Lightning on its way to the earth always follows the best conductor and consequently will leap from side to side to find a building or a tree. It is attracted to pointed things rather than to round or blunt things, and for this reason lightning rods are made with sharp points. Buildings properly fitted with lightning rods are safe from being struck by lightning, because the rods lead the electricity into the earth. When a cloud filled with electricity comes over the rods, the electricity will flow down them until the cloud is discharged. We see no flash and hear no thunder; and we may feel sure that the building will not be struck. The tops of lightning rods are usually silvered or gilded, so that they will not rust and become worthless. The lower end of the rod must be carried down into damp earth; if the earth is dry it is better to carry the end into a well, because dry earth is not so good a conductor as moist earth and the lightning might leap from the rod at the lower end and go into the cellar of the building. High chimneys should have rods on them because soot is a good conductor, as is also the vapor which arises when fires are burning.