Blau Marietta. Complete Dictionary of Sc
Blasius of Parma
Blau
Hitherto unnoticed “ Quaestiones” by Blasius of Parma (?)”,
Manuscripta, XX (1976): 119–136. The author maintains
that this text cannot be surely attributed to Blasius.
Questio de intensione et remissione formarum: Federici Vescovini,
Graziella, “La Quaestio de intensione et remissione formarum di
Biagio Pelacani da Parma”, Physis, XXXI (1994): 433–535
from the ms. Venice, Biblioteca Marciana, ms. VI, 62 (2549).
Questiones super Tractaus logice Magistri Petri Hispani. Edited by
Joël Biard and Graziella Federici Vescovini, avec la coll. de
Orsola Rignani et Valeria Sorge. Paris: J. Vrin, 2001.
Questiones circa Tractatum proportionum Magistri Thome
Braduardini. Edited by Joël Biard et Sabine Rommevaux.
Paris: J. Vrin, 2005.
OTHER SOURCES
Biard, Joël. “L’être et la mesure dans l’intension et la rémission
des formes (Jean Buridan, Blaise de Parme).” Medioevo 27
(2002): 415–447.
———. “Le système des senses dans la philosophie naturelle du
XIVe siècle (Jean de Jandun, Jean Buridan, Blaise de Parme).”
Micrologus 10 (2002): 335–354.
———. “Mathématique et philosophie dans les ‘Questions’ de
Blaise de Parme sur le ‘Traité des rapports’ de Thomas
Bradwardine.” Revue d’Histoire des Sciences 56 (2003):
383–400.
Buzzetti, Dino. “Blasius Pelacani, the Paradoxes of Implication
and the Notion of Logical Consequence.” In Medieval and
Renaissance Logic in Spain. Acts of the 12th European
Symposium on Medieval Logic and Semantics held at the
University of Navarra (Pamplona 26-30 May 1997), edited by
Ignacio Angelelli and Perez Ilarbe, 97–135. Paloma, Spain:
Olms, 1998.
Federici Vescovini, Graziella. “Biagio Pelacani: filosofia,
astrologia e scienza agli inizi dell’età moderna.” In Filosofia,
scienza e astrologia nel Trecento Europeo. Biagio Pelacani
Parmense, edited by Graziella Federici Vescovini and
Barocelli, Francesco, 39–52. A cura di con un intervento di
Raymond. Klibansky. Padova: Il Poligrafo, 1992.
Rommevaux, Sabine. “L’irrationalité de la diagonale et du côté
d’un même carré dans les ‘Questions’ de Blaise de Parme sur
le ‘Traité des rapports’ de Bradwardine.” Revue d’Histoire des
Sciences 56 (2003): 401–418.
Sorge, Valeria. “‘Contra communiter philosophantes’: a
proposito della fisiologia della visione in Biagio Pelacani da
Parma.” Atti dell’Accademia di scienze morali e politiche della
Società nazionale di scienze, lettere e arti di Napoli 106 (1996):
299–322, 455–474.
———.”L’influenza di Alhazen sulla dottrina della visione in
Biagio Pelacani da Parma.” In Filosofia e scienza classica,
arabo-latina medievale e l’età moderna, edited by Graziella
Federici Vescovini, 113–127. Louvain-La-Neuve: FIDEM,
1999.
Stefano Caroti
298
BLAU, MARIETTA (b. Vienna, Austria, 29
April 1894; d. Vienna, 27 January 1970), physics, radioactivity, method of nuclear photographic emulsions, photomultiplier technology.
Blau developed the method of photographic emulsions
that enabled the recording of tracks of atomic particles and
became known for the discovery of “contamination stars,”
explosions of atomic nuclei produced by high-energy cosmic-ray particles. She elaborated a theory on the effect of xrays on biological objects. Using photomultipliers, she
designed the first electrically modified scintillation counter
and several user-friendly medical instruments for radioactive measurements. She was nominated twice for the Nobel
Prize. Blau received the Schrödinger Prize and the Ignaz
Lieben Prize of the Austrian Academy of Sciences.
Blau was born in fin de siècle Vienna as the third
child of an upper-class Jewish family. Her father, Markus
Blau, was a lawyer in the kaiser’s courts and an important
music publisher. Her mother, Florentine Goldenzweig,
was the sister of Josef Weinberger, the main publisher of
Gustav Mahler’s works in Europe. During her childhood,
Blau attended some of the best Viennese schools and in
1905 was sent to the private Mädchen Obergymnasium,
the only school with official state recognition to prepare
women for academic studies. In 1914, when the young
men were drafted and women had more access to education, Blau enrolled at the University of Vienna to study
physics and mathematics. During the last year of her studies she conducted her Praktikum (practical training) at the
Institute for Radium Research, one of the four most
important radioactivity research centers in Europe. In
1918, Blau submitted her dissertation on the absorption
of diverging gamma rays, and her first paper appeared
both in the annual bulletin of the Radium Institute and in
the Sitzungsberichte of the Austrian Academy of Sciences.
Blau’s research topic turned out to be important for
clinical treatments of cancer. Discovered by a French
physicist, Paul Villard, gamma rays had occupied the
interest of the radioactivity community since 1900.
Because of their penetrating power, which is much higher
than that of x-rays, gamma rays proved to be crucial in
killing cancerous cells. Eventually, that research topic led
Blau to medical physics and to the Laboratory for Medical
Radiology at Guido Holzknecht’s clinic in Vienna where
she worked as a research assistant after defending her thesis in 1919.
Blau hovered at the boundary of medicine and
physics for the rest of her career. In 1921, she left Vienna
to accept a position as a physicist in Eppens and Co.,
which manufactured x-ray tubes in Fürstenau, Germany.
