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Hildegard Kallmann Collection

Identifier: AR 4692

Scope and Content Note

The Hildegard Kallmann Collection consists almost entirely of personal letters to her by her friend Julie Braun-Vogelstein. In addition are a few papers with biographical and family information.

Four folders hold Julie Braun-Vogelstein's handwritten letters and postcards to Hildegard Kallmann in Los Angeles, providing a description of the highlights of twelve years in Braun-Vogelstein's life. These letters clearly demonstrate the women's close friendship – Braun-Vogelstein nearly always uses endearments for the younger Hilde Kallmann, usually addressing her as "mein liebes Hildekind" (my dear Hilde-child) and signing as "Tante Julie" (aunt Julie) and even "deine Wahlmutter" (your adopted mother). Many letters offer advice or encouragement to Kallmann while she pursued her degrees and some include personal anecdotes or updates on Braun-Vogelstein's work. News of friends is also frequent along with Braun-Vogelstein's brief greetings to Curt Kallmann. Other prominent subjects include health concerns and travel plans. Some letters respond to Kallmann's worries about her mother in Germany. Most of Braun-Vogelstein's letters were sent from her home in New York or from Hanover, New Hampshire although others were sent from Europe. Letters written in 1942 and 1943 are in English, the remainder are in German.

In the first folder is a letter by Hildegard Kallmann's brother, K. Frank Korf, with an overview of her life, including her scientific achievements and friendship with Julie Braun-Vogelstein, as well as a brief history of the Mossner family from whom the family descended. With her brother's letter is a selected list of her publications and an announcement of her final exam, including her dissertation's abstract. The last folder of the collection holds a previous inventory of the collection's correspondence. This inventory lists each letter of Julie Braun-Vogelstein, including its format (letter or postcard), location, date, and number of pages.


  • 1941-1955; 1978
  • Majority of material found within 1941-1953


Language of Materials

The collection is in German and English.

Access Restrictions

Open to researchers.

Use Restrictions

There may be some restrictions on the use of the collection. For more information, contact:

Leo Baeck Institute, Center for Jewish History, 15 West 16th Street, New York, NY 10011


Biographical Note

Hildegard Korf was born in 1908 in Gelsenkirchen, Germany. She studied philosophy at the University of Berlin and later studied metallurgy at the city's Technische Hochschule. While at the University of Berlin she met Julie Braun-Vogelstein, with whom she maintained a life-long friendship. Since 1936 she worked at the Dresden Zeiss Works.

Under the Nuremberg Laws, Hildegard and her brother K. Frank Korf were considered "Mischlinge zweiten Grades," with their Jewish ancestry from the Mossner family on their mother's side. When Julie Braun-Vogelstein left Germany for the United States in 1935, she left her Zehlendorf estate in the care of Hildegard Korf and of her attorney, Curt Kallmann. In 1939 Curt Kallmann called Hildegard Korf for assistance after hearing the Gestapo were about to arrest him; she aided him in escaping to Stockholm, Sweden. In Stockholm Curt Kallmann suffered a nervous breakdown which prevented him from immigrating alone to the United States in spite of having a visa. Upon recommendation of the American consul Hildegard Korf and Curt Kallmann got married, and she escorted him to the United States by way of Siberia and Japan.

While in the United States, Hildegard Kallmann pursued her scientific interests at the University of California at Los Angeles, receiving her Bachelor's degree in physics in 1945, her Master's in 1947 and her doctorate in 1955, including studies in the upper atmosphere, thermodynamics, and atomic and molecular physics. Her dissertation was titled "A Study of the Structure of the Ionosphere." In 1947 she joined the Rand Corporation in Santa Monica, California as a research analyst, becoming a research physicist in 1953 and remaining with them until 1964. She also became a consultant to the U.S. Air Force and the National Aeronautics and Space Administration (NASA), a member of the National Academy of Science, and authored a number of papers related to research on the atmosphere, altitude, and space, among other related subjects. In addition, she was chair of the international Committee for Space Research (COSPAR) in Brussels, Belgium, which devised the "international reference atmosphere" to determine orbit and flight planning for satellites and spacecrafts in the upper atmosphere. In 1964 she became guest professor at the observatory at the University of Utrecht, Holland.

Hildegard and Curt Kallmann divorced in 1958; she married Jan Bijl. She died of a heart attack in the Hague, Netherlands on November 7, 1968.


0.25 Linear Feet


The Hildegard Kallmann Collection holds the letters of Julie Braun-Vogelstein to the physicist Hildegard Kallmann during the 1940s and 1950s. In addition it contains some information on her life and family background.


The collection is arranged in one series.

Other Finding Aid

A 3-page inventory lists each letter from Julie Braun-Vogelstein to Hildegard Kallmann, along with its number, format, date and location. This inventory has been retained in the last folder of the collection.

Digitization Note

The collection was digitized and made accessible in its entirety.

Related Material

Closely related are the papers of the Julie Braun-Vogelstein Collection (AR 25034).

The archives of the Smithsonian National Air and Space Museum include the Hildegard Korf Kallmann-Bijl Collection (2.08 linear feet, finding aid available online, accession number 1989-0042).

Processing Information

The collection was initially processed by Ilse Turnheim in November 1978, at which time an item-level inventory was created.
Guide to the Papers of Hildegard Kallmann 1941-1955, 1978 AR 4692
In Progress
Processed by Dianne Ritchey and Ilse Turnheim
© 2013
Language of description
Script of description
Language of description note
Description is in English.
Digitization made possible by the Conference on Jewish Material Claims against Germany.
Edition statement
This version was derived from HildegardKallmann.xml

Repository Details

Part of the Leo Baeck Institute Repository

15 West 16th Street
New York NY 10011 United States