board of Transportation, and the Board’s reply of July 11, 1947. Courtesy of Victor Hess Papers, Fordham University Archives, Bronx, New York.

pile (figure 8), a historic monument containing the Great Hall, famous for a pre-elec­tion speech made there by Abraham Lincoln. Thomas Edison describes in his autobi­ography how he took courses at night at Cooper Union – his only formal education. Cooper Union remains an active fixture in New York cultural life, with concerts and lectures galore; it is well worth a visit.

Cooper Union’s students are selected competitively; it is supported by its endow­ment and some fortuitous real-estate holdings, greatly enhanced now by alumni con-

Fig. 8. Cooper Union for the Advancement of Science and Art. A plaque that was placed on the build­ing in 1950 by The New York Community Trust notes that the building is one of the Landmarks of New York and reads: ‘‘Peter Cooper, inventor, civic leader, philanthropist, founded this institution offering free education to all. In its Great Hall, birthplace of many important social and political movements, America’s leading citizens have spoken, among them Abraham Lincoln whose 1860 address here con­tributed to his presidential nomination. Designed by Frederick A. Peterson. This building was opened in 1859.’’ Photograph by the author.

tributions. In the list of the ‘‘best 331 colleges” in America, as rated by the Princeton Review in 2002, Cooper Union is ranked as the ‘‘hardest school to get into,’’ followed by Harvard and Princeton!

The Nineteenth Century

The Athens of the North continued to flourish throughout the nineteenth century. There are too many historically significant figures associated with Edinburgh during this period to mention them all, particularly if I were to include those who merely stud­ied at the University, so I will confine myself to those associated with a specific place or places in Edinburgh (apart from the University, which again would expand the num­bers too greatly).21

Since we have just been on St. John’s Hill, I will begin with John James Waterston (1811-1883), whose family ran a firm of stationery supplies and lived in a home adja­cent to their sealing-wax factory on St. John’s Hill (the factory building still stands; it is now a University building). Waterston’s paper on the kinetic theory of gases, which he submitted to the Philosophical Transactions of the Royal Society in 1845 while working for the British Navy in Bombay, India, was dismissed on the grounds that he was unknown to the community of physicists and thus could not possibly have anything of significance to say (a good example of the old adage that “it’s not what you know but who you know that counts”). Thanks to the good offices of Lord Rayleigh, John William Strutt (1842-1919), Waterston’s paper was eventually published in 1892,22 by which time, of course, the kinetic theory had been established. Lord Rayleigh thus pro­vided an introduction to it, explaining that it was being published posthumously to give Waterston due credit for his work. Nonetheless, Waterston’s entry in the new Oxford Dictionary of National Biography, at only 21 lines, is considerably shorter than any of the other figures I discuss.23

Much better known is William J. Macquorn Rankine (1820-1872), another physicist who lived in a home overlooking Salisbury Crags and who shared Waterston’s interest in heat. Rankine was born in what is now the Edinburgh suburb of Stockbridge, imme­diately north of the New Town, and later lived in Gibraltar House (now demolished) on St. Leonard’s Bank, which runs along the crest of another volcanic sill, St. Leonard’s Crags. Smaller than Salisbury Crags, this sill was intruded between the bedding planes of deeper sedimentary layers and was less elevated when the ground was tilted (raised to the west and depressed to the east), resulting – after the ice age had done its work – in a lower sill running roughly parallel to part of Salisbury Crags and providing a won­derful aspect onto them. Rankine, as much engineer as physicist, left Edinburgh in 1851, relocating to Glasgow, the major Scottish center for engineering of all kinds. Waterston did not return to Edinburgh from India until 1857. Rankine might have returned to Edinburgh in 1868 when he competed for the University’s Chair of Engi­neering, but the appointment went instead to Fleeming Jenkin (1833-1885).

The rest of our nineteenth-century physicists lived in the New Town. From St. Leonard’s Bank, walk a short distance west back to Nicolson Street and then north down what locals call “the Bridges” (South and North Bridge) to the eastern end of Princes Street. Alternatively, cross Nicolson Street and keep heading due west a short distance to George Square, hub of the present University, and then head due north to George IV Bridge over the Cowgate from the high ground where Greyfriars Church is located to the west-east spine of the High Street. From there a road north winds steeply down the Mound, cutting through Princes Street Gardens to the west-east middlepoint of Princes Street (a flight of steps takes a more direct route down). Either way, you get a sense of the unique topography of Edinburgh: “Spreading over many swelling hills and deep ravines, that in some instances are spanned by enormous bridges of stone, it [Edinburgh] exhibits a striking peculiarity and boldness in its features that render it totally unlike any other city in the world….”24

Turning left and walking west along Princes Street toward the Castle looming above eventually brings you to Edinburgh’s West End – the west end of Princes Street. The road now becomes Shandwick Place and a short way along it the Georgian tenements typical of the New Town bend back north and south from the road to form two impres­sive curved terraces. The physicist David Brewster (1781-1868) lived on the northern one at 10 Coates Crescent (figure 8) after he was appointed Principal and Vice Chan­cellor of the University of Edinburgh in 1859. Regarded as one of the preeminent inter­national scientific figures of his day, Brewster received many scientific honors. He was a prolific writer, producing at least 299 scientific papers and numerous encyclopedia articles, reviews, and popular essays, taking the total to about 1240 pieces. He also is remembered as the inventor of the kaleidoscope.

