Germany (Poland) > Posen: 15 Wert-Mark octagonal zinc business token of the watthour-meter factory business founded by Jewish electrical-engineer Prof. Dr. Hermann Aron (1845-1913), who invented first accurate watt-hour meter; c. 1917; 21.75 x 21.75mm, 1.95g. His business included factories in London, Paris & Vienna; son Manfred assumed management of business, and with growing anti-Semitism, in 1929, changed name to "Nora" (Aron backwards) & in 1933 to "Heliowatt" - by then 4th largest manufacturer in field in Germay. The business was sold to Siemens in 1935 & the family fled to America.