Lead is a highly corrosion resistant metal in some environments and an attempt has been made to show its strength and weakness under long-term corrosion in land and marine conditions by means of examples taken from archaeological contexts. Some analyses and thicknesses are given of the corrosion films found on them. The importance of fine grain size and the role of certain impurities in obtaining this may be one reason why the older leads are often more resistant than modern leads. See also AATA 15-853.