Fig. 8. Part of Coates Crescent in the West End. The second door from the left is No. 10, where David Brewster (1781-1868) lived when he was Principal of the University of Edinburgh. Although Edinburgh has a policy of marking significant buildings with commemorative plaques, there is no plaque for Brew­ster, nor for any of the other famous scientific residents mentioned here. Photograph by the author.

Brewster’s appointment in 1859 as Principal of the University is all the more remarkable because his earlier application in 1833 for the Chair of Natural Philosophy had failed when the Town Council judged that his protege, James David Forbes (1809-1868), was more sound politically. Forbes was born at 86 George Street in the heart of the New Town and died in Bristol (where he had gone, alas too late, for health reasons). He is buried in the cemetery nearest to his birthplace, in Dean Village. Forbes did important experimental work on the polarization and refraction of radiant heat, thereby indicating its similarity to visible light and promoting the idea of a continuous spectrum of radiation. Perhaps his greatest claim to fame, however, is that he taught two other notable Edinburgh physicists, James Clerk Maxwell (1831-1879) and Peter Guthrie Tait (1831-1901), both of whom competed for Forbes’s chair when he died.

Tait won. Born in Dalkeith, the same small town where Maclaurin had made his family home, but educated in Edinburgh, Tait and William Thomson (1824-1907), later Lord Kelvin, published their Treatise on Natural Philosophy, a new survey of energy physics, in 1867. More controversially, Tait and Balfour Stewart (1828-1887) published their Unseen Universe or Physical Speculations on a Future State in 1875, which was an attempt to display the harmony between the new energy physics and Christian faith. At the time of his death in 1901, Tait was living at Wardie, a large house on Granton Harbour on a rise overlooking the shore of the Forth a little east of Leith, Edinburgh’s neighboring port. He seems to have been responsible for renaming the house Chal­lenger Lodge (figure 9), presumably after HMS Challenger, a ship that had been used to carry out experiments for him. The house now forms the old part of the sprawling St. Columba’s Hospice on Boswall Road, a home for palliative care opened in 1977. Tait is buried in the Churchyard of St. John’s East Church, Constitution Street, Leith. The area around Granton Harbour remains quite busy as a small industrial center and is not as attractive as Cramond to its west, or Newhaven to its east.

Maxwell, who needs no introduction, was born at 14 India Street, an elegant Geor­gian house toward the northwest corner of the New Town. India Street is a straight road located just west of the Royal Circus, one of the circular terraces that are spec­tacular features of the New Town. The house today is the headquarters of the James Clerk Maxwell Foundation; there is a small museum in it devoted to Maxwell’s work. A virtual tour of the house also offers a sense of the splendors of the New Town.[12] The University’s Physics Building, at the separate campus for science and engineering departments known as King’s Buildings, about a mile and a half south of George Square, is called the James Clerk Maxwell Building, but by itself this undistinguished building hardly provides a good reason to go there.

Fleeming Jenkin, who beat Rankine to the Chair of Engineering at the University of Edinburgh in 1868, had been Tait’s classmate and Maxwell’s junior by one year at the Edinburgh Academy,[13] which is located on Henderson Row on the northern out­skirts of the New Town. He did important work in telegraphy and filed over thirty-five

Fig. 9. Home of Peter Guthrie Tait (1831-1901) when he was Professor of Natural Philosophy at the University of Edinburgh. The back of the house looks out across Granton Harbour, and the Firth of Forth to Fife, and on a clear day to the southernmost Highland hills. Photograph by the author.

patents, but he also is remembered for his critique of Charles Darwin’s Origin of Species (1859), in which he pointed to what then seemed to be insurmountable prob­lems concerning the hereditability of evolutionary variations. At the time of his death in 1885 he was living at 3 Great Stuart Street, a prestigious street in the West End that emerges from the architectural splendors of Randolph Crescent, passes through the oval terraces of Ainslie Place, and ends at the circular Georgian terraces of Moray Place.

