D O C . 2 4 L E O A R O N S A S P H Y S I C I S T 2 0 5
Published in Sozialistische Monatshefte 53 (1919): 1055–1056, on 17 November 1919.
At the turn of the century, Leo Arons (1860–1919) had been stripped of his position as Privat-
dozent in physics at the University of Berlin because of political activity on behalf of the Social Dem-
ocratic Party. The German imperial establishment viewed such activity as undermining the existing
order and, under what came to be known as the lex Arons, explicitly forbade civil servants from active
involvement in political affairs. In his defense, Arons argued that the state had no right to dictate
matters of individual conscience (see Arons 1900, p. 33). For a summary of the Arons case, see Wolff,
S. 1999, pp. 192–199.
Einstein praised Arons as “an intrepid champion of free speech” (“ein mutiger Vorkämpfer des
freien Wortes”; Einstein to Leo Arons, 12 November 1918 [Vol. 8, Doc. 653]) in response to Arons’s
appeal in late 1918 for a national congress of academics to support the new republican government.
Following Einstein’s obituary, a number of reflections on contributions by Arons to Berlin com-
munal politics, trade unions, teaching, and applied science were published in the same issue of the
Sozialistische Monatshefte, pp. 1056–1074.
Cohn and Arons 1886.
Cohn and Arons 1888.
Arons 1890, 1892b; Arons and Rubens 1891a, 1891b.
Arons’s “chromoscope” was capable of reproducing an infinite number of colors (Arons 1910,
1912), but Arons could not provide a method for producing a desired hue or of establishing a rela-
tionship between a physical color and a physiological response to it (see Ostwald 1919, pp. 172–173).
The chromoscope was made obsolete by Ostwald’s much simpler device and above all by his
“Farbenlehre,” a systematic classification and identification of colors (Ostwald 1918–1922).