Carl Friedrich Gaus and Wilhelm Eduard Weber, 19th century.

Carl Friedrich Gaus (1777-1855), German mathematician, and Wilhelm Eduard Weber (1804-1891), German physicist. Gaus, together with Baron Augustin Louis Cauchy, founded the modern form of complex analysis, which was to have a profound effect on mathematics for the rest of the 19th century. He was also the inventor of the heliotrope, a surveying instrument. Weber pioneered the precise measurement of electrical quantities. He worked with Gaus to investigate the precision measurement of magnetic quantities. 'Weber' is now used for the SI (the international system of standard scientific units) unit of magnetic flux. Published by the International Telecommunication Union, 1955-1964. Dimensions: 230mm x 190mm.