Chemical element of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin "natrium". The same applies to "W" (wolfram) for tungsten, "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "K" (kalium) for potassium, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and
Chemical Corps affiliation with the corps. The Chemical Corps branch insignia consists of a cobalt blue, enamel benzene ring superimposed over two crossed gold retorts. The branch insignia, which was adopted in 1918 by the fledgling Chemical Service, measures .5 inches in height by 1.81 inches in width. Crossed shells with a dragon head was also commonly used in France for the Chemical service. The Chemical Warfare Service approved the insignia in 1921 and in 1924 the ring adopted the cobalt blue enamel. When the Chemical Warfare Service changed designations to the Chemical Corps in 1946 the symbol was retained. The regimental