156,999. Treanor, F. P. Feb. 11, 1920. Engine and like cylinders.-In order to fill in defects, the part is cleaned by a reamer &c., wiped out with a strong solution of caustic soda and then a metal skin is deposited and subsequently the defect is filled in with metal. For depositing the metal skin a copper bath A with rubber edges B and insulated clamp D is applied to the defective part and filled with electrolyte. The casting is heated locally to about 70‹ C. and connected to the terminal of an electric circuit, the other being connected to the bath at F. In a modification, the bath is filled with a solution of sulphate of copper and no electric current is required. The bath is then removed, the part heated to 300‹ C., the surface tinned, and an alloy such as that described in Specification 156,426, [Class 82 (i), Metals, Extracting &c.], is worked in with a copper bit aided by a blowpipe or other source of heat.