A year later she moved to the Institute of Medical Physics
in Frankfurt am Main, where she worked as a research
assistant. For more than a year Blau instructed doctors in
N E W D I C T I O N A RY O F S C I E N T I F I C B I O G R A P H Y
Blau
Blau
radiobiology, while she conceived and elaborated a theory
on the effect of x-rays on biological objects. At that time
the Frankfurt Institute was the epicenter of target theory
in Germany, which described the impinging of radiation
on living tissues as particles hitting a target. The theory’s
aim was to use radiation to probe the structure of the
organic world. Blau played an instrumental role in developing the statistical analysis of biophysical processes that
constituted “hits,” which was the main research project of
Friedrich Dessauer, the director of the institute (Beyler,
1997, pp. 39–46). Working with Kamillo Altenburger,
she studied the number of “hits” that were entailed in
order for a biological process to occur. Her research career
in Germany was interrupted abruptly in the fall of 1923
when her mother became ill and she had to return to
Vienna. Although she left Dessauer’s laboratory, Blau
retained her ties. Later she contributed a piece on photographic investigations of radioactive rays in a multiauthored volume edited by Dessauer on the boundary
between physics and medicine (Blau, 1931).
was prepared in highly concentrated preparations by Elizabeth Rona, an experienced experimenter at the Institute.
In 1925, Blau detected for the first time the trajectories of slow protons. As the grain thickness of proton
tracks was appreciably smaller than that of alpha tracks, it
was evident to her that the photographic conditions
(emulsion characteristics and development conditions)
would have to be improved if high-energy protons—with
smaller ionization thickness—were to be observed. In the
following years, the method was applied to the disintegration of various atoms and detected the tracks of faster protons. Blau also improved the quality of the processing
techniques and emulsions and was able to increase the
thickness of the emulsion layers. However, what proved to
be decisive for Blau’s career and for the success of her
method was the exposure of the emulsions to cosmic radiation. In this achievement, Blau’s collaborator was Hertha
Wambacher.
Nine years younger than Blau, Wambacher entered
the institute as a Praktikum student, having Blau as her
main but informal advisor in her dissertation on the
impact of photographic desensitizers on the imprints of
alpha, beta, and gamma rays on photographic plates. As
Wambacher proved, a major desensitizer of photographic
emulsions was the organic dye pinakryptol yellow. In June
1932, the two women coauthored their first paper. Just
five months after James Chadwick’s discovery of the neutron, Blau and Wambacher were able to detect photographically protons liberated by unseen neutrons. These
protons did not leave an imprint unless the photographic
plates were desensitized by means of pinakryptol yellow.
As a consequence of this first success in photographically
detecting the ionization protons and explaining the effect
of desensitization, Blau was invited by the German photographic giant Agfa, “as their guest of honor,” and a
medal was bestowed upon her by the Photographic Association (Blau, curriculum vitae). Additionally, in the fall of
1932, Blau received a scholarship from the Association of
Austrian Academic Women to spend six months at Robert
Pohl’s physics institute in Göttingen and the rest of her
stipendium time at Marie Curie’s Institut du Radium in
Paris. But during Blau’s absence from her home institute,
Wambacher teamed with Gerhard Kirsch—a Viennese
physicist, a Nazi, and Pettersson’s main collaborator—on
an investigation of neutrons from beryllium, using Blau’s
photographic method. On Blau’s return in 1934, both the
institute and Vienna had changed, affected profoundly by
the political upheavals of 1933.
Photographic Emulsions. Between 1923 and 1938, Blau’s
research was centered at the Radium Institute in Vienna.
Still, when she attempted to obtain a position as Dozentin
(instructor) at the University of Vienna, the response was
astounding; “You are a woman and a Jew and together this
is too much” (Halpern, 1997, p. 197). In the 1920s, the
Radium Institute was less conservative than the university,
hosting an astonishing number of women researchers and
welcoming Jews. During this time, thanks to the Swedish
physicist Hans Pettersson, the institute proved to be a
major participant in a serious controversy over the artificial disintegration of light elements. The second participant was Rutherford’s laboratory in Cambridge, England.
Blau joined Pettersson’s group in Vienna, and with her
expertise on the use of photography in radioactivity, she
was immediately assigned to develop a new method for
tracking charged nuclear particles, that of photographic
emulsions.
Rutherford’s discovery of the phenomenon of artificial disintegration by alpha particles prompted the need
for more sensitive tools to detect and measure the emitted
protons, a need that became urgent during the ViennaCambridge controversy.The method of photographic
emulsions had been already used by S. Kinoshita and
Maximilian Reinganum in the beginning of the 1910s to
identify trajectories of alpha particles through emulsions.
In early 1924, Blau was assigned by Pettersson to use the
same method to observe recoil protons produced by alpha
particles in paraffin. With weak radioactive sources she
could observe the lower-energy particles, but the accuracy
of the measurement was limited. The only strong source
available was polonium. To prevent darkening of the plate
by gamma radiation, Blau worked with polonium, which
N E W D I C T I O N A RY O F S C I E N T I F I C B I O G R A P H Y
Political Unrest. In the context of the wider European
political crisis and Hitler’s rise to power in Germany, the
political situation in Vienna became increasingly unstable.
The socialists lost power and control of the city in 1934,
299
Marietta Blau. AGNES RHODE PERSONAL PAPERS.
giving rise to Austrian fascists and to the Nazis consequently. After her return from Paris, Blau continued her
collaboration with Wambacher under an obvious political
tension within the institute.
The two women worked on two fronts. First, they
improved the emulsion technique by thickening the photographic plates to allow a better deposit of the particle
tracks. Ilford, the English photographic company, offered
to produce sufficiently thick plates, and Blau suggested
that new development methods had to be created. Second, while still struggling to alter their apparatus to suit
their experimental needs, Blau and Wambacher applied
the photographic technique to neutron studies. Their collaboration turned out to be threatening for Blau’s existence at the institute. In June 1934, Wambacher joined
the National Socialist Party and around that time became
intimately involved with an ardent Nazi, Georg Stetter,
assistant at the Second Physics Institute of Vienna and
member of Pettersson’s group.
