Danish chemist and astronomer (1873-1967) who, with Henry Norris Russell, developed the Hertzsprung-Russell diagram, a scatter plot showing the relationship between the luminosities of stars versus their stellar classifications. Collection of correspondence between Ejnar Hertzsprung and Cambridge astronomer Arthur Beer, comprising four letters by Hertzsprung (three TLSs and one ALS) plus some of Beer’s retained carbon copies, dating from 1938 to 1957. The ALS, dated November 29, 1938, in part: “There is as yet no answer to my request concerning the admittance of Professor Prager to Holland. In order to accelerate (if possible) the treatment I have yesterday by express letter asked for a personal audience of the minister of justice at the Hague. The only news I have is that my request has been put into the pile of papers marked speed. But that does not mean a quick answer, I fear, as the government is at present overloaded with other requests of the same kind.” This presumably refers to Richard Prager, a German astronomer who had been imprisoned by the Nazis in 1938; after his friends in England secured his release in 1939, Prager moved to the US and took a position at the Harvard Observatory. Hertzsprung’s three typed letters are brief and concern articles and publications. The three typed letters are stapled together at the left edge, and are interleaved with Beer’s retained carbons. In overall fine condition.