Charles Piazzi Smyth (1819-1900), Scotland’s second Astronomer Royal, was less distinguished for his contributions to science than other nineteenth-century scientists, but he was one of Edinburgh’s more fascinating characters who left a continuing mark on its daily life.25 After ten years as an assistant at the Royal Observatory at the Cape of Good Hope, South Africa, Piazzi Smyth was appointed as the Scottish Astronomer Royal and Regius Professor of Astronomy at the University of Edinburgh in 1846. Edinburgh’s Royal Observatory (figure 10) had been built in 1818 and had been declared at a royal visit to be the Royal Observatory of George IV in 1822; it stands on Calton Hill, which overlooks the east end of Princes Street. Given the city’s popular designation as Auld Reekie, Edinburgh’s Royal Observatory hardly compared as a site

Fig. 10. The former Royal Observatory of Scotland, now the City Observatory, on Calton Hill is a pop­ular tourist attraction. Photograph by the author.

for astronomical observations to the Royal Observatory at the Cape of Good Hope, so Piazzi Smyth soon mounted an expedition to Tenerife in the Canary Islands and ascended its volcanic peak, Teide, to measure sky transparency, star-image quality, and the intensity of solar radiation. His purpose was to assess it as a potential site for an observatory,26 but the proposed Teide Observatory came to nothing until 1964 when it became one of the first international observatories. Later, Piazzi Smyth carried out many pioneering experiments in spectroscopy at the Royal Observatory in Edinburgh, but they failed to win the recognition they deserved. Increasingly eccentric and deaf as he grew older, his performance as both Astronomer Royal and Regius Professor was judged to be inadequate by those to whom he was answerable. He was not much admired by the time he retired in 1888.

A major reason was his involvement in measurements of the Great Pyramid of Giza in Egypt, and his acceptance of absurd jingoistic claims that the inch derived from the sacred cubit described in the Bible and was supposedly manifested in the dimensions of the Great Pyramid. Piazzi Smyth’s attempts to link the imperial standard of measure to sacred metrology, originally undertaken in opposition to British plans to switch to the French metric system, came to have religious as well as patriotic connotations for him. His book, Our Inheritance in the Great Pyramid of 1864,27 drew to him a large cult following (which still thrives),28 but it seriously overshadowed his contemporary scien-

Fig. 11. Royal Terrace, where Charles Piazzi Smyth (1819-1900) was provided with an official resi­dence (the building on the right) as Astronomer Royal. A path on the right of the building goes direct­ly up to the Observatory. Photograph by the author.

tific reputation. Before he retired (and left Edinburgh) he was living in a grand house at Royal Terrace (figure 11), a street on the north side of Calton Hill and running below it. The old Royal Observatory where he used to work, now called the City Observato­ry, is one of the major tourist attractions on Calton Hill.

Although most Edinburgh residents today have never heard of Piazzi Smyth, they repeatedly hear one of his legacies. Every day at 1:00 P. M. a cannon is fired from the Cas­tle Esplanade. It is easy to distinguish tourists from locals at the west end of Princes Street when the gun goes off – the tourists jump in alarm while the locals merely check their watches. This aid for the city’s timekeepers was introduced by Piazzi Smyth in 1861.

Nine years earlier, in 1852, Piazzi Smyth had arranged for a visual time signal for mariners and others stationed at the Leith docks by using Edinburgh’s Nelson monu­ment. Very different from London’s single column, Edinburgh’s tribute to Nelson’s vic­tory at the Battle of Trafalgar in 1805 is a round tower (supposed to resemble an upturned telescope) standing on Calton Hill (just a few yards away from Piazzi Smyth’s observatory) in a prominent position as seen from Princes Street. On top of the tower is a mast that pierces a large white ball (figure 12). Every day just before 1:00 P. M. the ball is hauled to the top of the mast and then released at exactly one o’clock; its descent can be seen in Leith. Historian Roderick W. Home has described a similar arrangement in Melbourne, Australia,29 which almost certainly was modeled on Piazzi Smyth’s inno-

Fig. 12. Edinburgh’s Nelson monument on Calton Hill, appropriated by Charles Piazzi Smyth (1819-1900) to hold the mast and time ball for the benefit of mariners down in Leith. Salisbury Crags and Arthur’s Seat are in the background. Photograph by the author.

vation. Since the descending ball was not always visible from the streets of Edinburgh, where the topography and buildings can conspire to obscure it, Piazzi Smyth later introduced the continuing tradition of the one o’clock gun.

District II

On the western side of FO’ tot is Nagy Imre ter (square), at the corner of which is FO’ tot 68, a building that houses the Roland von Eotvos Physical Society (Eotvos Lorand Fizikai Tarsulat) and also serves as headquarters for other scientific and technical soci­eties. A white marble plaque on the left of the entrance reads:

Nobel Laureates: Philipp Lenard 1905, Robert Barany 1914, Richard Zsigmondy 1925, Albert Szent-Gyorgyi 1937, Georg von Hevesy 1943, Georg von Bekesy 1961, Eugene Wigner 1963, Dennis Gabor 1971, Janos Polanyi 1986, Elie Wiesel 1986, Gyorgy Olah 1994, John Harsanyi 1994

Another white marble plaque on the right of the entrance reads:

