will always give off sparks of the same length for the same sample. The compressed air applies in essence the same "pressure" each time. This makes observations of the spark length a much more reliable characteristic for comparison. Automated spark testing Automated spark testing has been developed to remove the reliance upon operator skill and experience, thereby increasing reliability. The system relies upon spectroscopy, spectrometry, and other methods to "observe" the spark pattern. It has been found that this system can determine the difference between two materials that give off sparks that are indistinguishable to the human eye. Spark characteristics Wrought iron Wrought iron sparks flow out in straight lines. The tails of the sparks widen out near the end, similar to a leaf. Mild steel Mild steel sparks are similar to wrought iron's, except they will have tiny forks and their lengths will vary more. The sparks will be white in color. Medium-carbon steel This steel has more forking than mild steel and a wide variety of spark lengths, with more near the grinding wheel. High-carbon steel High-carbon steel has a bushy spark pattern (much forking) that starts at the grinding wheel. The sparks are not as bright as the medium-carbon steel ones. Manganese steel Manganese steel has medium length sparks that fork twice before ending. High-speed steel High-speed steel has a faint red spark that sparks at the tip. 300-series stainless steel These sparks are not so dense as the carbon steel sparks, do not fork, and are orange to straw in color. 310-series stainless steel These sparks are much shorter and thinner than the 300-series sparks. They are red to orange in color and do not fork. 400-series stainless steel 400-series sparks are similar to 300-series sparks, but are slightly longer and have forks at the ends of the sparks. Cast iron Cast iron has very short sparks that begin at the grinding wheel. Nickel and cobalt high-temperature alloys These sparks are thin and very short, they are dark-red in color, and do not fork. Cemented carbide Cemented carbide has sparks under 3 inches, which are dark-red in color and do not fork. Titanium Although titanium is a non-ferrous metal, it gives off a great deal of sparks. These sparks are easily distinguishable from ferrous metals, as they are a very brilliant, blinding, white color. History In 1909, Max Bermann, an engineer in Budapest, was the first