2. Evolution of corrosion problems

The maritime museum at Paestum near Naples has one room dedicated to the 6th century B.C., and another to the 3rd century B.C. However, when it comes to the nailing techniques used on the wooden planks of the hull, in the former only large stumps of rust can be seen, which in this case are the remains of steel nails driven through a copper support washer, whereas in the latter, both the washers and the intact nails are made of copper. The Romans didn't know the reason for the corrosion or the solution, but...