Our Titans: Janos Bolyai, Zoltan Bay, Roland von Eotvos, Anyos Jedlik, Theodor von Karman, Sandor Korosi Csoma, John von Neumann, Ignacz Semmelweis, Istvan Szechenyi, Leo Szilard and to the Memory of Their Fellow Scientists, 1996

In the lounge of the building are large posters describing the life and work of the above Hungarian-born Nobel Prize winners. On the second floor is the headquarters of the Eotvos Physical Society where there are impressive photographs of its presidents and outstanding members, both physicists and physics teachers, including Anyos Jedlik (1800-1895), Roland von Eotvos (1848-1919), Sandor Mikola (1871-1945), Karoly Novobatzky (1884-1967), Zoltan Gyulai (1887-1968), Jozsef Oveges (1895-1979), Zoltan Bay (1900-1992), and Miklos Vermes (1905-1990).

In 1885 Eotvos and his colleagues organized regular meetings of physicists and mathematicians to discuss recent developments in science at a table in the Karpatia Restaurant (Karpatia Etterem) at Ferenciek tere 7-8 close to the University Library (Egyetemi Konyvtar), which was built in 1875 at Karolyi Mihaly utca 10 in the V Dis­trict (see below). They met on Thursday afternoons, which remains today as the tradi­tional time when physics colloquia are held at Eotvos University. It is called the Ort – vay Physical Colloquium after Rudolf Ortvay (1885-1945), who was not a distin­guished theoretical physicist but was a great organizer.

Eotvos founded the Mathematical and Physical Society in the fall of 1891 and became its first president. He set out its goals as follows:

To further the development of science at our meetings by word of mouth, and pub­lish everything that deserves the attention of the expert in a journal. This goal does not seem to be more than that of a self-educating student circle, and yet if we pay due attention to it, our work will have merit, it will fulfill an important task. If we succeed in achieving the objective that each Hungarian teacher of physics and math­ematics becomes a real physicist and mathematician, then we serve not only our schools, but we also will raise the level of science in our country. Self-education car­ried out with dedication and seriousness also will contribute to the desirable situa­tion that in the future researchers and developers of science will come from among us. I hereby declare the Mathematical and Physical Society founded.9

After Eotvos’s death in 1919, the Society has borne the name of its founder, becoming the Roland von Eotvos Mathematical and Physical Society. In 1950 it was divided into the Janos Bolyai Mathematical Society and the Roland von Eotvos Physical Society. The original society began publishing a journal in 1891,Mathematical and Physical Let­ters (Mathematikai es Physikai Lapok); in 1950 the Eotvos Physical Society took over the title of its physics column, Physics Review (Fizikai Szemle) and began publishing its own journal under that name. Since 1894 the Society also has edited a journal for high school students and has organized competitions for them. A number of the win­ners of the Eotvos Competition became distinguished scientists, including Gyozo Zem – plen (1879-1916), Lipot Fejer (1880-1959), Theodor von Karman (1881-1963), Denes Konig (1884-1944), Alfred Haar (1885-1933),Marcell Riesz (1886-1969),Gabor Szego (1895-1965), Leo Szilard (1898-1964), Laszlo Tisza (born 1907), and Edward Teller (1908-2003).

The scientific and educational sections of the Eotvos Physical Society have enriched the scientific lives of physicists and physics teachers by sponsoring national and international lectures, seminars, and conferences. The Society also established prizes to honor distinguished members and non-members. The highest award of the Society is the Eotvos Medal, which was established in 1969.The bronze Eotvos Award was established for non-members in 1979. The Prometeus Prize with a bronze medal was established in 1974 for the popularization of physics. The other major prizes of the Society, for most of which bronze medals were created in 1987, are as follows: The San – dor Mikola Memorial Award was established in 1961 in honor of Sandor Mikola (1871- 1945), an outstanding teacher and solid-state physicist; it carries a bronze medal and has been awarded since 1981 “in recognition of modern, systematic, exper­imentally-based physics teaching and of significant work that advances the promotion thereof” The Imre Brody Prize has been awarded since 1950 for outstanding research in applied physics. Imre Brody (1890-1945) was an outstanding physicist and the inventor of the krypton light bulb; with Egon Orowan (1901-1989) and Michael Polanyi (1891-1976) he also made the mass production of krypton feasible. The Rezso

Schmid Prize for research on the structure of matter has been awarded since 1950. Rezso Schmid (1904-1943) was the founder of molecular spectroscopy in Hungary. The Pal Selenyi Prize has been given to outstanding experimental physicists since 1964. Pal Selenyi (1884-1954) was a superb experimental physicist and the inventor of photocopying and the photometer.10 The Zoltan Gyulai Prize was established in 1969 for important new results in solid-state physics. Zoltan Gyulai (1880-1968) was co-dis­coverer of the Gyulai-Hartly effect, a consequence of natural crystal defects, and cre­ated a center for crystal physics first in Debrecen and later at the University of Budapest. The Karoly Novobatzky Prize has gone to distinguished theoretical physi­cists since 1969; it is named after Karoly Novobatzky (1884-1967), who introduced new commutation laws for the electromagnetic vector potential.11 The Laszlo Detre Prize was established in 1975 to recognize significant results in the fields of astrono­my and atomic physics. I discuss Detre (1906-1974) further below in connection with the Konkoly Observatory. The Gyorgy Szigeti Prize has gone to outstanding researchers in semiconductors and luminescence since 1989. Gyorgy Szigeti (1905-1978) developed the technology of fluorescent tubes and was the founder and director of the Institute for Technical Physics Research at Foti tot 56 in the IV District (see below).

