Charles Jastrow Mendelsohn (December 8, 1880 – September 27, 1939) was an American cryptographer and classicist. ^[1] He was the only child of Rabbi Samuel Mendelsohn and Esther Jastrow. ^{[1] [2] [3]}

He was born in Wilmington, North Carolina. ^[1]

Education

He graduated from the Episcopal Academy, Philadelphia in 1896. ^[1] He was a Harrison Scholar at the University of Pennsylvania, which he graduated with a Bachelor of Arts in 1900 and a PhD in 1904. ^[1] He was a member of Phi Beta Kappa. ^[1] He joined the faculty of College of the City of New York as a tutor in Greek in 1905, becoming an instructor in 1907. ^[1] He was a professor of ancient languages in 1917. ^[3]

Military service

During World War I he served in the censorship department of the Post Office Department in 1917, dealing with foreign language, postal and newspaper censorship. ^{[1] [3]} His work came to the attention of Herbert Yardley and he was recruited into Military Intelligence, section 8 (MI-8). ^[3] From 1918–19 he was a captain in the Military Intelligence Division of the War Department General Staff. ^[1]

He led a team dealing with German diplomatic correspondence, breaking at least six diplomatic ciphers. ^[3] Two messages dealt with German attempts to get support from Mexico. ^[3]

He received an honorable discharge. ^[3]

Return to civilian life

He returned to City College in 1920 as a professor of history. ^{[1] [3]} He remained interested in cryptography, writing papers and became interested in the history of the topic, collecting many books on it. ^[1]

He remained in contact with Herbert Yardley and did part time cryptographic work for the Black Chamber. ^[3] Together they published the Universal Trade Code, a commercial code. ^[3] He wrote several works for the Black Chamber, including The Zimmermann Telegram of January 16, 1917, and its Cryptographic Background and Studies in German Diplomatic Codes Employed During the World War. ^[3]

Death

In 1939, he was recalled to active duty as a result of World War II, but while preparing he contracted meningitis and died of it. ^{[1] [3]}

His library, which had been called "probably the most important cryptographic library in America, if not in the world" was bequeathed to the University of Pennsylvania. ^[1]

He had never married and was survived by his mother. ^[1] He was buried in the Hebrew Cemetery at Oakdale Cemetery, Wilmington, North Carolina. ^[1]

Publications

• Studies in the Word-Play in Plautus ^[1]
• The Zimmermann Telegram of January 16, 1917, and its Cryptographic Background ^[3]
• Studies in German Diplomatic Codes Employed During the World War ^[3]

References