Continuing their cooperation, in 1936 the two
women exposed their emulsions on the Haferlekar, a
mountain near Innsbruck, for four months in order to
300
secure high-intensity radiation. Their research project
consisted in determining the existence of heavy particles
such as protons, neutrons, and alpha particles in cosmic
rays, which at the time was considered quite doubtful.
Upon first examination of the plates, they observed proton tracks longer than anyone else had at that time. Yet, to
their surprise, Blau and Wambacher observed in the emulsion a “contamination star” (several tracks emanating
from a point) that could neither be explained by irregularities in the emulsion nor by unknown radioactive products during the handling and storage of the plates in the
laboratory. The assumption was that the large “stars” originated from the disintegration of heavy particles, probably
bromine or silver, and that the smaller ones originated
perhaps from light elements in the gelatin. Given the theoretical limitations of nuclear physics of the time, the two
women could not determine the nature of the primary
particle and the exact process of the disintegration. These
impressive results, which American historian Peter Galison considers the first “golden event” using emulsions,
provoked the interest of the scientific community (1997,
p. 44). In 1937, on the basis of their discovery, Blau and
N E W D I C T I O N A RY O F S C I E N T I F I C B I O G R A P H Y
Blau
Blau
Wambacher were awarded the Ignaz Lieben Prize of the
Austrian Academy of Sciences.
While the two women were preparing a publication,
Stetter approached Blau. He accused her of being unfair
to Wambacher and expected her to change the order of
the names on their publication since Wambacher was,
after all, he argued, the first to look into the microscope
and find the star. Blau refused. In the midst of the world’s
serious political upheavals and Blau’s tenuous position,
Ellen Gleditsch, a Norwegian expert on radioactivity, took
a personal interest in her situation and offered her a temporary position as a research assistant in her laboratory in
Oslo. Under the enormous pressure from her own exadvisee and Stetter, Blau rushed to arrange research matters with Wambacher, an arrangement which was a total
defeat for her.
As the agreement went, Wambacher, in collaboration
with Gustav Ortner, another Nazi at the institute, were
going to investigate the relation of the grain and density
of the tracks recorded on the photographic emulsions to
the energy of the particles produced by them. By measuring the grain thickness of the tracks one could even estimate the energy of the particles that were not brought to
rest in the emulsion but passed through. This process had
the potential of identifying the particles and the total
energy released in the process, the two key points of Blau’s
and Wambacher’s earlier work. Blau agreed to continue
the absorption experiments, a less promising and more
tiresome task. Luckily, she left Vienna on a 7:00 a.m. train
to Oslo a day before the Germans paraded triumphantly
into Austria on 12 March 1938.
to 1944, Blau centered her work in Mexico, deeply frustrated by the lack of research opportunities and by the
teaching overload. Only through the efforts of the Jewish
community in Mexico, was she able to enter the United
States in May 1944.
Exile. While Blau knew that she could only remain in
Oslo for a limited time, Berta Karlik, a young colleague
then and later director of the Radium Institute, encouraged Pettersson to reclaim the instruments he brought to
Vienna in the early 1920s. Given the simplicity of the
photographic emulsions method and its tabletop scale,
portable objectives and microscopes could, at least temporarily, ensure Blau’s research prospects.
In November 1938, after Albert Einstein’s recommendation, Blau left Norway to accept a position at the
Polytechnic School in Mexico City. On her way to Mexico the Gestapo confiscated her scientific notebooks, forcing her zeppelin down in Hamburg. She later speculated
that those ended up at the hands of her Nazi colleagues in
Vienna. However, with or without Blau’s scientific notebooks, Wambacher continued to use the experimental
facilities of the Radium Institute. Within two weeks of the
Anschluss, she was promoted to the position of assistant at
the First and Second Physics Institutes. Publications in
major German journals accompanied her rapid promotion in the university ranks. On the contrary, from 1940
N E W D I C T I O N A RY O F S C I E N T I F I C B I O G R A P H Y
Photomultipliers and Scintillation Counters. Blau was
one of the first to suggest the use of a photomultiplier in
combination with a scintillation counter. The original
scintillation counter consisted of a thin glass plate spread
with an equally thin layer of zinc sulfide. When the plate
was struck by charged particles, the screen produced light
flashes that were observed through a microscope specifically designed to increase their brightness. The instrument
had extensively been used at the Radium Institute during
the Cambridge-Vienna controversy. Working for competitive industrial corporations after the Second World War,
Blau sought possibilities for professional existence by saving and modifying an old-familiar technique; her past
secured her present.
In the physics department of the International Rare
Metals Refinery, her first position in the United States,
Blau teamed up with B. Dreyfus in combining the use of
a photomultiplier tube to a scintillation screen for the
measurement of alpha ray sources (Blau and Dreyfus,
1945). Putting together a fluorescent screen with the photomultiplier, which took a very small amount of light and
converted it into an amplified electrical signal, and using
strong polonium sources, Blau and Dreyfus had in fact
described the first electrically modified scintillation
counter. As the references to Elizabeth Kara-Michailova’s
and Berta Karlik’s work show, both colleagues in Vienna,
Blau was the driving force in designing the device. In
1933, after abandoning the ordinary scintillation counter,
Karlik had worked on the determination of alpha particle
ranges utilizing a photoelectric cell, a sensitive electric
device for the detection of the scintillations that replaced
the fragile and unreliable human optical system. Karlik’s
method, however, was seldom used, as Blau explained,
given the limited range of measurements of the ordinary
photocells and the lack of adequate and constant alphasources. Thanks to the multiplier phototube, Blau overcame the earlier difficulties.