We now walk to a number of important sites, first going west on Kacsa u. (which leads into Varsanyi Iren utca) and then circling northward roughly clockwise.

Kando Kalman u. 6. There is a plaque on this house that reads:

Kalman Kando (1869-1931) Mechanical Engineer, Member of the Hungarian Acad­emy of Sciences brought World Fame for the Ganz Electrical Company by intro­ducing Induction Motors. Pioneer of Electrifying the Railways and Designer of the Electric Engine named after him. Erected by the Council of Budapest, The Capitol, in 1971

Frankel Leo u. (street) 17-19, Hospital of the Ignorantines (formerly the National Institute for Rheumatology and Physiotherapy). There is a bronze bust of Anyos Jed – lik (1800-1895) here.

Varsanyi Udvar (yard) 2, rear building at Varsanyi Iren utca 33. There is a plaque ded­icated to Jozsef Oveges (1895-1979) here that reads:

The esteemed Teacher of Physics renowned for his Experiments and his Commit­ment to Natural Sciences, Jozsef Oveges lived and worked in this house. This Plaque was erected to Commemorate the 90th Anniversary of his Birth by the Council of Budapest, The Capitol, TIT [Society for Popularizing Science], MTESZ [Association of Technical and Scientific Societies] and National Television in 1985

Lovohaz u. 39, Electric Works of the Ganz Rt Shareholding Company. This company was established in 1878. Karoly Zipernowsky constructed electric generators here based on Jedlik’s dynamo concept, and in 1885 he and his co-workers constructed and patented the iron-core transformer. This was a key component for the distribution of alternating-current electricity, which was first realized on a large scale between 1885 and 1892 by the Ganz Electric Works in Rome. The plaque at the entrance to the Ganz-Ansaldo Factory reads:

In Remembrance of Karoly Zipernowsky, Miksa Deri, Otto Titusz Blathy, Engineers of the Electrotechnical Department of Ganz and Partner Company who invented the Electric Transmission Transformer. Erected by the Ganz Electrical Company and the Hungarian Electrotechnical Society

Kitaibel Pal u. 1, Institute of Meteorology. In this institute there is a gypsum bust and painting of Miklos Konkoly-Thege (1842-1916).

Cimbalom u. 12. This was the last Budapest residence of Laszlo Jozsef Biro (1899-1985), the Hungarian-Argentinian inventor of the ball-point pen, the biro. A marble plaque was erected on it to mark it.

Huvosvolgyi u. 21-23, former location of the Janos Bolyai Honved Technical Academy. In its aula there is a woodcut of Janos Bolyai (1802-1860) with the inscription:

The Royal Hungarian Janos Bolyai Honved Technical Academy, Predecessor of today’s Janos Bolyai Military Technical College, was working in this Building edu­cating Technical Officers for the Hungarian Army. Erected by the Honved Bolyai Foundation in 1995

Physics in Berlin I: The Historical City Center[19]

Dieter Hoffmann[20]

Hans-Jurgen Treder has written that, ‘‘During the nearly 60 years that spanned the call of Hermann Helmholtz to become professor of physics in the Berlin University… in 1871, and Erwin Schrodinger’s call to the chair of theoretical physics [in 1927] …, the general history of physics was closely connected to the history of physics in Berlin.’’1 Besides Helmholtz and Schrodinger, the list of famous physicists who worked in Berlin during those six decades includes Albert Einstein, Max Planck, Max von Laue, Walther Nernst, Gustav Hertz, James Franck, and Lise Meitner, to name but some of them.2 But the heyday of physics in Berlin arose neither by chance nor out of the blue: It resulted from a long historical process that began with the foundation of the Brandenburg Academy of Science in 1700 by Gottfried Wilhelm Leibniz; the present Academy of Science in Berlin is the direct descendent of that society. With the founding of the Academy in the capital of Prussia, science established itself in Berlin as a constituent part of its social life. It was predominantly in the context of mathematical research and the fields of mechanics and astronomy that physics was practiced at first. The names of such renowned scientists as Leonhard Euler, Joseph Louis Lagrange, Johann Heinrich Lambert, and Franz Ulrich Theodosius Aepinus bear witness to the remarkably high level that mathematical and physical research had reached in Berlin as early as the 18th century. There was no other city in Germany at that time where there was such a large and extraordinary community of mathematicians, physicists, and chemists teaching and carrying out research. You will find a reminder of this early period in the history of physics in Berlin at Behrenstrasse 21 (a street parallel to the western part of Unter den Linden), where Leonhard Euler lived during his Berlin period from 1743 to 1766. Of course, this is not Euler’s original house, since large parts of Berlin were totally destroyed by reconstructing or bombing during the following two centuries.

