The deterioration of Muntz metal by selective corrosion is illustrated by four types, including tubing, sheets, and forgings. The metal becomes red in color, very weak, and brittle which takes place when the piece is exposed to some electrolyte. One of the most important conditions favorable to this type of corrosion, which occurs commonly while the metal is immersed in sea water, is the accelerating effect of the closely adhering deposits of basic zinc chloride resulting form the attack of the metal. Other influences which may accelerate the rate of attack are contact with substances more electronegative than either the alpha or beta constituents, an increase of temperature, and the effect of stresses to which the material may be subjected while in service. Thorough annealing of Muntz metal does not entirely prevent the selective corrosion of the beta constituent.