Through her hybrid instrument Blau sought to
merge the competing prewar and postwar cultures in
physics research. The shift from the ordinary photocells to
photomultipliers, in Blau’s experimental practice, was not
just a simple replacement of two pieces in an instrument.
The transformation was a deeper, conceptual one for both
the experimenter and the instrument. From a researchoriented position in the Radium Institute in Vienna,
Blau’s occupation shifted to industrial physics in the postwar United States. The corporations that she worked for
301
Blau
Blau
1944 to 1948 were deeply involved in the manufacture of
nuclear weapons, the commerce of uranium and radium,
and the industrial uses of radium. In the beginning of
1948, Blau moved to the Gibbs Manufacturing and
Research Corporation and with J. R. Carlin she worked
on industrial applications of radioactivity. Her creative
time and efforts were taken up by a number of radioactive
devices such as resistors, electrostatic voltmeters, leveling
systems, and micrometers.
In her effort to find a decent research position, Blau
moved again within the next few months, this time to the
Canadian Radium and Uranium Corporation. Carrying
over her knowledge in medical physics to the Radium Corporation, Blau designed a photomultiplier scintillation
counter for medical use. Designed for “persons not very
familiar with radioactive measurements,” Blau’s scintillation counter was a convenient and practical instrument for
wide use in hospitals and medical laboratories (Blau and
Smith, 1948, p. 68). Despite the fact that she was the first
to design and suggest medical applications of the photomultiplier scintillation counter, Blau remained peripheral
and isolated in the competitive world of industrial physics.
In 1950, she moved to the Brookhaven National Laboratory where she had restricted access to the high-energy
physics facilities. Remaining faithful to the experimental
tradition of the 1930s, Blau was unable to continue her
research in the new settings of big science. Although
Erwin Schrödinger nominated Blau and Wambacher for a
Nobel Prize based on their pioneer work on photographic
emulsions in this same year, the Nobel Prize committee
almost unanimously intended to give the prize to someone who was doing follow-up work to the previous year’s
prize winner, Hideki Yukawa, on the existence of mesons.
While the committee recognized the importance of Blau’s
contributions, the prize was eventually awarded to the
physicist Cecil Powell, who had adapted Blau’s method to
his industry-like laboratory in Bristol and turned it to a
powerful tool for making “foundational discoveries concerning mesons and their properties” (Nobel Committee
Report, 1950).
friends such as Karlik. She died on 27 January 1970, in the
intensive care ward of the Lainz hospital, lonely and
unknown to the international physics community.
Return to Vienna. Because of prolonged exposure to
radioactivity, in the late 1950s, Blau developed cataracts,
requiring an operation. In the dusk of her life facing financial and health problems, Vienna seemed the most suitable
destination. She finally returned in 1960. A number of old
colleagues tried to gather funds for her and Schrödinger
put her up for the Schrödinger Prize, which she received in
1962. Poor, disconnected from any major scientific network, and bitter about several members of the Radium
Institute for reaccepting the Nazi Stetter as one of the
heads of the Physics Institute after the end of the war, Blau
distanced herself from serious research and from old
302
BIBLIOGRAPHY
WORKS BY BLAU
“Über die Absorption divergenter-Strahlung.” Sitzungsberichte
der Kaiserlichen Akademie der Wissenschaften in Wien,
Mathematisch-naturwissenschaftliche Klasse, Abteilung 2a, 127
(1918): 1253–1279.
With Kamillo Altenburger. “Über einige Wirkungen von
Strahlen.” Zeitschrift für Physik 12 (1922): 315–329.
“Über photographische Untersuchungen mit radioaktiven
Strahlungen.” In Zehn Jahre Forschung auf dem physikalischmedizinischen Grenzgebiet, edited by Friedrich Dessauer.
Leipzig, Germany: Georg Thieme, 1931.
With Hertha Wambacher. “Disintegration Processes by Cosmic
Rays with the Simultaneous Emission of Several Heavy
Particles.” Nature 140 (1937): 585.
Curriculum Vitae. 1941 (unpublished). Grenander Department
of Special Collections and Archives, State University of New
York at Albany.
With B. Dreyfus. “The Multiplier Photo-Tube in Radioactive
Measurements.” The Review of Scientific Instruments 16
(1945): 245–248.
With J. R. Carlin. “Industrial Applications of Radioactivity.”
Electronics 21 (April 1948): 78–82.
With J. E. Smith. “Beta-Ray Measurements and Units.”
Nucleonics 2 (June 1948): 67–74.
OTHER SOURCES
Beyler, Richard. “‘Imagine a Cube Filled with Biological
Material’: Reconceptualizing the Organic in German
Biophysics, 1918–1945.” In Fundamental Changes in Cellular
Biology in the 20th Century, edited by Charles Galperin, Scott
F. Gilbert, and Brigitte Hoppe. Proceedings of the 20th
International Congress of History of Science, Liège, Belgium
20–26 July 1997. Turnhout, Belgium: Brepols, 1999.
Galison, Peter. “Marietta Blau: Between Nazis and Nuclei.”
Physics Today 50 (1997): 42–48.
Halpern, Leopold. “Marietta Blau: Discoverer of the Cosmic Ray
‘Stars.’” In A Devotion to Their Science: Pioneer Women in
Radioactivity, edited by M. Rayner-Canham and G. RaynerCanham. London: McGill-Queen’s University Press, 1997.
Lindh, Axel. “Nobel Committee Report on Marietta Blau and
Hertha Wambacher.” Uppsala 1 July 1950 (unpublished).
Nobel Archive of the Center for History of Science, The
Royal Swedish Academy of Sciences. Stockholm.
Rentetzi, Maria. “Gender, Politics, and Radioactivity Research in
Interwar Vienna: The Case of the Institute for Radium
Research.” Isis 95 (2004): 359–393.