The beginning of a genuine and continuous development of physics in Berlin came in 1810 with the foundation of the University of Berlin, today Humboldt University. But the reputation of its first professors did not extend much beyond the city’s borders, and conditions for research and teaching also were very modest. This changed in the middle of the century when Gustav Magnus began to teach physics and gathered about

him young and talented scientists in a private laboratory that he had established – basi­cally as his own expense – in his pleasant and spacious house, the so-called Magnus Haus (figure 1) located at Am Kupfergraben 7,3 just opposite the famous Pergamon Museum. It soon became the center of one of the most important schools of physics in the 19th century in Germany. Furthermore, the colloquium founded by Magnus in 1843 developed into the world-famous Berlin Physical Colloquium, and the idea of estab­lishing a Physical Society in Berlin also emerged in 1845,4 as Werner von Siemens said, from this ‘‘stimulating circle of gifted young scientists.’’5 Since 1958, which was the cen­tenary of the birth of Max Planck,6 the Physical Society has occupied the Magnus Haus-first the Physical Society of the German Democratic Republic and since 1990 the reunited German Physical Society. Following a total renovation in 1993-94, the Mag­nus Haus is being used by the German Physical Society as a center of communication between physicists and the public through the sponsorship of regular talks and discus­sions. The building itself was constructed in the middle of the 18th century with the expansion of Berlin as the Prussian capital and European metropolis. It is one of the last surviving palaces in Berlin. You should ring the doorbell and take a look inside at the beautiful staircase and the garden in back. Inside you also will find posters on the history of the Magnus Haus and its place in physics in Berlin.

Fig. 1. The Magnus Haus, Am Kupfergraben 7. Courtesy of the German Physical Society.

Fig. 2. Plaque on the Magnus Haus installed by the German Physical Society in 1930 giving the names of famous colleagues and students who worked there. Courtesy of the German Physical Society.

Joseph Louis Lagrange, a leading member of the Academy during the reign of Fred­erick II, lived in this palace between 1774 and 1782. Magnus bought it just after his mar­riage in 1840, and his much-younger wife lived in it after his death in 1870 up to the end of the century. It then was occupied by the famous theater director Max Reinhard. A plaque on the left-front corner of the building placed there by the German Physical Soci­ety in 1930 lists the names of some of the most famous students of Magnus (figure 2).

Fig. 3. The Helmholtz monument in front of Humboldt University on Unter den Linden. Photograph by the author.

The street Am Kupfergraben was a favorite residential area for professors of the Uni­versity. For instance, in the next block at Number 5 the famous philosopher G. W. Hegel lived until his death in 1831. The University is only a few steps away. We enter the Uni­versity from its main entrance on Unter den Linden. Just in front is a monument of Hermann von Helmholtz (figure 3), which was designed by the sculptor Ernest Herter in 1899. The most important period in the history of physics in Berlin began with Helmholtz, but under modest conditions. The institute of physics was located in the eastern wing of the University in rooms with very limited space and ones that did not permit precision experimental research because of disturbances from the traffic. Nev­ertheless, some physicists who subsequently became famous, for instance the young Ludwig Boltzmann, were attracted by the personality and scientific reputation of Helmholtz and worked there in the 1870s.

These modest conditions were only temporary, however, because Helmholtz accept­ed the call to Berlin only under the condition that he would obtain a new and proper institute as soon as possible. This was constructed for him between 1874 and 1879 and represented the beginning of a general institutional revolution in German physics.7 Albert A. Michelson worked there in the winter of 1880-81. Before we walk to Helmholtz’s institute, however, we should mention that the University of Berlin was one of the first universities to establish a special chair and institute for theoretical physics. The first occupants of the chair were Gustav Kirchhoff (1874-87) and Max Planck (1889-1927). The rooms of the institute were located in the basement of the western wing of the main building of the University. In the court of the University is also located a Planck statue by the famous sculptor Bernhard Heiliger. It was already created in 1949, but for his modern design it was viewed with disfavour by contempo­rary politicians and physicists as well. Therefore it was banished until 2006 in a physics institute in a suburb of Berlin. A plaque on the street front of this wing reminds us that Max Planck founded the quantum theory there. Other famous chair holders were Max von Laue (1920-43), Erwin Schrodinger (1927-33), Werner Heisenberg (1942-45), and Pascual Jordan (1944- 45).

