"Let us begin with this piece. It looks new, and has a bright surface. We may say that zinc is a bluish-white metal, with a high metallic lustre.
"Now look at this piece. Can we call this bright?""No," said Will and Norah together, "it is dull and tarnished.""It is not only tarnished," said Fred, "it is rusted. There is a thin coating of rust on the surface. But teacher asked us to remember that, when zinc once becomes covered with a thin coat of rust, it will not rust any further. The rust does not eat into the metal, as it does into iron. Take it in your hand, Norah, and scrape it lightly with the knife, and you will find it quite bright inside."Norah did so, and found it just as Fred said. "But I say, Fred," she cried, "how light it seems.""Yes," said Fred, "it is light. It is the lightest of all the metals.
