Roentgen (unit) this derivative quantity the roentgen equivalent physical (rep) to distinguish it from the ICR roentgen. The introduction of the roentgen measurement unit, which relied upon measuring the ionisation of air, replaced earlier less accurate practices that relied on timed exposure, film exposure, or fluorescence. This led the way to setting exposure limits,and the National Council on Radiation Protection and Measurements of the United States established the first formal dose limit in 1931 as 0.1 roentgen per day. The International X-ray and Radium Protection Committee, now known as the International Commission on Radiological Protection (ICRP) soon followed with a limit of
Wilhelm Loewenthal Moisés Ville, the first colony of the JCA. It has been proven by banking records that Lowenthal died in Berlin two years later, after leaving Brussels. In the colony, Lowenthal's name graces the principal thoroughfare. Wilhelm Loewenthal Wolff Wilhelm Lowenthal ( – ) was a Polish-born, naturalized French Doctor of Medicine. Born in Rybnik, Poland, after graduating from the University of Berlin, Lowenthal (or Löwenthal, with the umlaut), went to the Caucasus to continue his medical research. At the same time, he was Professor at the University of Geneva, in its branch at the Lausanne, Switzerland. He corresponded regularly with