stone,” which is zinc in combination with oxygen and carbonic acid. A substance called “zinc white” has been lately introduced as a substitute for white lead, and would certainly supersede it, but the zinc is found to be deficient in “body,” which means, the power of covering anything over which it is laid-on in a thin layer, but as zinc white does not blacken in foul air, and white lead does, it has a great advantage, and it is to be hoped that some improvement in its manufacture may improve its “body.” Zinc is chiefly used for roofs, gutters, water-pipes, cisterns, and various vessels for holding water, as it does not rust so easily as iron. What is called “galvanised iron,” is iron dipped into melted Zinc in the same way that tin-plate is.