Rosner, Robert, and Brigitte Strohmaier, eds. Marietta Blau—
Sterne der Zetrümmerung. Wien: Böhlau Verlag, 2003.
Includes a complete list of Blau’s publications.
Maria Rentetzi
N E W D I C T I O N A RY O F S C I E N T I F I C B I O G R A P H Y
Blau
Hitherto unnoticed “ Quaestiones” by Blasius of Parma (?)”,
Manuscripta, XX (1976): 119–136. The author maintains
that this text cannot be surely attributed to Blasius.
Questio de intensione et remissione formarum: Federici Vescovini,
Graziella, “La Quaestio de intensione et remissione formarum di
Biagio Pelacani da Parma”, Physis, XXXI (1994): 433–535
from the ms. Venice, Biblioteca Marciana, ms. VI, 62 (2549).
Questiones super Tractaus logice Magistri Petri Hispani. Edited by
Joël Biard and Graziella Federici Vescovini, avec la coll. de
Orsola Rignani et Valeria Sorge. Paris: J. Vrin, 2001.
Questiones circa Tractatum proportionum Magistri Thome
Braduardini. Edited by Joël Biard et Sabine Rommevaux.
Paris: J. Vrin, 2005.
OTHER SOURCES
Biard, Joël. “L’être et la mesure dans l’intension et la rémission
des formes (Jean Buridan, Blaise de Parme).” Medioevo 27
(2002): 415–447.
———. “Le système des senses dans la philosophie naturelle du
XIVe siècle (Jean de Jandun, Jean Buridan, Blaise de Parme).”
Micrologus 10 (2002): 335–354.
———. “Mathématique et philosophie dans les ‘Questions’ de
Blaise de Parme sur le ‘Traité des rapports’ de Thomas
Bradwardine.” Revue d’Histoire des Sciences 56 (2003):
383–400.
Buzzetti, Dino. “Blasius Pelacani, the Paradoxes of Implication
and the Notion of Logical Consequence.” In Medieval and
Renaissance Logic in Spain. Acts of the 12th European
Symposium on Medieval Logic and Semantics held at the
University of Navarra (Pamplona 26-30 May 1997), edited by
Ignacio Angelelli and Perez Ilarbe, 97–135. Paloma, Spain:
Olms, 1998.
Federici Vescovini, Graziella. “Biagio Pelacani: filosofia,
astrologia e scienza agli inizi dell’età moderna.” In Filosofia,
scienza e astrologia nel Trecento Europeo. Biagio Pelacani
Parmense, edited by Graziella Federici Vescovini and
Barocelli, Francesco, 39–52. A cura di con un intervento di
Raymond. Klibansky. Padova: Il Poligrafo, 1992.
Rommevaux, Sabine. “L’irrationalité de la diagonale et du côté
d’un même carré dans les ‘Questions’ de Blaise de Parme sur
le ‘Traité des rapports’ de Bradwardine.” Revue d’Histoire des
Sciences 56 (2003): 401–418.
Sorge, Valeria. “‘Contra communiter philosophantes’: a
proposito della fisiologia della visione in Biagio Pelacani da
Parma.” Atti dell’Accademia di scienze morali e politiche della
Società nazionale di scienze, lettere e arti di Napoli 106 (1996):
299–322, 455–474.
———.”L’influenza di Alhazen sulla dottrina della visione in
Biagio Pelacani da Parma.” In Filosofia e scienza classica,
arabo-latina medievale e l’età moderna, edited by Graziella
Federici Vescovini, 113–127. Louvain-La-Neuve: FIDEM,
1999.
Stefano Caroti
298
BLAU, MARIETTA (b. Vienna, Austria, 29
April 1894; d. Vienna, 27 January 1970), physics, radioactivity, method of nuclear photographic emulsions, photomultiplier technology.
Blau developed the method of photographic emulsions
that enabled the recording of tracks of atomic particles and
became known for the discovery of “contamination stars,”
explosions of atomic nuclei produced by high-energy cosmic-ray particles. She elaborated a theory on the effect of xrays on biological objects. Using photomultipliers, she
designed the first electrically modified scintillation counter
and several user-friendly medical instruments for radioactive measurements. She was nominated twice for the Nobel
Prize. Blau received the Schrödinger Prize and the Ignaz
Lieben Prize of the Austrian Academy of Sciences.
Blau was born in fin de siècle Vienna as the third
child of an upper-class Jewish family. Her father, Markus
Blau, was a lawyer in the kaiser’s courts and an important
music publisher. Her mother, Florentine Goldenzweig,
was the sister of Josef Weinberger, the main publisher of
Gustav Mahler’s works in Europe. During her childhood,
Blau attended some of the best Viennese schools and in
1905 was sent to the private Mädchen Obergymnasium,
the only school with official state recognition to prepare
women for academic studies. In 1914, when the young
men were drafted and women had more access to education, Blau enrolled at the University of Vienna to study
physics and mathematics. During the last year of her studies she conducted her Praktikum (practical training) at the
Institute for Radium Research, one of the four most
important radioactivity research centers in Europe. In
1918, Blau submitted her dissertation on the absorption
of diverging gamma rays, and her first paper appeared
both in the annual bulletin of the Radium Institute and in
the Sitzungsberichte of the Austrian Academy of Sciences.
Blau’s research topic turned out to be important for
clinical treatments of cancer. Discovered by a French
physicist, Paul Villard, gamma rays had occupied the
interest of the radioactivity community since 1900.
Because of their penetrating power, which is much higher
than that of x-rays, gamma rays proved to be crucial in
killing cancerous cells. Eventually, that research topic led
Blau to medical physics and to the Laboratory for Medical
Radiology at Guido Holzknecht’s clinic in Vienna where
she worked as a research assistant after defending her thesis in 1919.
