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Magnetism is the ability of matter to attract other to itself. The ancient Greeks were the first to discover this phenomenon in a mineral they named magnetite. Later on Bergmann, Becharee, and Faraday discovered that all matter including liquids and gasses were affected by magnetism, but only a few responded to a noticeable extent. The earliest known use of magnetism to inspect took place as early as 1868. Cannon barrels were checked for defects by magnetizing the barrel then sliding a magnetic compass along the barrels length. These early inspectors were able to locate flaws in the barrels by monitoring the needle of the compass. This was a form of nondestructive testing but the term was not commonly used until some time after world war 1. In the early 1920s, William Hoke realized that magnetic particle ( colored metal shavings) could be used with magnetism as a means of locating defects. Hoke discovered that a surface or subsurface flaw in a magnetized material caused the magnet...