Brass Compass Sundial 4 inch with Wooden Box Decorative shiny brass sundial compass, Made By solid Brass Used for Camping & Hiking etc. Collectibles Decorative Compass. sundials using light to indicate time, a line of light may be formed by allowing the sun's rays through a thin slit or focusing them through a cylindrical lens. A spot of light may be formed by allowing the sun's rays to pass through a small hole or by reflecting them from a small circular mirror Functionality : magnetic compass points directions through needle like vintage compasses