At the back of the main building of the University, in the vestibule of the Auditori­um Maximum, is a plaque commemorating another revolutionary of modern physics, Albert Einstein. During the 1920s Einstein gave some of his lectures on relativity there, but his place of work was not the University but the Academy, located a block west on Unter den Linden in the direction of the Brandenburg Gate. The grey sandstone build­ing accommodates the old Royal Library, now the State Library, and was dedicated in 1914, the same year that Einstein moved to Berlin. The Prussian Academy of Science was located in the front wing of the building and in its meeting room the members of the Academy, mostly professors and directors of Berlin’s scientific institutions, came together every other week for talks and discussions. This was the location, for instance, where Einstein reported on his new gravitational theory for the first time, in 1916; a plaque commemorates that important talk in the passageway to the library. There also are other memorials to Einstein’s period in Berlin (1914-1932).12 You can find a plaque on the house where he lived from 1917 to 1932 at Haberlandstrasse 5 (which today is a new building because the old one was destroyed during the war, and after the war the street also was renamed Nordlinger Strasse). Another Einstein plaque you find at his first Berlin flat at Ehrenbergstr. 33 in Berlin-Dahlem. One more is in the Archenhold – Sternwarte (a public observatory housing the world’s longest telescope at more than 20 meters) in Treptow (one of Berlin’s eastern districts) where Einstein gave one of his early public talks on his General Theory of Relativity. Another memorial place for Ein­stein is the great synagogue on Oranienburger Strasse, only a short walk from the Uni­versity and right in the middle of Berlin’s new tourist scene, where Einstein sometimes played his violin in public concerts. If you have enough time for an excursion into the vicinity of Berlin, then you also should visit Einstein’s marvelous summer house Am Waldrand 15-17, in the village of Caputh, about 10 kilometers from Potsdam and acces­sible by city bus from Potsdam.

But we must not forget that Einstein was one of the many scientists and scholars who were expelled from Germany by the Nazis, and that his books were probably among the many burned in the ‘‘Bucherverbrennung’’ on May 10,1933. That macabre Nazi spectacle occurred at today’s August-Bebel-Platz (formerly the site of the Opera) on Unter den Linden just across the street from the University. A monument there reminds us of that infamous event.

As mentioned above, Helmholtz accepted the call to Berlin only on condition that he would obtain a new and modern institute of physics.8 After many difficulties this institute was constructed for him between 1874 and 1879 as part of a complex of new science building for the University (figure 4a). This area is reached by a short walk down Unter den Linden towards the Brandenburg Gate and turning right on Wil – helmstrasse. One block north on Wilhelmstrasse turn right again on Dorotheenstrasse. You will see a red brick building with its front on Dorotheenstrasse in the typical archi­tecture for German university buildings at the end of the 19th century. This is not the old physics institute but the Physiology Institute of Emil Du Bois-Reymond. Both institutes were built together and designed similarly. The Physiology Institute was located on the Dortheenstrasse and Helmholtz’s institute was on the opposite side of this street with its front on the river Spree (now called Am Reichstagsufer). Helmholtz’s institute was destroyed during the final and very heavy battles of World War II, since Hitler’s Reichskanzlei and the administration district with the Reichstag were not far away.

Helmholtz’s institute was one of the most modern and best-equipped institutes of physics in Germany at the end of the 19th century; the cost of construction amounted to 1,500,000 Reichsmarks. Many famous physicists worked or were educated there; the list of directors alone reads like a Who’s Who of modern physics: Helmholtz, August Kundt, Emil Warburg, Heinrich Rubens, Walther Nernst, Arthur Wehnelt, and Christ­ian Gerthsen. Others who worked there include Heinrich Hertz, Wilhelm Wien, Henry Rowland, Michael Pupin, James Franck, Gustav Hertz, and Peter Pringsheim. Cumula­tively around the turn of the century, Helmholtz’s institute probably housed the high­est density of Nobel Prize winners, past and future, in Berlin, and in the 1920s in the whole world. Furthermore, his institute housed the offices and rooms of the German Physical Society where its meetings took place. Max Planck, for instance, presented his radiation law there and founded quantum theory in the fall of 1900. Today a new build­ing that accommodates the studios of German public television is located at this site. At its entrance gate a plaque has been placed recently that indicates the remarkable history of this site (figure 4b). For an impression of the physical atmosphere of Helmholtz’s institute, you should go into the old Du Bois-Reymond Physiology Insti­tute or into the Institute of Physical Chemistry; the latter is located nearby on Bun- senstrasse. In both you will find two old lecture rooms and in the vestibules a few show­cases that give some information on the history of these institutes and display a few his­torical instruments; unfortunately, most of the old ones were destroyed in the war. At the entrance to the former Institute of Physical Chemistry there is a plaque stating that Walther Nernst and Max Bodenstein worked there and that Nernst presented his heat theorem (the third law of thermodynamics) in a lecture during his first term in Berlin in 1905. In the old lecture room upstairs there also is an old Nernst candle. This insti­tute was also where Nernst and his students carried out their famous low-temperature investigations that advanced the development of the early quantum theory.9 Also worth noting is that Hans Landolt was one of Nernst’s predecessors, and after the war the famous East German dissident Robert Havemann was the institute’s director before he was prohibited from teaching and carrying out research there by Communist Party officials in 1964.10

