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
1890s in Western fashion 1890s in Western fashion Fashion in the 1890s in European and European-influenced countries is characterized by long elegant lines, tall collars, and the rise of sportswear. It was an era of great dress reforms led by the invention of the drop-frame safety bicycle, which allowed women the opportunity to ride bicycles more comfortably, and therefore, created the need for appropriate clothing. Fashionable women's clothing styles shed some of the extravagances of previous decades (so that skirts were neither crinolined as in the 1850s, nor protrudingly bustled in back as in the late 1860s and mid-1880s, nor tight as in the