Blau hovered at the boundary of medicine and
physics for the rest of her career. In 1921, she left Vienna
to accept a position as a physicist in Eppens and Co.,
which manufactured x-ray tubes in Fürstenau, Germany.
A year later she moved to the Institute of Medical Physics
in Frankfurt am Main, where she worked as a research
assistant. For more than a year Blau instructed doctors in
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radiobiology, while she conceived and elaborated a theory
on the effect of x-rays on biological objects. At that time
the Frankfurt Institute was the epicenter of target theory
in Germany, which described the impinging of radiation
on living tissues as particles hitting a target. The theory’s
aim was to use radiation to probe the structure of the
organic world. Blau played an instrumental role in developing the statistical analysis of biophysical processes that
constituted “hits,” which was the main research project of
Friedrich Dessauer, the director of the institute (Beyler,
1997, pp. 39–46). Working with Kamillo Altenburger,
she studied the number of “hits” that were entailed in
order for a biological process to occur. Her research career
in Germany was interrupted abruptly in the fall of 1923
when her mother became ill and she had to return to
Vienna. Although she left Dessauer’s laboratory, Blau
retained her ties. Later she contributed a piece on photographic investigations of radioactive rays in a multiauthored volume edited by Dessauer on the boundary
between physics and medicine (Blau, 1931).
was prepared in highly concentrated preparations by Elizabeth Rona, an experienced experimenter at the Institute.
In 1925, Blau detected for the first time the trajectories of slow protons. As the grain thickness of proton
tracks was appreciably smaller than that of alpha tracks, it
was evident to her that the photographic conditions
(emulsion characteristics and development conditions)
would have to be improved if high-energy protons—with
smaller ionization thickness—were to be observed. In the
following years, the method was applied to the disintegration of various atoms and detected the tracks of faster protons. Blau also improved the quality of the processing
techniques and emulsions and was able to increase the
thickness of the emulsion layers. However, what proved to
be decisive for Blau’s career and for the success of her
method was the exposure of the emulsions to cosmic radiation. In this achievement, Blau’s collaborator was Hertha
Wambacher.
Nine years younger than Blau, Wambacher entered
the institute as a Praktikum student, having Blau as her
main but informal advisor in her dissertation on the
impact of photographic desensitizers on the imprints of
alpha, beta, and gamma rays on photographic plates. As
Wambacher proved, a major desensitizer of photographic
emulsions was the organic dye pinakryptol yellow. In June
1932, the two women coauthored their first paper. Just
five months after James Chadwick’s discovery of the neutron, Blau and Wambacher were able to detect photographically protons liberated by unseen neutrons. These
protons did not leave an imprint unless the photographic
plates were desensitized by means of pinakryptol yellow.
As a consequence of this first success in photographically
detecting the ionization protons and explaining the effect
of desensitization, Blau was invited by the German photographic giant Agfa, “as their guest of honor,” and a
medal was bestowed upon her by the Photographic Association (Blau, curriculum vitae). Additionally, in the fall of
1932, Blau received a scholarship from the Association of
Austrian Academic Women to spend six months at Robert
Pohl’s physics institute in Göttingen and the rest of her
stipendium time at Marie Curie’s Institut du Radium in
Paris. But during Blau’s absence from her home institute,
Wambacher teamed with Gerhard Kirsch—a Viennese
physicist, a Nazi, and Pettersson’s main collaborator—on
an investigation of neutrons from beryllium, using Blau’s
photographic method. On Blau’s return in 1934, both the
institute and Vienna had changed, affected profoundly by
the political upheavals of 1933.
Photographic Emulsions. Between 1923 and 1938, Blau’s
research was centered at the Radium Institute in Vienna.
Still, when she attempted to obtain a position as Dozentin
(instructor) at the University of Vienna, the response was
astounding; “You are a woman and a Jew and together this
is too much” (Halpern, 1997, p. 197). In the 1920s, the
Radium Institute was less conservative than the university,
hosting an astonishing number of women researchers and
welcoming Jews. During this time, thanks to the Swedish
physicist Hans Pettersson, the institute proved to be a
major participant in a serious controversy over the artificial disintegration of light elements. The second participant was Rutherford’s laboratory in Cambridge, England.
Blau joined Pettersson’s group in Vienna, and with her
expertise on the use of photography in radioactivity, she
was immediately assigned to develop a new method for
tracking charged nuclear particles, that of photographic
emulsions.
Rutherford’s discovery of the phenomenon of artificial disintegration by alpha particles prompted the need
for more sensitive tools to detect and measure the emitted
protons, a need that became urgent during the ViennaCambridge controversy.The method of photographic
emulsions had been already used by S. Kinoshita and
Maximilian Reinganum in the beginning of the 1910s to
identify trajectories of alpha particles through emulsions.
In early 1924, Blau was assigned by Pettersson to use the
same method to observe recoil protons produced by alpha
particles in paraffin. With weak radioactive sources she
could observe the lower-energy particles, but the accuracy
of the measurement was limited. The only strong source
available was polonium. To prevent darkening of the plate
by gamma radiation, Blau worked with polonium, which
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Political Unrest. In the context of the wider European
political crisis and Hitler’s rise to power in Germany, the
political situation in Vienna became increasingly unstable.
The socialists lost power and control of the city in 1934,
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Marietta Blau. AGNES RHODE PERSONAL PAPERS.
giving rise to Austrian fascists and to the Nazis consequently. After her return from Paris, Blau continued her
collaboration with Wambacher under an obvious political
tension within the institute.
The two women worked on two fronts. First, they
improved the emulsion technique by thickening the photographic plates to allow a better deposit of the particle
tracks. Ilford, the English photographic company, offered
to produce sufficiently thick plates, and Blau suggested
that new development methods had to be created. Second, while still struggling to alter their apparatus to suit
their experimental needs, Blau and Wambacher applied
the photographic technique to neutron studies. Their collaboration turned out to be threatening for Blau’s existence at the institute. In June 1934, Wambacher joined
the National Socialist Party and around that time became
intimately involved with an ardent Nazi, Georg Stetter,
assistant at the Second Physics Institute of Vienna and
member of Pettersson’s group.