Before leaving this rich historical area, go north on Wilhelmstrasse, cross the river Spree, and view the Reichstag building on your left. Then reverse direction, go south on Wilhelmstrasse, cross Unter den Linden, and look for Wilhelmstrasse 68 on your


Fig. 4. (a) Helmholtz’s Institute of Physics, Am Reichstagufer, which was destroyed in the war. Cour­tesy of the German Physical Society. (b) ARD-Hauptstadtstudio (German public television studios) located today on the same site. The old building on the left is the Institute for Physical Chemistry. Cour­tesy of the German Physical Society.


left. This building was where the former Prussian Ministry of Education was located. This was the place where Prussia’s very successful science policy was shaped by the powerful Friedrich Althoff and the Minister of Education Friedrich Schmidt-Ott. Schmidt-Ott also was the president of the ‘‘Notgemeinschaft der Deutschen Wis – senschaft’’ founded in 1920, but this influential institution did not have its offices there but instead in the Berlin Castle, which was totally destroyed during and after the war. It was located on today’s Schlossplatz – today an empty and dreary place not far from Humboldt University at the eastern end of Unter den Linden.

Going north again on Wilhelmstrasse and crossing the river Spree, after some 100 meters you will come to the world-famous Charite hospital. This hospital was where famous physicians, for instance Robert Koch and Ferdinand Sauerbruch, worked. One of the first institutes of biophysics and radiology also was established at the Charite in 1923 by Walter Friedrich, one of the co-discoverers of X-ray diffraction. This institute was located in the building on the southwestern corner of today’s Robert-Koch-Platz 1. Following the small street along side of this house you come to Hessische Strasse on your left and another complex of university science buildings on your right. These were built in 1900 and housed the Chemical Institute of Emil Fischer (figure 5a). Here the so-called ‘‘Holzwerkstatt’’ also was located in which Otto Hahn and Lise Meitner (fig­ure 5b) began their collaboration on radioactivity research. A plaque on the front of the building commemorates their work. In 1912 they moved to the newly founded Kaiser-Wilhelm-Institute for Chemistry in Berlin-Dahlem. There is also a plaque for East Germany’s dissident and physicochemist Robert Havemann, who gave there his famous lectures “Dialectic without Dogma” in 1963/64.

Going north on Hessische Strasse a few steps, you come to Invalidenstrasse, where you will see three very similar buildings that dominate the skyline and are typical of the imperial architecture at the end of the 19th century. To the left is the former Geo­logical State Institute, in the middle is the Museum of Natural History with its remark­able collections (containing, for instance, reconstructions of dinosaurs), and on the right is the former College of Agriculture, today part of Humboldt University. At the back of this building the College’s Physical Institute was located. Besides Helmholtz’s Physical Institute on the Reichstagsufer, this Physical Institute was another important and productive research institution in Berlin: Otto von Baeyer, Erich Regener, and Richard Bornstein, for example, were professors there. For four decades after the war this institute was the main location for physical research at Humboldt University; a new institute was constructed only in 1984 on the opposite side of the street at the cor­ner of Invalidenstrasse and Chausseestrasse; today the Institute is located at the Cam­pus Adlershof, about ten miles away in a south-eastern suburb of Berlin. There in the inner courtyard you can find a monument with the names of famous physicists who were connected with Berlin’s university. Unfortunately, the famous geophysicist, Alfred Wegener, the creator of the continental drift hypothesis, is not mentioned since he was only a student there. However, a plaque on his old high school (Gymnasium) not far from the city center at Wallstrasse 26 indicates that he also was born and edu­cated in Berlin.

We conclude our present excursion tracing the history of physics in Berlin with a short walk south on Chausseestrasse and enter the gate of the cemetery (Dortheen-


Fig. 5. (a) Emil Fischer’s Institute of Chemistry, which housed the ‘‘Holzwerkstatt’’ in its basement. Photograph by the author. (b) Otto Hahn and Lise Meitner in the so-called “Holzwerkstatt.” Courtesy of the Archiv der Max-Planck-Gesellschaft, Berlin-Dahlem.


stadtischer Friedhof) at Chausseestrasse 126, where you can find the graves of Gustav Magnus, A. Borsig, J. G. Fichte, G. W. Hegel, A. W. Hofmann, and also some other well – known public figures such as Bertolt Brecht. The graves of other famous physicists are located in other cemeteries in Berlin. You will be given further information on these locations (some of which are also noted elsewhere11) in the sequel to this article, in which we will tour places of interest in the western districts of Berlin around the Tech­nical University in Charlottenburg and in Dahlem and on the outskirts of Berlin around Potsdam.