Silver the periodic table) is useful in nuclear reactors because of its high thermal neutron capture cross-section, good conduction of heat, mechanical stability, and resistance to corrosion in hot water. The word "silver" appears in Anglo-Saxon in various spellings, such as "seolfor" and "siolfor". A similar form is seen throughout the Germanic languages (compare Old High German "silabar" and "silbir"). The chemical symbol Ag is from the Latin word for "silver", "argentum" (compare Ancient Greek ἄργυρος, "árgyros"), from the Proto-Indo-European root *"h₂erǵ-" (formerly reconstructed as "*arǵ-"), meaning "white" or "shining": this was the usual Proto-Indo-European word for the metal, whose reflexes
CB military symbol system. Military symbols evolved out of the First World War from the British in part for secrecy, and to simplify reference to chemicals by something other than a chemical name. These symbols were sometimes applied as marking on weapons to indicate the agent contents. Military symbols constantly changed and had transitory definitions. For example, mustard gas was assigned the military symbol originally HS for "Hun Stuff". Later in the First World War the S in HS signified mustard gas that had about 25% solvent added to it. This was only in England, as HS was adopted as the military symbol