Continuing their cooperation, in 1936 the two
women exposed their emulsions on the Haferlekar, a
mountain near Innsbruck, for four months in order to
300
secure high-intensity radiation. Their research project
consisted in determining the existence of heavy particles
such as protons, neutrons, and alpha particles in cosmic
rays, which at the time was considered quite doubtful.
Upon first examination of the plates, they observed proton tracks longer than anyone else had at that time. Yet, to
their surprise, Blau and Wambacher observed in the emulsion a “contamination star” (several tracks emanating
from a point) that could neither be explained by irregularities in the emulsion nor by unknown radioactive products during the handling and storage of the plates in the
laboratory. The assumption was that the large “stars” originated from the disintegration of heavy particles, probably
bromine or silver, and that the smaller ones originated
perhaps from light elements in the gelatin. Given the theoretical limitations of nuclear physics of the time, the two
women could not determine the nature of the primary
particle and the exact process of the disintegration. These
impressive results, which American historian Peter Galison considers the first “golden event” using emulsions,
provoked the interest of the scientific community (1997,
p. 44). In 1937, on the basis of their discovery, Blau and
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Wambacher were awarded the Ignaz Lieben Prize of the
Austrian Academy of Sciences.
While the two women were preparing a publication,
Stetter approached Blau. He accused her of being unfair
to Wambacher and expected her to change the order of
the names on their publication since Wambacher was,
after all, he argued, the first to look into the microscope
and find the star. Blau refused. In the midst of the world’s
serious political upheavals and Blau’s tenuous position,
Ellen Gleditsch, a Norwegian expert on radioactivity, took
a personal interest in her situation and offered her a temporary position as a research assistant in her laboratory in
Oslo. Under the enormous pressure from her own exadvisee and Stetter, Blau rushed to arrange research matters with Wambacher, an arrangement which was a total
defeat for her.
As the agreement went, Wambacher, in collaboration
with Gustav Ortner, another Nazi at the institute, were
going to investigate the relation of the grain and density
of the tracks recorded on the photographic emulsions to
the energy of the particles produced by them. By measuring the grain thickness of the tracks one could even estimate the energy of the particles that were not brought to
rest in the emulsion but passed through. This process had
the potential of identifying the particles and the total
energy released in the process, the two key points of Blau’s
and Wambacher’s earlier work. Blau agreed to continue
the absorption experiments, a less promising and more
tiresome task. Luckily, she left Vienna on a 7:00 a.m. train
to Oslo a day before the Germans paraded triumphantly
into Austria on 12 March 1938.
to 1944, Blau centered her work in Mexico, deeply frustrated by the lack of research opportunities and by the
teaching overload. Only through the efforts of the Jewish
community in Mexico, was she able to enter the United
States in May 1944.
Exile. While Blau knew that she could only remain in
Oslo for a limited time, Berta Karlik, a young colleague
then and later director of the Radium Institute, encouraged Pettersson to reclaim the instruments he brought to
Vienna in the early 1920s. Given the simplicity of the
photographic emulsions method and its tabletop scale,
portable objectives and microscopes could, at least temporarily, ensure Blau’s research prospects.
In November 1938, after Albert Einstein’s recommendation, Blau left Norway to accept a position at the
Polytechnic School in Mexico City. On her way to Mexico the Gestapo confiscated her scientific notebooks, forcing her zeppelin down in Hamburg. She later speculated
that those ended up at the hands of her Nazi colleagues in
Vienna. However, with or without Blau’s scientific notebooks, Wambacher continued to use the experimental
facilities of the Radium Institute. Within two weeks of the
Anschluss, she was promoted to the position of assistant at
the First and Second Physics Institutes. Publications in
major German journals accompanied her rapid promotion in the university ranks. On the contrary, from 1940
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Photomultipliers and Scintillation Counters. Blau was
one of the first to suggest the use of a photomultiplier in
combination with a scintillation counter. The original
scintillation counter consisted of a thin glass plate spread
with an equally thin layer of zinc sulfide. When the plate
was struck by charged particles, the screen produced light
flashes that were observed through a microscope specifically designed to increase their brightness. The instrument
had extensively been used at the Radium Institute during
the Cambridge-Vienna controversy. Working for competitive industrial corporations after the Second World War,
Blau sought possibilities for professional existence by saving and modifying an old-familiar technique; her past
secured her present.
In the physics department of the International Rare
Metals Refinery, her first position in the United States,
Blau teamed up with B. Dreyfus in combining the use of
a photomultiplier tube to a scintillation screen for the
measurement of alpha ray sources (Blau and Dreyfus,
1945). Putting together a fluorescent screen with the photomultiplier, which took a very small amount of light and
converted it into an amplified electrical signal, and using
strong polonium sources, Blau and Dreyfus had in fact
described the first electrically modified scintillation
counter. As the references to Elizabeth Kara-Michailova’s
and Berta Karlik’s work show, both colleagues in Vienna,
Blau was the driving force in designing the device. In
1933, after abandoning the ordinary scintillation counter,
Karlik had worked on the determination of alpha particle
ranges utilizing a photoelectric cell, a sensitive electric
device for the detection of the scintillations that replaced
the fragile and unreliable human optical system. Karlik’s
method, however, was seldom used, as Blau explained,
given the limited range of measurements of the ordinary
photocells and the lack of adequate and constant alphasources. Thanks to the multiplier phototube, Blau overcame the earlier difficulties.
Through her hybrid instrument Blau sought to
merge the competing prewar and postwar cultures in
physics research. The shift from the ordinary photocells to
photomultipliers, in Blau’s experimental practice, was not
just a simple replacement of two pieces in an instrument.
