English: Photo of magnetic field of a horseshoe magnet. The magnetic field was made visible by sprinkling a layer of iron filings on a sheet of paper laid on top of the magnet. The filings are shaped like tiny needles, and orient themselves with their long axis parallel to the magnetic field at each point. The field pattern is slightly unsymmetrical, showing the magnet's righthand pole is slightly stronger than its left. Alterations to image: Converted to greyscale, increased brightness of high value pixels to eliminate background tint, cropped image rectangular, rotated image 90° CW, used clone tool to replace box with initials 'F. E. A.' in lower left corner.