The transformation was a deeper, conceptual one for both
the experimenter and the instrument. From a researchoriented position in the Radium Institute in Vienna,
Blau’s occupation shifted to industrial physics in the postwar United States. The corporations that she worked for
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1944 to 1948 were deeply involved in the manufacture of
nuclear weapons, the commerce of uranium and radium,
and the industrial uses of radium. In the beginning of
1948, Blau moved to the Gibbs Manufacturing and
Research Corporation and with J. R. Carlin she worked
on industrial applications of radioactivity. Her creative
time and efforts were taken up by a number of radioactive
devices such as resistors, electrostatic voltmeters, leveling
systems, and micrometers.
In her effort to find a decent research position, Blau
moved again within the next few months, this time to the
Canadian Radium and Uranium Corporation. Carrying
over her knowledge in medical physics to the Radium Corporation, Blau designed a photomultiplier scintillation
counter for medical use. Designed for “persons not very
familiar with radioactive measurements,” Blau’s scintillation counter was a convenient and practical instrument for
wide use in hospitals and medical laboratories (Blau and
Smith, 1948, p. 68). Despite the fact that she was the first
to design and suggest medical applications of the photomultiplier scintillation counter, Blau remained peripheral
and isolated in the competitive world of industrial physics.
In 1950, she moved to the Brookhaven National Laboratory where she had restricted access to the high-energy
physics facilities. Remaining faithful to the experimental
tradition of the 1930s, Blau was unable to continue her
research in the new settings of big science. Although
Erwin Schrödinger nominated Blau and Wambacher for a
Nobel Prize based on their pioneer work on photographic
emulsions in this same year, the Nobel Prize committee
almost unanimously intended to give the prize to someone who was doing follow-up work to the previous year’s
prize winner, Hideki Yukawa, on the existence of mesons.
While the committee recognized the importance of Blau’s
contributions, the prize was eventually awarded to the
physicist Cecil Powell, who had adapted Blau’s method to
his industry-like laboratory in Bristol and turned it to a
powerful tool for making “foundational discoveries concerning mesons and their properties” (Nobel Committee
Report, 1950).
friends such as Karlik. She died on 27 January 1970, in the
intensive care ward of the Lainz hospital, lonely and
unknown to the international physics community.
Return to Vienna. Because of prolonged exposure to
radioactivity, in the late 1950s, Blau developed cataracts,
requiring an operation. In the dusk of her life facing financial and health problems, Vienna seemed the most suitable
destination. She finally returned in 1960. A number of old
colleagues tried to gather funds for her and Schrödinger
put her up for the Schrödinger Prize, which she received in
1962. Poor, disconnected from any major scientific network, and bitter about several members of the Radium
Institute for reaccepting the Nazi Stetter as one of the
heads of the Physics Institute after the end of the war, Blau
distanced herself from serious research and from old
302
BIBLIOGRAPHY
WORKS BY BLAU
“Über die Absorption divergenter-Strahlung.” Sitzungsberichte
der Kaiserlichen Akademie der Wissenschaften in Wien,
Mathematisch-naturwissenschaftliche Klasse, Abteilung 2a, 127
(1918): 1253–1279.
With Kamillo Altenburger. “Über einige Wirkungen von
Strahlen.” Zeitschrift für Physik 12 (1922): 315–329.
“Über photographische Untersuchungen mit radioaktiven
Strahlungen.” In Zehn Jahre Forschung auf dem physikalischmedizinischen Grenzgebiet, edited by Friedrich Dessauer.
Leipzig, Germany: Georg Thieme, 1931.
With Hertha Wambacher. “Disintegration Processes by Cosmic
Rays with the Simultaneous Emission of Several Heavy
Particles.” Nature 140 (1937): 585.
Curriculum Vitae. 1941 (unpublished). Grenander Department
of Special Collections and Archives, State University of New
York at Albany.
With B. Dreyfus. “The Multiplier Photo-Tube in Radioactive
Measurements.” The Review of Scientific Instruments 16
(1945): 245–248.
With J. R. Carlin. “Industrial Applications of Radioactivity.”
Electronics 21 (April 1948): 78–82.
With J. E. Smith. “Beta-Ray Measurements and Units.”
Nucleonics 2 (June 1948): 67–74.
OTHER SOURCES
Beyler, Richard. “‘Imagine a Cube Filled with Biological
Material’: Reconceptualizing the Organic in German
Biophysics, 1918–1945.” In Fundamental Changes in Cellular
Biology in the 20th Century, edited by Charles Galperin, Scott
F. Gilbert, and Brigitte Hoppe. Proceedings of the 20th
International Congress of History of Science, Liège, Belgium
20–26 July 1997. Turnhout, Belgium: Brepols, 1999.
Galison, Peter. “Marietta Blau: Between Nazis and Nuclei.”
Physics Today 50 (1997): 42–48.
Halpern, Leopold. “Marietta Blau: Discoverer of the Cosmic Ray
‘Stars.’” In A Devotion to Their Science: Pioneer Women in
Radioactivity, edited by M. Rayner-Canham and G. RaynerCanham. London: McGill-Queen’s University Press, 1997.
Lindh, Axel. “Nobel Committee Report on Marietta Blau and
Hertha Wambacher.” Uppsala 1 July 1950 (unpublished).
Nobel Archive of the Center for History of Science, The
Royal Swedish Academy of Sciences. Stockholm.
Rentetzi, Maria. “Gender, Politics, and Radioactivity Research in
Interwar Vienna: The Case of the Institute for Radium
Research.” Isis 95 (2004): 359–393.
Rosner, Robert, and Brigitte Strohmaier, eds. Marietta Blau—
Sterne der Zetrümmerung. Wien: Böhlau Verlag, 2003.
Includes a complete list of Blau’s publications.
Maria Rentetzi
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